Association Between Pre-Pregnancy Body Mass Index and Maternal and Neonatal Outcomes of Singleton Pregnancies After Assisted Reproductive Technology

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.

The effect of female body mass index on cumulative live birth rate in women undergoing in vitro fertilization according to age

The aim of this study was to explore the impact of female body mass index (BMI) on cumulative live birth rates (CLBR) in patients treated with in vitro fertilization (IVF) and embryo transfer. A total of 2377 patients who visited the Reproductive Medical Center, Luoyang Maternal and Child Health Hospital from January 2015 to December 2021. The patients underwent the first IVF cycles. According to female BMI, patients were divided into 3 groups, group A: BMI ≤ 18.5 kg/m2 (underweight), group B: BMI: 18.5 to 24.0 kg/m2 (normal), group C: BMI ≥ 24.0 kg/m2 (overweight/obesity). Patient basic parameters and clinical outcomes were compared among these 3 groups. Multivariate logistic regression analysis was used to explore the impact of BMI on CLBR. In all treatment cycles, patients' basic parameters were significantly different among 3 BMI groups. Age of underweight patient was younger than patients in the other 2 groups (28.45 ± 5.32 vs 29.89 ± 5.00 vs 30.74 ± 5.40; P = .000). In addition, number of oocytes retrieved was also significantly higher in group A (11.25 ± 5.97 vs 11.07 ± 5.49 vs 10.52 ± 5.02; P = .000). CLBR in these 3 groups were 66.40%, 65.98%, and 59.14%, respectively. In logistic analysis, overweight/obesity was associated with CLBR in young patients (aOR = 0.822, 95% CI: 0.817-0.957, P = .000). However, in the cycles of older patients, the effect of overweight/obesity on the CLBR was not significant (aOR = 0.986, 95% CI: 0.903-1.027, P > .05). Overweight/obesity is a predictor for CLBR in younger patients (<35 years old), but not in advanced age patients undergoing their first IVF/intracytoplasmic sperm injection treatment cycles.

Medical and Psychological Aspects of Pregnancy in Women with Obesity and after Bariatric Surgery

Chronic diseases are potential risk factors for pregnancy duration and neonatal outcomes. This narrative review aimed to summarize the research results on the specifics of pregnancy in women with obesity and after bariatric surgery. PubMed and Google Scholar databases were searched. Systematic reviews, meta-analyses, clinical trials, and references to identified articles from the last ten years (2013-2023) were included. Ultimately, 107 literature items were qualified. It has been shown that women with obesity planning pregnancy should reduce their body weight because obesity is a risk factor for adverse obstetric and neonatal outcomes. Bariatric surgery effectively reduces excessive body weight and the health risks in women with obesity during pregnancy and their offspring. However, at least a year interval between surgery and conception is recommended. An interdisciplinary medical team should provide patient care during pregnancy with knowledge and skills related to people after bariatric surgery. Due to the increased risk of mental disorders, especially depression, it is necessary to constantly monitor the mental state of women and provide psychological support and education on a healthy lifestyle during pregnancy and the postpartum period.

The association between body mass index and live birth and maternal and perinatal outcomes after in-vitro fertilization: a national cohort study

Objective

To investigate the association between female body mass index (BMI) and live birth rates and maternal and perinatal outcomes after in-vitro fertilization (IVF).

Methods

We performed a national, population-based cohort study including women undergoing IVF between 2002 and 2020. The cohort included 126,620 fresh cycles and subsequent frozen embryo transfers between 2007 and 2019 (subpopulation 1) and 58,187 singleton deliveries between 2002 and 2020 (subpopulation 2). Exposure was female BMI (kg/m2) categorized according to the World Health Organization as underweight (<18.5), normal weight (18.5-24.9, reference), overweight (25.0-29.9), class I obesity (30.0-34.9), class II obesity (35.0-39.9), and class III obesity (≥40.0). The primary outcome in subpopulation 1 was cumulative live birth per started fresh IVF cycle, including fresh and subsequent frozen embryo transfers. Primary outcomes in subpopulation 2 were hypertensive disorders of pregnancy and preterm birth at less than 37 weeks. Risk ratios (RRs) with 95% confidence intervals (CIs) for the association between BMI class and outcomes were calculated using generalized linear models after adjustment for relevant confounders.

Results

The cumulative live birth rate decreased significantly with increasing BMI from 32.6% in normal-weight women to 29.4% in overweight women, 27.0% in women in obesity class I, 21.8% in women in obesity class II, and 7.6% in women in obesity class III. The risk of hypertensive disorders of pregnancy increased significantly and progressively with increasing BMI, from 4.6% in normal-weight women to 7.8% in overweight women and 12.5%, 17.9%, and 20.3% in women in obesity classes I, II, and III. The risk of preterm birth followed a similar pattern, from 6.3% in normal-weight women to 7.5% in overweight women and 8.9%, 9.9%, and 15.3% in women in obesity classes I, II, and III. The risks of other perinatal complications, such as perinatal death, showed an even more pronounced increase.

Conclusion

Using a large and complete national cohort of women undergoing IVF, we demonstrate a dose-dependent decrease in live birth rate and a substantial increase in maternal and perinatal complications with increasing BMI. Strategies to improve this situation are warranted.

Impact of maternal body mass index on outcomes of singleton pregnancies after assisted reproductive technology: a 14-year analysis of the US Nationwide Inpatient Sample

BACKGROUND

Obesity is increasing globally, which affects multiple human functions, including reproductive health. Many women with overweight and obesity of child-bearing years are treated with assisted reproductive technology (ART). However, the clinical impact of body mass index (BMI) on pregnancy outcomes after ART remains to be determined. Therefore, this population-based retrospective cohort study aimed to assess whether and how higher BMI affects singleton pregnancy outcomes.

METHODS

This study used the large nationally representative database of the US National Inpatient Sample (NIS), extracting data of women with singleton pregnancies who had received ART from 2005 to 2018. Diagnostic codes of the International Classification of Diseases, Ninth and Tenth edition (ICD-9 and ICD-10) were used to identify females admitted to US hospitals with delivery-related discharge diagnoses or procedures and secondary diagnostic codes for ART, including in vitro fertilization. The included women were further categorized into three groups based on BMI values < 30, 30-39, and ≥ 40 kg/m². Univariate and multivariable regression analysis were conducted to assess the associations between study variables and maternal and fetal outcomes.

RESULTS

Data of totally 17,048 women were included in the analysis, which represented a population of 84,851 women in the US. Number of women in the three BMI groups were 15, 878 (BMI < 30 kg/m²), 653 (BMI 30-39 kg/m²), and 517 (BMI ≥ 40 kg/m²), respectively. The multivariable regression analysis revealed that, compared to BMI < 30 kg/m², BMI 30-39 kg/m² was significantly associated with increased odds for pre-eclampsia and eclampsia (adjusted OR = 1.76, 95% CI = 1.35, 2.29), gestational diabetes (adjusted OR = 2.25, 95% CI = 1.70, 2.98), and Cesarean delivery (adjusted OR = 1.36, 95% CI = 1.15, 1.60). Further, BMI ≥ 40 kg/m² was associated with greater odds for pre-eclampsia and eclampsia (adjusted OR = 2.25, 95% CI = 1.73, 2.94), gestational diabetes (adjusted OR = 3.64, 95% CI = 2.80, 4.72), disseminated intravascular coagulation (DIC) (adjusted OR = 3.79, 95% CI = 1.47, 9.78), Cesarean delivery (adjusted OR = 1.85, 95% CI = 1.54, 2.23), and hospital stay ≥ 6 days (adjusted OR = 1.60, 95% CI = 1.19, 2.14). However, higher BMI was not significantly associated with greater risk of the fetal outcomes assessed.

CONCLUSIONS

Among US pregnant women who received ART, having a higher BMI level independently increases the risk for adverse maternal outcomes such as pre-eclampsia and eclampsia, gestational diabetes, DIC, longer hospital stays, and higher rates of Cesarean delivery, while risk is not increased for fetal outcomes.