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

[First-line management of infertile couple. Guidelines for clinical practice of the French College of Obstetricians and Gynecologists 2022]

OBJECTIVE

To update the 2010 CNGOF clinical practice guidelines for the first-line management of infertile couples.

MATERIALS AND METHODS

Five major themes (first-line assessment of the infertile woman, first-line assessment of the infertile man, prevention of exposure to environmental factors, initial management using ovulation induction regimens, first-line reproductive surgery) were identified, enabling 28 questions to be formulated using the Patients, Intervention, Comparison, Outcome (PICO) format. Each question was addressed by a working group that had carried out a systematic review of the literature since 2010, and followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) methodology to assess the quality of the scientific data on which the recommendations were based. These recommendations were then validated during a national review by 40 national experts.

RESULTS

The fertility work-up is recommended to be prescribed according to the woman's age: after one year of infertility before the age of 35 and after 6months after the age of 35. A couple's initial infertility work-up includes a single 3D ultrasound scan with antral follicle count, assessment of tubal permeability by hysterography or HyFOSy, anti-Mullerian hormone assay prior to assisted reproduction, and vaginal swabbing for vaginosis. If the 3D ultrasound is normal, hysterosonography and diagnostic hysteroscopy are not recommended as first-line procedures. Chlamydia trachomatis serology does not have the necessary performance to predict tubal patency. Post-coital testing is no longer recommended. In men, spermogram, spermocytogram and spermoculture are recommended as first-line tests. If the spermogram is normal, it is not recommended to check the spermogram. If the spermogram is abnormal, an examination by an andrologist, an ultrasound scan of the testicles and hormonal test are recommended. Based on the data in the literature, we are unable to recommend a BMI threshold for women that would contraindicate medical management of infertility. A well-balanced Mediterranean-style diet, physical activity and the cessation of smoking and cannabis are recommended for infertile couples. For fertility concern, it is recommended to limit alcohol consumption to less than 5 glasses a week. If the infertility work-up reveals no abnormalities, ovulation induction is not recommended for normo-ovulatory women. If intrauterine insemination is indicated based on an abnormal infertility work-up, gonadotropin stimulation and ovulation monitoring are recommended to avoid multiple pregnancies. If the infertility work-up reveals no abnormality, laparoscopy is probably recommended before the age of 30 to increase natural pregnancy rates. In the case of hydrosalpinx, surgical management is recommended prior to ART, with either salpingotomy or salpingectomy depending on the tubal score. It is recommended to operate on polyps>10mm, myomas 0, 1, 2 and synechiae prior to ART. The data in the literature do not allow us to systematically recommend asymptomatic uterine septa and isthmoceles as first-line surgery.

CONCLUSION

Based on strong agreement between experts, we have been able to formulate updated recommendations in 28 areas concerning the initial management of infertile couples.

Bariatric Surgery in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine condition in premenopausal women and is a common cause of anovulatory subfertility. Although obesity does not form part of the diagnostic criteria, it affects a significant proportion of women with PCOS and is strongly implicated in the pathophysiology of the disease. Both PCOS and obesity are known to impact fertility in women; obesity also reduces the success of assisted reproductive technology (ART). With or without pharmacotherapy, lifestyle intervention remains the first-line treatment in women with PCOS and obesity. Bariatric surgery is still an experimental treatment in women with PCOS and subfertility. This review will present an overview of the pathophysiology of PCOS and obesity and the role of bariatric surgery. Although data are sparse regarding the impact of bariatric surgery on subfertility in women with PCOS and obesity, existing studies point to a beneficial role in treating metabolic and reproductive dysfunction.

Cellular atlases of ovarian microenvironment alterations by diet and genetically-induced obesity

Obesity, which can arise from genetic or environmental factors, has been shown to cause serious damages to the reproductive system. The ovary, as one of the primary regulators of female fertility, is a complex organ comprised of heterogeneous cell types that work together to maintain a normal ovarian microenvironment (OME). Despite its importance, the effect of obesity on the entire ovary remains poorly documented. In this study, we performed ovary single-cell and nanoscale spatial RNA sequencing to investigate how the OME changed under different kinds of obesity, including high-fat diet (HFD) induced obesity and Leptin ablation induced obesity (OB). Our results demonstrate that OB, but not HFD, dramatically altered the proportion of ovarian granulosa cells, theca-interstitial cells, luteal cells, and endothelial cells. Furthermore, based on the spatial dynamics of follicular development, we defined four subpopulations of granulosa cell and found that obesity drastically disrupted the differentiation of mural granulosa cells from small to large antral follicles. Functionally, HFD enhanced follicle-stimulating hormone (FSH) sensitivity and hormone conversion, while OB caused decreased sensitivity, inadequate steroid hormone conversion, and impaired follicular development. These differences can be explained by the differential expression pattern of the transcription factor Foxo1. Overall, our study provides a powerful and high-resolution resource for profiling obesity-induced OME and offers insights into the diverse effects of obesity on female reproductive disorders.

Comprehensive Review of Anesthetic Evaluation and Management in Obese Female Patients Undergoing In Vitro Fertilization

Obesity has become a global health epidemic with profound implications for various medical specialties, including reproductive medicine. This comprehensive review focuses on the anesthetic evaluation and management of obese patients undergoing in vitro fertilization (IVF) procedures. Obesity, as defined by BMI, is associated with infertility and poses unique challenges for anesthetic care. The review also addresses the timing of anesthesia concerning IVF procedures, the impact of obesity on IVF success rates, and the importance of emotional and psychological support for obese patients undergoing IVF. Challenges and future directions in the field are highlighted, focusing on ongoing research, emerging technologies, and the role of multidisciplinary teams in managing these complex cases. In conclusion, this review underscores the critical role of tailored anesthesia and perioperative care in optimizing outcomes for obese patients undergoing IVF. It provides valuable insights for anesthetic providers, reproductive specialists, and healthcare teams, emphasizing the need for a patient-centered approach to address the unique challenges posed by obesity in the context of assisted reproductive technology.

Obesity and In Vitro Fertilization

Obesity is a highly prevalent chronic disease with a significant effect on reproductive-age women. The clinical implications of obesity on fertility and pregnancy are well studied citing ovulatory dysfunction, hormonal imbalances, higher miscarriage rates, and increased maternal and neonatal risks. For this reason, many patients with obesity seek reproductive specialists to help build their families. Despite this literature base, the effect of weight loss interventions prior to assisted reproductive technology (ART) is lacking. This review aims to outline the impact of obesity on ART, specifically in vitro fertilization (IVF). Response differences to treatment protocols compared with normal weight counterparts, limitations of access to care, and the mixed results of weight-reduction strategies prior to fertility treatment will be addressed. The known data surrounding benefits of lifestyle modification, pharmacologic therapies, and surgical interventions for obesity prior to IVF are outlined and found to emphasize a need for further research to determine the optimal approach for infertility patients with obesity.

Benefits and Risks of Bariatric Surgery on Women's Reproductive Health: a Narrative Review

Bariatric surgery (BS) is escalating as the most efficient and endurable therapy for severe obesity. Women's reproductive health is essential to women's quality of life and is receiving increasing attention. However, despite the high prevalence of BS among women, the effect of BS on reproductive health remains underemphasis. The purpose of this narrative review is to provide an overview of BS on women's reproductive health, including their reproductive health before, during, and after pregnancy. Although limited attention has been given, current evidence highlights the substantial implications of bariatric surgery on reproductive health and reminds us of the importance of adopting decision-making conversations about reproductive health before bariatric surgery.

Fertility outcomes following bariatric surgery

Obesity impacts human health in more than one way. The influence of obesity on human reproduction and fertility has been extensively examined. Bariatric surgery (BS) has been used as an effective tool to achieve long-term weight loss in both sexes. BS improves hormonal profiling, increasing the odds of spontaneous pregnancy and success rates following assisted reproductive techniques in infertile females. For obese males, BS does improve sexual function and hormonal profile; however, conflicting reports discuss reduced sperm parameters following BS. Although the benefits of BS in the fertility field are acknowledged, many areas call for further research, like choosing the safest surgical techniques, determining the optimal timing to get pregnant, and resolving the uncertainty of sperm parameters.

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.

Worth the wait? Preconception weight reduction in women and men with obesity and infertility: a narrative review

Short and long-term weight reduction interventions are considered in the preconception period for women and men with obesity and infertility as obesity is associated with poorer reproductive outcomes. Short-term weight loss achieved with diet, exercise, and medications does not improve per cycle conception or live birth rates in women undergoing ovulation induction, intrauterine insemination, or in vitro fertilization (IVF), but may increase the rate of natural conception. Long-term weight loss achieved through surgical interventions may increase spontaneous conceptions, particularly among women with polycystic ovary syndrome, and may increase the live birth rate from IVF, though these findings are limited by recent evidence. There is a clear need for additional treatment options and well-designed weight loss intervention trials that address the heterogeneous causes of obesity among women and men with infertility and include fertility outcomes and perinatal morbidity as outcome measures.

Obesity and reproduction

PURPOSE OF REVIEW

The objective of this review is to highlight the recent literature on how obesity affects reproductive capacity in men and women.

RECENT FINDINGS

The relationship between fertility and obesity is complex and involves the hypothalamic-pituitary-ovarian axis, neuroendocrine systems and adipose tissue. The exact pathophysiology of how obesity lowers fertility rates is unknown, but is likely multifactorial involving anovulation, insulin resistance and alterations in gonadotropins. In addition, there is controversy on whether oocyte quality or endometrial receptivity plays a larger role in obese infertile women. Data on effects of bariatric surgery and weight loss on obese infertile men and women are mixed.

SUMMARY

Obesity alters the hormonal profile, gonadotropin secretion, embryo development and in-vitro fertilization outcomes in both men and women.

Outcomes of in-vitro fertilization after bariatric surgery: a national register-based case-control study

STUDY QUESTION

Does previous bariatric surgery (BS) in women affect cumulative live birth rate in IVF?

SUMMARY ANSWER

Women having had BS seem to have the same cumulative live birth rate as non-operated women of the same BMI at IVF treatment.

WHAT IS KNOWN ALREADY

Because of the perinatal risks of obesity to mother and infant as well as impaired outcomes of IVF, obese women are advised to reduce their weight, but it is not clear whether previous BS could affect IVF results.

STUDY DESIGN, SIZE, DURATION

This national register-based case–control study included all cases of BS (n = 30 436) undergoing IVF (n = 153) from 2007 until 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Swedish women between 18 and 45 years operated with BS, with at least one first started cycle of IVF after surgery, were included. For each woman having IVF after BS (n = 153), up to five non-operated control women (n = 744) starting their first IVF cycle during the study period were matched for age, parity and BMI at treatment. The primary outcome in this study was the cumulative live birth rate (CLBR) after the first IVF cycle, defined as all live births after the first cycle including fresh and frozen embryo transfers.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no significant difference in CLBR between the BS group and the matched controls (29.4% compared to 33.1%), even though the number of retrieved oocytes (7.6 vs 8.9, P = 0.005) and frozen embryos (1.0 vs 1.5, P = 0.041) were significantly fewer in the BS group. There was no association between cumulative live birth and BS, adjusted odds ratio 1.04, 95% CI (0.73, 1.51). However, the birth weight was significantly lower in the children born to mothers with previous BS, mean (SD) 3190 (690) vs 3478 (729) g, P = 0.037.

LIMITATIONS, REASONS FOR CAUTION

Confounders such as age, BMI and previous childbirth were accounted for by the matching design of the study, but there were no data on indication for IVF, anti-Müllerian hormone, smoking or previous comorbidities. The study was exploratory and did not reach sufficient power to detect potential smaller differences in live birth rates.

WIDER IMPLICATIONS OF THE FINDINGS

The findings concur with those in previously published smaller studies and provide somewhat reassuring results considering IVF outcomes after BS with a CLBR comparable to that of controls, despite a lower mean birth weight.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by grants from the Southern Health Care Region of Sweden. The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

The Impact of Bariatric Surgery on Assisted Reproductive Technology Outcomes: A Systematic Review

OBJECTIVE

There is a paucity of literature on the impact of bariatric surgery on artificial reproductive technology (ART) outcomes. This topic should be examined, given that most bariatric surgery candidates are of reproductive age and those with obesity are significantly more likely to experience poor fertility outcomes. This systematic review aimed to determine if bariatric surgery impacts ART outcomes and if effects vary between females and males.

DATA SOURCES

MEDLINE, EMBASE, SCOPUS, and the Cochrane Central Register of Controlled Trials were searched for English studies published between January 1978 and May 2021.

STUDY SELECTION

Studies with participants who had had bariatric surgery and subsequently underwent ART (i.e., in vitro fertilization or intracytoplasmic sperm injection) were eligible for inclusion. Screening, data abstraction, and risk of bias assessment were conducted independently and in duplicate.

DATA EXTRACTION AND SYNTHESIS

Of the 279 articles screened for eligibility, 25 were sought for full text review, and 7 were included for analysis. Four studies (57%) examined ART interventions in females, while 3 (43%) examined interventions in males. Data on cumulative live birth rate (CLBR) was extracted for all 7 studies (N = 169). There were 50 live births with CLBRs ranging from 0.0% to 80.0%. Changes to female secondary outcomes were varied. Data on male secondary outcomes were contradictory: 1 study indicated improved sperm parameters following bariatric surgery, while 2 showed decreased parameters, with certain participants seeing improvements after several months.

CONCLUSION

Bariatric surgery prior to ART may have an impact on CLBRs; however, high-quality research is needed to delineate the direct effects of bariatric surgery on ART outcomes. Various sex-specific outcomes should be considered prior to recommending ART after bariatric surgery. Future research should determine the optimal type of bariatric surgery and timing of ART following bariatric surgery.

Effects of Acupuncture on Endometrium and Pregnancy Outcomes in Patients with Polycystic Ovarian Syndrome Undergoing In Vitro Fertilization-Embryo Transfer: A Randomized Clinical Trial

OBJECTIVE

To observe the effect of acupuncture on endometrium and pregnancy outcomes in patients with polycystic ovary syndrome (PCOS) infertility undergoing in vitro fertilization-embryo transfer (IVF-ET).

METHODS

Eighty-three patients were randomly assigned to observation group (40 cases) and control group (43 cases) according to the random numbers generated by SPSS software. The patients of the two groups received GnRH agonist long protocol as a routine treatment. In the observation group, acupuncture was given at two acupoint groups for 30 min once every other day. Group 1 included Guanyuan (CV 4), Qihai (CV 6), Zhongji (CV 3), bilateral acupoints Zigong (EX-CA1). Group 2 included Mingmen (GV 4), Yaoyangguan (GV 3), bilateral Shenshu (BL 23) and Ciliao (BL 32). The two groups of acupoints were used alternately. The whole needling process was performed at the time of ovulation induction until the transplantation day and consisted of 3 courses, while the control group did not receive acupuncture interventions. The Gn dosage and Gn stimulation time, endometrial thickness and type (A, B, and C), serum oestradiol (E2) and progesterone (P) levels on the day of injection of human chorionic gonadotropin (hCG), clinical pregnancy rate, as well as live birth rate were observed. Adverse reactions were also be recorded. All patients were followed up for the pregnant rate 14 days after IVF-ET and live birth rate after pregnancy. All adverse reactions (AEs) of acupuncture were recorded during the trial.

RESULTS

The Gn dosage and Gn stimulation time in the observation group were lower in the observation group than in the control group (P<0.01). The proportion of type A endometrium in the observation group were higher than that in the control group (P<0.05). The serum E₂ and P levels on the day of hCG injection was lower and the clinical pregnancy rate was higher in the observation group compared to those in the control group (P<0.05). There was no serious AEs during this trial.

CONCLUSION

Acupuncture can improve the proportion of type A endometrium, regulate the levels of serum E₂ and P on the day of hCG injection, and improve the pregnancy rate in patients with PCOS infertility undergoing IVF-ET.

Body mass index is associated with miscarriage rate and perinatal outcomes in cycles with frozen-thawed single blastocyst transfer: a retrospective cohort study

Background

The association between body mass index (BMI) and IVF cycle outcomes remain inconclusive. In addition, the impact of BMI on perinatal outcomes has been less well-studied. The aim of this study was to assess the effects of BMI on pregnancy outcomes, as well as maternal and neonatal outcomes.

Methods

This was a retrospective cohort study on 10,252 frozen-thawed cycles with single blastocyst transfer between January 2016 and December 2019. Patients were divided into four groups: underweight (< 18.5 kg/m²), normal-weight (18.5–24 kg/m²), overweight (24–28 kg/m²), and obesity (≥ 28 kg/m²), according to the Chinese classification. Multivariate logistic regression and multivariate general linear model were used for statistical analysis.

Results

The rates of live birth and clinical pregnancy were comparable among groups. Miscarriage rate was higher in the obese women than that in the normal controls (27.51 vs. 20.91%, aOR = 1.453 (1.066–1.982)). Using the normal-weight women as reference, the underweight women had lower incidences of preterm birth (6.97 vs. 11.19%, aOR = 0.611 (0.422–0.884)), macrosomia (4.90 vs. 8.65%, aOR = 0.544 (0.353–0.837)) and large-for-gestational age (LGA, 11.18 vs. 16.54%, aOR = 0.643 (0.477–0.866)); the overweight women had higher prevalence of gestational diabetes (6.56 vs. 3.82%, aOR = 1.744 (1.232–2.468)), hypertension (4.42 vs. 2.32%, aOR = 1.822 (1.186–2.800)), macrosomia (12.93 vs. 8.65%, aOR = 1.596 (1.240–2.054)) and LGA (23.22 vs. 16.54%, aOR = 1.549 (1.270–1.890)); the obese women had higher incidences of preterm birth (16.87 vs. 11.19%, aOR = 1.646 (1.068–2.536)), cesarean delivery (93.98 vs. 87.91%, aOR = 2.078 (1.083–3.987)), gestational hypertension (4.82 vs. 2.32%, aOR = 2.138 (1.005–4.547)), macrosomia (14.88 vs. 8.65%, aOR = 1.880 (1.192–2.964)) and LGA (25.60 vs. 16.54%, aOR = 1.764 (1.218–2.555)).

Conclusions

BMI has no significant effect on the chance of pregnancy or live birth, but obesity increases the risk of miscarriage. Underweight is associated with better maternal and neonatal outcomes, while overweight and obesity are associated with worse maternal and neonatal outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04443-2.

The impact of bariatric surgery on assisted reproductive technology outcomes: a systematic review protocol

BACKGROUND

Individuals with obesity are at higher risk of experiencing complications during their pregnancy and may also experience infertility, requiring assisted reproductive technologies (ART) to conceive. The current body of literature demonstrates that bariatric surgery decreases an individual's risk of developing a variety of obesity-related obstetrical conditions during and after pregnancy. However, the effects of bariatric surgery on ART outcomes are not well understood. Therefore, the paucity in the literature warrants a need to determine these effects.

METHODS

We will search electronic databases, including MEDLINE, Embase, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL), as well as the gray literature and the reference lists of included articles. We will screen all studies published between January 1978 and the present day that explore the impact of bariatric surgery on ART outcomes for women and men. We will include observational studies. Two independent reviewers will assess the studies for inclusion and extract data for each article. The main outcome that will be analyzed is live birth rate. Secondary outcomes such as time to conception, number of rounds of ART, type of bariatric surgery, and length of time between bariatric surgery and initiation of ART will also be recorded. Risk of bias will be conducted using the National Institutes of Health Study Quality Assessment Tools. A random effects model will be used to account for statistical analysis and results will be pooled with forest plots. In the event of statistical and reporting heterogeneity, we will provide a qualitative synthesis and narrative review of the results.

DISCUSSION

This review will provide information on the outcomes of ART following bariatric surgery and may help healthcare professionals make informed decisions about the length of time between bariatric surgery and initiation of ART. The study findings may be of interest to various stakeholders including patients, bariatric surgeons, obstetricians, and gynecologists, and those who specialize in obesity medicine and reproductive endocrinology and infertility. We plan to disseminate our findings through presentations, publications, and social media releases to individuals who are navigating infertility and are interested in undergoing or have undergone bariatric surgery, healthcare professionals, policymakers, and researchers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021252561.

A Retrospective Evaluation of Pregnancy Outcomes Following Bariatric Surgery: A Single-Center Experience

BACKGROUND

Bariatric and metabolic surgery (BMS) is an effective treatment for obesity and its complications, but its effect on pregnancy outcomes is inconclusive. The present study aimed to investigate women's pregnancy status and outcomes as well as the impact of pregnancy intervals after BMS.

METHODS

The menstrual cycle and fertility status of women who underwent BMS in our centre between July 2010 and January 2021 were retrospectively analyzed and followed up until one-year post-delivery. The pregnancy outcomes after BMS were observed, including changes in weight, pregnancy interval, pregnancy complications, weight and health status of the newborn (premature birth, admission to neonatology, or deformity).

RESULTS

We identified 31 women who were successfully conceived after BMS. There were statistical differences in weight and menstrual status before and post-operation (P < 0.05), and 77.97% of them had remission or recovery of obesity-related comorbidities. Eighteen patients delivered successfully after BMS, but there were still 12 cases of spontaneous abortion and 1 case of induced abortion. The abortion rate in pregnancy intervals less than 2 years was higher than those ≥2 years (P = 0.045). Of the women who delivered successfully, 5 had pregnancy-specific complications, including gestational diabetes mellitus and hypertensive disorder of pregnancy. However, the growth and development of the newborn are normal since the birth follow-up.

CONCLUSION

The present results suggest that the abortion rate in pregnancy intervals less than 2 years was higher than those ≥2 years. It is recommended that postoperative patients avoid pregnancy until their weight is stable to reduce the risk of adverse pregnancy outcomes.

Obesity and oocyte quality: Significant implications for ART and Emerging mechanistic insights

The prevalence of obesity in adults worldwide, and specifically in women of reproductive age, is concerning given the risks to fertility posed by the increased risk of type 2 diabetes, metabolic syndrome and other non-communicable diseases. Obesity has a multi-systemic impact in female physiology that is characterized by the presence of oxidative stress, lipotoxicity, and the activation of pro-inflammatory pathways, inducing tissue-specific insulin resistance and ultimately conducive to abnormal ovarian function. A higher body mass is linked to Polycystic Ovary Syndrome, dysregulated menstrual cycles, anovulation, and longer time to pregnancy, even in ovulatory women. In the context of ART, compared to women of normal BMI, obese women have worse outcomes in every step of their journey, resulting in reduced success measured as live birth rate. Even after pregnancy is achieved, obese women have a higher chance of miscarriage, gestational diabetes, pregnancy complications, birth defects, and most worryingly, a higher risk of stillbirth and neonatal death. The potential for compounding effects of ART on pregnancy complications and infant morbidities in obese women has not been studied. There is still much debate in the field on whether these poorer outcomes are mainly driven by defects in oocyte quality, abnormal embryo development or an unaccommodating uterine environment, however the clinical evidence to date suggests a combination of all three are responsible. Animal models of maternal obesity shed light on the mechanisms underlaying the effects of obesity on the peri-conception environment, with recent findings pointing to lipotoxicity in the ovarian environment as a key driver of defects in oocytes that have not only reduced developmental competence but long-lasting effects in offspring health.

Association between clinical and IVF laboratory parameters and miscarriage after single euploid embryo transfers

BACKGROUND

The goal of this study was to investigate which factors, excluding embryo aneuploidies, are associated with miscarriage in patients who have undergone a single euploid blastocyst transfer.

METHODS

Retrospective, observational and multicenter study with 2832 patients undergoing preimplantational genetic testing for aneuploidies (PGT-A) due to repeated implantation failure, recurrent pregnancy loss, advanced maternal age or severe male factor were transferred one single euploid embryo.

RESULTS

One of the main findings was a significant relationship between body mass index (BMI) and miscarriage rates (13.4% in underweight women, 12.1% in normal weight, 14.5% in overweight, and 19.2% in obese women, odds ratio [OD] 1.04; 95% confidence interval [CI], 1.01-1.07 p = 0.006). Endometrial thickness (OD 0.65; 95%, 0.52-0.77 p = 0.04) and type of endometrial preparation (natural cycle or hormone replacement cycle) (OD 0.77; 95%, 0.52-0.77, p = 0.04) were also associated with miscarriage rates.

CONCLUSIONS

BMI was strongly associated to miscarriage rates. We also observed a weaker association with endometrial thickness and with the type of endometrial preparation (natural cycle or hormone replacement cycle). None of the other studied variables (biopsy day, maternal and male age, duration of infertility, cycle length, previous miscarriages, previous live births, previous In Vitro Fertilization (IVF) cycles, endometrial pattern and/or diagnosis) were associated with miscarriage rates.

Body mass index and subfertility: multivariable regression and Mendelian randomization analyses in the Norwegian Mother, Father and Child Cohort Study

STUDY QUESTION

What is the association between BMI and subfertility?

SUMMARY ANSWER

We observed a J-shaped relationship between BMI and subfertility in both sexes, when using both a standard multivariable regression and Mendelian randomization (MR) analysis.

WHAT IS KNOWN ALREADY

High BMI in both women and men is associated with subfertility in observational studies and this relationship is further substantiated by a few small randomized controlled trials of weight reduction and success of assisted reproduction. Women with low BMI also have lower conception rates with assisted reproduction technologies.

STUDY DESIGN, SIZE, DURATION

Cohort study (the Norwegian Mother, Father and Child Cohort Study), 28 341 women and 26 252 men, recruited from all over Norway between 1999 and 2008.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women (average age 30, average BMI 23.1 kg/m2) and men (average age 33, average BMI 25.5 kg/m2) had available genotype data and provided self-reported information on time-to-pregnancy and BMI. A total of 10% of couples were subfertile (time-to-pregnancy ≥12 months).

MAIN RESULTS AND THE ROLE OF CHANCE

Our findings support a J-shaped association between BMI and subfertility in both sexes using multivariable logistic regression models. Non-linear MR validated this relationship. A 1 kg/m2 greater genetically predicted BMI was linked to 18% greater odds of subfertility (95% CI 5% to 31%) in obese women (≥30.0 kg/m2) and 15% lower odds of subfertility (-24% to -2%) in women with BMI <20.0 kg/m2. A 1 kg/m2 higher genetically predicted BMI was linked to 26% greater odds of subfertility (8-48%) among obese men. Low genetically predicted BMI values were also related to greater subfertility risk in men at the lower end of the BMI distribution. A genetically predicted BMI of 23 and 25 kg/m2 was linked to the lowest subfertility risk in women and men, respectively.

LIMITATIONS, REASONS FOR CAUTION

The main limitations of our study were that we did not know whether the subfertility was driven by the women, men or both; the exclusive consideration of individuals of northern European ancestry; and the limited amount of participants with obesity or BMI values <20.0 kg/m2.

WIDER IMPLICATIONS OF THE FINDINGS

Our results support a causal effect of obesity on subfertility in women and men. Our findings also expand the current evidence by indicating that individuals with BMI values <20 kg/m2 may have an increased risk of subfertility. These results suggest that BMI values between 20 and 25 kg/m2 are optimal for a minimal risk of subfertility.

STUDY FUNDING/COMPETING INTEREST(S)

The MoBa Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Norwegian Ministry of Education and Research. This project received funding from the European Research Council under the European Union's Horizon 2020 research and innovation program (grant agreement No 947684). It was also partly supported by the Research Council of Norway through its Centres of Excellence funding scheme, project number 262700. Open Access funding was provided by the Folkehelseinstituttet/Norwegian Institute of Public Health. D.A.L. is a UK National Institute for Health Research Senior Investigator (NF-SI-0611-10196) and is supported by the US National Institutes of Health (R01 DK10324) and a European Research Council Advanced Grant (DevelopObese; 669545). The funders had no role in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication. D.A.L. receives (or has received in the last 10 years) research support from National and International government and charitable bodies, Roche Diagnostics and Medtronic for research unrelated to the current work. The rest of the authors declare that no competing interests exist.

TRIAL REGISTRATION NUMBER

N/A.

Lifestyle intervention prior to IVF does not improve embryo utilization rate and cumulative live birth rate in women with obesity: a nested cohort study

STUDY QUESTION

Does lifestyle intervention consisting of an energy-restricted diet, enhancement of physical activity and motivational counseling prior to IVF improve embryo utilization rate (EUR) and cumulative live birth rate (CLBR) in women with obesity?

SUMMARY ANSWER

A 6-month lifestyle intervention preceding IVF improved neither EUR nor CLBR in women with obesity in the first IVF treatment cycle where at least one oocyte was retrieved.

WHAT IS KNOWN ALREADY

A randomized controlled trial (RCT) evaluating the efficacy of a low caloric liquid formula diet (LCD) preceding IVF in women with obesity was unable to demonstrate an effect of LCD on embryo quality and live birth rate: in this study, only one fresh embryo transfer (ET) or, in case of freeze-all strategy, the first transfer with frozen-thawed embryos was reported. We hypothesized that any effect on embryo quality of a lifestyle intervention in women with obesity undergoing IVF treatment is better revealed by EUR and CLBR after transfer of all fresh and frozen-thawed embryos.

STUDY DESIGN, SIZE, DURATION

This is a nested cohort study within an RCT, the LIFEstyle study. The original study examined whether a 6-month lifestyle intervention prior to infertility treatment in women with obesity improved live birth rate, compared to prompt infertility treatment within 24 months after randomization. In the original study between 2009 and 2012, 577 (three women withdrew informed consent) women with obesity and infertility were assigned to a lifestyle intervention followed by infertility treatment (n = 289) or to prompt infertility treatment (n = 285).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Only participants from the LIFEstyle study who received IVF treatment were eligible for the current analysis. In total, 137 participants (n = 58 in the intervention group and n = 79 in the control group) started the first cycle. In 25 participants, the first cycle was cancelled prior to oocyte retrieval mostly due to poor response. Sixteen participants started a second or third consecutive cycle. The first cycle with successful oocyte retrieval was used for this analysis, resulting in analysis of 51 participants in the intervention group and 72 participants in the control group. Considering differences in embryo scoring methods and ET day strategy between IVF centers, we used EUR as a proxy for embryo quality. EUR was defined as the proportion of inseminated/injected oocytes per cycle that was transferred or cryopreserved as an embryo. Analysis was performed per cycle and per oocyte/embryo. CLBR was defined as the percentage of participants with at least one live birth from the first fresh and subsequent frozen-thawed ET(s). In addition, we calculated the Z-score for singleton neonatal birthweight and compared these outcomes between the two groups.

MAIN RESULTS AND THE ROLE OF CHANCE

The overall mean age was 31.6 years and the mean BMI was 35.4 ± 3.2 kg/m² in the intervention group, and 34.9 ± 2.9 kg/m² in the control group. The weight change at 6 months was in favor of the intervention group (mean difference in kg vs the control group: −3.14, 95% CI: −5.73 to −0.56). The median (Q25; Q75) number of oocytes retrieved was 4.00 (2.00; 8.00) in the intervention group versus 6.00 (4.00; 9.75) in the control group, and was not significantly different, as was the number of oocytes inseminated/injected (4.00 [2.00; 8.00] vs 6.00 [3.00; 8.75]), normal fertilized embryos (2.00 [0.50; 5.00] vs 3.00 [1.00; 5.00]) and the number of cryopreserved embryos (2.00 [1.25; 4.75] vs 2.00 [1.00; 4.00]). The median (Q25; Q75) EUR was 33.3% (12.5%; 60.0%) in the intervention group and 33.3% (16.7%; 50.0%) in the control group in the per cycle analysis (adjusted B: 2.7%, 95% CI: −8.6% to 14.0%). In the per oocyte/embryo analysis, in total, 280 oocytes were injected or inseminated in the intervention group, 113 were utilized (transferred or cryopreserved, EUR = 40.4%); in the control group, EUR was 30.8% (142/461). The lifestyle intervention did not significantly improve EUR (adjusted odds ratio [OR]: 1.36, 95% CI: 0.94–1.98) in the per oocyte/embryo analysis, taking into account the interdependency of the oocytes per participant. CLBR was not significantly different between the intervention group and the control group after adjusting for type of infertility (male factor and unexplained) and smoking (27.5% vs 22.2%, adjusted OR: 1.03, 95% CI: 0.43–2.47). Singleton neonatal birthweight and Z-score were not significantly different between the two groups.

LIMITATIONS, REASONS FOR CAUTION

This study is a nested cohort study within an RCT, and no power calculation was performed. The randomization was not stratified for indicated treatment, and although we corrected our analyses for baseline differences, there may be residual confounding. The limited absolute weight loss and the short duration of the lifestyle intervention might be insufficient to affect EUR and CLBR.

WIDER IMPLICATIONS OF THE FINDINGS

Our data do not support the hypothesis of a beneficial short-term effect of lifestyle intervention on EUR and CLBR after IVF in women with obesity, although more studies are needed as there may be a potential clinically relevant effect on EUR.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by a grant from ZonMw, the Dutch Organization for Health Research and Development (50-50110-96-518). A.H. has received an unrestricted educational grant from Ferring pharmaceuticals BV, The Netherlands. B.W.J.M. is supported by an NHMRC Investigator grant (GNT1176437). B.W.J.M. reports consultancy for Guerbet, has been a member of the ObsEva advisory board and holds Stock options for ObsEva. B.W.J.M. has received research funding from Guerbet, Ferring and Merck. F.J.M.B. reports personal fees from membership of the external advisory board for Merck Serono and a research support grant from Merck Serono, outside the submitted work.

TRIAL REGISTRATION NUMBER

The LIFEstyle RCT was registered at the Dutch trial registry (NTR 1530). https://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1530.

The threshold effect of factors associated with spontaneous abortion in human-assisted reproductive technology

We explored the independent risk factors associated with cases of spontaneous abortion in infertile patients treated with human-assisted reproductive technology (ART) and established a smooth curve fit and perform a threshold effect analysis can provide guidance and a valuable reference for predicting the probability of spontaneous abortion. This was a retrospective cohort study of 16,097 patients successfully conceived with ART in Shangqiu First People's Hospital from June 2013 to December 2018. Overall, 2,378 (14.77%) had an abortion and 13,719 (85.23%) did not have an abortion. Multivariate logistic regression analysis showed that female age (OR 1.050; 95% CI 1.032–1.069; P < 0.001), male age (OR 1.100; 95% CI 1.086–1.115; P < 0.001), follicular-stimulating hormone (OR 1.049; 95% CI 1.022–1.076; P < 0.001), anti-Mullerian hormone (OR 0.893; 95% CI 0.862–0.925; P < 0.001) and the number of fetuses at pregnancy diagnosis were independent factors associated with spontaneous abortion. The threshold effect analysis found that when female age > 32 years (cut-off point) old, age and the risk of spontaneous abortion were positively correlated. When follicular-stimulating hormone > 6.1 IU/L (cut-off point), follicular-stimulating hormone was positively correlated with the occurrence of spontaneous abortion, When anti-Mullerian hormone ≤ 3.1 ng/mL (cut-off point), anti-Mullerian hormone was negatively correlated with the occurrence of spontaneous abortion and there was a linear positive correlation between antral Follicle Counting and live birth. In addition, the older the male age, the higher the incidence of abortion. The smooth curve fit and threshold effect analyses can provide a more detailed estimate of the probability of spontaneous abortion for pregnant couples.

Obesity and IVF: weighing in on the evidence

Obesity is associated with serious health risks, and its rising prevalence represents a growing public health emergency. Ongoing research into the association of obesity and assisted reproductive technology (ART) outcomes aims to disentangle selective detrimental effects of obesity on the oocyte and the endometrium. More translational studies involving women with severe obesity and in the third-party reproduction setting will help improve the standard of care in the provision of ART services for obese patients.