Prepregnancy and early adulthood body mass index and adult weight change in relation to fetal loss

BMI status and weight trajectories across females' reproductive years and risk of adverse pregnancy outcomes: a prospective cohort study

BACKGROUND

Prepregnancy body mass index (BMI) is a well-established risk factor of adverse pregnancy outcomes (APOs). The associations of long-term and short-term weight trajectories with APOs are less clear.

OBJECTIVES

This study aimed to determine the associations of weight trajectories during females' reproductive years, before and between pregnancies, with risk of APOs.

METHODS

We followed 16,241 females (25,386 singleton pregnancies) participating in a prospective cohort, the Nurses' Health Study II. Weight at age 18 y, current weight, and height were assessed at baseline (1989), and weight was updated biennially. Pregnancy history was self-reported in 2009. The primary outcome was a composite of hypertensive disorders of pregnancy (HDP), gestational diabetes (GDM), preterm birth, and stillbirth. Secondary outcomes were individual APOs. The associations of weight change with APOs were estimated using log-binomial regression, adjusting for demographic, lifestyle, reproductive factors, and baseline BMI (in kg/m2).

RESULTS

The mean (standard deviation [SD]) age at first in-study pregnancy was 33.7 (4.1) y. The mean (SD) time from age 18 y to pregnancy, baseline to pregnancy, and between pregnancies was 16.3 (4.0), 6.1 (3.0), and 2.9 (1.6) y, with a corresponding weight change of 6.4 (9.1), 3.1 (5.8), and 2.3 (4.8) kg, respectively. Of the pregnancies, 4628 (18.2%) were complicated by ≥1 APOs. Absolute weight change since age 18 y was most strongly associated with APOs. Compared with females whose weight remained stable (0-2 kg) since age 18, females who gained >2 kg had higher risk of APO (2.1-9.9 kg, relative risk [RR]: 1.12; 95% confidence interval [CI]: 1.02, 1.23; 10.0-14.9 kg, RR: 1.43; 95% CI: 1.29, 1.60; ≥15 kg, RR: 1.87; 95% CI: 1.69, 2.08), primarily driven by HDP and GDM. The associations of per 1 kg weight gain before and between pregnancies with HDP were nearly identical.

CONCLUSIONS

Weight trajectories prior to and between pregnancies were associated with the risk of APOs, particularly HDP. Longer periods of weight gain, corresponding to greater absolute weight gain, were most strongly associated with higher risk of APOs.

Examining the Role of Nutrition in Cancer Survivorship and Female Fertility: A Narrative Review

Female cancer survivors have a higher chance of experiencing infertility than females without a history of cancer diagnosis. This risk remains high despite advances in fertility treatments. There is a need to augment fertility treatments with cost-effective methods such as nutritional guidance to improve fertility chances. The aim of this review article is to connect the current literature on cancer survivorship nutrition and fertility nutrition, focusing on the importance of integrating nutritional guidance into fertility counseling, assessment, and treatment for female cancer survivors. Consuming a healthful diet comprising whole grains, soy, fruits, vegetables, seafood, and unsaturated fats has improved both female fertility and cancer survivorship. Similarly, maintaining a healthy body weight also improves female fertility and cancer survivorship. Therefore, dietary interventions to support female cancer survivors with fertility challenges are of immense importance. The period of follow-up fertility counseling and assessment after cancer treatment may provide a unique opportunity for implementing nutritional guidance for female cancer survivors. Dietary interventions are a promising strategy to improve pregnancy chances and overall quality of life among female cancer survivors; thus, researchers should investigate perceptions regarding fertility, barriers, and challenges to changing nutrition-related behaviors, and preferences for nutritional guidance to support fertility treatments in this population.

Pathological features of early pregnancy disorders in women living at high altitude in KSA

Objectives

Pregnancy at high altitudes is relatively challenging because of hypobaric hypoxia, which is associated with a smaller uterine artery diameter and diminished blood flow. Here, we investigated the histopathological characteristics of early pregnancy disorders among pregnant women living in a high-altitude region (approximately 2200 m above sea level).

Methods

This cross-sectional study used retrospective data collection from a single tertiary hospital in a high-altitude region in KSA. Age and histopathology were analyzed in 495 women diagnosed with early pregnancy disorders (mainly miscarriage) in 2018-2020.

Results

Approximately one-fifth of pregnancies in this high-altitude region were lost before 24 weeks' gestation, whereas 1150/6044 experienced miscarriage; 495 samples from those participants were sent for histopathological analysis. A total of 269 (54.34%) patients were younger than 35 years. Missed miscarriages accounted for 49.3% of miscarriages, followed by inevitable miscarriages (34.2%), which had a relatively higher frequency among mothers older than 35 years. The correlation between age and inevitable miscarriage was significant; ectopic pregnancy was diagnosed in 6.8%, molar pregnancy was detected in 6.26%, and blighted ovum was observed in 3.4%.

Conclusion

The miscarriage rate in this high-altitude region was 19% of all pregnancies. Approximately half of the affected women were in their 30s. Missed miscarriage cases were relatively high in this region. The percentage of molar pregnancy was higher than those reported in prior studies, thus suggesting a need for monitoring and genetic workup practices. Furthermore, studies involving a larger population at high altitudes will be crucial for further risk assessment in addition to national studies on women living at sea level.

Weight Cycling in Women: Adaptation or Risk?

Obesity, dieting, and weight cycling are common among reproductive-age women. Weight cycling refers to intentional weight loss followed by unintentional weight regain. Weight loss is accompanied by changes in gut peptides, adipose hormones, and energy expenditure that promote weight regain to a tightly regulated set point. While weight loss can improve body composition and surrogate markers of cardiometabolic health, it is hypothesized that the weight regain can result in an overshoot effect, resulting in excess weight gain, altered body composition, and negative effects on surrogate markers of cardiometabolic health. Numerous observational studies have examined the association of weight cycling and health outcomes. There appears to be modest association between weight cycling with type 2 diabetes mellitus and dyslipidemia in women, but no association with hypertension, cardiovascular events, and overall cancer risk. Interestingly, mild weight cycling may be associated with a decreased risk of overall and cardiovascular mortality. Little is known about the effects of weight cycling in the preconception period. Although obesity and weight gain are associated with pregnancy complications, preconception weight loss does not appear to mitigate the risk of most pregnancy complications related to obesity. Research on preconception weight cycling may provide insight into this paradox.

Substantial Weight Gain in Adulthood Is Associated with Lower Probability of Live Birth Following Assisted Reproduction

BACKGROUND

Overweight and obesity among women have been associated with lower success of assisted reproduction technologies (ARTs). However, the relation of adolescent body weight and adult weight change to ART outcomes is not well understood.

OBJECTIVE

Our objective was to evaluate the associations of female BMI (in kg/m2) at 18 y and weight change from 18 y to current age with ART outcomes.

METHODS

We included 486 women in a prospective cohort at the Massachusetts General Hospital Fertility Center (2004-2018) who underwent 863 ART cycles. At study entry, height and weight were measured by research personnel. Women recalled their weight at 18 y. Restricted cubic splines were used to evaluate the associations between BMI at 18 y and weight change since 18 y and ART outcomes adjusting for age, race, education, smoking, and height and accounting for the correlated cycles within women.

RESULTS

Women had a median (range) BMI of 20.6 (14.8 to 36.4) at 18 y and 23.3 (16.1 to 45.8) at study entry. The median (range) weight change since 18 y was 7.4 kg (-12.1 to 60.1 kg). There was no association between BMI at 18 y and clinical ART outcomes. Long-term weight change had a nonlinear association with live birth such that higher weight gain since 18 y (particularly ≥15 kg) and weight loss were both associated with lower odds of live birth. The negative association between weight change and live birth was stronger in women ≥22.5 kg/m2 at 18 y such that each 10-kg increase was associated with a 30% (6%, 48%) lower odds of live birth.

CONCLUSIONS

Weight gain in adulthood is negatively associated with ART success, particularly among women who were heavier at 18 y. These results add to the growing literature supporting the benefits of preventing weight gain in adulthood on female fertility.

Short-term weight change and live birth among women with unexplained infertility and polycystic ovary syndrome undergoing ovulation induction

OBJECTIVE

To determine if short-term weight change among women with unexplained infertility (UI) and polycystic ovary syndrome (PCOS) undergoing ovulation induction is associated with live birth.

DESIGN

Secondary analysis of randomized trials.

SETTING

Multicenter fertility trial sites.

PATIENT(S)

A total of 900 women with UI and 750 women with PCOS.

MAIN OUTCOME MEASURE(S)

Live birth.

INTERVENTION(S)

Weight assessment at enrollment and start of up to 4-5 cycles of clomiphene, letrozole, or gonadotropins and intrauterine insemination for women with UI and clomiphene or letrozole with regular intercourse for women with PCOS.

RESULT(S)

Weight data were available for 856 women with UI and 697 women with PCOS. Mean weight change was -0.2 ± 0.3 kg among women with UI and +2.2 ± 0.2 kg among women with PCOS and did not differ based on treatment allocation. There were 115 women with PCOS (16.4%) who gained ≥3 kg. Increased body mass index and three or more cycles were associated with weight gain in women with PCOS. There was no difference in live birth rate among women with PCOS and ≥3 kg weight gain and women with PCOS who did not gain weight.

CONCLUSION(S)

Women with PCOS gained an average of 2.2 kg regardless of the medication received, whereas women with UI experienced no short-term weight change during ovulation induction. Weight gain in women with PCOS was not associated with live birth rate.

Recent advances in understanding the relationship between long- and short-term weight change and fertility

The impact of excess body weight on fertility is well recognized among both women attempting to conceive spontaneously and those attempting to conceive with medical assistance. Although many leading societies of reproductive medicine have proposed weight loss as a means to counteract the negative consequences of obesity on fertility, there is limited research on this topic. In this review, we provide a brief overview of the recent advances in the literature focused on how long- and short-term weight change affects fertility among women. Overall, despite initial hope that weight loss may be beneficial for fertility, two large well-conducted randomized controlled trials have consistently shown that short-term weight loss among overweight and obese women undergoing infertility treatment does not improve a woman's probability of live birth. The observational evidence among women attempting to conceive without medical assistance also suggests limited benefits of weight loss on fecundity or pregnancy loss. In contrast, substantial weight gain between consecutive pregnancies, in the year prior to pregnancy attempt, and throughout adulthood appears to be harmful for not only time to pregnancy but also pregnancy maintenance. Future research focused on efforts to prevent weight gain during adulthood is needed to better understand whether these types of interventions may have beneficial effects on fertility.

The impact of maternal lifestyle factors on periconception outcomes: a systematic review of observational studies

The main risk factors for important reproductive health issues such as subfertility and perinatal mortality largely originate in the periconception period. To evaluate associations between modifiable maternal lifestyle factors and periconception outcomes, a systematic search was conducted for relevant studies published from 1990 to February 2017 on Embase, Medline, Web of Science, Cochrane database, PubMed and Google Scholar. The initial search identified 6166 articles, of which 49 studies were eligible for inclusion. Fecundity (the capacity to have a live birth) showed significant inverse associations with smoking, alcohol use and poor diet. Studies regarding time to pregnancy showed a decline in fecundity ratios (the monthly conception rate among exposed relative to unexposed couples) with increasing body mass index (BMI). Furthermore, risk of first-trimester miscarriage was found to be increased in smokers, alcohol and caffeine consumers, and with increasing BMI. Vitamin supplement use showed a decrease in this risk. This review demonstrates that maternal modifiable lifestyle factors affect periconception outcomes. If couples planning a pregnancy are more aware and supported to adopt healthy lifestyles during the periconceptional 'window of opportunity', short-term reproductive health as well as health in later life and even of future generations can be further improved.

Associations of vomiting and antiemetic use in pregnancy with levels of circulating GDF15 early in the second trimester: A nested case-control study

Background: Although nausea and vomiting are very common in pregnancy, their pathogenesis is poorly understood. We tested the hypothesis that circulating growth and differentiation factor 15 (GDF15) concentrations in early pregnancy, whose gene is implicated in hyperemesis gravidarum, are associated with nausea and vomiting. Methods: Blood samples for the measurement of GDF15 and human chorionic gonadotrophin (hCG) concentrations were obtained early in the second trimester (median 15.1 (interquartile range 14.4-15.7) weeks) of pregnancy from 791 women from the Cambridge Baby Growth Study, a prospective pregnancy and birth cohort. During each trimester participants completed a questionnaire which included questions about nausea, vomiting and antiemetic use. Associations with pre-pregnancy body mass indexes (BMI) were validated in 231 pregnant NIPTeR Study participants. Results: Circulating GDF15 concentrations were higher in women reporting vomiting in the second trimester than in women reporting no pregnancy nausea or vomiting: 11,581 (10,977-12,219) (n=175) vs. 10,593 (10,066-11,147) (n=193) pg/mL, p=0.02). In women who took antiemetic drugs during pregnancy (n=11) the GDF15 levels were also raised 13,157 (10,558-16,394) pg/mL (p =0.04). Serum GFD15 concentrations were strongly positively correlated with hCG levels but were inversely correlated with maternal BMIs, a finding replicated in the NIPTeR Study. Conclusions: Week 15 serum GDF15 concentrations are positively associated with second trimester vomiting and maternal antiemetic use in pregnancy. Given GDF15's site of action in the chemoreceptor trigger zone of the brainstem and its genetic associations with hyperemesis gravidarum, these data support the concept that GDF15 may be playing a pathogenic role in pregnancy-associated vomiting.

Factors affecting pregnancy weight gain and relationships with maternal/fetal outcomes in Turkey

Objectives:

To determine the effects of pre-pregnancy body mass index (BMI) and gestational weight gain on maternal and fetal complications, and to examine whether Turkish women achieve the recommended gestational weight gain. We also investigated the relationship between pregnancy weight gain and mode of delivery, with an examination of maternal anthropometry.

Methods:

A retrospective cross-sectional study was conducted on a population of 986 pregnant women between November 2011 and November 2015 at Atatürk Education and Research Hospital, Ankara, Turkey. Maternal age, BMI, monthly weight gain during pregnancy, infant birth weight, gender, and maternal and fetal adverse outcomes were evaluated.

Results:

The frequency of maternal complications was positively associated with elevated pre-pregnancy BMI (p<0.05), and weight gain during pregnancy was associated with parity and increased infant birth weight (p<0.05). However, no correlations were observed between mean pregnancy weight gain and maternal complications (p>0.05). The percentage of women who gained the Institute of Medicine (IOM)-recommended amount of weight was the highest in the underweight BMI group (54.1%) and the lowest in the obese BMI group (24.3%). Pregnancy weight gain exceeded IOM recommendations in the overweight (56.3%) and obese (52.5%) groups.

Conclusions:

While maternal weight gain during pregnancy affects neonatal body weight, higher pre-pregnancy BMI has an adverse effect on recommended weight gain during pregnancy, with increased maternal complications.

Recent attempted and actual weight change in relation to pregnancy loss: a prospective cohort study

OBJECTIVE

To assess weight change and attempted weight loss during the 12-18 months before spontaneous conception in relation to the risk of pregnancy loss.

DESIGN

Prospective cohort study.

SETTING

United States, 2007-2011.

METHODS

Women (n = 629) who were attempting pregnancy reported at baseline any weight loss attempts over the past 12 months, and their minimum and maximum weights during that time. Follow up lasted one to six menstrual cycles and throughout pregnancy. Using bodyweight measured at 4 weeks' gestation, participants were categorised as having weight loss ≥5%, weight gain ≥5%, both, or neither, over the previous 12-18 months. Log-binomial models adjusted for potential confounders.

MAIN OUTCOME MEASURES

Risk ratio (RR) and 95% confidence interval (CI) of pregnancy loss.

RESULTS

Attempted weight loss was reported by 44% of women and actual weight loss by 11%, but neither was consistently associated with pregnancy loss. The RR for recent weight gain ≥5% was 1.65 (CI 1.09, 2.49).

CONCLUSIONS

Weight gain over the period spanning 12-18 months pre-conception to 4 weeks' gestation may increase the risk of pregnancy loss among fertile women with prior pregnancy losses. Attempted and actual weight loss were not associated with pregnancy loss; however, replication is needed from larger studies with data on particular weight-loss methods.

TWEETABLE ABSTRACT

Recent weight gain before and around the time of conception may increase the risk of pregnancy loss.

Systematic review and meta-analysis on the association of prepregnancy underweight and miscarriage

BACKGROUND

Maternal underweight, overweight and obesity have been associated with a higher risk of miscarriage. Most individual reports and all meta-analyses have addressed high body mass index.

OBJECTIVES

To review the literature and summarize the risk of miscarriage in underweight women vs those with normal weight.

METHODS

A Medline Search (1st January 1990-20th November 2015, human, in English, French, Italian, Spanish or Portuguese) was conducted. Both spontaneous pregnancies and pregnancies after assisted reproduction techniques were considered. Cohort and case control studies were included if they reported data on the outcome of interest (clinical miscarriage), in underweight and normal weight women. Information on clinical miscarriage in other body mass index categories was collected when available. Two investigators reviewed the abstracts, full text papers and extracted data. Review Manager 5.1 software was used to summarize the results.

RESULTS

32 studies (30 cohort, 2 case control) and a total of 265,760 women were included. In cohort studies, the relative risk (RR) of clinical miscarriage in underweight women was 1.08, 95% CI 1.05-1.11; p<0.0001). The corresponding figures were RR 1.09, 95% CI 1.04-1.13; p<0.0001 for overweight women and RR 1.21, 95% CI 1.15-1.27; p<0.00001 for obese women. In case control studies, the odds ratio (OR) of clinical miscarriage in underweight women was 1.02, 95% CI 0.46-2.30; p=0.95). The corresponding figures were OR 1.01, 95% CI 0.88-1.16; p=0.89 for overweight women and OR 1.26, 95% CI 1.01-1.57; p=0.04 for obese women. The limitations of this study are that it is restricted to studies with information on underweight women and that I² ranges from 0 to 91% in different subgroups.

CONCLUSION

We conclude that maternal underweight is associated with a slightly increased risk of clinical miscarriage, similar to that of overweight women and lower than the risk observed in obesity. The heterogeneity displayed in some subgroups limits the strength of the conclusion.

Pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion

PURPOSE

To investigate the relation between pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion (SAB).

METHODS

Our prospective cohort study included 15,590 pregnancies from 11,072 women with no history of SAB in the Nurses' Health Study II (1991-2009). Beverage intake was assessed every 4 years using a validated questionnaire. Pregnancies were self-reported with case pregnancies lost spontaneously at <20 weeks gestation. Multivariable log-binomial regression models with generalized estimating equations were used to estimate the relative risks (RRs) and 95 % confidence intervals (CIs).

RESULTS

There was a positive linear trend across categories of pre-pregnancy caffeine intake and risk of SAB such that women consuming >400 mg/day had 1.11 (95 % CI 0.98, 1.25) times the risk of SAB compared to women consuming <50 mg/day (p trend = 0.05). Total coffee intake had a positive, linear association with SAB. Compared to women with no pre-pregnancy coffee intake, women consuming ≥4 servings/day had a 20 % (6, 36 %) increased risk of SAB (p trend = 0.01). There was no difference in the association between caffeinated and decaffeinated coffee and risk of SAB. Pre-pregnancy intake of caffeinated tea, caffeinated soda, and decaffeinated soda had no association with SAB.

CONCLUSIONS

Pre-pregnancy coffee consumption at levels ≥4 servings/day is associated with increased risk of SAB, particularly at weeks 8-19.

Contributions of the Nurses' Health Studies to Reproductive Health Research

OBJECTIVES

To review the Nurses' Health Study's (NHS's) contribution to identifying risk factors and long-term health consequences of reproductive events.

METHODS

We performed a narrative review of the NHS I, NHS II, NHS3, and Growing Up Today Study (GUTS) publications between 1976 and 2016.

RESULTS

Collection of detailed reproductive history to identify breast cancer risk factors allowed the NHS to document an association between menstrual irregularities, a proxy for polycystic ovary syndrome (PCOS), and increased risk of diabetes and cardiovascular disease. The NHS II found that infertility associated with ovulation problems and gestational diabetes are largely preventable through diet and lifestyle modification. It also identified developmental and nutritional risk factors for pregnancy loss, endometriosis, and uterine leiomyomata. As women in NHS II age, it has become possible to address questions regarding long-term health consequences of pregnancy complications and benign gynecologic conditions on chronic disease risk. Furthermore, the NHS3 and GUTS are allowing new lines of research into human fertility, PCOS, and transgenerational effects of environmental exposures.

CONCLUSIONS

The multigenerational resources of the NHSs and GUTS, including linkages of related individuals across cohorts, can improve women's health from preconception through late adulthood and onto the next generation.

Association of Fecundity With Changes in Adult Female Weight

OBJECTIVE

To evaluate whether weight change since age 18 years, current body mass index (BMI), and BMI at age 18 years are associated with fecundity.

METHODS

Our study included 1,950 women in the Nurses' Health Study 3 (2010-2014), a prospective cohort study, currently attempting pregnancy. Height, current weight, and weight at age 18 years were self-reported on the baseline questionnaire. Every 3-6 months thereafter, women reported the current duration of their pregnancy attempt. Multivariable-accelerated failure time models were used to estimate the time ratios and 95% confidence intervals (CIs).

RESULTS

For every 5-kg increase in body weight from age 18 years, current duration of pregnancy attempt increased by 5% (95% CI 3-7%). Compared with women who maintained weight, the adjusted median current duration was 0.5 months shorter in those who lost weight, 0.3 months longer for those who gained 4-9.9 kg and 10-19.9 kg, and 1.4 months longer for those who gained 20 kg or more (P trend ≤.001). The adjusted time ratio (95% CI) for a 5-kg/m increase in current BMI was 1.08 (1.04-1.12). After multivariable adjustment (including adjustment for current BMI), being underweight at age 18 years (BMI less than 18.5) was associated with a longer current duration of pregnancy attempt compared with normal-weight women (time ratio 1.25, 95% CI 1.07-1.47); however, being overweight or obese at age 18 years was not associated with fecundity.

CONCLUSION

Gaining weight in adulthood, being overweight or obese in adulthood, and being underweight at age 18 years were associated with a modest reduction in fecundity.

LEVEL OF EVIDENCE

II.