Body mass index restrictions in fertility treatment: a national survey of OB/GYN subspecialists

Addressing weight bias in reproductive medicine: a call to revisit body mass index restrictions for in vitro fertilization treatment

The prevalence of obesity has doubled among reproductive-age adults in the US over the past 40 years and is projected to impact half of the population by 2030. Obesity is associated with a twofold to threefold increase in infertility, largely because of anovulation, and is associated with a lower rate of pregnancy with ovulation induction among anovulatory women. As a result of these trends and associations, in vitro fertilization (IVF) care will need to be adapted to provide safe, effective, and equitable access for patients with obesity. Research over the past 10 years has demonstrated safe sedation practices and effective procedure modifications for oocyte retrievals and embryo transfers in patients with obesity undergoing IVF treatment. We encourage IVF medical directors to revisit body mass index restrictions for IVF treatment in favor of individualized patient risk assessments to minimize weight bias and provide timely access to safe and effective IVF care for patients with obesity and infertility.

The impact of obesity on reproductive health and metabolism in reproductive-age females

Obesity is a highly prevalent chronic disease that impacts >40% of reproductive-aged females. The pathophysiology of obesity is complex and can be understood simply as a chronic energy imbalance whereby caloric intake exceeds caloric expenditure with an energy surplus stored in adipose tissue. Obesity may be categorized into degrees of severity as well as different phenotypes on the basis of metabolic health and underlying pathophysiology. Obesity and excess adiposity have a significant impact on fertility and reproductive health, with direct effects on the hypothalamic-pituitary-ovarian axis, the ovary and oocyte, and the endometrium. There are significant adverse pregnancy outcomes related to obesity, and excess weight gain before, during, and after pregnancy that can alter the lifelong risk for metabolically unhealthy obesity. Given the high prevalence and pervasive impact of obesity on reproductive health, there is a need for better and individualized care for reproductive-aged females that considers obesity phenotype, underlying pathophysiology, and effective and sustainable interventions to treat obesity and manage weight gain before, during, and after pregnancy.

Systematic review and meta-analysis of pregnancy outcomes in women with polycystic ovary syndrome

Screening for polycystic ovary syndrome (PCOS) in antenatal care is inadequate, largely owing to the lack of clarity around whether PCOS is an independent risk factor for pregnancy complications. This systematic review and meta-analysis include 104 studies and 106,690 pregnancies in women with and without PCOS from inception until 13th July 2022. We report that women with PCOS are younger and have higher body mass index (BMI) around conception and have greater gestational weight gain. The odds of miscarriage, gestational diabetes mellitus, gestational hypertension, pre-eclampsia and cesarean section are higher in women with PCOS. The increased odds of adverse outcomes in PCOS remain significant when age and BMI are matched and when analyses are restricted to high-quality studies. This work informed the recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome, emphasizing that PCOS status should be captured in all women who are planning to, or have recently become pregnant to facilitate prevention of adverse outcomes and improve pregnancy outcomes.

Mild obesity does not affect perinatal outcome in gestational carrier cycles

STUDY QUESTION

Does BMI of gestational carriers (GCs) affect perinatal outcomes after embryo transfer?

SUMMARY ANSWER

Overweight and class I obesity in GCs does not affect the rate of good perinatal outcomes.

WHAT IS KNOWN ALREADY

The use of GCs is increasing, but uniform guidance regarding optimal BMI for GCs is lacking. Women with obesity who conceive without fertility treatment or through autologous or donor in vitro fertilization are at higher risk of adverse maternal and fetal outcomes, but data on obesity in GCs are very limited.

STUDY DESIGN, SIZE, DURATION

We performed a retrospective cohort study of 1121 GC cycles from January 2015 to December 2020 at US Fertility, the largest national partnership of fertility practices in the USA.

PARTICIPANTS/MATERIALS, SETTING, AND METHODS

All GC cycles performed at a large network of fertility practices were reviewed. Same-sex partners undergoing co-IVF were excluded. The primary outcome was good perinatal outcome from the first embryo transfer, defined as a singleton live birth at ≥37 weeks of gestation with birth weight between 2500 and 4000 g. Secondary outcome measures included frequencies of live birth, clinical pregnancy, miscarriage, full-term birth, low birth weight, large for gestational age, and cesarean delivery. A generalized linear model (log-binomial) was used for each to compare outcomes across BMI groups using normal BMI (20-24.9 kg/m2) as the reference group. Risk ratios and 95% CIs were estimated for each category group relative to normal BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified 1121 cycles in which GCs underwent first embryo transfer, of which 263 (23.5%) were in GCs with BMI >30. Demographics and reproductive history for GCs did not differ by BMI groups. The age of intended parents, use of frozen eggs, and fresh embryo transfers were higher with increasing BMI group. There were no statistically significant associations between BMI and good perinatal outcomes, live birth, clinical pregnancy, biochemical, spontaneous abortion, or low birth weight. However, among live births, higher BMI was significantly associated with birth by cesarean (P = 0.015) and large for gestational age infants (P = 0.023).

LIMITATIONS, REASONS FOR CAUTION

This was a retrospective study, and there may be unmeasured confounders. The number of patients with BMI <20 or ≥35 was small, limiting the power for these groups. We were not able to assess all maternal and fetal outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

In this study, we did not identify any significant impact of BMI on the chances of having a good perinatal outcome. Prior research studies have been inconsistent and this is the largest study to date.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was received for this work. The authors do not have any conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

The Challenge of Weight Stigma for Women in the Preconception Period: Workshop Recommendations for Action from the 5th European Conference on Preconception Health and Care

Weight stigma is a well-recognised public health issue affecting many members of society including women during the preconception period. The impacts of preconception weight stigma on women are significant and may result in decreased access to and uptake of healthcare, and mental health concerns. The consequences of this weight stigma may translate to negative maternal outcomes and even intergenerational effects on the child. Eliminating weight stigma is therefore imperative. The aim of this paper is to report recommendations to reduce weight stigma for preconception women produced at a workshop with clinical and academic experts on preconception health and weight stigma at the 5th European Conference on Preconception Health and Care. The recommendations are related to two key areas: general societal recommendations prompting all people to acknowledge and adjust our attitudes towards larger-bodied people; and healthcare-specific recommendations imploring clinicians to upskill themselves to reduce weight stigma in practice. We therefore call for urgent approaches to address societal weight-stigmatising attitudes and norms related to both the general population and preconception women, while providing professional development opportunities for healthcare professionals relating to weight stigma. Eliminating weight stigma for preconception women may have positive impacts on the outcomes for mothers and children during pregnancy and beyond.

Patient perceptions of body mass index restrictions limiting fertility care for women with high body mass index

RESEARCH QUESTION

What is the patient experience of women with high body mass index (BMI) with BMI restrictions that limit fertility care?

DESIGN

Qualitative study using in-depth, semi-structured interview methodology. Interview transcripts were analysed for iterative themes in accordance with principles of grounded theory.

RESULTS

Forty women with a BMI of 35 kg/m2 or higher with scheduled or completed appointment at the Reproductive Endocrinology and Infertility (REI) clinic completed an interview. Most participants experienced BMI restrictions as unjust. Many perceived that BMI restrictions on fertility care may be medically justified and were in support of weight loss discussions to improve chances of pregnancy; however, several argued that they should have autonomy to commence treatment following an individualized risk assessment. Participants offered recommendations to improve discussion of BMI restrictions and weight loss, including framing the conversation as supportive of their reproductive goals and offering proactive referral to weight loss support to prevent the perception that BMI is a categorical exclusion to future fertility care.

CONCLUSIONS

Participant experiences highlight a need for enhanced strategies for communicating BMI restrictions and weight loss recommendations in ways that are perceived to be supportive of patients' fertility goals without further contributing to weight bias and stigma experienced in medical settings. Opportunities for training to mitigate experiences of weight stigma may be beneficial for clinical and non-clinical staff. Evaluation of BMI policies should be undertaken within the context of clinic policies that permit or prohibit fertility care for other high-risk groups.

Reproductive Surgery in Females with Obesity: Reproductive Consequences of Obesity and Applications for Surgical Care

Obesity is the most common medical problem in women of reproductive age. The surgical applications for this population, many of who are interested in current or future fertility, are critical to safe and effective evaluation and management of issues that impact the reproductive system. As rates of obesity continue to rise worldwide, it is projected that one in two individuals will have obesity by 2030 leading to increasing numbers of individuals affected by a disease process that has implications for their gynecologic surgical care, fertility-related assessment, and infertility treatment. Offering patients with obesity access to safe reproductive surgery is a cornerstone of reproductive autonomy. This review will summarize current recommendations regarding surgical concepts for the operating room, office hysteroscopy, oocyte retrieval, and embryo transfer in female patients with obesity.

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.

Elevated body mass index in modified natural cycle frozen euploid embryo transfers is not associated with live birth rate

PURPOSE

To assess the impact of elevated BMI on the success of modified natural cycle frozen embryo transfers (mNC-FET) of euploid embryos.

METHODS

This retrospective cohort study at a single academic institution reviewed mNC-FET involving single euploid blastocysts from 2016 to 2020. Comparison groups were divided by pre-pregnancy BMI (kg/m2) category: normal weight (18.5-24.9), overweight (25-29.9) or obese (≥ 30). Underweight BMI (< 18.5) was excluded from the analysis. The primary outcome was live birth rate (LBR) and secondary outcome was clinical pregnancy rate (CPR), defined as presence of fetal cardiac activity on ultrasound. Absolute standardized differences (ASD) were calculated to compare descriptive variables and p-values and multivariable logistic regressions with generalized estimating equations (GEE) were used to compare pregnancy outcomes.

RESULTS

562 mNC-FET cycles were completed in 425 patients over the study period. Overall, there were 316 transfers performed in normal weight patients, 165 in overweight patients, and 81 in obese weight patients. There was no statistically significant difference in LBR across all BMI categories (55.4% normal weight, 61.2% overweight, and 64.2% obese). There was also no difference for the secondary outcome, CPR, across all categories (58.5%, 65.5%, and 66.7%, respectively). This was confirmed in GEE analysis when adjusting for confounders.

CONCLUSION

While increased weight has commonly been implicated in poor pregnancy outcomes, the effect of BMI on the success of mNC-FET remains debated. Across five years of data from a single institution using euploid embryos in mNC-FET cycles, elevated BMI was not associated with reduced LBR or CPR.

Effects of preconception weight loss after lifestyle intervention on fertility outcomes and pregnancy complications

It is well documented that obesity decreases natural fertility among men and women as well as pregnancy chances after conventional infertility and assisted reproductive technology (ART)-based treatments. Moreover, pregnancy complications are increased in women with overweight and obesity. General guidelines on the treatment of obesity recommend lifestyle intervention, including diet and exercise as the first-line treatment, coupled with or without medical treatments, such as weight loss medication or bariatric surgery, to reduce complications of obesity in adults. In the context of infertility in various countries and infertility clinics, there is a body mass index limit for public refund of infertility treatment of women with obesity. In this respect, it is important to investigate the evidence of effects of lifestyle intervention preceding infertility treatment on reproductive outcomes. The combined results of 15 randomized controlled trials (RCTs) of the effectiveness of preconception lifestyle intervention on reproductive outcomes documented in the latest systemic review and meta-analysis, together with the most recent RCT performed in 2022 are discussed. The current evidence suggests that greater weight loss and increase in clinical pregnancy, live birth, and natural conception rates after lifestyle intervention compared with no intervention were observed, but it seems no beneficial effect of lifestyle intervention preceding ART was observed on these parameters. With respect to potential harm of lifestyle intervention, there is no significant increased risk of early pregnancy loss, although the most recent RCT (not included in the systematic review and meta-analysis) showed a trend toward an increased risk. Complications during pregnancy, such as early pregnancy loss and maternal as well as fetal and neonatal complications, are underreported in most studies and need further analysis in an individual participant data meta-analysis. Limitations of the studies as well as future perspectives and challenges in this field of research will be highlighted.

Body Size, Fertility, and Reproductive Justice: Examining the Complex Interplay between BMI, Reproductive Health, and Access to Care

The relationship between obesity and reproduction is highly complex. While there are clear obstetrical and fertility risks associated with elevated BMI, it is less clear how weight loss impacts these outcomes. Increasingly, patients considered obese according to BMI are being denied access to fertility care, thus leaving them without treatment options for their disease (infertility). Notably, BMI cutoffs disproportionately affect historically marginalized populations in the United States and people of lower socioeconomic status (SES). This paper uses a reproductive justice framework to discuss access to reproductive healthcare based on BMI. In doing so, we connect obesity to larger systems of structural inequalities. We conclude that rather than strict BMI cutoffs, a more holistically patient-centered approach is appropriate taking into account the overall health of the individual, available scientific data, clinical capabilities, and the patient’s value system. This will ultimately make reproductive medicine more accessible to all patients.

Obesity and reproduction: a committee opinion

The purpose of this American Society for Reproductive Medicine Practice Committee report is to provide clinicians with principles and strategies for the evaluation and treatment of couples with infertility associated with obesity. This revised document replaces the Practice Committee document titled "Obesity and reproduction: an educational bulletin" last published in 2015 (Fertil Steril 2015;104:1116-26).