The Role of Overweight and Obesity in In Vitro Fertilization Outcomes of Poor Ovarian Responders

Impact of body weight on IVF: pathophysiology, outcomes, and clinical considerations

PURPOSE OF REVIEW

This study aimed to examine if excess body weight impacts the outcomes of IVF treatment cycles.

RECENT FINDINGS

While data on the effect and/or association of excess weight on IVF outcomes continue to produce mixed results, recent studies stratifying analyses by age are yielding clarity on a detrimental potential of obesity on IVF outcomes. Specifically, IVF outcomes in the third decade of life are susceptible to adverse implications of excess weight, as reflected in lower clinical pregnancy and live birth rates. Plausible pathogenic mechanisms underlying the detrimental impact of excess weight on IVF outcomes include inflammation, DNA repair, insulin resistance, and the targets of such mechanisms that include the spectrum of players critical to reproductive success, including the oocyte, sperm, embryo, and uterine receptivity.

SUMMARY

The detrimental implications of excess weight on IVF outcomes are more pronounced by age, and inflammatory processes seem to be particularly relevant to the interplay of weight excess, adiposity, and IVF cycle outcomes.

Predicting factors of ovarian responses in infertile women with polycystic ovary syndrome undergoing IVF/ICSI

PURPOSE

Women with polycystic ovary syndrome (PCOS) show greater heterogeneity in ovarian responses during ovarian stimulation. We aimed to investigate the potential predicting factors among individualized basic parameters that affect poor or hyper ovarian responses in PCOS patients.

METHODS

We retrospectively screened 2058 women with PCOS who underwent their first cycle of in vitro fertilization/intracytoplasmic sperm injection. Spearman correlation analysis and multivariable linear regression model were applied to screen potential variables impacting the number of oocyte retrieved. Further, women with PCOS were divided into poor, sub-optimal, optimal, and hyper responders based on oocyte-retrieved numbers. Logistic regression model and receiver operating characteristic (ROC) curve were used to testify the predicting effect of screened parameters on ovarian response.

RESULTS

Multivariable linear regression showed that body mass index (BMI) and follicle-stimulating hormone (FSH) were significantly negatively correlated with oocyte numbers, while luteinizing hormone and anti-Müllerian hormone (AMH) showed a positive correlation. Logistic regression model showed that high BMI (RR: 1.141, 95% CI: 1.090, 1.195) and FSH (RR: 1.161, 95% CI: 1.043, 1.293) were risk factors for poor and sub-optimal ovarian response, but not for hyper response. High AMH level was a risk factor (RR: 1.118, 95% CI: 1.075, 1.163) for hyper ovarian response. The optimal cutoff value was BMI = 23.25 kg/cm2, FSH = 6.375 IU/L, and AMH = 9.8 ng/mL, respectively.

CONCLUSIONS

Individualized basic parameters including BMI, FSH, and AMH are crucial for predicting ovarian response of women with PCOS, providing valuable information for formulating personalized diagnosis and treatment plans.

Obesity and overweight and associated factors among women with infertility undergoing assisted reproductive technology treatment in a low income setting

Elevated Body Mass Index in infertile women has important implications for medically assisted reproduction. The prevalence and impact of elevated BMI on assisted reproductive technology treatment outcomes in low-income settings remain under-studied and little known. This study investigated the prevalence of elevated BMI and associated socio-demographic characteristics among infertile women in Ghana. Retrospective analysis of five-years data of 3,660 infertile women attending clinic in Ghana for assisted conception treatment was carried out. The data was analysed using the SPSS-22; descriptive statistics performed and chi square used to assess associations between categorical variables, p-value below 0.05 was considered statistically significant. Overall, 76.83% of women with infertility had elevated BMI, of whom 39.56% were obese and 37.27% were overweight. Majority of participants with elevated BMI was aged between 30-49 years. (p < 0.001). Infertility prevalence and BMI increased with increasing level of education (p < 0.003). Secondary infertility was more common among overweight or obese women. Traders had the highest prevalence of overweight and obesity followed by civil servants and health workers. Elevated BMI was highly prevalent among women seeking infertility care in Ghana, particularly so among those with secondary infertility. Traders had the highest prevalence of elevated BMI, probably reflecting their predominantly sedentary lifestyles.

Impact of BMI on fertility in an otherwise healthy population: a systematic review and meta-analysis

BACKGROUND

An increased body mass index (BMI) can lead to subfertility; however, current literature fails to exclude the effect of other confounding medical conditions, raising questions regarding the direct link between increased BMI and fertility outcomes.

OBJECTIVES

To conduct a systematic review and meta-analysis to elucidate the effects of increased BMI on fertility outcomes in females with no other comorbidities.

SEARCH STRATEGY

A comprehensive search was conducted using EMBASE, MEDLINE and the Cochrane library from January 2000 until July 2023.

DATA COLLECTION AND ANALYSIS

Two authors independently conducted data extraction and assessed study quality. Odds ratio (OR) (dichotomous data), standardised mean difference (SMD) (continuous data) and 95% CIs were calculated.

MAIN RESULTS

Nine eligible studies were identified: one natural conception and eight assisted reproductive technology (ART). Aggregated data revealed women with BMI ≥25 were less likely to attain clinical pregnancy (OR 0.76, 95% CIs 0.62 to 0.93, p=0.007), with BMI ≥30 associated with a further decreased likelihood of clinical pregnancy (OR 0.61, 95% CIs 0.39 to 0.98, p=0.04). Women with raised BMI required longer duration of stimulation (SMD=0.08, 95% CIs 0.00 to 0.16, p=0.04) and obtained reduced oocytes (SMD=-0.11, 95% CIs -0.18 to -0.04, p=0.002).

CONCLUSIONS

These data demonstrate an adverse impact of being overweight/obese on ART outcomes in women with no other diagnosed medical comorbidities and highlight the distinct lack of data concerning the effects of isolated obesity on natural conception. Infertility represents an enormous burden for couples and society; it is essential to identify and tackle modifiable risk factors to improve chances of conception.

PROSPERO REGISTRATION NUMBER

CRD42022293631.

Gene expression and demographic analyses in women with the poor ovarian response: a computational approach

PURPOSE

Poor response to ovarian stimulation (POR) typically is reflected as decreased follicular response and low estradiol (E2) levels following ovarian stimulation by FSH/HMG. Many genes are involved in oocyte maturation, and demographic features and lifestyle can affect the oocyte maturity and developmental competence. The present study was conducted to investigate the magnitude of gene expression and lifestyle habits in POR women as compared to healthy women, using different statistical and computational methods.

METHODS

Fifty women in the two groups were studied. The study groups included POR women (n = 25) with 1-9 released oocytes, and the control group (normal women, n = 25) with 9-15 released oocytes. Quantitative PCR was used to estimate the expression of FIGLA, ZAR1, WNT4, LHX8, APC, H1FOO, MOS, and DMC1 genes in granulosa cells.

RESULTS

The results showed no significant difference in the magnitude of the studied genes' expression and linear discriminant analysis did not differentiate the studied groups based on all the genes together. Redundancy analysis (RDA) and latent factor mixed model (LFMM) results produce no significant association between the genes' expression magnitude and the geographical variables of the patients' local habitat. Linear discriminant analysis (LDA) of the demographic features differentiated the two groups of women.

CONCLUSION

Our results indicate that demographic features may have an effect on sample gene expression levels.

Maternal obesity: A potential disruptor of female fertility and current interventions to reduce associated risks

Currently, obesity has achieved epidemic levels in reproductive-aged women with a myriad of consequences. Obesity is susceptible to several reproductive complications that eventually affect fertility rates. These complications originate from the deteriorated quality of oocytes from mothers with obesity, which increases the probability of chromosomal aneuploidy, elevated reactive oxygen species production, compromised embryonic developmental competency, and eventually reduced fertility. Maternal obesity is linked to pregnancy complications such as implantation error, abortion, miscarriage, and early pregnancy loss. This review highlights the adverse effects of maternal obesity on female fertility, with a focus on the mechanistic link between maternal obesity and oocyte quality and discusses possible measures to reduce its associated risks.

Association between obesity and fecundity in patients undergoing intrauterine insemination

Objective

To determine if an association exists between body mass index (BMI) and fecundity after intrauterine insemination (IUI).

Design

Retrospective cohort study.

Setting

Academic-based fertility clinic.

Patients

Patients undergoing IUI July 2007 to May 2012.

Interventions

None.

Main Outcome Measures

Primary outcome: live-birth rate (LBR) per IUI cycle; secondary outcomes: positive pregnancy test and clinical pregnancy rates (CPRs).

Results

A total of 1959 cycles were performed on 661 women (mean age, 31.9 ± 4.9 years). When examined by obesity class, LBR and CPR were similar for women with class I, II, and III obesity when compared with women with normal BMI. However, class III obese women (adjusted risk ratio [aRR], 1.70; 95% confidence interval [CI], 1.12-2.59) had increased pregnancy rates compared with normal BMI, but no differences in pregnancy rates were observed for women with class I or II obesity. In addition, pregnancy rates (aRR, 1.50; 95% CI, 1.12-2.02) and CPR (aRR, 1.51; 95% CI, 1.07-2.14) were higher in overweight women relative to normal BMI. Notably, among patients with ovulatory dysfunction, CPRs after IUI were reduced by 43% in obese women (aRR, 0.57; 95% CI, 0.37-1.07), whereas women without ovulatory dysfunction were twice as likely to achieve a clinical pregnancy when they were obese (aRR, 1.96; 95% CI, 1.19-3.24). The CIs for the obesity risk ratios in each stratum of ovulatory function exhibited no overlap, suggesting evidence of potential effect modification by ovulatory function.

Conclusions

LBRs after IUI were similar across BMI subgroups. This is in contrast to research of in vitro fertilization treatments showing lower LBR with increasing BMI. However, obesity may adversely affect IUI CPR in those with ovulatory dysfunction in particular. The reason for this discrepancy is unclear and warrants further study.

Association of HOMA-IR with Ovarian Sensitivity Index in Women Undergoing IVF/ICSI: A Retrospective Cohort Study

BACKGROUND

Insulin resistance (IR) may adversely impact the in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) outcomes. However, the association of IR with ovarian sensitivity during controlled ovarian hyperstimulation (COH) remains controversial.

PURPOSE

We aimed to explore the association between homeostasis model assessment of insulin resistance (HOMA-IR) and ovarian sensitivity index (OSI).

PATIENTS AND METHODS

In this retrospective cohort study, 7836 patients aged between 20 and 39 years with good ovarian reserve were included consecutively between June 2018 and May 2022. HOMA-IR was calculated to evaluate the degree of IR and OSI was used to measure ovarian sensitivity. Owing to skewed distribution, HOMA-IR and OSI were log e transformed to Ln HOMA-IR and Ln OSI. Smoothing splines were generated by generalized additive models to explore the correlation between Ln HOMA-IR and Ln OSI. Then, the relationship between Ln HOMA-IR and Ln OSI was tested with multivariable linear regression model after adjustments for the potential confounders.

RESULTS

We observed negative association between Ln HOMA-IR and Ln OSI after adjustment for potential confounders by using smoothing spline fitting curves in generalized additive model. In the multivariable linear regression model, after full adjustments, each one unit increase in Ln HOMA-IR was related to reduced Ln OSI values (β = -0.12, 95% CI, -0.15, -0.09). As sensitivity analysis, those who had HOMA-IR of quartile 3 (HOMA-IR 2.33-3.43) and quartile 4 (HOMA-IR ≥3.43) had decreases in Ln OSI values (β = -0.07, 95% CI -0.11, -0.03 and β = -0.18, 95% CI -0.22, -0.13, respectively) when compared with patients in the quartile 1 (HOMA-IR <1.63). Furthermore, stratified and interaction analysis showed a strong inverse association of Ln HOMA-IR with Ln OSI in subgroups of PCOS patients and overweight/obese populations (P-value for interaction <0.0001).

CONCLUSION

HOMA-IR value was negatively associated with the ovarian sensitivity assessed by OSI. Among the PCOS and overweight/obese populations, this inverse relationship may be strong. These findings will increase the understanding of the contribution of IR to the development of decreased ovarian sensitivity within the assisted reproductive technology (ART) setting. It may have implications for optimizing gonadotropin dose manipulation in patients with IR undergoing IVF/ICSI.

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.

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.

Do Follicles of Obese Patients Yield Competent Oocytes/Embryos?

AIM

This study evaluated the competency of oocytes/embryos derived from follicles >15 mm in diameter from obese patients, compared with nonobese patients.

PATIENTS AND METHODS

A cohort study was conducted in a single tertiary medical center between July 2018 and May 2019. Before ultrasound-guided follicular aspiration, follicles were measured and those with maximal dimensional size >15 mm were tracked. Microscopic examination of the follicular aspirates was performed by an embryologist. Each follicle aspirated was evaluated for oocyte maturation, oocyte fertilization, and embryo quality.

RESULTS

457 follicles were measured: 380 (83.2%) in nonobese and 77 (16.8%) in obese patients. No in-between group differences were observed in the causes of infertility, patients' demographics, or ovarian stimulation characteristics. Oocytes were achieved during aspiration from 277 (72.8%) and 54 (70.0%) of the nonobese and obese groups, respectively (p = 0.67). No in-between group differences were observed in fertilization (2PN/oocyte), top quality embryo (TQE) per zygote (2PN), and TQE per follicle.

CONCLUSION

Oocyte recovery rate from follicles >15 mm is unrelated to patients' BMI. Moreover, the oocytes recovered from obese patients are competent yielding comparable zygote and TQE per follicle/oocyte, compared with nonobese patients. Further investigation is required to strengthen this finding.

Palmitic acid induces ceramide accumulation, mitochondrial protein hyperacetylation, and mitochondrial dysfunction in porcine oocytes

Low oocyte quality is a possible causal factor of obesity-induced infertility. High palmitic acid (PA) concentration in follicular fluid is a crucial feature noted in obese women. This study examined how high PA concentration reduced mitochondrial quality in oocytes and investigated a possible countermeasure against mitochondrial dysfunction. Cumulus cell-oocyte complexes were obtained from the ovaries of gilts, and incubated in medium containing PA (0.5 mM) or vehicle (BSA) for 44 h. Culturing oocytes at high PA concentration induced mitochondrial dysfunction determined by high reactive oxygen species and low ATP content in oocytes. Furthermore, high PA levels increased mitochondrial acetylation levels determined by a high degree of co-localization of TOMM20 and acetylated-lysine. In addition, high PA levels reduced the expression of Sirtuin 3 (SIRT3) and phosphorylated AMP-activated protein kinase (AMPK), while the AMPK activator, AICAR, restored mitochondrial function as well as oocyte ability and reduced the acetylation of mitochondrial protein. Supplementation of culture medium with dorsomorphin dihydrochloride (an AMPK inhibitor) reduced mitochondrial function and increased mitochondrial protein acetylation. Treatment of oocytes with LB100 (an inhibitor of AMPK dephosphorylation) reduced mitochondrial acetylation levels and restored mitochondrial function. Furthermore, high PA levels increased ceramide accumulation in oocytes, and addition of ceramide to the culture medium also induced mitochondrial dysfunction and increased mitochondrial acetylation. This detrimental effect of ceramide was diminished by AICAR treatment of oocytes. Our results indicated that PA induces ceramide accumulation and downregulates the AMPK/SIRT3 pathway causing mitochondrial protein hyperacetylation and dysfunction in oocytes.

Effect of body mass index on the outcome of IVF cycles among patients with poor ovarian response

OBJECTIVE

To assess the effects of body mass index (BMI) on the outcome of IVF cycles among poor responders.

METHODS

A prospective cohort study in Egypt enrolled 185 poor responders who underwent intracytoplasmic sperm injection via an antagonist protocol between 2012 and 2017. Participants were classified into three groups by BMI (calculated as weight in kilograms divided by the square of height in meters): 18.5-24.9 (normal, n=48); 25-29.9 (overweight, n=54); 30 or higher (obese, n=83). Outcomes were clinical pregnancy rate, implantation rate, chemical pregnancy rate, gonadotropin dose, number of oocytes and embryos, and cancellation rate.

RESULTS

There was no significant difference among the three groups in gonadotropin dose; duration of stimulation; endometrial thickness on trigger day; number of oocytes retrieved, injected, or fertilized; number of embryos, transferred embryos, or frozen embryos; or day of embryo transfer. Frequency of implantation (11/81 [14%] vs 6/96 [6%] or 5/155 [3%]), chemical pregnancy (20 [42%] vs 14 [30%] or 12 [14%]) and clinical pregnancy (15 [31%] vs 12 [22%] and 9 [11%]) was significantly higher for normal than for overweight or obese women, respectively.

CONCLUSION

Implantation, chemical pregnancy, and clinical pregnancy rates were inversely related to increasing BMI. CLINICALTRIALS.GOV: NCT03457233.

Should high BMI be a reason for IVF treatment denial?

Our aim was to examine the influence of BMI on the live-birth rate following IVF/ICSI and evaluate its specific contribution among other factors thus enabling accurate reproductive policy development. All patients that underwent IVF/ICSI at our center during January 2012-July 2015 were included in this retrospective study. A total of 1654 ICSI cycles were divided into four groups according to the patient's BMI (kg/m²): group I (normal weight): <25 (943 cycles); group II (overweight): 25-30 (403 cycles); group III (obese): 30-35 (212 cycles); group IV (morbid obesity): >35 (96 cycles). Comparing the four groups of BMI, mean age and number of previous ART cycles was significantly lower in group I compared to groups II, III and IV. Length of treatment was significantly shorter in group I compared to groups II, III and IV. Ovarian response to COH was comparable in terms of mean estradiol and progesterone levels on the day of hCG administration mean number of oocytes retrieved, fertilized and number of embryos transferred. Endometrial thickness was significantly lower in group IV. Outcome measures, such as implantation rate, clinical pregnancy rate (CPR) per cycle and per ET, as well as live-birth rates did not differ significantly between the groups, although in group IV LBR per cycle and per ET was lower. Multivariate logistic regression stepwise analysis found a significant correlation between age and BMI but did not find correlation between BMI and clinical pregnancy (p = 0.436) or LB (p = 0.206). The results of our relatively large retrospective study did not demonstrate a significant impact of BMI on the ART cycle outcome. Therefore, BMI should not be a basis for IVF treatment denial.

Effect of body mass index on the outcomes of controlled ovarian hyperstimulation in Chinese women with polycystic ovary syndrome: a multicenter, prospective, observational study

PURPOSE

The purpose of the present study is to explore the influence of body mass index (BMI) on outcomes of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) techniques in Chinese women with polycystic ovary syndrome (PCOS).

METHODS

This was a multicenter, prospective, observational study that enrolled 800 subjects with PCOS from nine hospitals in China. Patients were categorized according to BMI categories: underweight, <18.5 kg/m²; normal, 19-23.9 kg/m²; overweight, 24-27.9 kg/m²; and obese, ≥28 kg/m². Total recombinant follicle-stimulating hormone (rFSH) dose used, estradiol, and progesterone levels on human chorionic gonadotropin (hCG) day; implantation rate; and biochemical, clinical, and ongoing pregnancy rates were compared among BMI categories. Hormone levels (estradiol, follicle-stimulating hormone (FSH), LH, testosterone, and progesterone) were measured using electrochemiluminescence assays.

RESULTS

Among the 774 subjects, 27.3 % were overweight and 8.1 % were obese. The rFSH dose used differed significantly among BMI categories (P < 0.001). The implantation rate was lower in obese subjects than that in normal-weight subjects (25.3 vs 45.7 %). Clinical pregnancy rate per transfer differed among BMI categories (P = 0.033), but there was no difference for biochemical (P = 0.327) and ongoing (P = 0.084) pregnancy rates. The miscarriage rate was similar among BMI categories.

CONCLUSIONS

More than one third of Chinese women with PCOS undergoing IVF/ICSI are overweight or obese. Elevated BMI is associated with reduced clinical pregnancy rate but similar ongoing pregnancy rates, suggesting that BMI has little impact on IVF outcomes.