Effect of overweight and obesity on assisted reproductive technology—a systematic review

Endometrium development patterns and BMI groups among in vitro fertilization patients; prognostic aspects

Introduction

The impact of the obesity pandemic on female reproductive capability is a factor that needs to be investigated. In addition, the link between endometrial thickness and in vitro fertilization (IVF) outcomes is contentious.

Goal

Our goal was to analyze the association among endometrium development, hormone levels, embryo quality, clinical pregnancy, anamnestic parameters, and body mass index (BMI) in women receiving IVF treatment.

Patients and methods

537 participants undergoing IVF/ICSI cycles with successful oocyte retrieval were enrolled. Subjects were divided into four BMI based groups: underweight (UW; n=32), normal weight (NW; n=324), overweight (OW; n= 115), obesity (OB; n=66). Anthropometric and anamnestic parameters, characteristics of stimulation, endometrial thickness on the day of hCG injection, at puncture, at embryo transfer, FSH, LH, AMH, partner's age and the semen analysis indicators, embryo quality, clinical pregnancy, were recorded and analyzed. Support Vector Machine (SVM) was built to predict potential pregnancies based on medical data using 22 dimensions.

Results

In accordance with BMI categories, when examining pregnant/non-pregnant division, the average age of pregnant women was significantly lower in the UW (30.9 ± 4.48 vs. 35.3 ± 5.49 years, p=0.022), NW (34.2 ± 4.25 vs. 36.3 ± 4.84 years, p<0.001), and OW (33.8 ± 4.89 vs. 36.3 ± 5.31 years, p=0.009) groups. Considering FSH, LH, and AMH levels in each BMI category, a statistically significant difference was observed only in the NW category FSH was significantly lower (7.8 ± 2.99 vs. 8.6 ± 3.50 IU/L, p=0.032) and AMH (2.87 ± 2.40 vs. 2.28 ± 2.01 pmol/L, p=0.021) was higher in pregnant women. There were no further statistically significant differences observed between the pregnant and non-pregnant groups across any BMI categories, especially concerning endometrial development. Surprisingly, BMI and weight correlated negatively with FSH (r=-0.252, p<0.001; r=-0.206, p<0.001, respectively) and LH (r= -0.213, p<0.001; r= -0.195, p<0.001) in the whole population. SVM model average accuracy on predictions was 61.71%.

Discussion

A convincing correlation between endometrial thickness development and patients' BMI could not be substantiated. However, FSH and LH levels exhibited a surprising decreasing trend with increasing BMI, supporting the evolutionary selective role of nutritional status. Our SVM model outperforms previous models; however, to confidently predict the outcome of embryo transfer, further optimization is necessary.

Pregnancy following assisted reproductive technology in morbidly obese patients: assessment of feto-maternal outcomes

PURPOSE

To examine feto-maternal characteristics and outcomes of morbidly obese pregnant patients who conceived with assisted reproductive technology (ART).

METHODS

This cross-sectional study queried the Healthcare Cost and Utilization Project's National Inpatient Sample. Study population was 48,365 patients with ART pregnancy from January 2012 to September 2015, including non-obesity (n = 45,125, 93.3%), class I-II obesity (n = 2445, 5.1%), and class III obesity (n = 795, 1.6%). Severe maternal morbidity at delivery per the Centers for Disease and Control Prevention definition was assessed with multivariable binary logistic regression model.

RESULTS

Patients in the class III obesity group were more likely to have a hypertensive disorder (adjusted-odds ratio (aOR) 3.03, 95% confidence interval (CI) 2.61-3.52), diabetes mellitus (aOR 3.08, 95%CI 2.64-3.60), large for gestational age neonate (aOR 3.57, 95%CI 2.77-4.60), and intrauterine fetal demise (aOR 2.03, 95%CI 1.05-3.94) compared to those in the non-obesity group. Increased risks of hypertensive disease (aOR 1.35, 95%CI 1.14-1.60) and diabetes mellitus (aOR 1.39, 95%CI 1.17-1.66) in the class III obesity group remained robust even compared to the class I-II obesity group. After controlling for priori selected clinical, pregnancy, and delivery factors, patients with class III obesity were 70% more likely to have severe maternal morbidity at delivery compared to non-obese patients (8.2% vs 4.4%, aOR 1.70, 95%CI 1.30-2.22) whereas those with class I-II obesity were not (4.1% vs 4.4%, aOR 0.87, 95%CI 0.70-1.08).

CONCLUSIONS

The results of this national-level analysis in the United States suggested that morbidly obese pregnant patients conceived with ART have increased risks of adverse fetal and maternal outcomes.

Genome-wide analyses identify 21 infertility loci and over 400 reproductive hormone loci across the allele frequency spectrum

Genome-wide association studies (GWASs) may help inform treatments for infertility, whose causes remain unknown in many cases. Here we present GWAS meta-analyses across six cohorts for male and female infertility in up to 41,200 cases and 687,005 controls. We identified 21 genetic risk loci for infertility (P≤5E-08), of which 12 have not been reported for any reproductive condition. We found positive genetic correlations between endometriosis and all-cause female infertility (rg=0.585, P=8.98E-14), and between polycystic ovary syndrome and anovulatory infertility (rg=0.403, P=2.16E-03). The evolutionary persistence of female infertility-risk alleles in EBAG9 may be explained by recent directional selection. We additionally identified up to 269 genetic loci associated with follicle-stimulating hormone (FSH), luteinising hormone, oestradiol, and testosterone through sex-specific GWAS meta-analyses (N=6,095-246,862). While hormone-associated variants near FSHB and ARL14EP colocalised with signals for anovulatory infertility, we found no rg between female infertility and reproductive hormones (P>0.05). Exome sequencing analyses in the UK Biobank (N=197,340) revealed that women carrying testosterone-lowering rare variants in GPC2 were at higher risk of infertility (OR=2.63, P=1.25E-03). Taken together, our results suggest that while individual genes associated with hormone regulation may be relevant for fertility, there is limited genetic evidence for correlation between reproductive hormones and infertility at the population level. We provide the first comprehensive view of the genetic architecture of infertility across multiple diagnostic criteria in men and women, and characterise its relationship to other health conditions.

Cluster analysis reveals a homogeneous subgroup of PCOS women with metabolic disturbance associated with adverse reproductive outcomes

BACKGROUND

Polycystic ovarian syndrome (PCOS) is a heterogeneous and complex reproductive endocrinological disease that could lead to infertility. There were many attempts to classify PCOS but it remains unclear whether there is a specific subgroup of PCOS that is associated with the best or worst reproductive outcomes of assisted reproductive techniques (ART).

METHODS

Infertile PCOS patients who underwent their first cycle of in vitro fertilization (IVF) in West China Second University Hospital, Sichuan University from January 2019 to December 2021 were included. Basic clinical and laboratory information of each individual were extracted. Unsupervised cluster analysis was performed. Controlled ovarian stimulation parameters and reproductive outcomes were collected and compared between the different clusters of PCOS.

RESULTS

Our analysis clustered women with PCOS into "reproductive", "metabolic", and "balanced" clusters based on nine traits. Reproductive group was characterized by high levels of testosterone (T), sex hormone-binding globulin (SHBG), follicular stimulation hormone (FSH), luteinizing hormone (LH), and anti-Müllerian hormone (AMH). Metabolic group was characterized by high levels of body mass index (BMI), fasting insulin, and fasting glucose. Balanced group was characterized by low levels of the aforementioned reproductive and metabolic parameters, except for SHBG. Compared with PCOS patients in reproductive and balanced clusters, those in metabolic cluster had lower rates of good quality day 3 embryo and blastocyst formation. Moreover, PCOS patients in the reproductive cluster had greater fresh embryo transfer (ET) cancelation rate and clinical pregnancy rate after fresh ET than metabolic cluster (odds ratio [OR] = 3.37, 95% confidence interval [CI]: 1.77-6.44, and OR = 6.19, 95% CI: 1.58-24.24, respectively). And compared with PCOS of metabolic cluster, PCOS of balanced cluster also had higher chance for fresh ET cancelation (OR = 2.83, 95% CI: 1.26-6.35).

CONCLUSION

Our study suggested that PCOS patients in metabolic cluster may be associated with adverse reproductive outcomes and might need individualized treatment and careful monitoring before and during ART.

Female obesity increases the risk of preterm birth of single frozen-thawed euploid embryos: a retrospective cohort study

INTRODUCTION

Obesity has been associated with an increased risk of reproductive failure, especially preterm birth. As preimplantation genetic testing for aneuploidies (PGT-A) is increasingly used worldwide, however, it is still unclear whether body mass index (BMI) has an effect on the preterm birth rate in patients undergoing in vitro fertilization (IVF) with PGT-A when transferring a single euploid blastocyst.

MATERIALS AND METHODS

This retrospective, single-center cohort study included 851 women who underwent the first cycle of frozen-thawed single euploid blastocyst transfer with PGT-A between 2015 and 2020. The primary outcome was the preterm birth rate. Secondary outcomes were clinical pregnancy, miscarriage, ectopic pregnancy, pregnancy complications, and live birth.

RESULTS

Patients were grouped by World Health Organization (WHO) BMI class: underweight (<18.5, n = 81), normal weight (18.5-24.9, n = 637), overweight (25-30, n = 108), and obese (≥30, n = 25). There was no difference in the clinical pregnancy, miscarriage, ectopic pregnancy, pregnancy complication, and live birth by BMI category. In multivariate logistic regression analysis, preterm birth rates were significantly higher in women with overweight (adjusted odds ratio [aOR] 3.18; 95% confidence interval [CI], 1.29-7.80, p = .012) and obese (aOR 1.49; 95% CI, 1.03-12.78, p = .027) compared with the normal weight reference group.

CONCLUSION

Women with obesity experience a higher rate of preterm birth after euploid embryo transfer than women with a normal weight, suggesting that the negative impact of obesity on IVF and clinical outcomes may be related to other mechanisms than aneuploidy.

Development and validation of a visualized prediction model for early miscarriage risk in patients undergoing IVF/ICSI procedures: a real-world multi-center study

Background

This study focuses on the risk of early miscarriage in patients undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). These patients commonly experience heightened stress levels and may discontinue treatment due to emotional burdens associated with repeated failures. Despite the identification of numerous potential factors contributing to early miscarriage, there exists a research gap in integrating these factors into predictive models specifically for IVF/ICSI patients. The objective of this study is to develop a user-friendly nomogram that incorporates relevant risk factors to predict early miscarriage in IVF/ICSI patients. Through internal and external validation, the nomogram facilitates early identification of high-risk patients, supporting clinicians in making informed decisions.

Methods

A retrospective analysis was conducted on 20,322 first cycles out of 31,307 for IVF/ICSI treatment at Sun Yat-sen Memorial Hospital between January 2011 and December 2020. After excluding ineligible cycles, 6,724 first fresh cycles were included and randomly divided into a training dataset (n = 4,516) and an internal validation dataset (n = 2,208). An external dataset (n = 1,179) from another hospital was used for validation. Logistic and LASSO regression models identified risk factors, and a multivariable logistic regression constructed the nomogram. Model performance was evaluated using AUC, calibration curves, and decision curve analysis (DCA).

Results

Significant risk factors for early miscarriage were identified, including female age, BMI, number of spontaneous abortions, number of induced abortions and medical abortions, basal FSH levels, endometrial thickness on hCG day, and number of good quality embryos. The predictive nomogram demonstrated good fit and discriminatory power, with AUC values of 0.660, 0.640, and 0.615 for the training, internal validation, and external validation datasets, respectively. Calibration curves showed good consistency with actual outcomes, and DCA confirmed the clinical usefulness. Subgroup analysis revealed variations; for the elder subgroup (age ≥35 years), female age, basal FSH levels, and number of available embryos were significant risk factors, while for the younger subgroup (age <35 years), female age, BMI, number of spontaneous abortions, and number of good quality embryos were significant.

Conclusions

Our study provides valuable insights into the impact factors of early miscarriage in both the general study population and specific age subgroups, offering practical recommendations for clinical practitioners. We have taken into account the significance of population differences and regional variations, ensuring the adaptability and relevance of our model across diverse populations. The user-friendly visualization of results and subgroup analysis further enhance the applicability and value of our research. These findings have significant implications for informed decision-making, allowing for individualized treatment strategies and the optimization of outcomes in IVF/ICSI patients.

Impact of body mass index on assisted reproductive technology outcomes in patients with polycystic ovary syndrome: a meta-analysis

The effect of obesity on pregnancy outcomes of patients with polycystic ovary syndrome (PCOS) undergoing assisted reproductive technology (ART) remains unclear. As such, a meta-analysis of recent studies was conducted to probe the effect of being overweight or obese on ART pregnancy outcomes in patients with PCOS. PubMed, Embase, MEDLINE, Scopus and Web of Science were searched from inception to 22 July 2023 without language restrictions. The main indicators were: live birth rate, clinical pregnancy rate, spontaneous abortion rate and multiple pregnancy rate. Ten studies were analysed, with a combined sample size of 247,845. Among patients with PCOS undergoing ART who were overweight or obese, the live birth rate, clinical pregnancy rate, implantation rate and number of retrieved oocytes were lower than in normal-weight patients with PCOS, and the spontaneous abortion rate was higher than in normal-weight patients with PCOS. Obese patients with PCOS undergoing ART had a lower multiple pregnancy rate and a lower number of mature oocytes compared with normal-weight patients with PCOS. The data showed that, among patients with PCOS, being overweight or obese has a negative effect on ART pregnancy outcomes. This meta-analysis may inform guidelines for pregnancy with ART, and encourage overweight or obese patients with PCOS to lose weight.

Should women with high body mass index be denied fertility treatments?

Obesity is an emerging global epidemic with a negative impact on fertility. Almost all guidelines and policies have a stringent limit of body mass index (BMI) to access fertility services which has promoted a debate amongst fertility practitioners globally. Proponents of placing such a limit point to the negative impact of elevated BMI on the outcome of fertility treatment, its cost effectiveness and the risk it poses to the intending mother and unborn child. Opponents of placing a restriction base their arguments on the lack of conclusive, robust evidence regarding the variables along with the ethical dilemmas of promoting discrimination and stigmatization by denying a couple their basic right of parenthood. In this review, we analyse these medical and ethical dilemmas in the light of current evidence. The focus is on female infertility.

Factors Affecting the Outcomes of First in vitro Fertilization and Embryo Transfer: A Retrospective Investigation

Background

The outcome of embryo transfer (ET) is multifactorial. A variety of patient-related, procedural-related, and operator-related factors are known to play a role. This study aims to evaluate the outcomes of ET and determine the factors that affect the outcome.

Methods

The study involved a retrospective design involving 300 first in vitro fertilization and embryo transfer (IVF-ET) cycles between 2011 and 2021. The outcome included 155 unsuccessful cycles and 145 successful IVF-ET leading to pregnancy. The outcomes were examined for different variables, including age, weight, height, body mass index, cause of infertility, number of embryos fertilized during the cycle, day of ET, whether the embryo was frozen, presence of blood or mucus during the procedure, the use of a stylet, tenaculum, uterine sound/dilator, and catheter type. Logistic regression was used to analyze factors affecting the outcomes of ET.

Results

The mean age was 27.84 ± 3.77 years. Patients who had blood during the procedure (32.9% vs 17.2%, p = 0.002), mucus (31% vs 20.7%, p = 0.049), or used the tenaculum (16.8% vs 6.9%, p = 0.012) were more likely to have unsuccessful IVF-ET. Logistic regression to adjust for related factors revealed that the presence of blood (AOR = 2.21, 95% CI 1.04 to 4.66, p = 0.038) during the ET had a higher likelihood of an unsuccessful outcome.

Conclusion

This study showed that the presence of blood during the ET cycle influenced clinical pregnancy. This highlights the importance of performing the procedure under atraumatic conditions.

Level of Evidence

Level III; retrospective comparative study.

Assessing the Impact of High Body Mass Index (BMI) on the Efficacy of Assisted Reproductive Technologies (ART) in Saudi Women: A Cross-Sectional Study Examining Ovarian Reserve and Treatment Outcomes

INTRODUCTION

The global surge in high body mass index (BMI) and obesity has led to various health complications. While numerous studies have shown that obesity disrupts female fertility, the specific effects of obesity on the success rate of assisted reproductive technology (ART) treatments in Saudi women have been less explored. This study aimed to delve into this gap, especially focusing on the correlation between BMI, ovarian reserve parameters, and ART outcomes among Saudi women.

METHODS

A cross-sectional study was carried out from January to August 2023, concentrating on Saudi women aged 18 and above who underwent ART treatments for infertility. A total of 1071 women participated, with 155 completing an online survey and 916 responding through a hard copy from several Saudi hospitals. The data encompassed demographics, medical history, anthropometric details, ovarian reserve parameters, and ART results. For the analysis, Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 28.0, Armonk, NY) was utilized, applying descriptive statistics, the Chi-square test, and a linear regression model to discern connections between BMI, participant characteristics, and ART outcomes. A p-value of less than 0.05 was considered statistically significant.

RESULTS

Most participants were aged 25-34 (406) years and held a bachelor's degree (707). Over half (560) received fertility treatments in the past, with 37.9% (406) having polycystic ovary syndrome (PCOS) and 23.5% (252) with other fertility-impacting medical conditions. Interestingly, 62.1% (665) had not undergone any ART cycles. Of those who did, 51.6% (553) had clinical pregnancies leading to live births. About 23.8% (308) of those with clinical pregnancies faced miscarriages without successful live births. Furthermore, 17.6% (189) reported complications or side effects from past ART procedures, and 31.4% (336) were on ART-related medications or supplements. The linear regression highlighted that individuals with normal weight tended to undergo more ART cycles. However, those with a higher BMI exhibited increased chances of achieving clinical pregnancies and live births.

CONCLUSION

The study underscores the crucial relationship between BMI and ART efficacy in Saudi women. The data reveals that BMI can significantly influence ART treatment outcomes, especially concerning the number of cycles, clinical pregnancies, and live births. Consequently, BMI should be an essential consideration when evaluating and optimizing the success rates of ART procedures.

The association between body mass index and live birth and maternal and perinatal outcomes after in-vitro fertilization: a national cohort study

Objective

To investigate the association between female body mass index (BMI) and live birth rates and maternal and perinatal outcomes after in-vitro fertilization (IVF).

Methods

We performed a national, population-based cohort study including women undergoing IVF between 2002 and 2020. The cohort included 126,620 fresh cycles and subsequent frozen embryo transfers between 2007 and 2019 (subpopulation 1) and 58,187 singleton deliveries between 2002 and 2020 (subpopulation 2). Exposure was female BMI (kg/m2) categorized according to the World Health Organization as underweight (<18.5), normal weight (18.5-24.9, reference), overweight (25.0-29.9), class I obesity (30.0-34.9), class II obesity (35.0-39.9), and class III obesity (≥40.0). The primary outcome in subpopulation 1 was cumulative live birth per started fresh IVF cycle, including fresh and subsequent frozen embryo transfers. Primary outcomes in subpopulation 2 were hypertensive disorders of pregnancy and preterm birth at less than 37 weeks. Risk ratios (RRs) with 95% confidence intervals (CIs) for the association between BMI class and outcomes were calculated using generalized linear models after adjustment for relevant confounders.

Results

The cumulative live birth rate decreased significantly with increasing BMI from 32.6% in normal-weight women to 29.4% in overweight women, 27.0% in women in obesity class I, 21.8% in women in obesity class II, and 7.6% in women in obesity class III. The risk of hypertensive disorders of pregnancy increased significantly and progressively with increasing BMI, from 4.6% in normal-weight women to 7.8% in overweight women and 12.5%, 17.9%, and 20.3% in women in obesity classes I, II, and III. The risk of preterm birth followed a similar pattern, from 6.3% in normal-weight women to 7.5% in overweight women and 8.9%, 9.9%, and 15.3% in women in obesity classes I, II, and III. The risks of other perinatal complications, such as perinatal death, showed an even more pronounced increase.

Conclusion

Using a large and complete national cohort of women undergoing IVF, we demonstrate a dose-dependent decrease in live birth rate and a substantial increase in maternal and perinatal complications with increasing BMI. Strategies to improve this situation are warranted.

Influence of maternal obesity on embryonic vitrification injury and subsequent pregnancy outcomes: A retrospective cohort study

Background

We previously reported that obese mice had significantly high lipid content in embryos, and excessive lipids are detrimental to embryonic development. However, whether maternal obesity has an effect on embryonic vitrification injury and subsequent pregnancy outcomes is still controversial. This study was conducted to clarify the influence of maternal obesity on embryonic vitrification injury and subsequent pregnancy outcomes by in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

Methods

We retrospectively collected medical record of IVF/ICSI patients from reproductive medicine centers in two tertiary hospitals. The patients were classified into a low-weight group (<18.5 kg/m2), normal-weight group (18.5-23.9 kg/m2), overweight group (24.0-27.9 kg/m2) and obese group (≥28.0 kg/m2) according to their body mass index (BMI). Multivariable logistic regression analysis was performed to compare pregnancy outcomes in fresh and frozen embryo transfer among different BMI groups to define the correlation between BMI and embryonic vitrification injury.

Results

A total of 44 773 women among 20-40 years old were recruited in this study, of which 27 797 underwent their first fresh embryo transfer and 16 976 underwent their first frozen embryo transfer. For fresh embryo transfer, there was no significant difference in the clinical pregnancy rate, live birth rate, and miscarriage rate of 4 BMI groups. For frozen-thawed embryo transfer, there was a significant increase in the clinical pregnancy rate of the overweight group (AOR = 1.14, 95% CI: 1.05-1.25) and the obese group (AOR = 1.24, 95% CI: 1.03-1.50), while the miscarriage rate (AOR = 1.42, 95% CI: 1.05-1.92) also showed a significant increase in the obese group compared to the normal-weight group.

Conclusion

This study provided a new understanding of the effect of maternal obesity on embryonic vitrification injury. Maternal obesity does not worsen the outcome of IVF/ICSI, particularly in the frozen-thawed group.

Disturbed ovarian morphology, oestrous cycling and fertility of high fat fed rats are linked to alterations of incretin receptor expression

Obesity is a major cause of infertility in females with a direct correlation between energy intake and reproductive dysfunction. To explore underlying mechanisms, disturbances in reproductive health and incretin/reproductive hormone receptor expression were studied in female Wistar rats fed a high-fat-diet for 20-weeks. Metabolic parameters and ovarian/adrenal gene expression were monitored along with estrous cycling and fertility upon mating. High-fat-feeding significantly increased body weight, plasma insulin and HOMA-IR, indicative of obesity and insulin resistance. Estrous cycles were prolonged compared to normal chow-fed rats, with 50 % having an average cycle length ≥ 7days. Reproductive outcomes revealed high-fat-diet reduced litter size by 48 %, with 16 % rats unable to achieve pregnancy. Furthermore, 80 % of the high-fat group took > 35 days to become pregnant compared to 33 % fed a normal-diet. Also, 35 % of pups born to high-fat-fed rats were eaten by mothers or born dead which was not observed with control rats. These changes were associated with downregulation of Amh, Npy2R and GcgR gene expression in ovaries with upregulation of InsR and Glp-1R genes. In adrenals, Glp-1R, GipR, Npy2R, InsR, GcgR, GshR and Esr-1 genes were upregulated. Histological analysis of high-fat-diet ovaries and adrenals revealed changes in morphology with significantly increased number of cysts and reduced adrenal capsule thickness. Circulating levels of insulin, testosterone and progesterone was significantly higher in high-fat group with reduced FSH levels in plasma. These data demonstrate that high-fat feeding disrupts female reproductive function and suggest important interactions between gut and reproductive hormones in ovaries and adrenals which merit further investigation.

Amino Acid Profiling of Follicular Fluid in Assisted Reproduction Reveals Important Roles of Several Amino Acids in Patients with Insulin Resistance

The global prevalence of insulin resistance (IR) is increasing continuously, influencing metabolic parameters and fertility. The metabolic changes due to IR can alter the molecular composition of plasma and other body fluids. Follicular fluid (FF) is derived mainly from plasma, and it is a critical microenvironment for the developing oocytes. It contains various metabolites and amino acids, and the quality of the oocytes is linked at least partially to amino acid metabolism. Our goal was to quantitatively determine the amino acid (AA) profile of FF in IVF patients and to compare IR and non-insulin resistance (NIR) groups to investigate the AA changes in their FF. Using UHPLC-based methods, we quantified the main 20 amino acids from human FF samples in the IR and NIR groups. Several amino acids (aspartate, glycine, glutamate, and cysteine) differed significantly (p < 0.05 or less) between the two groups. The most significant alterations between the IR and NIR groups were related to the glutathione metabolic pathway involving glycine, serine, and threonine. Since insulin resistance alters the amino acid composition of the FF, the oocytes may undergo metabolism-induced changes resulting in poor oocyte quality and less fertility in the insulin resistance groups.

How effective are lifestyle interventions for overweight women trying to conceive?

PURPOSE OF REVIEW

To summarize and critically review the current knowledge on the effectiveness of lifestyle modifications for overweight women trying to conceive.

RECENT FINDINGS

Overweight is associated with a wide spectrum of disorders, which may directly or indirectly affect fertility [from menstrual cycle irregularities to a lower chance of live birth after assisted reproductive technology (ART) treatment]. Weight loss through nonpharmaceutical lifestyle interventions is achievable. Weight loss can normalize menstrual cycle irregularities and can increase fecundability. Pregnancy-associated risks, such as gestational diabetes can be decreased by preconception weight reduction.

SUMMARY

Weight loss through lifestyle changes (i.e., lower caloric intake and increased physical activity), may increase fecundability and may have a positive impact on the course of pregnancy, delivery, and neonatal outcomes. Accordingly, women should be motivated to reduce their weight before conception. However, the effectiveness of life-style intervention programs for women actively seeking medical support in achieving pregnancy has not convincingly been demonstrated. In the few randomized controlled trials (RCTs), selection bias for trial participation by patient motivation may have been present, yet participant attrition was still high and mean effects were small, casting doubts on the utility of such programs in routine care. Pharmacological and surgical intervention may be more effective or necessary complements to lifestyle intervention programs.

L-carnitine enhances developmental potential of bovine oocytes matured under high lipid concentrations in vitro

Maternal obesity elevates non-esterified fatty acids (NEFA) follicular concentrations. Bovine cumulus-oocyte complexes (COCs) matured in vitro under high NEFA have altered metabolism and reduced quality. Systemically, obesity promotes altered mitochondrial metabolism linked to L-carnitine insufficiency. We hypothesized that L-carnitine supplementation during IVM of bovine COCs in the presence of high NEFA would lessen the negative effects of exposure to excessive lipids on embryonic development and oxidative stress. COCs were collected from abattoir ovaries and matured in four groups: CON (control), LC (3 mM L-carnitine), HN (high NEFA: 200uM oleic, 150uM palmitic and 75uM stearic acid), and HNLC (HN and LC). Mature oocytes were assayed for aerobic and anaerobic metabolism utilizing oxygen and pH microsensors or fertilized in vitro (D0). Cleavage (D3) and blastocyst (D7, D8) rates were assessed. D3 embryos with ≥ 4 cells were stained for cytosolic and mitochondrial ROS. D8 blastocysts were assayed for gene transcript abundance of metabolic enzymes. Oocyte metabolism was not affected by IVM treatment. D3 formation of embryos with ≥ 4 cells were lower in LC or HN than CON or HNLC; blastocyst rates were greater for CON and lower for HN than LC and HNLC. D3 embryo mitochondrial and cytosolic ROS were reduced in HNLC when compared to other groups. IVM in HN altered blastocyst gene transcript abundance when compared to CON, but not LC or HNLC. In conclusion, supplementation with L-carnitine protects oocytes exposed to high NEFA during IVM and improves their developmental competence, suggesting that high lipid exposure may lead to L-carnitine insufficiency in bovine oocytes.

Neighborhood disadvantage is associated with decreased ovarian reserve in women with overweight and obesity

OBJECTIVE(S)

To evaluate the association between neighborhood disadvantage and ovarian reserve stratified by body mass index (BMI).

DESIGN

Cross-sectional cohort study.

SETTING

Single academic medical center.

PATIENT(S)

A total of 193 healthy reproductive-age women with regular menstrual cycles in the St. Louis, Missouri metropolitan area.

INTERVENTION(S)

Residence in a disadvantaged neighborhood.

MAIN OUTCOME MEASURE(S)

Ovarian reserve as assessed by ovarian antral follicle count (AFC) and serum anti-Müllerian hormone (AMH) concentration.

RESULT(S)

Women (n = 193) ranged from 20 to 44 years. The majority had overweight or obesity (59%, n = 117) with mean BMI of 28±7 kg/m2. Forty-eight women lived in the most disadvantaged neighborhood quartile, of which 75% had overweight or obesity, compared with 54% of the 145 women living in the 3 less disadvantaged neighborhood quartiles. When controlling for age, race, and smoking status, women with overweight or obesity living in the most disadvantaged neighborhoods had significantly lower AMH compared with those living in the less disadvantaged neighborhoods. Antral follicle count did not differ among women with overweight or obesity by neighborhood of residence. Neighborhood disadvantage was not associated with ovarian reserve by AFC or AMH in women with normal weight or underweight status.

CONCLUSION(S)

Living in a socioeconomically deprived area is associated with lower markers of ovarian reserve among women with an elevated BMI.

Obesity increases the odds of multiple pregnancies: A nationwide register-based cohort study in Finland

OBJECTIVE

To investigate the effects of increased pre-pregnancy body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters) on the risk of having spontaneous multiple pregnancies using a nationwide register-based study sample.

METHODS

Data from the National Medical Birth Register (MBR) (2004-2018) were used to evaluate the effects of a higher pre-pregnancy BMI on the risk of multiple pregnancies. Lower and higher pre-pregnancy BMI classes, using the WHO classification, were compared with a normal weight class. A logistic regression model was used to assess the primary outcomes. Adjusted odds ratios (aOR) with 95% confidence intervals (CI) between the groups were compared. The model was adjusted by maternal age, maternal height, and maternal smoking status.

RESULTS

The odds of multiple pregnancies were higher among women in the overweight group (aOR 1.07, 95% CI 1.02-1.12), obesity class I group (aOR 1.11, 95% CI 1.04-1.18), and obesity class II group (aOR 1.15, 95% CI 1.03-1.28) compared with women in the non-overweight BMI class. Women in the underweight group had lower odds for multiple pregnancies (aOR 0.82, 95% CI 0.73-0.93).

CONCLUSION

The odds of multiple pregnancies slightly increase with pre-pregnancy obesity, and this should be acknowledged as a minor risk factor for multiple pregnancies.

Ovarian inflammation mediated by Toll-like receptor 4 increased transcripts of maternal effect genes and decreased embryo development†

Obese women are subfertile and have reduced assisted reproduction success, which may be due to reduced oocyte competence. We hypothesize that consumption of a high-fat/high-sugar diet induces ovarian inflammation, which is a primary contributor to decreased oocyte quality and pre-implantation embryo development. To test this hypothesis, C57BL/6 (B6) mice with a normal inflammatory response and C3H/HeJ (C3H) mice with a dampened inflammatory response due to dysfunctional Toll-like receptor 4 were fed either normal chow or high-fat/high-sugar diet. In both B6 and C3H females, high-fat/high-sugar diet induced excessive adiposity and hyperglycemia compared to normal chow-fed counterparts. Conversely, ovarian CD68 levels and oocyte expression of oxidative stress markers were increased when collected from B6 high-fat/high-sugar but not C3H high-fat/high-sugar mice. Following in vitro fertilization of in vivo matured oocytes, blastocyst development was decreased in B6-high-fat/high-sugar but not C3H high-fat/high-sugar mice. Expression of cumulus cell markers of oocyte quality were altered in both B6 high-fat/high-sugar and C3H high-fat/high-sugar. However, there were no diet-dependent differences in spindle abnormalities in either B6 or C3H mice, suggesting potential defects in cytoplasmic maturation. Indeed, there were significant increases in the abundance of maternal effect gene mRNAs in oocytes from only B6 high-fat/high-sugar mice. These differentially expressed genes encode proteins of the subcortical maternal complex and associated with mRNA metabolism and epigenetic modifications. These genes regulate maternal mRNA degradation at oocyte maturation, mRNA clearance at the zygotic genome activation, and methylation of imprinted genes suggesting a mechanism by which inflammation induced oxidative stress impairs embryo development.

Body mass index is negatively associated with a good perinatal outcome after in vitro fertilization among patients with polycystic ovary syndrome: a national study

Objective

To evaluate the association between body mass index (BMI) and good perinatal outcomes after in vitro fertilization (IVF) among women with polycystic ovary syndrome (PCOS).

Design

Retrospective cohort study using 2012-2015 Society for Assisted Reproductive Technology Clinic Outcomes Reporting System data.

Setting

Fertility clinics.

Patients

To identify patients most likely to have PCOS, we included women with a diagnosis of ovulation disorder and serum antimüllerian hormone >4.45 ng/mL. Exclusion criteria included age ≥ 41 years, secondary diagnosis of diminished ovarian reserve, preimplantation genetic testing, and missing BMI or primary outcome data.

Interventions

None.

Main Outcome Measures

Good perinatal outcome, defined as a singleton live birth at ≥ 37 weeks with birth weight ≥ 2,500 g and ≤ 4,000 g.

Results

The analysis included 9,521 fresh, autologous IVF cycles from 8,351 women. Among women with PCOS, the proportion of cycles with a good perinatal outcome was inversely associated with BMI: underweight 25.1%, normal weight 22.7%, overweight 18.9%, class I 18.4%, class II 14.9%, and class III or super obesity 12.2%. After adjusting for confounders, women in the highest BMI category had 51% reduced odds of a good perinatal outcome compared with normal weight women (adjusted odds ratio 0.49, 95% confidence interval 0.36-0.67).

Conclusions

Among women with PCOS undergoing fresh, autologous IVF, the odds of a good perinatal outcome decline with increasing BMI. Women with PCOS should be counseled that the odds of achieving a good perinatal outcome decrease as their weight increases.

Update on obesity and assisted reproductive technology

Background

The effect of obesity on IVF consequences is still debatable.

Main body

Obesity is linked to a greater likelihood of maternal and fetal complications all through gestation, including miscarriage, premature births, fetal demise, and adverse pregnancy outcomes. There was no increase in chromosomal abnormality percentages with increasing body mass index (BMI), implying that poor oocyte “performance” in obese patients could be caused by variables other than chromosomal expertise. Ribonucleic acid (RNA)-sequence research showed molecular changes in the oocytes of obese patients. Each 5-unit rise in female BMI is attributed with both a 5% and 7% reduction in hazard for CPR and LBR, in both, and a 9% rise in the comparative chance of miscarriage. There is no clinical or moral mandate for establishing a societal BMI limit for rejecting a client or couple direct exposure to infertility treatment. Assessment with an interdisciplinary approach prior to an IVF treatment should be done to assess the safety of oocyte retrieval under anesthesia, taking into account variables including body mass index and comorbid conditions. On LBR, there is no convincing evidence of the significance of lifestyle modification for losing weight. There is contradictory information on the impacts of weight loss surgery on pregnancy outcomes. IVF success rate was unaffected by weight loss surgery.

Conclusion

Obesity has been linked to anovulation, decreased ovarian response to ovulatory prescription medications, changed oocyte and endometrial activity, an elevated risk of fertility problems, and reduced rates of live birth following IVF.

Effect of BMI on the value of serum progesterone to predict clinical pregnancy outcome in IVF/ICSI cycles: a retrospective cohort study

Background

Numerous research have investigated the predictor role of progesterone (P) level on the human Chorionic Gonadotropin (hCG) trigger day of assisted reproductive technology (ART) outcomes. However, the relationship of progesterone levels on hCG day to clinical pregnancy outcomes in IVF/ICSI cycles for patients with different BMI groups is still elusive. This study aimed to investigate the effects of progesterone elevation on triggering day on clinical pregnancy rate (CPR) of IVF/ICSI cycles in patients with different female BMI.

Methods

We conducted a retrospective cohort study included 6982 normal-weight parents (18.5Kg/m2≤BMI<25Kg/m2) and 2628 overweight/obese patients (BMI≥25Kg/m2) who underwent fresh day 3 cleavage embryo transfer (ET) in IVF/ICSI cycles utilizing GnRH agonist to control ovarian stimulation.

Results

The interaction between BMI and P level on triggering day on CPRs was significant (p<0.001). The average level of serum P was reduced with the increase in maternal BMI. Serum P adversely affected CPR in distinct BMI groups. In the normal weight group, CPRs were decreasedas serum P concentrations gradually increased (p<0.001 for overall trend). The CPRs (lower than 65.8%) of progesterone level > 1.00 ng/ml on triggering day were significantly lower than that (72.4%) of progesterone level <0.5 ng/ml. In the overweight/obese group, CPRs showed a decrease statistically with progesterone levels of ≥2.00 ng/ml compared to progesterone levels of <0.5 ng/ml (51.0% VS. 64.9%, p=0.016). After adjusting for confounders, progesterone elevation (PE) negatively correlated with CPRs only in the normal weight group (OR: 0.755 [0.677-0.841], p<0.001), not in the overweight/obese group (p=0.063).

Conclusion

Women with higher BMI exhibited a lower progesterone level on triggering day. Additionally, PE on hCG day is related to decreased CPRs in GnRH agonist IVF/ICSI cycles with cleavage embryo transfers regardless of women's BMI level (normal weight VS. overweight/obesity).

Overweight and obesity affect the efficacy of vaginal vs. intramuscular progesterone for luteal-phase support in vitrified-warmed blastocyst transfer

OBJECTIVE

To compare the difference in the live birth rates (LBRs) between vaginal progesterone and intramuscular progesterone as luteal-phase support in programmed vitrified-warmed blastocyst transfer cycles and determine whether the association was moderated by overweight/obesity.

DESIGN

Retrospective cohort study.

SETTING

Tertiary reproductive medicine center.

PATIENT(S)

Patients who underwent transfer of single vitrified-warmed blastocyst in a programmed cycle between January 2018 and June 2021.

INTERVENTION(S)

Vaginal or intramuscular progesterone as luteal-phase support. Analysis was performed using the generalized estimating equation framework and multivariate regression models. Interaction testing was used to determine whether overweight/obesity (body mass index of ≥25 kg/m²) moderated the association between progesterone replacement and LBRs.

MAIN OUTCOME MEASURE(S)

The primary outcome was live birth. The secondary outcomes were biochemical pregnancy, clinical pregnancy, miscarriage, and total pregnancy loss.

RESULT(S)

A total of 6,905 programmed cycles (4,616 with vaginal progesterone and 2,289 with intramuscular progesterone) were included in the analysis. In the general cohort who underwent cryopreserved blastocyst transfer, the LBRs were 46.23% and 48.62% in the vaginal and intramuscular progesterone groups, respectively (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.82-1.01; adjusted OR [aOR], 0.89; 95% CI, 0.81-0.98), with a significantly increased rate of pregnancy losses in the vaginal progesterone group compared with that in the intramuscular progesterone group (22.22% vs. 18.90%; OR, 1.23; 95% CI, 1.08-1.39; aOR, 1.23; 95% CI, 1.08-1.40). Among normal-weight women, the LBR in the vaginal progesterone group was lower than that in the intramuscular progesterone group (aOR, 0.84; 95% CI, 0.75-0.95). On the other hand, among women with overweight/obesity, the LBRs were similar between the 2 groups of progesterone replacement (aOR, 1.06; 95% CI, 0.86-1.33). Interaction testing of the routes of progesterone administration and overweight/obesity was significant.

CONCLUSION(S)

Luteal-phase support with vaginal progesterone was associated with reduced LBRs compared with intramuscular progesterone for vitrified-warmed blastocyst transfer, and the association was modified by maternal overweight/obesity. Further research is needed to better understand the mechanisms behind the association.

Effect of ovulation before or after intrauterine insemination on pregnancy outcome in patients with unexplained infertility or polycystic ovarian syndrome

OBJECTIVE

To investigate the relationship between ovulation and pregnancy outcomes in patients undergoing intrauterine insemination (IUI).

METHODS

The clinical data from 784 patients, diagnosed with polycystic ovarian syndrome (PCOS) or unexplained infertility, underwent 1624 IUI cycles were analyzed retrospectively. Ovulation was observed by transvaginal ultrasonography on the day of IUI. The clinical pregnancy rate (CPR), abortion rate (AR), and live birth rate (LBR) were analyzed.

RESULTS

The study included 1031 pre-ovulation IUI cycles (63.49%) and 593 post-ovulation IUI cycles (36.51%). The CPR was 13.05%, the AR was 15.57%, and the LBR was 11.02%. Ovulation before or after IUI affected the CPR (11.06% VS 16.53%, p = .002) and LBR (9.41% VS 13.83%, p = .006) per cycle, but did not affect the AR (14.91% VS 16.33%, p = .149). The sex ratio of children was not related to ovulation (p = .948). After adjusting for baseline characteristics and logistic regression, the CPR (OR = 1.931, 95% CI 1.062-1.931, p = .019) and LBR (OR = 1.389, 95% CI 1.007-1.916, p = .045) of post-ovulation insemination were higher than those of pre-ovulation insemination significantly.

CONCLUSION

Pregnancy outcomes were affected by ovulation on the day of IUI in patients with unexplained infertility or PCOS. Post-ovulation insemination may improve the CPR of IUI.

The association of obesity with euploidy rates in women undergoing in vitro fertilization with preimplantation genetic testing

PURPOSE

The purpose of this study was to determine the impact of body mass index (BMI) on euploidy rates for in vitro fertilization (IVF) cycles with preimplantation genetic testing (PGT) utilizing primarily next-generation sequencing (NGS).

METHODS

This retrospective cohort study included women aged ≤ 45 years who underwent IVF/PGT between September 2013 and September 2020 at a single university-affiliated fertility center. The primary outcome was euploidy rate. Secondary outcomes included peak serum estradiol (E2), number of oocytes retrieved, oocyte maturation rate, high-quality blastulation rate, clinical loss rate (CLR), clinical pregnancy rate (CPR), and ongoing pregnancy/live birth rate (OPR/LBR).

RESULTS

The study included 1335 IVF cycles that were stratified according to BMI (normal, n = 648; overweight, n = 377; obese, n = 310). The obese group was significantly older with significantly lower baseline FSH, peak E2, high-quality blastulation rate, and number of embryos biopsied than the normal group. Overall euploidy rates were not significantly different between BMI groups (normal 36.4% ± 1.3; overweight 37.3% ± 1.8; obese 32.3% ± 1.8; p = 0.11), which persisted after controlling for covariates (p = 0.82) and after stratification of euploidy rate by age group and by number of oocytes retrieved per age group. There were no significant differences in CLR, CPR, and OPR/LBR across BMI groups.

CONCLUSIONS

Despite a lower high quality blastulation rate with obesity, there is not a significant difference in euploidy rates across BMI groups in women undergoing IVF/PGT.

Adaptive data-driven models to best predict the likelihood of live birth as the IVF cycle moves on and for each embryo transfer

PURPOSE

To dynamically assess the evolution of live birth predictive factors' impact throughout the in vitro fertilization (IVF) process, for each fresh and subsequent frozen embryo transfers.

METHODS

In this multicentric study, data from 13,574 fresh IVF cycles and 6,770 subsequent frozen embryo transfers were retrospectively analyzed. Fifty-seven descriptive parameters were included and split into four categories: (1) demographic (couple's baseline characteristics), (2) ovarian stimulation, (3) laboratory data, and (4) embryo transfer (fresh and frozen). All these parameters were used to develop four successive predictive models with the outcome being a live birth event.

RESULTS

Eight parameters were predictive of live birth in the first step after the first consultation, 9 in the second step after the stimulation, 11 in the third step with laboratory data, and 13 in the 4th step at the transfer stage. The predictive performance of the models increased at each step. Certain parameters remained predictive in all 4 models while others were predictive only in the first models and no longer in the subsequent ones when including new parameters. Moreover, some parameters were predictive in fresh transfers but not in frozen transfers.

CONCLUSION

This work evaluates the chances of live birth for each embryo transfer individually and not the cumulative outcome after multiple IVF attempts. The different predictive models allow to determine which parameters should be taken into account or not at each step of an IVF cycle, and especially at the time of each embryo transfer, fresh or frozen.

BMI and miscarriage after IVF

PURPOSE OF REVIEW

To summarize recent findings related to the risk of miscarriage in women with elevated BMI undergoing IVF, and the mechanisms involved in said risk.

RECENT FINDINGS

Miscarriage rates are increased in overweight and obese women in both natural and assisted reproduction. Oocyte and embryo quality assessed according to classic morphological static parameters does not seem to be affected by excessive female body weight. Despite the initial lack of consensus between studies regarding embryo morphokinetics in obese women, blastocyst formation and quality have recently been shown to be similar across BMI groups, even in the case of euploid embryos. However, some metabolomic differences have been described in oocytes and embryos from obese women, thus pointing to a functional alteration. In women with elevated BMI, the percentage of aneuploid embryos is similar to that of normal weight women, and rates of miscarriage are higher, despite the transfer of euploid embryos. Therefore, the origin of the increased pregnancy loss rate after IVF in these women may be related to metabolomic, epigenetic or mitochondrial oocyte and embryo disturbances, or to the abnormal endocrine, metabolic and inflammatory uterine environment induced by obesity, which seems to be also responsible for other numerous complications during pregnancy and the in-utero fetal programming of postnatal diseases. A displacement of the window of implantation in obese women undergoing artificial endometrial preparation has recently been described and may be related to the poorer embryo implantation rates and increased risk of miscarriage observed following fresh and frozen embryo transfers with autologous oocytes, and with donated ova in recipients with extremely high BMI.

SUMMARY

Female obesity is related to poorer outcome in natural and assisted conception, including an increased risk of miscarriage. Embryo morphology, assessed by conventional methods or by morphokinetics, does not seem to be affected by excess weight, with similar blastocyst formation and quality than normal weight women reported in IVF cycles. Embryo aneuploidy is not increased, and higher miscarriages rates are seen after euploid embryo transfer in obese women. Disturbances of the uterus or its environment induced by female obesity seem to be the most likely cause of the increased risk of miscarriage, although metabolomic, epigenetic or mitochondrial oocyte and embryo dysfunction cannot be ruled out as cannot congenital anomalies. In the context of all the above, weight reduction before pregnancy should be advised in obese women trying to become pregnant.

Lipid metabolism and endometrial receptivity

BACKGROUND

Obesity has now been recognized as a high-risk factor for reproductive health. Although remarkable advancements have been made in ART, a considerable number of infertile obese women still suffer from serial implantation failure, despite the high quality of embryos transferred. Although obesity has long been known to exert various deleterious effects on female fertility, the underlying mechanisms, especially the roles of lipid metabolism in endometrial receptivity, remain largely elusive.

OBJECTIVE AND RATIONALE

This review summarizes current evidence on the impacts of several major lipids and lipid-derived mediators on the embryonic implantation process. Emerging methods for evaluating endometrial receptivity, for example transcriptomic and lipidomic analysis, are also discussed.

SEARCH METHODS

The PubMed and Embase databases were searched using the following keywords: (lipid or fatty acid or prostaglandin or phospholipid or sphingolipid or endocannabinoid or lysophosphatidic acid or cholesterol or progesterone or estrogen or transcriptomic or lipidomic or obesity or dyslipidemia or polycystic ovary syndrome) AND (endometrial receptivity or uterine receptivity or embryo implantation or assisted reproductive technology or in vitro fertilization or embryo transfer). A comprehensive literature search was performed on the roles of lipid-related metabolic pathways in embryo implantation published between January 1970 and March 2022. Only studies with original data and reviews published in English were included in this review. Additional information was obtained from references cited in the articles resulting from the literature search.

OUTCOMES

Recent studies have shown that a fatty acids-related pro-inflammatory response in the embryo-endometrium boundary facilitates pregnancy via mediation of prostaglandin signaling. Phospholipid-derived mediators, for example endocannabinoids, lysophosphatidic acid and sphingosine-1-phosphate, are associated with endometrial receptivity, embryo spacing and decidualization based on evidence from both animal and human studies. Progesterone and estrogen are two cholesterol-derived steroid hormones that synergistically mediate the structural and functional alterations in the uterus ready for blastocyst implantation. Variations in serum cholesterol profiles throughout the menstrual cycle imply a demand for steroidogenesis at the time of window of implantation (WOI). Since 2002, endometrial transcriptomic analysis has been serving as a diagnostic tool for WOI dating. Numerous genes that govern lipid homeostasis have been identified and, based on specific alterations of lipidomic signatures differentially expressed in WOI, lipidomic analysis of endometrial fluid provides a possibility for non-invasive diagnosis of lipids alterations during the WOI.

WIDER IMPLICATIONS

Given that lipid metabolic dysregulation potentially plays a role in infertility, a better understanding of lipid metabolism could have significant clinical implications for the diagnosis and treatment of female reproductive disorders.

Protocol of the Fit-For-Fertility study: a multicentre randomised controlled trial assessing a lifestyle programme targeting women with obesity and infertility

INTRODUCTION

Women with obesity are at a higher risk of infertility as well as gestational and neonatal complications. Lifestyle changes are universally recommended for women with obesity seeking fertility treatments, but such intervention has only been assessed in very few robust studies. This study's objectives are therefore to assess the clinical outcomes and cost-effectiveness of an interdisciplinary lifestyle intervention (the Fit-For-Fertility Programme; FFFP) targeting women with obesity and subfertility in a diverse population.

METHODS AND ANALYSIS

This pragmatic multicentre randomised controlled trial (RCT) will include 616 women with obesity (body mass index ≥30 kg/m² or ≥27 kg/m² with polycystic ovary syndrome or at-risk ethnicities) who are evaluated at a Canadian fertility clinic for subfertility. Women will be randomised either to (1) the FFFP (experimental arm) alone for 6 months, and then in combination with usual care for infertility if not pregnant; or (2) directly to usual fertility care (control arm). Women in the intervention group benefit from the programme up to 18 months or, if pregnant, up to 24 months or the end of the pregnancy (whichever comes first). Women from both groups are evaluated every 6 months for a maximum of 18 months. The primary outcome is live birth rate at 24 months. Secondary outcomes include fertility, pregnancy and neonatal outcomes; lifestyle and anthropometric measures; and cost-effectiveness. Qualitative data collected from focus groups of participants and professionals will also be analysed.

ETHICS AND DISSEMINATION

This research study has been approved by the Research Ethics Board (REB) of Centre intégré universtaire de santé et des services sociaux de l'Estrie-CHUS (research coordinating centre) on 10 December 2018 and has been or will be approved successively by each participating centres' REB. This pragmatic RCT will inform decision-makers on improving care trajectories and policies regarding fertility treatments for women with obesity and subfertility.

TRIAL REGISTRATION NUMBER

NCT03908099.

PROTOCOL VERSION

1.1, 13 April 2019.

Impact of obesity on medically assisted reproductive treatments

Increasing evidence has demonstrated that obesity impairs female fertility and negatively affects human reproductive outcome following medically assisted reproduction (MAR) treatment. In the United States, 36.5% of women of reproductive age are obese. Obesity results not only in metabolic disorders including type II diabetes and cardiovascular disease, but might also be responsible for chronic inflammation and oxidative stress. Several studies have demonstrated that inflammation and reactive oxygen species (ROS) in the ovary modify steroidogenesis and might induce anovulation, as well as affecting oocyte meiotic maturation, leading to impaired oocyte quality and embryo developmental competence. Although the adverse effect of female obesity on human reproduction has been an object of debate in the past, there is growing evidence showing a link between female obesity and increased risk of infertility. However, further studies need to clarify some gaps in knowledge. We reviewed the recent evidence on the association between female obesity and infertility. In particular, we highlight the association between fat distribution and reproductive outcome, and how the inflammation and oxidative stress mechanisms might reduce ovarian function and oocyte quality. Finally, we evaluate the connection between female obesity and endometrial receptivity.

Maternal body mass index is not associated with increased rates of maternal embryonic aneuploidy

OBJECTIVE

To evaluate the relationship between maternal body mass index (BMI) and embryonic aneuploidy of maternal origin.

DESIGN

Retrospective cohort analysis.

SETTING

University hospital-based reproductive center.

PATIENTS

Maternal origin of aneuploidy was available for 453 cycles and 1,717 embryos.

INTERVENTIONS

Data regarding BMI were collected before egg retrieval. Comparison groups included underweight (BMI, <18.5 kg/m²), normal weight (BMI, 18.5-24.9 kg/m²), overweight (BMI, 25-29.9 kg/m²), and obese (BMI, ≥30 kg/m²). Overall embryonic aneuploidy and maternal aneuploidy rates were compared. The aneuploidy rate was the number of embryos with either maternal or mixed (maternal and paternal) aneuploidy divided by the total number of embryos tested.

MAIN OUTCOME MEASURES

Overall embryonic aneuploidy and maternal aneuploidy rates.

RESULTS

Maternal aneuploidy rate was 51.5% for BMI of ≥30 kg/m² and 39.3% for BMI of <30 kg/m². Female age as well as several in vitro fertilization characteristics were significantly different across groups and were included in the adjusted model. Both the overall embryonic aneuploidy rate (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.11-1.59) and the maternal aneuploidy rate (OR, 1.64; 95% CI, 1.25-2.16) increased with increasing maternal BMI. However, after controlling for significant confounders, BMI did not significantly predict the rate of maternal aneuploidy (OR, 1.16; 95% CI, 0.85-1.59).

CONCLUSIONS

Maternal BMI did not correlate with embryonic aneuploidy of maternal origin after adjusting for confounders.

The Lifestyle Modifications and Endometrial Proteome Changes of Women With Polycystic Ovary Syndrome and Obesity

Polycystic ovary syndrome (PCOS) is a polyendocrine disorder and the most common endocrinopathy in women of reproductive age. Affected women have an elevated prevalence of being overweight and obese. Our study sought to determine how weight loss associated with lifestyle changes affects the endometrium specific proteome, endocrine-metabolic characteristics, and motor capabilities of obese women with PCOS and infertility. A group of 12 infertile women under the age of 38 with PCOS and BMI ≥30 kg/m² were included in the study. An evaluation was performed by a gynecologist and an endocrinologist. The weight-loss program lasted 8 weeks under the guidance of a professional trainer. Endometrial sampling during a period of implantation window for proteome determination was performed before and after weight loss. In endometrial samples at the end of the study increased protein abundance was recorded for Legumain, Insulin-like growth factor-binding protein 7, Hepatocyte growth factor receptor, Keratin, type II cytoskeletal 7, and Cystatin-B, while the B-lymphocyte antigen CD20 protein abundance decreased. Our results also indicate significantly lowered fasting blood glucose level and free testosterone concentration and significant improvements in body composition and physical capacity. This study may open up the venues for investigating important biomarkers that may affect endometrial receptivity.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT04989244?term=NCT04989244&draw=2&rank=1, identifier: NCT04989244.

The effectiveness of weight-loss lifestyle interventions for improving fertility in women and men with overweight or obesity and infertility: A systematic review update of evidence from randomized controlled trials

Being overweight or obese can have a negative impact on fertility outcomes. This systematic review updates randomized controlled trial (RCT) findings on the effectiveness of weight loss interventions in reducing weight and improving reproductive outcomes of women and men with overweight or obesity and infertility. Eligible studies, published since the last review, were identified by searching databases from March 20, 2016 until March 31, 2020. RCTs involving any type of lifestyle intervention were considered. Eight RCTs were identified and aggregated with seven RCTs included in our previous review. Meta-analyses revealed that women randomized to a combined diet and exercise intervention were more likely to become pregnant, risk ratio (RR) = 1.87 (95% CI 1.20, 2.93) and achieve a live birth RR = 2.20 (95% CI 1.23, 3.94), compared to women in control groups who received no or minimal intervention. This pattern was not replicated in trials where control groups received immediate access to assisted reproductive technology (ART). No eligible randomized trials involving men were identified. Data were largely obtained from small scale studies. Better designed, adequately powered, robust randomized trials are needed to better understand the effect of weight loss interventions on reproductive outcomes in both women and men.

Body mass index, not race, may be associated with an alteration in early embryo morphokinetics during in vitro fertilization

OBJECTIVE

To assess the relationship between maternal body mass index (BMI) and embryo morphokinetics on time-lapse microscopy (TLM).

DESIGN

Retrospective cohort study.

METHODS

All IVF cycles between June 2015 and April 2017 were reviewed. Female BMI prior to egg retrieval was collected through chart review. BMI (kg/m2) classification included underweight (< 18.5), normal weight (18.5-25), overweight (25-30), and obese (≥ 30). Embryos' morphokinetic parameters were assessed with TLM and included time to syngamy, 2-cell, 3-cell, 4-cell, and 8-cell. A generalized linear mixed model was used to control for potential confounders and multiple embryos resulting from a single IVF cycle.

RESULTS

A total of 2150 embryos from 589 IVF cycles were reviewed and included in the analysis. Classification based on BMI was as follows: underweight (N = 56), normal weight (N = 1252), overweight (N = 502), and obese (N = 340). After adjusting for race and use of intracytoplasmic sperm injection, the mean time to the 8-cell stage in the underweight group was 4.3 (95% CI: - 8.31, - 0.21) h less than in the normal weight group (P = 0.025) and 4.6 (95% CI: - 8.8, - 0.21) h less than in the obese group (p = 0.022). No significant difference was noted between race and TLM after controlling for possible confounders.

CONCLUSIONS

Embryos from underweight women were demonstrated to have a faster time to the 8-cell stage than normal weight or obese women. No significant difference was noted for race. This study demonstrates that weight can be a factor contributing to embryo development as observed with TLM.

Early pregnancy loss: Do Per- and polyfluoroalkyl substances matter?

Per- and poly-fluorinated substances (PFASs) with endocrine disrupting effect can efficiently transfer across the blood-follicle barrier. However, it is still controversial and attracting extensive public concern that whether PFASs can affect the human fertility potential. Therefore, we aimed to analyze the associations of women's exposure to PFASs with pregnancy loss, the relevant processes of fertilization, zygote implantation, and embryo development by using a prospective cohort study. The women undergoing in vitro fertilization-embryo transfer (IVF-ET) treatment were recruited in Beijing City (Beijing Center) and Yantai City (Yantai Center) in China during 2015-2017. A total of 305 women were recruited before the IVF-ET treatment. Twelve PFASs were measured in their serum samples collected in the day before the IVF-ET treatment, as well as in the human chorionic gonadotropin (hCG) day. The three IVF-ET outcomes were included, i.e. hCG test negative, clinical pregnancy failure (CPF), and preclinical spontaneous abortion. Nine serum PFASs had detection rate of >70% in Beijing and Yantai centers. The exposure patterns to PFASs between these two centers were overall different. For Beijing Center, we only found a positive association of perflurodecanoic acid (PFDA) with the risk of CPF [RR = 2.28 (95 %CI: 1.02-5.11)], but there is a reverse trend in Yantai Center with [RR = 0.45 (95 %CI: 0.23-0.85)]. However, the serum concentration of PFDA in Beijing Center was relatively lower than that of Yantai Center. Other significant associations of the detected PFASs with the IVF-ET outcomes, or with the relevant clinical processes, were not found. The multi-pollutant regression model of the Bayesian kernel machine regression suggested that there were no joint effects between various PFASs on the concerned outcomes. Overall, we suggest that most PFAS were not associated with early pregnancy loss at the current exposure levels. As for the PFDA, there may exist susceptibility of different populations.

Blastocyst formation is similar in obese and normal weight women: a morphokinetic study

STUDY QUESTION

Does the embryo cleavage pattern and rate of blastocyst formation differ between normal weight and obese women undergoing IVF?

SUMMARY ANSWER

Embryo morphokinetic development, final blastocyst formation rate and blastocyst morphology do not differ between obese and normal weight women.

WHAT IS KNOWN ALREADY

Female obesity has been related to impaired IVF outcomes. Although the mechanisms responsible for this detrimental effect are thought to include impaired oocyte and embryo quality and reduced endometrial receptivity, they are yet to be confirmed. Embryo quality has been commonly assessed using static morphological criteria. Only three studies have analysed the progress of embryos up to the blastocyst stage in women with elevated BMI, but they have used small samples of patients or have obtained contradictory results.

STUDY DESIGN, SIZE, DURATION

This retrospective, cohort study, was performed from January 2016 to May 2020. A total of 3316 ICSI cycles from 2822 women were included, of which 1251 cycles were part of a preimplantation genetic testing programme. In total, 17 848 embryos were analysed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study reports on the IVF cycles of infertile women, with a known BMI, who underwent ICSI and whose embryos were grown until the fifth/sixth day of development in a time-lapse system. Patients were grouped as follows. Underweight was defined as a BMI <18.5 kg/m2; normal weight was a BMI of 18.5-24.9 kg/m2; overweight was a BMI of 25-29.9 kg/m2; and obesity was a BMI of ≥30 kg/m2. Embryo development was assessed on an external computer with analysis software.

MAIN RESULTS AND THE ROLE OF CHANCE

Despite an initial slower pattern of embryo development, the blastocyst formation rate on day 5 or on day 5 plus day 6 did not differ in obese women with respect to the other three BMI groups. Moreover, based on the evaluation of inner cell mass and the trophectoderm on both days of blastocyst development, embryo quality was similar across the BMI groups, as were the pattern of development and arrest up to blastocyst formation and the distribution of the categories of full, expanded and hatching blastocysts.

LIMITATIONS, REASONS FOR CAUTION

Limitations include the retrospective analysis of data, the use of BMI as the only parameter to define normal/abnormal female body weight, and the lack of complete information about clinical outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

Blastocyst formation and embryo morphokinetics are not affected by female obesity, and the poorer IVF outcomes described for such women are probably due to deficient endometrial receptivity. The role of endometrial progesterone exposure on the day of embryo transfer should be analysed in future studies as a possible determining factor.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used and there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Body Mass Index Showed No Impact on the Outcome of In Vitro Fertilization in Progestin-Primed Ovarian Stimulation Protocol

Purpose

To assess whether body mass index (BMI) affects the outcome of in vitro fertilization (IVF) in progestin-primed ovarian stimulation (PPOS) protocol.

Methods

A retrospective study was conducted in the Reproductive Medicine Center, Renmin Hospital of Wuhan University, from June 2016 to June 2017. 636 infertile women who received PPOS protocol in IVF treatment were divided into three groups according to BMI. The data of basic characteristics, embryological outcomes, and cycle characteristics of controlled ovarian stimulation of different groups were collected and studied. Result(s). There was no significant difference in almost all the basic characteristics, embryological outcomes of controlled ovarian stimulation, and cycle characteristics of controlled ovarian stimulation among the three groups. There was a tendency that the duration of infertility was decreased with the increase of patients' weight, although there was no significant difference (P=0.051). However, overweight patients had a higher fertilization rate than normal weight patients and underweight patients (70.3 vs. 67.7 vs. 66.8, P=0.008), but two-pronuclei (2PN) fertilization rate and cleavage rate showed no significant difference among the three groups. Conclusion(s). BMI showed no impact on the outcome of the ovarian stimulation outcome in PPOS protocol. PPOS protocol may benefit overweight patients, for it attains the same effect with normal patients and requires no increase in gonadotropin (Gn) dose and Gn duration.

Association between abnormal body mass index and pregnancy outcomes in patients following frozen embryo transfer: a systematic review and meta-analysis

BACKGROUND

There has been increasing interest in the relationship between body mass index(BMI) and pregnancy outcomes, especially in women undergoing frozen embryo transfer(FET). Several observational studies have been published, but so far with conflicting results.

METHODS

A systematic review and meta-analysis was conducted according to PRISMA guidelines. Pubmed, Embase, Cochrane Library, Clinicaltrails.gov and Web of Science databases were searched based on established search strategy from inception through January 2021.

RESULTS

Twelve studies were eligible. In women following FET, high BMI (BMI ≥ 23 kg/m²) was associated with an impaired live birth rate (LBR, OR: 0.89, 95% CI: 0.82-0.96, P = 0.002), but wasn't associated with the implantation rate or the clinical pregnancy rate. Subgroup analysis revealed higher LBR for women didn't complicated by polycystic ovary syndrome (PCOS, OR: 0.96, 95% CI: 0.85-1.08, P = 0.46) and women with blastocyst transferred (OR: 0.89, 95% CI: 0.68-1.16, P = 0.40). LBR did not differ between the low BMI group (BMI < 18.5 kg/m²) and the normal weight group.

CONCLUSIONS

Our study showed that high BMI in women is negatively associated with LBR in FET cycles, whereas low BMI isn't. The results of subgroup analysis implied a need for women with a high BMI to get individualized weight management and treatment. Further evidence is still required to optimize preconception health and develop Nutritional and exercise guidelines.

Maternal body mass index associates with blastocyst euploidy and live birth rates: the tip of an iceberg?

RESEARCH QUESTION

Does maternal preconceptional body mass index (BMI) associate with mean blastocyst euploidy rate (m-ER) per patient and live birth rate (LBR) after vitrified-warmed euploid single embryo transfer (SET)?

DESIGN

Observational study conducted between April 2013 and March 2020 at a private IVF clinic, involving 1811 Caucasian women undergoing trophectoderm biopsy and comprehensive chromosome testing. The outcomes of 1125 first vitrified-warmed euploid SET were also analysed. Patients were clustered as normal weight (BMI 18.5-25; n = 1392 performing 859 SET), underweight (BMI <18.5; n = 160 performing 112 SET) and overweight (BMI >25; n = 259 performing 154 SET). m-ER per patient was the primary outcome. The secondary outcomes were all clinical outcomes per euploid SET. All data were adjusted for confounders through regression analyses.

RESULTS

The m-ER per patient decreases as maternal BMI increases from 17 up to 22-23 before reaching a plateau. A linear regression adjusted for maternal age confirmed this moderate association (unstandardized coefficient B: -0.6%, 95% confidence interval [CI]: -1.1 to -0.1%, P = 0.02). All clinical outcomes were similar between normal weight and underweight women. Overweight women, instead, showed higher miscarriage rate per clinical pregnancy (n = 20/75, 26.7% versus n = 67/461, 14.5%; odds ratio [OR] adjusted for blastocyst quality and day of full blastulation: 2.0, 95% CI: 1.1-3.6, P = 0.01) and lower LBR per SET (n = 55/154, 35.7% versus n = 388/859, 45.2%; OR adjusted for blastocyst quality and day of full blastulation: 0.67, 95% CI: 0.46-0.96, P = 0.03).

CONCLUSION

These data indicate a need for future research on more sensitive metrics to assess body fat mass and distribution, as well as on the mechanisms leading to lipotoxicity, thereby impairing embryo competence and/or endometrial receptivity. Overweight women should be informed of their higher risk for miscarriage and, whenever possible, encouraged to lose weight, especially before transfer.

Effect of Orlistat on Live Birth Rate in Overweight or Obese Women Undergoing IVF-ET: A Randomized Clinical Trial

CONTEXT

Obesity management prior to infertility treatment remains a challenge. To date, results from randomized clinical trials involving weight loss by lifestyle interventions have shown no evidence of improved live birth rate.

OBJECTIVE

This work aimed to determine whether pharmacologic weight-loss intervention before in vitro fertilization and embryo transfer (IVF-ET) can improve live birth rate among overweight or obese women.

METHODS

We conducted a randomized, double-blinded, placebo-controlled trial across 19 reproductive medical centers in China, from July 2017 to January 2019. A total of 877 infertile women scheduled for IVF who had a body mass index of 25 or greater were randomly assigned to receive orlistat (n = 439) or placebo (n = 438) treatment for 4 to 12 weeks. The main outcome measurement was the live birth rate after fresh ET.

RESULTS

The live birth rate was not significantly different between the 2 groups (112 of 439 [25.5%] with orlistat and 112 of 438 [25.6%] with placebo; P = .984). No significant differences existed between the groups as to the rates of conception, clinical pregnancy, or pregnancy loss. A statistically significant increase in singleton birth weight was observed after orlistat treatment (3487.50 g vs 3285.17 g in the placebo group; P = .039). The mean change in body weight during the intervention was -2.49 kg in the orlistat group, as compared to -1.22 kg in the placebo group, with a significant difference (P = .005).

CONCLUSION

Orlistat treatment, prior to IVF-ET, did not improve the live birth rate among overweight or obese women, although it was beneficial for weight reduction.

Overweight and obesity significantly reduce pregnancy, implantation, and live birth rates in women undergoing In Vitro Fertilization procedures

OBJECTIVE

The objective of this study was to evaluate the effects of overweight and obesity on fertility outcomes in IVF procedures.

METHODS

This was a retrospective and nonrandomized study that included 191 IVF/ICSI cycles using non-donor oocytes performed between July 2016 and December 2018 that were allocated according to Body Mass Index (BMI) in three groups: Normal group: 18.5-24.9 (n=67 women), Overweight group: 25.0-29.9 (n=86 women) and Obesity group: ≥30.0 (n=38 women). We compared fertilization rates, embryo quality at day 3, development and quality of blastocyst, pregnancy rates, implantation rates, and live birth rates.

RESULTS

Patients from all groups had similar stimulation days, but those women with overweight and obesity used more hormones compared to women with normal weight (p<0.05). Fertilization rates, zygotes that underwent cleavage and good-quality embryos at Day 3 were similar between the three evaluated groups. The groups of overweight and obesity had embryos at Day 3 with significantly less cells, compared to those from the normal group (p<0.05). The blastocyst development rate was significantly lower in women with overweight and obesity compared to women with normal BMI (p<0.05); but, the percentages of good blastocysts were similar in all studied patients. Pregnancy, implantation and live birth rates were significantly lower in the group of women with overweight and obesity, compared to those women with normal weight (p<0.05). Obese women had significantly more miscarriages compared to those in the other groups (p<0.05).

CONCLUSIONS

Our data shows that an increased BMI affects embryo development and significantly reduces the pregnancy, implantation and live birth rates.

The influence of obesity on incidence of complications in patients hospitalized with ovarian hyperstimulation syndrome

OBJECTIVE

To study the impact of body habitus on risk of complications resulting from ovarian hyperstimulation syndrome (OHSS) in hospitalized patients.

METHODS

This is a retrospective observational study examining the National Inpatient Sample between January 2012 and September 2015. Patients were women < 50 years of age diagnosed with OHSS, classified as non-obese, class I-II obesity, or class III obesity. Intervention included multinomial logistic regression to identify factors associated with obesity and binary logistic regression for independent risk factors for complications. Main outcome measures were incidence of (i) any or (ii) multiple complication(s).

RESULTS

Of 2745 women hospitalized with OHSS, 2440 (88.9%) were non-obese, 155 (5.6%) had class I-II obesity, and 150 (5.5%) had class III obesity. Obese women (either class I-II or III) had a higher degree of comorbidity, had lower incomes, and were less likely to have private insurance than non-obese women (all P < 0.001). Obese women had lower rates of OHSS-related complications than non-obese women (any complication: non-obese 65.2%, class I-II 54.8%, and class III 46.7%, P < 0.001; and multiple complications: non-obese 38.5%, class I-II 32.3%, and class III 20.0%, P < 0.001). In the multivariable model, obesity remained independently associated with a decreased risk of complications (class I-II odds ratio 0.57, 95% confidence interval 0.39-0.83, P = 0.003; class III odds ratio 0.30, 95% confidence interval 0.20-0.44, P < 0.001). Obese women were also less likely to require paracentesis (non-obese 32.8%, class I-II 9.7%, and class III 13.3%, P < 0.001).

CONCLUSION

Our study suggests that obesity is associated with decreased OHSS-related complication rates in hospitalized patients.

Association between maternal prepregnancy body mass index and pregnancy outcomes following assisted reproductive technology: A systematic review and dose-response meta-analysis

This systematic review investigated dose-response relationship between maternal prepregnancy body mass index (BMI) and pregnancy outcomes following assisted reproductive technology, including clinical pregnancy rate (CPR), miscarriage rate (MR), and live birth rate (LBR). We searched four major databases and finally included 105 studies involving more than 271,632 pregnant women. We performed linear or nonlinear dose-response meta-analyses using random effects models. At per-woman level, pooling of unadjusted estimates shown an inverted J-shaped relationship between maternal BMI and CPR; pooling of adjusted estimates showed a linear association, suggesting statistical association between higher maternal BMI and lower CPR (adjusted OR [aOR] for 5-unit increase in BMI: 0.96, 95%CI: 0.94-0.98). At per-cycle level, linear dose-response relationship was found between maternal BMI and CPR (crude relative risk, RR, [cRR] for 5-unit increase in BMI 0.97, 0.96-0.98; aOR 0.96, 0.94-0.99). Linear dose-response relationship was established between maternal BMI and the outcomes of MR or LBR (higher BMI associated with higher MR [cRR 1.15, 1.08-1.22] and lower LBR [cRR 0.91, 0.88-0.94] at per-woman level). Sensitivity analyses showed no significant changes. In conclusion, there is dose-response relationship between maternal BMI and pregnancy outcomes following assisted reproductive technology. Higher BMI values may suggest suboptimal pregnancy outcomes.

The association between obesity and weight loss after bariatric surgery on the vaginal microbiota

BACKGROUND

Obesity and vaginal microbiome (VMB) dysbiosis are each risk factors for adverse reproductive and oncological health outcomes in women. Here, we investigated the relationship between obesity, vaginal bacterial composition, local inflammation and bariatric surgery.

METHODS

Vaginal bacterial composition assessed by high-throughput sequencing of bacterial 16S rRNA genes and local cytokine levels measured using a multiplexed Magnetic Luminex Screening Assay were compared between 67 obese and 42 non-obese women. We further assessed temporal changes in the microbiota and cytokines in a subset of 27 women who underwent bariatric surgery.

RESULTS

The bacterial component of the vaginal microbiota in obese women was characterised by a lower prevalence of a Lactobacillus-dominant VMB and higher prevalence of a high diversity (Lactobacillus spp., and Gardnerella- spp. depleted) VMB, compared with non-obese subjects (p<0.001). Obese women had higher relative abundance of Dialister species (p<0.001), Anaerococcus vaginalis (p=0.021), and Prevotella timonensis (p=0.020) and decreased relative abundance of Lactobacillus crispatus (p=0.014). Local vaginal IL-1β, IL-4, IL-6, IL-8, IFNγ, MIP-1α and TNFα levels were all higher among obese women, however, only IL-1β and IL-8 correlated with VMB species diversity. In a subset of obese women undergoing bariatric surgery, there were no significant overall differences in VMB following surgery; however, 75% of these women remained obese at 6 months. Prior to surgery, there was no relationship between body mass index (BMI) and VMB structure; however, post-surgery women with a Lactobacillus-dominant VMB had a significantly lower BMI than those with a high diversity VMB.

CONCLUSIONS

Obese women have a significantly different vaginal microbiota composition with increased levels of local inflammation compared to non-obese women. Bariatric surgery does not change the VMB; however, those with the greatest weight loss 6-month post-surgery are most likely to have a Lactobacillus-dominant VMB. Video abstract.

Influence of pretreatment of insulin on the phosphorylation of extracellular receptor kinase by gonadotropin-releasing hormone and gonadotropins in cultured human granulosa cells

OBJECTIVE

To investigate the influence of pretreatment of insulin on the phosphorylation of ERK1/2 by gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in cultured human granulosa cells.

STUDY DESIGN

Human granulosa cells were collected from 20 women (age: 20-35 years) who underwent controlled ovarian hyperstimulation for in vitro fertilization and embryo transfer at Asan Medical Center (Seoul, South Korea). The presence of the receptors for insulin, GnRH, FSH, and LH in human granulosa cells was identified by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The granulosa cells were treated with 10 nM insulin or 10 nM GnRH for 5 min or 30 min and with 10 nM FSH or 10 nM LH for 24 h or 48 h. The cells were also pretreated with insulin for 30 min prior to treatment with GnRH, FSH, or LH. Western blot analysis was used to analyze ERK1/2 phosphorylation.

RESULTS

RT-PCR showed that the receptors for insulin, GnRH, FSH, and LH were expressed in human granulosa cells. Insulin, GnRH, FSH, and LH could activate ERK1/2 phosphorylation. Pretreatment with insulin inhibited ERK1/2 phosphorylation induced by GnRH and FSH while augmenting ERK1/2 phosphorylation induced by LH.

CONCLUSIONS

Insulin might have a negative effect on GnRH and FSH regulation by attenuating the action of GnRH and FSH in the phosphorylation of ERK1/2 in human granulosa cells. In contrast, insulin might have a positive effect on LH regulation by potentiating the action of LH in the phosphorylation of ERK1/2. Our results showed that insulin is clearly an important regulator of human reproductive function at the ovarian level.

IVF outcomes in patients with a history of bariatric surgery: a multicenter retrospective cohort study

STUDY QUESTION

How does a history of dramatic weight loss linked to bariatric surgery impact IVF outcomes?

SUMMARY ANSWER

Women with a history of bariatric surgery who had undergone IVF had a comparable cumulative live birth rate (CLBR) to non-operated patients of the same BMI after the first IVF cycle.

WHAT IS KNOWN ALREADY

In the current context of increasing prevalence of obesity in women of reproductive age, weight loss induced by bariatric surgery has been shown to improve spontaneous fertility in obese women. However, little is known on the clinical benefit of bariatric surgery in obese infertile women undergoing IVF.

STUDY DESIGN, SIZE, DURATION

This exploratory retrospective multicenter cohort study was conducted in 10 287 IVF/ICSI cycles performed between 2012 and 2016. We compared the outcome of the first IVF cycle in women with a history of bariatric surgery to two age-matched groups composed of non-operated women matched on the post-operative BMI of cases, and non-operated severely obese women.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The three exposure groups of age-matched women undergoing their first IVF cycle were compared: Group 1: 83 women with a history of bariatric surgery (exposure, mean BMI 28.9 kg/m2); Group 2: 166 non-operated women (non-exposed to bariatric surgery, mean BMI = 28.8 kg/m2) with a similar BMI to Group 1 at the time of IVF treatment; and Group 3: 83 non-operated severely obese women (non-exposed to bariatric surgery, mean BMI = 37.7 kg/m2). The main outcome measure was the CLBR. Secondary outcomes were the number of mature oocytes retrieved and embryos obtained, implantation and miscarriage rates, live birth rate per transfer as well as birthweight.

MAIN RESULTS AND THE ROLE OF CHANCE

No significant difference in CLBR between the operated Group 1 patients and the two non-operated Groups 2 and 3 was observed (22.9%, 25.9%, and 12.0%, in Groups 1, 2 and 3, respectively). No significant difference in average number of mature oocytes and embryos obtained was observed among the three groups. The implantation rates were not different between Groups 1 and 2 (13.8% versus 13.7%), and although lower (6.9%) in obese women of Group 3, this difference was not statistically significant. Miscarriage rates in Groups 1, 2 and 3 were 38.7%, 35.8% and 56.5%, respectively (P = 0.256). Live birth rate per transfer in obese patients was significantly lower compared to the other two groups (20%, 18%, 9.3%, respectively, in Groups 1, 2 and 3, P = 0.0167). Multivariate analysis revealed that a 1-unit lower BMI increased the chances of live birth by 9%. In operated women, a significantly smaller weight for gestational age was observed in newborns of Group 1 compared to Group 3 (P = 0.04).

LIMITATIONS, REASONS FOR CAUTION

This study was conducted in France and nearly all patients were Caucasian, questioning the generalizability of the results in other countries and ethnicities. Moreover, 950 women per group would be needed to achieve a properly powered study in order to detect a significant improvement in live birth rate after bariatric surgery as compared to infertile obese women.

WIDER IMPLICATIONS OF THE FINDINGS

These data fuel the debate on the importance of pluridisciplinary care of infertile obese women, and advocate for further discussion on whether bariatric surgery should be proposed in severely obese infertile women before IVF. However, in light of the present results, infertile women with a history of bariatric surgery can be reassured that surgery-induced dramatic weight loss has no significant impact on IVF prognosis.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by unrestricted grants from FINOX-Gédéon Richter and FERRING Pharmaceuticals awarded to the ART center of the Clinique Mathilde to fund the data collection and the statistical analysis. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

NCT02884258.

Effect of pre-pregnancy body mass index on neonatal outcomes in women undergoing autologous frozen-thawed embryo transfer

OBJECTIVE

To investigate the associations between pre-pregnancy body mass index (BMI) and neonatal outcomes in women undergoing autologous frozen-thawed embryo transfer (FET).

DESIGN

Retrospective cohort study.

SETTING(S)

University-affiliated reproductive medical center.

PATIENT(S)

A total of 16,240 women with singleton deliveries achieved by autologous FET.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Neonatal outcomes included preterm birth (PTB), low birth weight (LBW), small-for-gestational age (SGA), large-for-gestational age (LGA), fetal macrosomia, and birth defects.

RESULT(S)

After adjusting for confounding factors, our study showed that in autologous FET cycles, the overweight women (23 kg/m²≤ BMI <27.5 kg/m²) were associated with increased rates of PTB (adjusted odds ratio [aOR], 1.226; 95% confidence interval [CI], 1.060-1.418), macrosomia (aOR, 1.692; 95% CI, 1.491-1.921), and LGA (aOR, 1.980; 95% CI, 1.715-2.286); and the obese women (BMI ≥27.5 kg/m²) were significantly associated with increased PTB (aOR, 1.503; 95% CI, 1.167-1.936), early PTB (aOR, 2.829; 95% CI, 1.679-4.765), very LBW (aOR, 3.087; 95% CI, 1.720-5.542), macrosomia (aOR, 2.325; 95% CI, 1.862-2.904), and LGA (aOR, 3.235; 95% CI, 2.561-4.085). The rate of SGA infants was higher in the underweight women (BMI <18.5 kg/m²) (aOR, 1.687; 95% CI, 1.375-2.071) than that in the normal-weight women (18.5 kg/m²≤ BMI ≤23 kg/m²). No significant difference was observed in the risk of birth defects between normal-weight cases and other BMI categories.

CONCLUSION(S)

Among women undergoing FET, pre-pregnancy BMI affected neonatal outcomes of singletons. BMI in Asian categories for overweight and obese showed significant increases in PTB, macrosomia, and LGA; early PTB and very LBW only increased in obese cases. In addition, underweight status was associated with increased risk of SGA. In contrast, there was no association between pre-pregnancy BMI and birth defects in FET cycles.

Body mass index is not associated with embryo ploidy in patients undergoing in vitro fertilization with preimplantation genetic testing

OBJECTIVE

To assess the association between body mass index (BMI) and embryo aneuploidy and mosaicism in a cohort of patients undergoing in vitro fertilization (IVF) with trophectoderm biopsy for preimplantation genetic testing for aneuploidy (PGT-A) using next-generation sequencing technology.

DESIGN

Retrospective cohort study.

SETTING

Academic center.

PATIENTS

Patients undergoing their first IVF cycle with trophectoderm biopsy and PGT-A at our center between January 1, 2017, and August 31, 2020. Patients classified as underweight on the basis of BMI (BMI <18.5 kg/m²) and patients who underwent fresh embryo transfers were excluded.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Number and proportion of aneuploid, mosaic, and euploid embryos.

RESULTS

The patients were stratified according to the World Health Organization's BMI classification: normal weight (18.5-24.9 kg/m², n = 1,254), overweight (25-29.9 kg/m², n = 351), and obese (≥30 kg/m², n = 145). Age-adjusted regression models showed no relationship between BMI classification and the number or proportion of aneuploid embryos. There were no statistically significant associations between BMI classifications and the number or proportion of mosaic or euploid embryos. A subgroup analysis of patients classified into age groups of <35, 35-40, and >40 years similarly showed no relationships between BMI and embryo ploidy outcomes.

CONCLUSION

Body mass index was not associated with the number or proportion of aneuploid, mosaic, or euploid embryos in this large cohort of patients undergoing IVF with PGT-A, suggesting that the negative effect of excess weight on reproductive outcomes was independent of the ploidy status of the embryo cohort.