High-quality embryos retain their implantation capability in overweight women

Synergistic effect between pre-pregnancy smoking and assisted reproductive technology on gestational diabetes mellitus in twin pregnancies

AIM

Women with twin pregnancies have an increased risk of gestational diabetes mellitus (GDM). Assisted reproductive technology (ART) and pre-pregnancy smoking were both associated with GDM. However, the relationships between pre-pregnancy smoking and ART and GDM in twin pregnancies were unclear. Herein, this study aims to explore the roles of pre-pregnancy smoking and ART in GDM among women with twin pregnancies.

METHODS

Data of women with twin pregnancies were extracted from the National Vital Statistics System (NVSS) database in 2016-2020 in this retrospective cohort study. Univariate and multivariate logistic regression analyses were used to explore the associations between pre-pregnancy smoking and ART and GDM in women with twin pregnancies. The evaluation index was odds ratios (ORs) with 95% confidence intervals (CIs). Subgroup analysis of age and BMI was also performed.

RESULTS

A total of 19,860 (9.15%) women had GDM in our study. After adjusting for covariates, we found that receiving ART was associated with high odds of GDM [OR = 1.41, 95% CI (1.34-1.48)], while pre-pregnancy smoking combined with ART was associated with higher odds of GDM [OR = 1.66, 95% CI (1.14-2.42)]. In addition, these relationships were also found in women who aged ≥ 35 years old [OR = 1.98, 95% CI (1.14-3.44)] and with BMI ≥ 25 kg/m2 [OR = 1.69, 95% CI (1.11-2.55)].

CONCLUSION

Pre-pregnancy smoking may further increase the risk of GDM from ART in women with twin pregnancies. In clinical, women who are ready to receive ART treatment are recommend to quit smoking, which may reduce the risk of GDM and prevent adverse pregnancy outcomes.

Intra-patient analysis of individual weight gain or loss between IVF cycles: cycle now and transfer later

STUDY QUESTION

What is the impact of clinically significant weight change on outcomes related to IVF cycle performance?

SUMMARY ANSWER

While individual weight loss did not significantly impact ovarian response to stimulation or other cycle outcome parameters in our study, some positive associations were found for individual weight gain.

WHAT IS KNOWN ALREADY

The role of weight-change in patients undergoing IVF has been largely studied by comparing weight loss in different cohorts of patients stratified by a static BMI. Specifically, obesity has been extensively studied in relation to its negative effects on assisted or unassisted conception outcomes and ovulatory function. Previous research has shown conflicting results, while BMI, which is commonly used as a marker of obesity, may not accurately reflect the underlying factors affecting fertility in obese patients.

STUDY DESIGN, SIZE, DURATION

This study utilized a retrospective within-patient repeated measurement analysis design to assess the impact of weight change on IVF outcomes in cycles where all embryos were cryopreserved at the blastocyst stage for transfer at a later date.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was conducted at an academically affiliated fertility center. The data included 961 women who underwent at least two IVF cycles between December 2014 and June 2020, with documented short-term weight gain (n = 607) or weight loss (n = 354) within 1 year from their initial IVF cycle. Multivariable generalized estimating equations (GEE) and generalized linear mixed models (GLMM) were employed to assess associations between weight change and outcomes across cycles.

MAIN RESULTS AND THE ROLE OF CHANCE

The multivariable models indicated that weight loss did not show any significant associations with the numbers of oocytes retrieved, or mature oocytes, the fertilization rate or the blastulation rate. However, weight gain demonstrated a minor positive association with the number of oocytes retrieved in both GEE models (coefficient: 0.01, 95% CI: 0.00-0.01) and GLMM models (0.01, 95% CI: 0.01-0.00). There was also a potential increase in the fertilization rate with weight gain, as indicated by a positive coefficient in both GEE models (coefficient: 0.01, 95% CI: 0.00-0.02) and GLMM models (coefficient: 0.01, 95% CI: 0.00-0.01). However, the association between weight gain and the embryo blastulation rate was not statistically significant in any model.

LIMITATIONS, REASONS FOR CAUTION

This study focused on cycle performance parameters instead of reproductive outcomes, which restricted our ability to evaluate the impact of weight change on cumulative live birth rates. Additionally, the study did not account for variables such as stimulation protocols, potentially introducing confounding factors and limiting the generalizability of the results.

WIDER IMPLICATIONS OF THE FINDINGS

Although obesity is associated with adverse obstetrical risks, there is less evidence of adverse reproductive outcomes in IVF cycles. We therefore recommend that an IVF cycle should not be delayed due to weight, so that the patient is not adversely affected by increasing age. The IVF cycle should aim to freeze all embryos, so that embryo transfer can then occur after weight loss, so as to limit the recognized obstetrical risks.

STUDY FUNDING/COMPETING INTEREST(S)

The study was not funded and there were no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Pre-gravid body mass index is associated with a higher risk of gestational hypertension in singleton pregnancy following frozen-thawed embryo transfer

Introduction

Although it is well-known that obesity increases the risk of gestational hypertension (GH) in both spontaneous and assisted reproductive technology (ART) pregnancies. Recent data show that, in ART pregnancies, frozen-thawed embryo transfer (FET) is associated with an even higher risk of GH compared with fresh transfer. However, the relationship between pre-gravid body mass index (BMI) and GH in FET pregnancies has seldom been reported.

Objective

The aim of this study is to examine the effect of pre-gravid BMI on GH in singleton pregnancy following FET.

Methods

A retrospective cohort study at a tertiary hospital, including a total of 7,502 women who achieved singleton pregnancy after FET, was included. All patients were enrolled only once. On the basis of the BMI definitions of the Working Group on Obesity in China (WGOC) and the World Health Organization, the women were divided into normal BMI, overweight, and obese groups. The main outcome was GH, and the effect of pre-pregnancy BMI on GH was assessed by generalized linear model.

Results

The risk of GH in our study population was 6.15%. According to the BMI definitions of the WGOC, the risk of GH in the obese group (15.55%) was significantly higher than that of the overweight group (8.26%, P < 0.001) and the normal BMI group (4.68%, P < 0.001). Pre-gravid overweight and obesity were associated with higher GH risk (OR, 1.77; 95% CI, 1.41-2.20; P < 0.001; OR, 3.69; 95% CI, 2.77-4.91; P < 0.001). A non-linear relationship between pre-gravid BMI and GH was observed. The risk of GH decreased with pre-gravid BMI level up to the turning point of BMI = 28.6 kg/m2 (OR, 1.16; 95% CI, 1.12-1.21; P < 0.001).

Conclusion

Pre-gravid overweight and obesity are associated with higher GH risk among singleton pregnancy following FET. Before the turning point of BMI = 26.8 kg/m2, the risk of GH may increase 16.4% with each one-unit increment of maternal BMI. Women preparing for FET should maintain a normal BMI to lower the chances of GH.

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.

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

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

Effect of Excessive Body Weight and Psoriasis in Women Undergoing ICSI Procedure and State of Health of the Newborn

Excessive body weight and some concomitant diseases, such as psoriasis, accompany women treated due to infertility by intracytoplasmic sperm injection (ICSI). This study is aimed to assess effect of obesity and psoriasis on quality of egg cells, embryos, course of pregnancy, and state of a newborn after treatment with ICSI. A total of 140 women were included into the study (110 healthy women and 30 with psoriasis). Among healthy women, BMI negatively correlated with total recovery rate, total oocyte score, blastocyst formation rate (BFR) and amount and quality of blastocysts (r < 0, p < 0.001). The relationships were similar in psoriasis, however apart from average blastocyst quality (p = 0.17) and BFR (p = 0.352). In healthy patients, BMI negatively correlated with gestational age at delivery (r = −0.444, p = 0.010) and APGAR (r = −0.481, p = 0.005). An excess of adipose tissue exerts an unfavourable effect on female reproductive functions, especially with a simultaneous burden of psoriasis. Excessive body weight is conducive to development of gestational diabetes and shortens the duration of pregnancy. The burden of psoriasis in combination with excessive body weight has an impact on the risk of occurrence of intrauterine growth restriction of foetus. Overweight and obesity negatively affect the state of a newborn, measured using APGAR scale.

Major Factors Affecting the Live Birth Rate After Frozen Embryo Transfer Among Young Women

In recent years, the freeze-all strategy has been widely adopted and applied. However, with the exception of age, the factors that affect the outcomes of frozen embryo transfer are still unclear. Therefore, the identification and mitigation of factors that influence the live birth rate after frozen embryo transfer is a good way to increase the "take-home-baby" rate of frozen embryo transfer. The objective of this study was to identify factors affecting the live birth rate after cleavage-stage frozen embryo transfer in young ovulatory women. This was a secondary analysis from a previously published multicenter randomized controlled trial (ChiCTR-IOR-14005406) that was originally designed to compare the live birth rate and perinatal complications after fresh embryo transfer to those after frozen embryo transfer among ovulatory women. This study was carried out using a portion of the data from the original randomized controlled trial, which included 917 young women who underwent cleavage-stage frozen embryo transfer. The 16 clinical candidate variables potentially affecting the live birth rate after frozen embryo transfer were analyzed. Univariable analysis and multivariable analysis were performed to assess the relationship between predictive factors and outcomes, with the aim of identifying independent predictors of live birth after frozen embryo transfer. In this study, the live birth rate was 53.0% (486/917). Three independent predictors were ultimately identified as the main factors affecting the live birth rate of ovulatory young women. Infertility duration [odds ratio (OR): 0.933, 95% confidence interval (CI): 0.876-0.995, p = 0.033], endometrial thickness before frozen embryo transfer (OR: 3.375, 95% CI: 1.556-7.321 p = 0.002), and the number of embryos transferred (OR: 2.653, 95% CI:1.226-5,743, p = 0.013) were the major factors contributing to the live birth rate after cleavage-stage frozen embryo transfer among young women. The cut-off point for infertility duration was 4.5 years, and the cut-off point for endometrial thickness was 0.89 cm. Infertility duration, endometrial thickness and number of embryos transferred might affect the live birth rate after frozen embryo transfer among young women. This result could help inform clinical decisions and counseling to increase the live birth rate after frozen embryo transfer among young women.

Risk of gestational diabetes mellitus following assisted reproductive technology: systematic review and meta-analysis of 59 cohort studies

OBJECTIVE

The use of assisted reproductive technology (ART) has been associated with an increased risk of gestational diabetes mellitus (GDM) in previous studies, but its risk has not been consistent. Therefore, we aimed to estimate the risk of GDM in women who conceived with ART via a systematic review and meta-analysis of cohort studies.

METHODS

ISI Web of Knowledge, Medline/PubMed, Scopus, and Embase databases were searched to identify studies that evaluated the risk of GDM through May 2017 using the relevant keywords. Two reviewers independently performed the screening, data extraction, and quality assessment. Meta-analysis was performed with a random effects model.

RESULTS

The search yielded 957 records relating to GDM and use of ART, from which 59 eligible cohorts were selected for meta-analysis (n = 96,785). There was evidence of substantial heterogeneity among these studies (χ₍₅₈₎² = 3072.34, p < .001; I²=98.1%). The pooled estimate of GDM risk using the random effects model was 9.00% (95% CI: 7.90-10.20). Visual inspection of the funnel plot indicated the presence of low publication bias, but Egger's test did not reveal publication bias.

CONCLUSIONS

The findings revealed that the risk of GDM was very high among women who conceived with ART treatment. GDM screening, management, and improved care are vital in ART pregnancy.

Effect of body mass index on pregnancy outcomes in a freeze-all policy: an analysis of 22,043 first autologous frozen-thawed embryo transfer cycles in China

BACKGROUND

Abnormal BMI is associated with discouraging IVF outcomes in fresh autologous or oocyte donor cycles, whether or not such a relation also holds true for women undergoing frozen-thawed embryo transfer (FET) remains unknown. In addition, it remains unclear the detrimental effect of abnormal BMI on IVF outcomes occurs at the level of ovary or endometrium.

METHODS

A retrospective study involved 22,043 first FET cycles of all women who had undergone a freeze-all policy during the period from January 2010 to June 2017. To control for the embryo factor, our analysis was restricted to women with high-quality embryo transfer. The main outcome measure was live birth rate per embryo transfer. The secondary endpoints included rates of implantation, clinical pregnancy, multiple pregnancy, and pregnancy loss. Multivariate logistic regression analysis was performed to detect the independent effect of BMI on live birth rate after adjusting for important confounding variables.

RESULTS

In the crude analysis, reproductive outcomes were similar between underweight women and normal-weight controls whereas all parameter outcomes were significantly worse in patients with obesity. After adjustment for a number of confounding factors, underweight women had a marginally significant decrease in rates of implantation (adjusted odds ratio (aOR) 0.91; 95% CI 0.85-0.96), clinical pregnancy (aOR 0.91; 95% CI 0.83-0.99), and live birth (aOR 0.91; 95% CI 0.83-0.99) as compared to the women with normal weight. Obesity was significantly associated with decreased implantation (aOR 0.80; 95% CI 0.73-0.87), clinical pregnancy (aOR 0.81; 95% CI 0.71-0.91), and live birth rates (aOR 0.70; 95% CI 0.62-0.80). Moreover, the pregnancy loss rate, both in the first (aOR 1.46; 95% CI 1.15-1.87) and in the second trimester (aOR 2.76; 95% CI 1.67-4.58), was significantly higher in the obesity group than that in the reference group.

CONCLUSIONS

Among women undergoing first FET with high-quality embryo transfer, low BMI has limited impact on pregnancy and live birth rates. On the contrary, obesity was associated with worse IVF outcomes. Our findings further highlighted that endometrial receptivity played an important role in the poor reproductive outcomes of women with abnormal weight status.

A systematic review and meta-analysis of lifestyle and body mass index predictors of successful assisted reproductive technologies

OBJECTIVE

Lifestyle (smoking, drinking alcohol) and body mass index (BMI) predictors of successful outcomes in assisted reproductive technology (ART) treatments were examined in this meta-analysis.

METHOD

A bibliographic search was undertaken using six databases. The review was informed by PRISMA/MOOSE guidelines. Meta-analytic data were analysed using random effects models.

RESULTS

We included 77 studies examining effects of BMI, smoking and drinking alcohol. Patients with a BMI< =24.9 were significantly more likely to achieve LB/pregnancy than with BMI> =25 OR = 1.219 (95% CI:1.128-1.319, z = 4.971, p < .001; I² = 53.779%, p = .001). Non-smokers were significantly more likely to achieve a LB or pregnancy than smokers OR = 1.457 (95% CI:1.228-1.727, z = 4.324, p < .001; I² = 51.883; p = .001). Meta-regression revealed the number of embryos transferred significantly moderated the effects of smoking on ART outcomes, and there was a trend indicating primary infertility and high BMI were also significant moderators. The evidence for drinking alcohol was inconclusive due to the small number of studies.

CONCLUSIONS

This meta-analysis confirms that ART treatment success can be predicted with lifestyle factors. Further, non-smokers' relative odds of pregnancy/live birth increase as more embryos were transferred but there was a trend that the odds of pregnancy/live birth decrease with primary infertility and high BMI.

PGR and PTX3 gene expression in cumulus cells from obese and normal weighting women after administration of long-acting recombinant follicle-stimulating hormone for controlled ovarian stimulation

PURPOSE

The present study aimed to determine clinical IVF parameters and gene expression in cumulus cells (CCs) in obese and normal weighting women after administration of 150 mcg of corifollitropin alfa for controlled ovarian hyperstimulation (COH).

METHODS

150 mcg of corifollitropin alfa and gonadotropin releasing hormone antagonist were used for COH. Analysis of CC gene expression was performed using quantitative real-time PCR.

RESULTS

We did not find significant differences in biochemical and clinical pregnancy rates between obese and normal weighting women. Obese women required twice as much of additional gonadotropins for ovarian stimulation and had a significantly lower proportion of good quality embryos on day 5 of IVF cycle. Expression of PGR and PTX3 was significantly higher in CCs of obese women.

CONCLUSION

Obese women require significantly larger amounts of gonadotropins to achieve similar IVF success rates as normal weighting women. Differences in CC gene expression and smaller proportion of good quality embryos may imply that oocytes derived from obese women are of lower quality. Further studies are needed to evaluate whether obesity itself or the higher amount of gonadotropins used in obese women causes this effect.

Effectiveness of high-dose transvaginal progesterone supplementation for women who are undergoing a frozen-thawed embryo transfer

PURPOSE

To evaluate the effectiveness of high-dose progesterone supplementation for women who are undergoing a frozen-thawed embryo transfer (FET).

METHODS

Among the 2010 FET cycles that were included in the present study, 1188 were 1200 mg/d of vaginal progesterone, while 822 were 900 mg/d. The dose of progesterone that was used was decided by the treatment period and additional progesterone supplementation was used when the serum progesterone levels were <9 ng/mL on luteal day 5.

RESULTS

The clinical pregnancy rate was higher in the 1200 mg group than in the 900 mg group. The mean serum progesterone level on luteal day 5 in the 1200 mg and 900 mg groups was 12.6 ng/mL and 13.4 ng/mL, respectively. The rate of additional progesterone supplementation was higher in the 1200 mg group. A logistic regression analysis identified a younger age (≤37 years) and the use of 1200 mg progesterone as independent predictive factors for the clinical pregnancy outcome. The analysis of the infant outcomes revealed no significant difference in the distribution of birth ages and weights.

CONCLUSION

High-dose transvaginal progesterone of 1200 mg/d as luteal support contributed to good pregnancy outcomes.

The influence of body mass index on pregnancy outcome following single-embryo transfer

PURPOSE

The association between obesity and reproductive outcome is controversial. The aim of this study is to evaluate the effects of obesity on clinical pregnancy rates following transfer of a single fresh embryo.

METHODS

A retrospective cohort study was conducted at a single tertiary medical center, including all first, fresh, single-embryo transfers using non-donor oocytes, during 2008-2013. We compared clinical pregnancy rate and pregnancy outcomes of singleton live births resulting from the transfer of a single fresh embryo in normal weight, overweight, and obese women, defined as body mass index (BMI) < 25 kg/m², ≥ 25 BMI <30 kg/m², and BMI ≥ 30 kg/m², respectively.

RESULTS

Overall, 1345 cases met the inclusion criteria with 864 single-embryo transfers (SETs) in normal weight women, 292 in overweight women, and 189 SETs in obese women, resulting in 538 clinical pregnancies and 354 singleton births. The clinical pregnancy rate per transfer was similar among the three groups (41.3, 37.6, 37.5%, respectively, p = 0.416). Similarly, there were no significant differences in live births or ongoing pregnancies. On multivariate logistic regression analysis, BMI did not impact the likelihood for clinical pregnancy (OR 0.98, 95% CI 0.96-1.008, p = 0.216).

CONCLUSIONS

Our study demonstrated that obesity has no detrimental effect on the clinical pregnancy rate resulting from the transfer of a single fresh embryo.

The correlation between raised body mass index and assisted reproductive treatment outcomes: a systematic review and meta-analysis of the evidence

Background

Public funding for fertility services within the United Kingdom is limited, and therefore, strict guidance exists regarding who can be offered treatment under the National Health Service (NHS). Body mass index (BMI) is a universal criteria adopted by both the public and private sector.

This study addresses an important aspect of the impact of a raised BMI on fertility treatment outcomes. We standardise the analysis of the data by only including studies incorporating the WHO BMI criteria; the current reference point for clinicians and clinical commissioning groups in ascertaining which group of patients should receive treatment. This study is an update of the previous systematic review performed in 2010, with the inclusion of a larger number of cycles from central databases such as the Society for Assisted Reproductive Technology (SART).

Methods

An electronic literature search was conducted through the Cochrane, Medline and Embase libraries. Data extraction for each outcome measure was pooled and expressed as an odds ratio with 95% confidence intervals. Where clinical heterogeneity was evident, the random effects model was used to calculate the risk ratio and a fixed effects model was used for the remaining studies. A p value < 0.05 was considered statistically significant.

Results

A total of 49 studies have been identified and included in this systematic review. Overweight and obese (BMI ≥ 25 kg/m²) women have a statistically significant lower live birth rate (OR 0.81, 95% CI 0.74–0.89, p < 0.00001) following Assisted Reproductive Technology (ART) when comparisons are drawn to women with a normal BMI. An increase is also demonstrated in the number of miscarriages experienced by women with a BMI ≥ 30 kg/m² (OR 1.52, 95% CI 1.28–1.81, p < 0.00001).

Conclusion

Although this review concludes that a clear impact of BMI on ART outcomes is demonstrated, there remains questions as to the pathophysiology underlying these differences. This review supports the government’s stringent criteria regarding BMI categories under which NHS funding is made available for ART, through a clear description of poor reproductive outcomes in women with a BMI ≥ 30 kg/m².

Increased incidence of gestational hypertension and preeclampsia after assisted reproductive technology treatment

OBJECTIVE

To determine the association between assisted reproductive technology (ART) treatment and the rate of combined gestational hypertension (GH), preeclampsia (PE).

DESIGN

Retrospective population study.

SETTING

Not applicable.

PATIENT(S)

A total of 596,520 mothers (3.6% ART mothers) who gave birth between 2007 and 2011.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Comparison of the rate of GH/PE for ART and non-ART mothers, with odds ratio (OR), adjusted odds ratio (AOR), and 95% confidence interval (CI) used to assess the association between ART and GH/PE.

RESULT(S)

The overall rate of GH/PE was 4.3%, with 6.4% for ART mothers and 4.3% for non-ART mothers. The rate of GH/PE was higher for mothers of twins than singletons (12.4% vs. 5.7% for ART mothers; 8.6% vs. 4.2% for non-ART mothers). The ART mothers had a 17% increased odds of GH/PE compared with the non-ART mothers (AOR 1.17; 95% CI, 1.10-1.24). After stratification by plurality, the difference in GH/PE rates between ART and non-ART mothers was not statistically significant, with AOR 1.05 (95% CI, 0.98-1.12) for mothers of singletons and AOR 1.10 (95% CI, 0.94-1.30) for mothers of twins.

CONCLUSION(S)

The changes in AOR after stratification indicated that multiple pregnancies after ART are the single most likely explanation for the increased rate of GH/PE among ART mothers. The lower rate of GH/PE among mothers of singletons compared with mothers of twins suggests that a policy to minimize multiple pregnancies after ART may reduce the excess risk of GH/PE due to ART treatment.

Does obesity have detrimental effects on IVF treatment outcomes?

Background

The aim of this study was to investigate the influence of body mass index (BMI) on the in vitro fertilization (IVF) treatment outcomes in a cohort of women undergoing their first IVF, using an intracytoplasmic sperm injection (ICSI).

Methods

This retrospective cohort study included 298 cycles from women younger than 38 years old undergoing IVF-ICSI at a university infertility clinic. The treatment cycles were divided into three groups according to the BMI of the women involved: normal weight (18.5 ≤ BMI < 25 kg/m², 164 cycles), overweight (25 ≤ BMI < 30 kg/m², 70 cycles), and obese (BMI ≥ 30 kg/m², 64 cycles). The underweight women (BMI < 18.5 kg/m²) were not included in the analysis due to small sample size (n = 22). The patient characteristics and IVF-ICSI treatment outcomes were compared between the BMI groups.

Results

The total gonadotropin dose (p <0.001) and duration of stimulation (p = 0.008) were significantly higher in the obese group when compared to the normal BMI group. There were no significant differences across the BMI categories for the other IVF-ICSI cycle outcomes measured, including the number of retrieved oocytes, mature oocytes, embryos suitable for transfer, proportion of oocytes fertilized, and cycle cancellation rates (p >0.05 for each). Additionally, clinical pregnancy, spontaneous abortion, and the ongoing pregnancy rates per transfer were found to be comparable between the normal weight, overweight, and obese women (p >0.05 for each).

Conclusion

Obese women might require a significantly higher dose of gonadotropins and longer stimulation durations, without greatly affecting the pregnancy outcomes.

The impact of maternal body mass index on in vitro fertilization outcomes

OBJECTIVE

To examine the effect of body mass index on gonadotropin dose requirements for ovarian stimulation, as well as other clinical outcomes in women undergoing in vitro fertilization.

METHODS

We performed a retrospective cohort study involving 752 women undergoing a total of 951 IVF or IVF-ICSI cycles at a private fertility clinic between January 2007 and May 2011. The 951 treatment cycles were divided into three groups according to the weight of the women involved: normal weight (BMI < 25 kg/m², 461 cycles), overweight (25 ≤ BMI < 30 kg/m², 277 cycles), and obese (BMI ≥ 30 kg/m², 179 cycles). Total gonadotropin dose requirements and clinical IVF cycle outcomes (cycle cancellation, clinical pregnancy, and live birth) were compared between the three BMI groups. We performed multivariable analyses, adjusting for potential confounders such as age at cycle start, day 3 serum FSH level, smoking, presence of polycystic ovary syndrome, and duration of infertility.

RESULTS

There were no significant differences between the three BMI groups for any of the IVF cycle outcomes measured, including the total FSH dose required for ovarian stimulation. The likelihood of cycle cancellation, clinical pregnancy, and live birth were not significantly different between normal weight, overweight, and obese women.

CONCLUSION

Obese women did not require significantly higher doses of gonadotropins for ovarian stimulation than normal weight individuals. At our centre, female obesity did not significantly affect the clinical outcomes of IVF treatment. However, given the conflicting results of existing studies, the effect of maternal obesity on IVF outcomes remains unclear.

Complications and outcome of assisted reproduction technologies in overweight and obese women

BACKGROUND

Based on a presumed negative impact of overweight and obesity on reproductive capacity and pregnancy outcome, some national guidelines and clinicians have argued that there should be an upper limit for a woman's BMI to access assisted reproductive technologies (ART). However, evidence on the risk of complications or expected success rate of ART in obese women is scarce. We therefore performed a systematic review on the subject.

METHODS

We searched the literature for studies reporting on complications or success rates in overweight and obese women undergoing ART. Articles were scored on methodological quality. We calculated pooled odds ratios (ORs) to express the association between overweight and obesity on the one hand, and complications and success rates of ART on the other hand. We only pooled results if data were available per woman instead of per cycle or embryo transfer.

RESULTS

We detected 14 studies that reported on the association between overweight and complications during or after ART, of which 6 reported on ovarian hyperstimulation syndrome (OHSS), 7 on multiple pregnancies and 6 on ectopic pregnancies. None of the individual studies found a positive association between overweight and ART complications. The pooled ORs for overweight versus normal weight for OHSS, multiple pregnancy and ectopic pregnancy were 1.0 [95% confidence interval (CI) 0.77-1.3], 0.97 (95% CI 0.91-1.04) and 0.96 (95% CI 0.54-1.7), respectively. In 27 studies that reported on BMI and the success of ART, the pooled ORs for overweight versus normal weight on live birth, ongoing and clinical pregnancy following ART were OR 0.90 (95% CI 0.82-1.0), 1.01 (95% CI 0.75-1.4) and OR 0.94 (95% CI 0.69-1.3), respectively.

CONCLUSIONS

Data on complications following ART are scarce and therefore a registration system should be implemented in order to gain more insight into this subject. In the available literature, there is no evidence of overweight or obesity increasing the risk of complications following ART. Furthermore, they only marginally reduce the success rates. Based on the currently available data, overweight and obesity in itself should not be a reason to withhold ART.

The impact of obesity on egg quality

Obesity in women is a concern in many countries. This causes numerous health issues; however, this review focuses on the impact of obesity on women's reproduction, and in particular the oocyte. Data from infertility clinics and experimental animal models that address the effects of obesity are presented. Bidirectional communication and metabolic support from the surrounding cumulus cells are critical for oocyte development, and the impact of obesity on these cells is also addressed. Both oocyte maturation and metabolism are impaired due to obesity, negatively impacting further development. In addition to reproductive hormones, obesity induced elevations in insulin, glucose, or free fatty acids, and changes in adipokines appear to impact the developmental competence of the oocyte. The data indicate that any one of these hormones or metabolites can impair oocyte developmental competence in vivo, and the combination of all of these factors and their interactions are the subject of ongoing investigations.