Does body mass index impact assisted reproductive technology treatment outcomes in gestational carriers

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.

Association with pre-pregnancy BMI on early pregnancy loss in infertility patients in first HRT-FET cycles: A retrospective cohort study

OBJECTIVE

To investigate the association between pre-pregnancy body mass index (BMI) and the early pregnancy loss rate in patients in first hormone replacement therapy-frozen-thawed embryo transfer (HRT-FET) cycles and find the threshold.

METHODS

A retrospective cohort study was conducted using a total of 14030 HRT-FET cycles at the Reproductive Center from January 2017 to December 2021. The association of pre-pregnancy BMI on early pregnancy loss rate in patients in HRT-FET cycles was assessed by performing univariate analysis, multivariable logistic regression, curve fitting and threshold effect analysis.

RESULTS

There were 2076 cycles of early pregnancy loss, and the pregnancy loss rate was 14.80%. After adjusting for confounding factors, the early pregnancy loss rate of the obese group was significantly higher than that of the normal weight group (P < 0.05). The threshold effect analysis showed that as the pre-pregnancy BMI ranged from 21.2 to 25.8 kg/m2, the early pregnancy loss rate came to the plateau phase at the low level. In addition, when the BMI was ≥ 25.8 kg/m2, the early pregnancy loss rate increased by 3% (aOR = 1.03, P = 0.01) with each 1 kg/m2 increment of BMI.

CONCLUSION

The early pregnancy loss rate might achieve a low level when the pre-pregnancy BMI was within the range of 21.2- 25.8 kg/m2. The early pregnancy loss rate would increase when pre-pregnancy BMI is more than 25.8 kg/m2. For patients in HRT-FET cycles, adjusting their pre-pregnancy BMI to the optimal level by following a healthy diet and daily exercise may help to reduce the early pregnancy loss.

Polymorphic Variants of Genes Encoding Angiogenesis-Related Factors in Infertile Women with Recurrent Implantation Failure

Recurrent implantation failure (RIF) is a global health issue affecting a significant number of infertile women who undergo in vitro fertilization (IVF) cycles. Extensive vasculogenesis and angiogenesis occur in both maternal and fetal placental tissues, and vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) family molecules and their receptors are potent angiogenic mediators in the placenta. Five single nucleotide polymorphisms (SNPs) in the genes encoding angiogenesis-related factors were selected and genotyped in 247 women who had undergone the ART procedure and 120 healthy controls. Genotyping was conducted by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). A variant of the kinase insertion domain receptor (KDR) gene (rs2071559) was associated with an increased risk of infertility after adjusting for age and BMI (OR = 0.64; 95% CI: 0.45-0.91, p = 0.013 in a log-additive model). Vascular endothelial growth factor A (VEGFA) rs699947 was associated with an increased risk of recurrent implantation failures under a dominant (OR = 2.34; 95% CI: 1.11-4.94, p_adj. = 0.022) and a log-additive model (OR = 0.65; 95% CI 0.43-0.99, p_adj. = 0.038). Variants of the KDR gene (rs1870377, rs2071559) in the whole group were in linkage equilibrium (D' = 0.25, r² = 0.025). Gene-gene interaction analysis showed the strongest interactions between the KDR gene SNPs rs2071559-rs1870377 (p = 0.004) and KDR rs1870377-VEGFA rs699947 (p = 0.030). Our study revealed that the KDR gene rs2071559 variant may be associated with infertility and rs699947 VEGFA with an increased risk of recurrent implantation failures in infertile ART treated Polish women.

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.

Risk Factors of Pregnancy Failure in Infertile Patients Undergoing Assisted Reproductive Technology

Background

Infertile couples need to use assisted reproductive technology (ART) to give birth. However, pregnancy failure after ART is not uncommon. At present, the results of studies on the causes of pregnancy failure after ART are inconsistent.

Methods

A retrospective cohort study involving 715 embryo transfer cycles was conducted at the Reproductive Medicine Center of Meizhou People's Hospital, from December 2015 to June 2022. According to the pregnancy, they were divided into clinical pregnancy group and pregnancy failure group. The relationship between demographic characteristics and pregnancy status between the two groups was analyzed.

Results

The pregnancy failure rate after ART was 49.7% (355/715). There were statistically significant distribution differences of maternal age, paternal age, COH protocols, and number of embryos transferred between clinical pregnancy and pregnancy failure groups (all P<0.01). Multiple logistic regression analysis shows that high maternal age (>35 years old vs ≤35 years old: OR 2.173, 95% CI: 1.386-3.407, P=0.001), and GnRH-a short protocol (GnRH-a short protocol vs GnRH-a long protocol: OR 2.139, 95% CI: 1.127-4.058, P=0.020) may increase risk of pregnancy failure in ART pregnancies, while two embryos transferred (two embryos transferred vs one embryo transferred: OR 0.563, 95% CI: 0.377-0.839, P=0.005) may reduce risk of pregnancy failure. In addition, high maternal age, GnRH antagonist protocol, and GnRH-a short protocol may increase risk of implantation failure, while two embryos transferred may reduce risk of implantation failure. And high maternal age may increase risk of biochemical pregnancy.

Conclusion

The risk of pregnancy failure increased in ART cycles with maternal age >35 years old and GnRH-a short protocol, while reduced with two embryos transferred.

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.