Body mass index, physical activity and fecundability in a North American preconception cohort study

Association between preconception body mass index and fertility in adult female: A systematic review and meta-analysis

Obesity potentially reduces fertility, but systematic reviews are lacking to summarize the existing literature. Therefore, we systematically summarized the association between preconception body mass index (BMI) and fertility in adult female based on existing reports. Up to September 2023, we conducted literature retrievals in different databases, including Web of Science, PubMed, Wiley, and ScienceDirect. Finally, 18 studies were included. Female with overweight/obesity (FOR = 0.85; 95% CI: 0.80, 0.90), obesity (FOR = 0.76; 95% CI: 0.69, 0.83), and overweight (FOR = 0.93; 95% CI: 0.88, 0.99) was associated with the significant time-to-pregnancy (TTP) prolongation (reduced fecundability). Interestingly, underweight was moderately associated with prolonged TTP in females (FOR = 0.95; 95% CI: 0.91, 0.99). Female overweight/obesity was associated with an increased risk of subfecundity (OR = 1.44; 95% CI: 1.20, 1.72) and infertility (OR = 1.60, 95% CI: 1.31-1.94). The findings emphasize the importance of considering appropriate preconception BMI at the population level for female fertility outcomes. In particular, prepregnancy obesity in females is strongly associated with prolonged TTP and increased risk of subfecundity. Scientific management of preconception BMI may improve fertility.

Economic evaluation of lifestyle interventions in infertility management: A systematic review

INTRODUCTION

Infertility, a global concern affecting both sexes, is influenced by modifiable and non-modifiable risk factors. While the literature predominantly underscores the clinical- and cost-effectiveness of lifestyle interventions in the realm of infertility treatment, a holistic compilation analysing the economic dimensions of such interventions is lacking. This systematic review aimed to fill this gap by evaluating the economic facets of lifestyle interventions in the management of infertility.

METHODS

An exhaustive search was conducted within the PubMed, Embase, and Scopus databases from their inception to February 2024. The aim was to find articles related to the economic aspects of lifestyle interventions in infertility management. These included clinical studies covering economic outcomes and economic evaluations. The Drummond Checklist was used to assess the quality of the included studies.

RESULTS

From an initial yield of 7555 articles, five studies were deemed eligible for inclusion, comprising three cost-effectiveness analyses, one prospective cohort study and a randomized controlled trial, all of which were undertaken in high-income countries (the Netherlands, Australia and Japan). These studies included patients receiving infertility treatments for conditions such as unexplained infertility, polycystic ovary syndrome, ovulation disorders, or mild male infertility, inclusive of individuals with and without obesity. The women who participated in these studies were up to 45 years of age. The findings suggested that integrating lifestyle intervention programmes tends to enhance pregnancy and live birth outcomes. These programmes encompass coaching, psychological or behavioural guidance, nutritional adjustments, exercise regimes, weight management, smoking cessation and mindfulness techniques. Moreover, these interventions are likely to be more cost-effective than standard infertility care.

CONCLUSION

For couples embarking on infertility treatments, the integration of lifestyle interventions into their management strategy not only fosters clinical benefits but also represents a cost-effective alternative to conventional care, particularly within high-income settings.

Impact of high-fat diet on ovarian epigenetics: Insights from altered intestinal butyric acid levels

Objective

To investigate the effects of a high-fat diet (HFD) on the gut bacterium Roseburia intestinalis and butyric acid levels, and to assess their impact on ovarian function and epigenetic markers in mice.

Methods

A total of 20 female ICR mice aged 4 weeks were randomly assigned to two groups and fed either a control diet (CD) or an HFD for 36 weeks. Post-intervention, ileal contents were analyzed for the quantification of butyric acid using ELISA, while feces were obtained for Roseburia intestinalis expression assessment via qPCR. Histological evaluations of intestinal and ovarian tissues included H&E and Alcian Blue-Periodic Acid Schiff (AB-PAS) staining, alongside immunohistochemical analysis for F4/80, and immunofluorescent detection of Occludin, ZO-1, 5 mC, and H3K36me3. Ovarian health was assessed through follicle counts and morphological evaluations. Statistical analyses were performed using GraphPad Prism 8.0, with P < 0.05 considered significant.

Results

After 36 weeks, the HFD group showed significantly higher body weight compared to the CD group (P < 0.01). The HFD led to a decrease in Roseburia intestinalis and butyric acid levels, a reduction in intestinal goblet cells, and an increase in intestinal inflammation. Histological analyses revealed impaired ovarian follicular development and enhanced inflammation in the HFD mice, with immunofluorescent staining showing downregulation of the ovarian epigenetic markers 5 mC and H3K36me3.

Conclusion

Our study demonstrates that long-term HFD negatively impacts ovarian function and epigenetic regulation. We found decreased levels of the gut bacterium Roseburia intestinalis and its metabolite, butyric acid, which contribute to these adverse effects. Additionally, the associated intestinal inflammation and compromised mucosal barrier may contribute to these adverse outcomes on female reproductive health.

PRO-FIT-CARE study: the feasibility assessment of a pilot online exercise intervention for persons living with obesity and female infertility

Introduction

Moderate-to-high physical activity participation is associated with a reduced risk of infertility. Yet, exercise interventions that target cardiorespiratory fitness, independent of weight loss, are lacking in obesity and female fertility research.

Purpose

The primary objective of the PRO-FIT-CARE (PROmoting FITness for CArdiometabolic & REproductive Health) study was to assess the feasibility of a moderate-to-high-intensity online exercise program for persons with obesity and female infertility.

Methods

Feasibility, safety, acceptability, and efficacy were assessed by examining: (1) recruitment and consent rate, (2) study retention, (3) adverse events, (4) participant satisfaction, (5) adherence, and (6) cardiorespiratory fitness.

Results

Eleven of thirty-two women contacted agreed to participate in the program (34.4% consent rate). Eight participants (72.7%) completed the study. One musculoskeletal injury was reported. There was a 30% adherence rate based on prescribed exercise intensity (60%-80% of heart rate maximum). One of eleven participants attended 80% of the exercise intervention. Based on a weekly satisfaction survey, the program had an overall high level of satisfaction. Compared to sex and age normative data, post-intervention, two of eight participants improved their cardiorespiratory fitness percentile rank.

Conclusion

The study highlights challenges with adherence to an online exercise program. While the program was safe and participants reported high levels of program satisfaction, approaches to improve adherence must be incorporated.

Endometrium development patterns and BMI groups among in vitro fertilization patients; prognostic aspects

Introduction

The impact of the obesity pandemic on female reproductive capability is a factor that needs to be investigated. In addition, the link between endometrial thickness and in vitro fertilization (IVF) outcomes is contentious.

Goal

Our goal was to analyze the association among endometrium development, hormone levels, embryo quality, clinical pregnancy, anamnestic parameters, and body mass index (BMI) in women receiving IVF treatment.

Patients and methods

537 participants undergoing IVF/ICSI cycles with successful oocyte retrieval were enrolled. Subjects were divided into four BMI based groups: underweight (UW; n=32), normal weight (NW; n=324), overweight (OW; n= 115), obesity (OB; n=66). Anthropometric and anamnestic parameters, characteristics of stimulation, endometrial thickness on the day of hCG injection, at puncture, at embryo transfer, FSH, LH, AMH, partner's age and the semen analysis indicators, embryo quality, clinical pregnancy, were recorded and analyzed. Support Vector Machine (SVM) was built to predict potential pregnancies based on medical data using 22 dimensions.

Results

In accordance with BMI categories, when examining pregnant/non-pregnant division, the average age of pregnant women was significantly lower in the UW (30.9 ± 4.48 vs. 35.3 ± 5.49 years, p=0.022), NW (34.2 ± 4.25 vs. 36.3 ± 4.84 years, p<0.001), and OW (33.8 ± 4.89 vs. 36.3 ± 5.31 years, p=0.009) groups. Considering FSH, LH, and AMH levels in each BMI category, a statistically significant difference was observed only in the NW category FSH was significantly lower (7.8 ± 2.99 vs. 8.6 ± 3.50 IU/L, p=0.032) and AMH (2.87 ± 2.40 vs. 2.28 ± 2.01 pmol/L, p=0.021) was higher in pregnant women. There were no further statistically significant differences observed between the pregnant and non-pregnant groups across any BMI categories, especially concerning endometrial development. Surprisingly, BMI and weight correlated negatively with FSH (r=-0.252, p<0.001; r=-0.206, p<0.001, respectively) and LH (r= -0.213, p<0.001; r= -0.195, p<0.001) in the whole population. SVM model average accuracy on predictions was 61.71%.

Discussion

A convincing correlation between endometrial thickness development and patients' BMI could not be substantiated. However, FSH and LH levels exhibited a surprising decreasing trend with increasing BMI, supporting the evolutionary selective role of nutritional status. Our SVM model outperforms previous models; however, to confidently predict the outcome of embryo transfer, further optimization is necessary.

The impact of metabolic surgery on natural conception rates in women with infertility, obesity and polycystic ovary syndrome: a retrospective study

BACKGROUND

Women with obesity and polycystic ovary syndrome (OPOS) are at high risk for infertility. However, the reproductive effects of metabolic surgery on women with infertility and OPOS have not been fully elucidated.

OBJECTIVES

We investigated the natural conception rates after metabolic surgery, and the variables associated with infertility in women with OPOS.

SETTING

Shanghai Sixth People's Hospital, Shanghai, China.

METHODS

This study included 72 women with infertility and OPOS who underwent metabolic surgery and were followed up for 4 years after surgery. Finally, 54 patients completed the study. Reproductive outcomes were assessed, along with changes in anthropometric parameters and metabolic indices before and 1 year after surgery (prepregnancy). Logistic regression analysis was used to identify variables influencing natural conception and delivery outcomes.

RESULTS

After metabolic surgery, 35 patients (64.8%) became pregnant naturally, while 16 were still unable to conceive naturally. Preoperative body mass index (BMI) tended to be lower in the natural conception group than in the no natural conception group (38.9 ± 6.9 versus 43.6 ± 11.0 kg/m2, P = .070) and there were no significant differences in weight loss between the 2 groups after surgery. Logistic regression analysis showed that the BMI 1 year after surgery (prepregnancy) was an independent predictor of natural conception, and receiver operating characteristic analysis showed that a BMI of 27.0 kg/m2 was the optimal cutoff for predicting successful natural conception after surgery.

CONCLUSIONS

Metabolic surgery can improve fertility in women with OPOS. Patients with a BMI < 27.0 kg/m2 1 year after surgery (prepregnancy) are more likely to become pregnant naturally and give birth.

Associations between weight-adjusted-waist index and infertility: Results from NHANES 2013 to 2020

Female infertility is a significant problem for women of reproductive age worldwide. Obesity has been proven to pose a danger for infertility in women. Weight-adjusted waist circumference index (WWI) is a recently created biomarker of obesity, and this research aims to explore the relationship between female infertility and WWI. Data for this investigation were gathered from National Health and Nutrition Examination Survey. We used weighted multivariate logistic regression, subgroup analysis, interaction testing, and smoothed curve fitting to investigate the relationship between infertility and WWI. A total of 6333 women were included and 708 (11.18%) had infertility. It was discovered that women with higher WWI had increased probabilities of infertility (OR = 1.92, 95% CI: 1.42-2.59) adjusting for confounders. In addition, WWI was linked to increased chances of infertility in women aged 28 to 36 years (OR = 1.59, 95% CI: 1.28-1.97). According to the results of this cross-sectional survey, WWI is positively associated with infertility among adult females in the U.S. And it can help identify infertile women and may help reduce the risk of infertility.

Activity Behaviors Before and During Pregnancy Are Associated With Women's Device-Measured Physical Activity and Sedentary Time in Later Parenthood: A Longitudinal Cohort Analysis

PURPOSE

To explore how activity behaviors before/during pregnancy relate to those in later parenthood, we assessed associations between sitting and moderate-/strenuous exercise before/during pregnancy, and sedentary time (SED) and moderate to vigorous physical activity (MVPA) 4-7 years postpartum ("later parenthood").

METHODS

Longitudinal data were from the Southampton Women's Survey, United Kingdom. Women reported time spent sitting (in hours per day), in moderate-strenuous exercise (hours per week), and in strenuous exercise (hours per week) at 3 time points before/during pregnancy (ie, preconception, at ∼12-wk and ∼34-wk gestation). From this, we derived 3 behavior trajectories for each woman. In later parenthood, women wore an accelerometer for ≤7 days (mean: 5.4 [SD: 1.8] d), which we used to derive 2 outcomes: minutes per day SED and in MVPA. Multilevel linear regression was used to explore associations between trajectories before/during pregnancy and device-measured SED/MVPA in later parenthood.

RESULTS

A total of 780 women provided valid data before/during pregnancy and in later parenthood. Consistent high sitters (vs low) were more sedentary 4-7 years postpartum (β = 39.5 min/d [95% confidence interval, 23.26 to 55.82]), as were women in groups who sat more in later pregnancy. Consistently high moderate/-strenuous exercisers (vs low) were 22% (95% confidence interval, 2%-47%) more active in later parenthood; those engaging in strenuous activity preconception tended to have higher MVPA as parents.

CONCLUSIONS

Trajectories of sitting and exercise before/during pregnancy are associated with SED and MVPA, respectively, in later parenthood. Interventions to reduce sitting in pregnancy and to encourage higher intensity activity preconception may benefit maternal and child health.

Association between weight-adjusted-waist index and female infertility: a population-based study

Aims

Obesity is detrimental to infertility. The association between weight-adjusted-waist index (WWI, a recently developed adiposity indicator) and infertility has not previously been confirmed.

Methods

The data for this study were obtained from the National Health and Nutrition Examination Survey (NHANES) 2013-2018. Each participant's WWI was calculated as their waist circumference in centimeters by the square root of weight in kilograms. Multivariable logistic regression and generalized additive model were utilized to investigate the relationship between WWI with infertility. We used smoothed curve fitting to explore the non-linear relationship. Subgroup analysis and interaction tests were also conducted.

Results

A total of 3,526 participants with ages from18 to 45 were enrolled, 364 of whom were infertile. With the higher WWI, infertility was more prevalent (OR = 1.42, 95% CI: 1.22-1.65), and this association was still consistent in subgroups (all P for interaction> 0.05). Smoothed curve fitting showed a positive non-linear relationship between WWI and infertility. Furthermore, we discovered that WWI had a stronger connection with the risk of infertility than other markers of obesity including WC, body mass index (BMI) and a body shape index (ABSI).

Conclusions

Weight-adjusted-waist index levels were positively linked to an increased risk of infertility in American females and showed a stronger association than other markers of obesity. Our research indicated WWI could help identify women with infertility, and managing obesity as determined by WWI may help to reduce the risk of infertility.

Association of male fatty acid intake with fecundability among couples planning pregnancy

STUDY QUESTION

To what extent is male fatty acid intake associated with fecundability among couples planning pregnancy?

SUMMARY ANSWER

We observed weak positive associations of male dietary intakes of total and saturated fatty acids with fecundability; no other fatty acid subtypes were appreciably associated with fecundability.

WHAT IS KNOWN ALREADY

Male fatty acid intake has been associated with semen quality in previous studies. However, little is known about the extent to which male fatty acid intake is associated with fecundability among couples attempting spontaneous conception.

STUDY DESIGN, SIZE, DURATION

We conducted an internet-based preconception prospective cohort study of 697 couples who enrolled during 2015-2022. During 12 cycles of observation, 53 couples (7.6%) were lost to follow-up.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were residents of the USA or Canada, aged 21-45 years, and not using fertility treatment at enrollment. At baseline, male participants completed a food frequency questionnaire from which we estimated intakes of total fat and fatty acid subtypes. We ascertained time to pregnancy using questionnaires completed every 8 weeks by female participants until conception or up to 12 months. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs for the associations of fat intakes with fecundability, adjusting for male and female partner characteristics. We used the multivariate nutrient density method to account for energy intake, allowing for interpretation of results as fat intake replacing carbohydrate intake. We conducted several sensitivity analyses to assess the potential for confounding, selection bias, and reverse causation.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 697 couples, we observed 465 pregnancies during 2970 menstrual cycles of follow-up. The cumulative incidence of pregnancy during 12 cycles of follow-up after accounting for censoring was 76%. Intakes of total and saturated fatty acids were weakly, positively associated with fecundability. Fully adjusted FRs for quartiles of total fat intake were 1.32 (95% CI 1.01-1.71), 1.16 (95% CI 0.88-1.51), and 1.43 (95% CI 1.09-1.88) for the second, third, and fourth vs the first quartile, respectively. Fully adjusted FRs for saturated fatty acid intake were 1.21 (95% CI 0.94-1.55), 1.16 (95% CI 0.89-1.51), and 1.23 (95% CI 0.94-1.62) for the second, third, and fourth vs the first quartile, respectively. Intakes of monounsaturated, polyunsaturated, trans-, omega-3, and omega-6 fatty acids were not strongly associated with fecundability. Results were similar after adjustment for the female partner's intakes of trans- and omega-3 fats.

LIMITATIONS, REASONS FOR CAUTION

Dietary intakes estimated from the food frequency questionnaire may be subject to non-differential misclassification, which is expected to bias results toward the null in the extreme categories when exposures are modeled as quartiles. There may be residual confounding by unmeasured dietary, lifestyle, or environmental factors. Sample size was limited, especially in subgroup analyses.

WIDER IMPLICATIONS OF THE FINDINGS

Our results do not support a strong causal effect of male fatty acid intakes on fecundability among couples attempting to conceive spontaneously. The weak positive associations we observed between male dietary fat intakes and fecundability may reflect a combination of causal associations, measurement error, chance, and residual confounding.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the National Institutes of Health, grant numbers R01HD086742 and R01HD105863. In the last 3 years, PRESTO has received in-kind donations from Swiss Precision Diagnostics (home pregnancy tests) and Kindara.com (fertility app). L.A.W. is a consultant for AbbVie, Inc. M.L.E. is an advisor to Sandstone, Ro, Underdog, Dadi, Hannah, Doveras, and VSeat. The other authors have no competing interests to report.

TRIAL REGISTRATION NUMBER

N/A.

Mitochondrial dysfunction in the offspring of obese mothers and it's transmission through damaged oocyte mitochondria: Integration of mechanisms

In vivo and in vitro studies demonstrate that mitochondria in the oocyte, are susceptible to damage by suboptimal pre/pregnancy conditions, such as obesity. These suboptimal conditions have been shown to induce mitochondrial dysfunction (MD) in multiple tissues of the offspring, suggesting that mitochondria of oocytes that pass from mother to offspring, can carry information that can programme mitochondrial and metabolic dysfunction of the next generation. They also suggest that transmission of MD could increase the risk of obesity and other metabolic diseases in the population inter- and trans-generationally. In this review, we examined whether MD observed in offspring tissues of high energetic demand, is the result of the transmission of damaged mitochondria from obese mothers' oocytes to the offspring. The contribution of genome-independent mechanisms (namely mitophagy) in this transmission were also explored. Finally, potential interventions aimed at improving oocyte/embryo health were investigated, to see if they may provide an opportunity to halter the generational effects of MD.

Impact of Physical Activity and Sedentary Behavior on Spontaneous Female and Male Fertility: A Systematic Review

BACKGROUND

Before pregnancy is recognized, ovulation, fertilization, and implantation must all occur. Physical activity and sedentary behavior may impact pregnancy success by altering each or all of these processes. The aim of this review was to review the association between physical activity and sedentary behavior with spontaneous female and male fertility.

METHOD

PubMed/MEDLINE, Web of Science, CINAHL, SPORTDiscus, and Embase were searched from inception to August 9, 2021. Eligible studies included randomized controlled trials or observational studies, published in English, describing an association between physical activity or sedentary behavior (exposures) and spontaneous fertility (outcome) among women or men.

RESULTS

Thirty-four studies from 31 unique populations were included in this review (12 cross-sectional studies, 10 cohort studies, 6 case-control studies, 5 randomized controlled trials, and one case-cohort study). Of the 25 studies among women, the majority identified mixed results (n = 11) or no association (n = 9) between physical activity and female fertility. Seven studies reported on female fertility and sedentary behavior, and 2 found sedentary behavior was associated with decreased female fertility. Of the 11 studies among men, most of the studies (n = 6) found that physical activity was associated with increased male fertility. Two of the studies reported on male fertility and sedentary behavior, and neither identified an association.

CONCLUSIONS

The association between spontaneous fertility and physical activity in both men and women remains unclear, and the association with sedentary behavior remains largely unexplored.

Associations between Residential Greenspace and Fecundability in a North American Preconception Cohort Study

BACKGROUND

Residential green space can have positive physiological effects on human health through various mechanisms, including reducing stress and/or depression or facilitating physical activity. Although green space has been consistently associated with improved birth outcomes in several studies, there has been limited study of its effect on other reproductive outcomes, including fertility.

OBJECTIVE

We examined associations between residential green space and fecundability, the per-cycle probability of conception.

METHODS

We analyzed data from 8,563 female participants enrolled between 2013 and 2019 in Pregnancy Study Online (PRESTO), a prospective preconception cohort study of North American couples attempting conception. Participants completed a baseline questionnaire on sociodemographic, behavioral, and reproductive factors, and bimonthly follow-up questionnaires for up to 12 months to ascertain pregnancies. Using geocoded addresses, we calculated residential green space exposure using the Normalized Difference Vegetation Index (NDVI) within 50-, 100-, 250-, and 500 -m buffers across multiple temporal scales: annual maximum, seasonal maximum, and seasonal mean. We used proportional probabilities regression models to estimate fecundability ratios (FRs), adjusting for sociodemographic, behavioral, and neighborhood characteristics. We also evaluated the extent to which associations were mediated by reductions in perceived stress or depressive symptoms and increased physical activity.

RESULTS

When comparing the highest (≥ 0.8 ) with the lowest (< 0.2 ) NDVI exposures within 50 m , we observed positive associations in the annual maximum NDVI [FR: 1.33; 95% confidence interval (CI): 1.06, 1.67] and seasonal maximum NDVI (FR: 1.19; 95% CI: 1.00, 1.41) models, but little association in the seasonal mean NDVI models (FR: 0.98; 95% CI: 0.73, 1.30). Restricted cubic splines showed evidence of nonlinearity in this association. Results were similar across buffer distances. Perceived stress, depressive symptoms, and physical activity explained ≤ 5 : 0 % of mediation across all NDVI metrics.

DISCUSSION

In this cohort, greater residential green space was associated with a modest increase in fecundability. https://doi.org/10.1289/EHP10648.

Preconception sleep duration, sleep timing, and shift work in association with fecundability and live birth among women with a history of pregnancy loss

OBJECTIVE

To evaluate the associations between preconception sleep characteristics and shift work with fecundability and live birth.

DESIGN

Secondary analysis of the Effects of Aspirin in Gestation and Reproduction study, a preconception cohort.

SETTING

Four US academic medical centers.

PATIENT(S)

Women aged 18-40 with a history of 1-2 pregnancy losses who were attempting to conceive again.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURES(S)

We evaluated baseline, self-reported sleep duration, sleep midpoint, social jetlag, and shift work among 1,228 women who were observed for ≤6 cycles of pregnancy attempts to ascertain fecundability. We ascertained live birth at the end of follow up via chart abstraction. We estimated fecundability odds ratios (FORs) using discrete, Cox proportional hazards models and risk ratios (RRs) for live birth using log-Poisson models.

RESULT(S)

Sleep duration ≥9 vs. 7 to <8 hours (FOR: 0.81, 95% confidence interval [CI], 0.61; 1.08), later sleep midpoints (3rd tertile vs. 2nd tertile: FOR: 0.85; 95% CI, 0.69, 1.04) and social jetlag (continuous per hour; FOR: 0.93, 95% CI: 0.86, 1.00) were not associated with reduced fecundability. In sensitivity analyses, excluding shift workers, sleep duration ≥9 vs. 7 to <8 hours (FOR: 0.62; 95% CI, 0.42; 0.93) was associated with low fecundability. Night shift work was not associated with fecundability (vs. non-night shift work FOR: 1.17, 95% CI, 0.96; 1.42). Preconception sleep was not associated with live birth.

CONCLUSION(S)

Overall, there does not appear to be a strong association between sleep characteristics, fecundability, and live birth. Although these findings may suggest weak and imprecise associations with some sleep characteristics, our findings should be evaluated in larger cohorts of women with extremes of sleep characteristics.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT00467363.

Modifiable Risk Factor Score and Fecundability in a Preconception Cohort in Singapore

IMPORTANCE

Although multiple modifiable risk factors have been identified for reduced fecundability (defined as lower probability of conception within a menstrual cycle), no scoring system has been established to systematically evaluate fecundability among females who are attempting to conceive.

OBJECTIVE

To examine the association of a risk score based on 6 modifiable factors with fecundability, and to estimate the percentage reduction in incidence of nonconception if all study participants achieved a minimal risk score level.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study obtained data from the S-PRESTO (Singapore Preconception Study of Long-Term Maternal and Child Outcomes) prospective cohort study. Females of reproductive age who were trying to conceive were enrolled from February 2015 to October 2017 and followed for 1 year, ending in November 2018. Data were analyzed from March to May 2022.

EXPOSURES

A reduced fecundability risk score was derived by giving participants 1 point for each of the following factors: unhealthy body mass index, unhealthy diet, smoking, alcohol intake, folic acid supplement nonuser, and older maternal age. Total scores ranged from 0 to 6 and were classified into 5 levels: level 1 (score of 0 or 1), level 2 (score of 2), level 3 (score of 3), level 4 (score of 4), and level 5 (score of 5 or 6).

MAIN OUTCOMES AND MEASURES

Fecundability, measured by time to conception in cycles, was analyzed using discrete-time proportional hazards models with confounder adjustment.

RESULTS

A total of 937 females (mean [SD] age, 30.8 [3.8] years) were included, among whom 401 (42.8%) spontaneously conceived within 1 year of attempting conception; the median (IQR) number of cycles before conception was 4 (2-7). Compared with participants with a level 1 risk score, those with level 2, 3, 4, and 5 risk scores had reductions in fecundability of 31% (adjusted fecundability ratio [FR], 0.69; 95% CI, 0.54-0.88), 41% (FR, 0.59; 95% CI, 0.45-0.78), 54% (FR, 0.46; 95% CI, 0.31-0.69) and 77% (FR, 0.23; 95% CI, 0.07-0.73), respectively. Assessment of the population attributable fraction showed that all participants achieving a minimal (level 1) risk level would be associated with a reduction of 34% (95% CI, 30%-39%) in nonconception within a year.

CONCLUSIONS AND RELEVANCE

Results of this study revealed the co-occurrence of multiple modifiable risk factors for lowered fecundability and a substantially higher conception rate among participants with no or minimal risk factors. The risk assessment scoring system proposed is a simple and potentially useful public health tool for mitigating risks and guiding those who are trying to conceive.

Preconception exposure to perfluoroalkyl and polyfluoroalkyl substances and couple fecundity: A couple-based exploration

Numerous studies have examined the adverse health effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) but it remains unclear whether preconception exposure to PFAS affects couple fecundity. This prospective preconception cohort study with 936 Chinese couples aimed to comprehensively assess the effects of PFAS on couple fecundity [measured by the time to pregnancy (TTP)] and infertility (i.e., TTP > 12 menstrual cycles) with a focus on the effects of partner-specific exposure and joint-effects of couple-based exposure. Twenty-five PFAS were quantified in plasma from each partner, including seven branched isomers, two chlorinated polyfluoroalkyl ether sulfonic acids, four emerging PFAS replacements [i.e., 6:2 fluorotelomer phosphate diester (6:2 diPAP) and three short-chain alternatives: perfluoro-n-butanoicacid, perfluorobutane sulfonate and perfluoroheptanoic acid (PFHpA)]. Using a two-phase regression approach composed of elastic net regression and principal component analysis, we found that exposure to 6:2 diPAP and PFHpA rather than legacy PFAS in women and the couple-based exposure patterns characterized by high level of female 6:2 diPAP were significantly associated with reduced couple fecundity, which was independent of the adjustment of co-exposed PFAS homogenous from both partners. For example, a ln unit increase in female 6:2 diPAP was associated with 15 % [fecundity odds ratio (FOR) = 0.85, 95 %CI: 0.76, 0.96)] lower odds of couple fecundability (i.e., longer TTP) and 45 % increased risk of infertility [OR = 1.45 (95 %CI: 1.16, 1.81)], respectively. While most PFAS in men were not associated with couple fecundity, certain PFAS (e.g., perfluorohexane sulfonic acid) in men were negatively associated with infertility risk. However, the combined effects of PFAS mixture in couples were nonsignificant. Our findings suggest that PFAS in men and women may exert different impacts on couple fecundity. Preconception exposure to 6:2 diPAP and PFHpA in women may have the potential to impair couple fecundity.

Dietary Supplement Intake and Fecundability in a Singapore Preconception Cohort Study

Subfertility is a global problem affecting millions worldwide, with declining total fertility rates. Preconception dietary supplementation may improve fecundability, but the magnitude of impact remains unclear. This prospective cohort study aimed to examine the association of preconception micronutrient supplements with fecundability, measured by time to pregnancy (TTP). The study was conducted at KK Women's and Children's Hospital, Singapore, between February 2015 and October 2017, on 908 women aged 18-45 years old, who were trying to conceive and were enrolled in the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO). Baseline sociodemographic characteristics and supplement intake were collected through face-to-face interviews. The fecundability ratio (FR) was estimated using discrete-time proportional hazard modelling. Adjusting for potentially confounding variables, folic acid (FA) (FR 1.26, 95% confidence interval 1.03-1.56) and iodine (1.28, 1.00-1.65) supplement users had higher fecundability compared to non-users. Conversely, evening primrose oil supplement users had lower fecundability (0.56, 0.31-0.99) than non-users. In this study, preconception FA and iodine supplementation were associated with shortened TTP, while evening primrose oil use was associated with longer TTP. Nonetheless, the association between supplement use and the magnitude of fecundability changes will need to be further confirmed with well-designed randomised controlled trials.

Effects of physical activity and sleep duration on fertility: A systematic review and meta-analysis based on prospective cohort studies

Objective

Subfertility is a common problem for couples in modern society. Many studies have confirmed that lifestyle factors can affect fertility although there are conflicting conclusions relating to the effects of physical activity and sleep duration on fertility. In this study, we aimed to summarize and analyze the available evidence.

Methods

PubMed, Web of Science, Cochrane, and Embase databases (as of October 14, 2022) were systematically searched for eligible prospective cohort studies. Data were extracted and effect values were combined. We also performed methodological quality and bias risk assessments for all the included studies.

Results

A total of 10 eligible articles were included in our analysis; seven investigated the relationship between physical activity and fertility, and three investigated the effect of sleep duration on fertility. Compared with the lowest level of physical activity, high intensity physical activity (the highest levels of physical activity) was negatively correlated with fertility [odds ratio (OR) = 0.84; 95% confidence interval (CI): 0.70, 1.00, I ² = 64%]. However, we did not find an association between moderate intensity physical activity and fertility (OR = 1.09; 95% CI: 0.98, 1.22, I ² = 60%). We observed an inverse association between limited sleep duration (≤ 7 h) and fertility (OR = 0.92; 95% CI: 0.84, 1.00, I ² = 0%) compared with 8 h of sleep. The relationship between long sleep duration (≥9 h) and fertility was not statistically significant (OR = 0.85; 95% CI: 0.60, 1.21, I ² = 83%). According to the Newcastle-Ottawa Scale score, the overall quality of the research articles included was ranked as medium to high (6-9). Through GRADE system, the quality of evidence for the impact of high intensity physical activity and limited sleep duration on fertility was moderate, while the quality of evidence for the impact of moderate intensity physical activity and long sleep duration on fertility was low.

Conclusion

The current evidence shows that high intensity physical activity and limited sleep time are negatively related to fertility. But there was great heterogeneity among studies, and the quality of research evidence was low to median. Thus, further high-quality research is needed to confirm this conclusion.

PROSPERO registration number

CRD42022298137.

Male personal heat exposures and fecundability: A preconception cohort study

BACKGROUND

Several studies indicate adverse effects of selected heat exposures on semen quality, but few studies have directly evaluated fertility as an endpoint.

OBJECTIVE

We evaluated prospectively the association between male heat exposures and fecundability, the per-cycle probability of conception.

MATERIALS AND METHODS

We analyzed data from 3041 couples residing in the United States or Canada who enrolled in a prospective preconception cohort study (2013-2021). At enrollment, males reported on several heat-related exposures, such as use of saunas, hot baths, seat heaters, and tight-fitting underwear. Pregnancy status was updated on female follow-up questionnaires every 8 weeks until conception or a censoring event (initiation of fertility treatment, cessation of pregnancy attempts, withdrawal, loss to follow-up, or 12 cycles), whichever came first. We used proportional probabilities regression models to estimate fecundability ratios (FR) and 95% confidence intervals (CIs) for the association between heat exposures and fecundability, mutually adjusting for heat exposures and other potential confounders.

RESULTS

We observed small inverse associations for hot bath/tub use (≥3 vs. 0 times/month: FR = 0.87, 95% CI: 0.70-1.07) and fever in the 3 months before baseline (FR = 0.94, 95% CI: 0.79-1.12; one cycle of follow-up: FR = 0.84, 95% CI: 0.64-1.11). Little association was found for sauna use, hours of laptop use on one's lap, seat heater use, time spent sitting, and use of tight-fitting underwear. Based on a cumulative heat metric, FRs for 1, 2, 3, and ≥4 versus 0 heat exposures were 0.99 (95% CI: 0.87-1.12), 1.03 (95% CI: 0.89-1.19), 0.94 (95% CI: 0.74-1.19), and 0.77 (95% CI: 0.50-1.17), respectively. Associations were stronger among men aged ≥30 years (≥4 vs. 0 heat exposures: FR = 0.60, 95% CI: 0.34-1.04).

CONCLUSION

Male use of hot tubs/baths and fever showed weak inverse associations with fecundability. Cumulative exposure to multiple heat sources was associated with a moderate reduction in fecundability, particularly among males aged ≥30 years.

Habitual physical activity levels in women attending the one stop infertility clinic: A prospective cross-sectional observational study

Optimisation of lifestyle factors such as smoking and alcohol are encouraged to improve fecundability rates in the fertility setting. Currently, routine fertility consultations do not involve counselling or imparting advice regarding habitual physical activity (PA) and/or structured exercise, despite data showing that vigorous PA can be associated with delayed time to pregnancy. Therefore, this study aimed to determine habitual PA in a sample of women attending the one stop infertility (OSI) clinic. 250 women attending a large tertiary level NHS fertility unit prospectively anonymously completed a questionnaire over a period of 9 months. Participant's (mean age 34±5years, mean BMI 29±7kg/m2) habitual PA levels varied from vigorous exercise on ≥5 days/week (8%, n=17), to no moderate or high intensity activities across the whole week (66%, n=29). The majority of women reported no structured exercise (72%, n=179). No association was identified between any domain of PA and BMI, age, alcohol units, regular periods, or time spent trying to conceive (P > 0.05). Participant's habitual PA levels varied widely and no association between any domain of PA and background of the women was identified. No existing evidence and/or guidelines to explicitly inform women attempting to conceive regarding recommended PA levels are available, despite PA being a modifiable, affordable, and feasible lifestyle choice with the possible potential to improve fertility. A large-scale, clinical trial assessing effects of PA on fecundability is warranted to gain insights into the potential of this lifestyle factor to improve fertility outcomes and to explore the underlying biological mechanisms involved.

Metabolic health status and fecundability in a Singapore preconception cohort study

BACKGROUND

Obesity compromises metabolic health and female fertility, yet not all obese women are similar in metabolic status. The extent to which fecundability is influenced by the metabolic health status of women who are overweight or obese before conception is unknown.

OBJECTIVE

This study aimed to: (1) determine the metabolic health status, and (2) examine the association between metabolic health status and fecundability of overweight and obese women trying to conceive in the Singapore PREconception Study of long-Term maternal and child Outcomes cohort study.

STUDY DESIGN

We conducted a prospective preconception cohort study of Asian women (Chinese, Malay, and Indian) aged 18 to 45 years trying to conceive who were treated from 2015 to 2017 in KK Women's and Children's Hospital in Singapore (n=834). We defined women to have metabolically unhealthy status if they: (1) met 3 or more modified Joint Interim Statement metabolic syndrome criteria; or (2) had homeostasis model assessment-insulin resistance index ≥2.5. Body mass index was categorized as normal (18.5-22.9 kg/m2), overweight (23-27.4 kg/m2), or obese (≥27.5 kg/m2) on the basis of cutoff points for Asian populations. Fecundability was measured by time to pregnancy in menstrual cycles within a year of enrolment. Discrete-time proportional hazards models were used to estimate fecundability odds ratios, with adjustment for confounders and accounting for left truncation and right censoring.

RESULTS

Of 232 overweight women, 28 (12.1%) and 25 (10.8%) were metabolically unhealthy by metabolic syndrome ≥3 criteria and homeostasis model assessment-insulin resistance ≥2.5, respectively. Of 175 obese women, 54 (30.9%) and 93 (53.1%) were metabolically unhealthy by metabolic syndrome ≥3 criteria and homeostasis model assessment-insulin resistance ≥2.5, respectively. Compared with metabolically healthy normal-weight women, lower fecundability was observed in metabolically unhealthy overweight women on the basis of metabolic syndrome criteria (fecundability odds ratios, 0.38 [95% confidence interval, 0.15-0.92]) and homeostasis model assessment-insulin resistance (fecundability odds ratios, 0.68 [95% confidence interval, 0.33-1.39]), with metabolic syndrome criteria showing a stronger association. Metabolically unhealthy obese women showed lower fecundability than the healthy normal-weight reference group by both metabolic syndrome (fecundability odds ratios, 0.35; 95% confidence interval, 0.17-0.72) and homeostasis model assessment-insulin resistance criteria (fecundability odds ratios, 0.43; 95% confidence interval, 0.26-0.71). Reduced fecundability was not observed in overweight or obese women who showed healthy metabolic profiles by either definition.

CONCLUSION

Overweight or obesity was not synonymous with having metabolic syndrome or insulin resistance. In our preconception cohort, metabolically unhealthy overweight and obese women showed reduced fecundability, unlike their counterparts who were metabolically healthy. These findings suggest that metabolic health status, rather than simply being overweight and obese per se, plays an important role in fecundability.

A Prospective Study of Male Depression, Psychotropic Medication Use, and Fecundability

We examined the associations of male depression and psychotropic medication use with fecundability in a North American preconception cohort study (2013–2020). Men aged ≥21 years completed a baseline questionnaire with questions on history of diagnosed depression, the Major Depression Inventory (MDI), and psychotropic medication use. Pregnancy status was updated via bimonthly female follow-up questionnaires until pregnancy or 12 menstrual cycles, whichever occurred first. Analyses were restricted to 2,398 couples attempting conception for ≤6 menstrual cycles at entry. We fit proportional probabilities models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for age (male and female), education, (male and female), race/ethnicity, physical activity, alcohol intake, body mass index, smoking, and having previously impregnated a partner. Nearly 12% of participants reported a depression diagnosis; 90.6% had low depressive symptoms (MDI <20), 3.5% had mild symptoms (MDI: 20–24), 2.7% had moderate symptoms (MDI: 25–29), and 3.3% had severe symptoms (MDI: ≥30). A total of 8.8% of participants reported current use of psychotropic medications. History of depression was associated with slightly reduced fecundability, although this result was also reasonably compatible with chance (FR = 0.89; 95% CI: [0.76, 1.04]). FRs for mild, moderate, and severe compared with low depressive symptoms were 0.89 (95% CI: [0.66, 1.21]), 0.90 (95% CI: [0.62, 1.31]), and 0.88 (95% CI: [0.65, 1.20]), respectively. This indicates little evidence of a dose–response relationship for depressive symptoms with fecundability, although estimates were imprecise. Current psychotropic medication use mediated 44% of the association between depressive symptoms and fecundability.

Retinal microvasculature and time to pregnancy in a multi-ethnic pre-conception cohort in Singapore

STUDY QUESTION

Can abnormalities in retinal microvasculature representing adverse microcirculatory perfusion and inflammation shed light on the pathophysiology of female fecundability?

SUMMARY ANSWER

In our prospective study, abnormalities in retinal vascular geometric morphology (i.e. sparser arteriolar fractal and larger venular bifurcation) during pre-conception phase are temporarily associated with a prolonged time-to-pregnancy (TTP).

WHAT IS KNOWN ALREADY

Suboptimal retinal microcirculatory morphology has been associated with obesity, psychological stress and hypertension, all of which are known risk factors for reduced female fecundability.

STUDY DESIGN, SIZE, DURATION

A total of 652 women of Chinese, Malay or Indian ethnicity 18-45 years of age and planning to conceive spontaneously within the next 12 months were recruited during the pre-conception period into the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO), from February 2015 to October 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

During recruitment, we collected information on socio-demographic factors, menstrual characteristics and lifestyle behaviors and made anthropometric measurements. We assessed the following retinal microvascular features: caliber, branching angle and fractal dimension. We conducted follow-up telephone surveys to track each participant's pregnancy status at 6, 9 and 12 months after enrolment. We ascertained clinical pregnancies via ultrasonography, with TTP measured by the number of menstrual cycles required to achieve a clinical pregnancy over a 1-year follow-up. Then, we performed discrete-time proportional hazards models to estimate the fecundability odds ratio (FOR) and 95% CI for each retinal microvascular feature in association with TTP, after adjusting for major confounders, including body mass index and fasting glycemic level at study entry.

MAIN RESULTS AND THE ROLE OF THE CHANCE

Among 652 recruited women, 276 (42.3%) successfully conceived within 1 year of follow-up. The mean (and SD) was 1.24 (0.05) Df for retinal arteriolar dimension fraction and 78.45 (9.79) degrees for retinal venular branching angle, respectively. Non-linear relationship testing was performed before multiple adjustment in all associations and a non-monotonic association was detected between retinal venular branching angle and TTP. Compared with women in the highest tertile of retinal arteriolar fractal dimension, women in the second tertile had a prolonged TTP (FOR: 0.68; 95% CI: 0.51-0.92), as did women in the lowest tertile (FOR: 0.73; 95% CI: 0.55-0.98). Compared with women in the middle tertile of retinal venular branching angle, women in the highest tertile had a borderline prolonged TTP (FOR: 0.75; 95% CI: 0.56-1.02). No other retinal vascular features were significantly associated with TTP.

LIMITATIONS, REASONS FOR CAUTION

We were unable to adjust for other potential confounding factors such as female sexual function (e.g. frequency of sexual intercourse), which might introduce a residual bias. Moreover, even though this is a prospective cohort design, our findings can identify the temporal relationship but not necessarily infer a causal relationship between maternal microvasculature and TTP. Lastly, our study involving mainly Chinese, Malay and Indian ethnicities might not be generalizable to other races or ethnicities.

WIDER IMPLICATIONS OF THE FINDINGS

Suboptimal microcirculation may lead to reduced female fecundability. In the future, in addition to conventional ultrasonographic evaluation of ovarian and uterine physiological function, assessing the retinal microvasculature might be useful for assessment of ovarian age, fertility prediction and endometrial evaluation before assisted reproductive techniques for fertility treatments.

STUDY FUNDING/COMPETING INTEREST(S)

This research is supported by the Singapore National Research Foundation (NRF) under its Translational and Clinical Research (TCR) Flagship Programme and administered by the Singapore Ministry of Health's National Medical Research Council (NMRC) (Singapore-NMRC/TCR/004-NUS/2008; NMRC/TCR/012-NUHS/2014) and Singapore National Medical Research Council Transition Award (NMRC TA/0027/2014). The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT03531658.

Fecundability in reproductive aged women at risk of sexual dysfunction and associated risk factors: a prospective preconception cohort study

BACKGROUND

Female sexual dysfunction (FSD) is a prevalent problem, affecting up to 41% of reproductive aged women worldwide. However, the association between female sexual function (FSF) and fecundability in women attempting to conceive remains unclear. We aimed 1) to examine the association between FSF in reproductive-aged preconception Asian women and fecundability, as measured by time-to-pregnancy in menstrual cycles, and 2) to examine lifestyle and behavioral factors associated with FSF.

METHODS

From the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO) prospective cohort, we evaluated FSF using the 6-item Female Sexual Function Index (FSFI-6) and ascertained time-to-pregnancy within a year of baseline assessment. We estimated fecundability ratio (FR) and 95% confidence interval (CI) using the discrete-time proportional hazards model, accounting for left-truncation and right censoring. We used multivariable logistic and linear regression models to identify potential factors related to FSF.

RESULTS

Among 513 participants, 58.9% had low FSF as defined by a total FSFI-6 score at or below the median value of 22. Compared to women with high FSF, those with low FSF had a 27% reduction in fecundability (FR 0.73; 95% CI 0.54, 0.99), with adjustment for age, ethnicity, education, parity and body mass index. Overall, the FRs generally reduced with decreasing FSFI-6 scores. Physical activity, obesity, absence of probable depression and anxiety were independently associated with reduced odds of low FSF and increased FSFI-6 scores, after adjusting for sociodemographic characteristics.

CONCLUSIONS

Low FSF is associated with a longer time-to-pregnancy. Early evaluation and optimization of FSF through increased physical activity and optimal mental health may help to improve female fecundity. The finding of obese women having improved FSF remains uncertain which warrants further investigations on plausibly mechanisms. In general, the current finding highlights the importance of addressing FSF in preconception care service for general women, which is currently lacking as part of the fertility promotion effort in the country.

Risk score to stratify miscarriage risk levels in preconception women

Spontaneous miscarriage is one of the most common complications of pregnancy. Even though some risk factors are well documented, there is a paucity of risk scoring tools during preconception. In the S-PRESTO cohort study, Asian women attempting to conceive, aged 18-45 years, were recruited. Multivariable logistic regression model coefficients were used to determine risk estimates for age, ethnicity, history of pregnancy loss, body mass index, smoking status, alcohol intake and dietary supplement intake; from these we derived a risk score ranging from 0 to 17. Miscarriage before 16 weeks of gestation, determined clinically or via ultrasound. Among 465 included women, 59 had miscarriages and 406 had pregnancy ≥ 16 weeks of gestation. Higher rates of miscarriage were observed at higher risk scores (5.3% at score ≤ 3, 17.0% at score 4–6, 40.0% at score 7–8 and 46.2% at score ≥ 9). Women with scores ≤ 3 were defined as low-risk level (< 10% miscarriage); scores 4–6 as intermediate-risk level (10% to < 40% miscarriage); scores ≥ 7 as high-risk level (≥ 40% miscarriage). The risk score yielded an area under the receiver-operating-characteristic curve of 0.74 (95% confidence interval 0.67, 0.81; p < 0.001). This novel scoring tool allows women to self-evaluate their miscarriage risk level, which facilitates lifestyle changes to optimize modifiable risk factors in the preconception period and reduces risk of spontaneous miscarriage.

Fecundability and Sterility by Age: Estimates Using Time to Pregnancy Data of Japanese Couples Trying to Conceive Their First Child with and without Fertility Treatment

Fecundability, the probability of conception in a month or in a menstrual cycle, varies across and within age groups for both women and men. Fertility treatment has become common in a number of countries including Japan, but its impact on the age pattern of fecundability is unknown. By utilizing the previously collected data on time to pregnancy (TTP) of Japanese couples trying to conceive their first child, the present study aimed to estimate fecundability and sterility by women’s age and to assess how the estimates may differ by including or excluding assisted conceptions. Duration between discontinuing contraception and conception (including both natural and assisted) resulted in a live birth was called TTP-all, and the duration ending with natural conception was called TTP-natural. TTP-natural was censored when a participant received fertility consultation or treatment. A zero-inflated beta distribution model was used to estimate a proportion of sterile (zero probability of conception) and a distribution of fecundability for each age group. Parameters of the distribution were estimated using the maximum likelihood method. When TTP-all and TTP-natural were used, the sterile proportion of the whole sample was, respectively, 2% and 14%, and the median (interquartile range) of fecundability was, respectively, 0.10 (0.04, 0.19) and 0.11 (0.05, 0.19). The median (interquartile range) of fecundability was 0.18 (0.10, 0.29) for women aged 24 years or younger and 0.05 (0.02, 0.13) for 35–39 years old when TTP-all was used, and the estimates were quite similar with those based on TTP-natural: it was 0.18 (0.10, 0.29) for women aged 24 years or younger and 0.06 (0.00, 0.15) for 35–39 years old. Exclusion of assisted conceptions resulted in larger proportions of sterility, but it had little impact on median or interquartile ranges of fecundability estimates. Fecundability is overall lower at higher ages, while interquartile ranges are overlapping, suggesting that inter-individual variability of fecundability within an age group is as large as the variability across age groups.

Preconception lifestyle advice for people with infertility

BACKGROUND

Infertility is a prevalent problem that has significant consequences for individuals, families, and the community. Modifiable lifestyle factors may affect the chance of people with infertility having a baby. However, no guideline is available about what preconception advice should be offered. It is important to determine what preconception advice should be given to people with infertility and to evaluate whether this advice helps them make positive behavioural changes to improve their lifestyle and their chances of conceiving.

OBJECTIVES

To assess the safety and effectiveness of preconception lifestyle advice on fertility outcomes and lifestyle behavioural changes for people with infertility.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, PsycINFO, AMED, CINAHL, trial registers, Google Scholar, and Epistemonikos in January 2021; we checked references and contacted field experts to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), randomised cross-over studies, and cluster-randomised studies that compared at least one form of preconception lifestyle advice with routine care or attention control for people with infertility.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Primary effectiveness outcomes were live birth and ongoing pregnancy. Primary safety outcomes were adverse events and miscarriage. Secondary outcomes included reported behavioural changes in lifestyle, birth weight, gestational age, clinical pregnancy, time to pregnancy, quality of life, and male factor infertility outcomes. We assessed the overall quality of evidence using GRADE criteria.

MAIN RESULTS

We included in the review seven RCTs involving 2130 participants. Only one RCT included male partners. Three studies compared preconception lifestyle advice on a combination of topics with routine care or attention control. Four studies compared preconception lifestyle advice on one topic (weight, alcohol intake, or smoking) with routine care for women with infertility and specific lifestyle characteristics. The evidence was of low to very low-quality. The main limitations of the included studies were serious risk of bias due to lack of blinding, serious imprecision, and poor reporting of outcome measures. Preconception lifestyle advice on a combination of topics versus routine care or attention control Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.79 to 1.10; 1 RCT, 626 participants), but the quality of evidence was low. No studies reported on adverse events or miscarriage. Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice on a combination of topics affects lifestyle behavioural changes: body mass index (BMI) (mean difference (MD) -1.06 kg/m², 95% CI -2.33 to 0.21; 1 RCT, 180 participants), vegetable intake (MD 12.50 grams/d, 95% CI -8.43 to 33.43; 1 RCT, 264 participants), alcohol abstinence in men (RR 1.08, 95% CI 0.74 to 1.58; 1 RCT, 210 participants), or smoking cessation in men (RR 1.01, 95% CI 0.91 to 1.12; 1 RCT, 212 participants). Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women with adequate folic acid supplement use (RR 0.98, 95% CI 0.95 to 1.01; 2 RCTs, 850 participants; I² = 4%), alcohol abstinence (RR 1.07, 95% CI 0.99 to 1.17; 1 RCT, 607 participants), and smoking cessation (RR 1.01, 95% CI 0.98 to 1.04; 1 RCT, 606 participants), on low quality evidence. No studies reported on other behavioural changes. Preconception lifestyle advice on weight versus routine care Studies on preconception lifestyle advice on weight were identified only in women with infertility and obesity. Compared to routine care, we are uncertain whether preconception lifestyle advice on weight affects the number of live births (RR 0.94, 95% CI 0.62 to 1.43; 2 RCTs, 707 participants; I² = 68%; very low-quality evidence), adverse events including gestational diabetes (RR 0.78, 95% CI 0.48 to 1.26; 1 RCT, 317 participants; very low-quality evidence), hypertension (RR 1.07, 95% CI 0.66 to 1.75; 1 RCT, 317 participants; very low-quality evidence), or miscarriage (RR 1.50, 95% CI 0.95 to 2.37; 1 RCT, 577 participants; very low-quality evidence). Regarding lifestyle behavioural changes for women with infertility and obesity, preconception lifestyle advice on weight may slightly reduce BMI (MD -1.30 kg/m², 95% CI -1.58 to -1.02; 1 RCT, 574 participants; low-quality evidence). Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice affects the percentage of weight loss, vegetable and fruit intake, alcohol abstinence, or physical activity. No studies reported on other behavioural changes. Preconception lifestyle advice on alcohol intake versus routine care Studies on preconception lifestyle advice on alcohol intake were identified only in at-risk drinking women with infertility. We are uncertain whether preconception lifestyle advice on alcohol intake affects the number of live births (RR 1.15, 95% CI 0.53 to 2.50; 1 RCT, 37 participants; very low-quality evidence) or miscarriages (RR 1.31, 95% CI 0.21 to 8.34; 1 RCT, 37 participants; very low-quality evidence). One study reported on behavioural changes for alcohol consumption but not as defined in the review methods. No studies reported on adverse events or other behavioural changes. Preconception lifestyle advice on smoking versus routine care Studies on preconception lifestyle advice on smoking were identified only in smoking women with infertility. No studies reported on live birth, ongoing pregnancy, adverse events, or miscarriage. One study reported on behavioural changes for smoking but not as defined in the review methods.

AUTHORS' CONCLUSIONS

Low-quality evidence suggests that preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births. Evidence was insufficient to allow conclusions on the effects of preconception lifestyle advice on adverse events and miscarriage and on safety, as no studies were found that looked at these outcomes, or the studies were of very low quality. This review does not provide clear guidance for clinical practice in this area. However, it does highlight the need for high-quality RCTs to investigate preconception lifestyle advice on a combination of topics and to assess relevant effectiveness and safety outcomes in men and women with infertility.

Preconception Care to Reduce the Risks of Overweight and Obesity in Women of Reproductive Age: An Integrative Review

Despite adverse pregnancy outcomes for women with overweight or obesity, preconception guidelines for achieving optimal wellness for women contemplating pregnancy regarding the risks of overweight or obesity are varied based upon national affiliation. The aim of this study was to synthesize the best evidence related to preconception counseling and care focused on overweight or obesity provided to women of reproductive age. An integrative review of original studies was conducted. PubMed, Cumulative Index in Nursing and Allied Health Literature, Ovid, Scopus, Web of Science, and Embase were included. Full-text, data-based articles were searched from 2009 to 2018, with reviews and synthesis completed in 2019 and 2020. Of 8703 initial articles, 31 articles remained in the review. Quality assessment and level of evidence were evaluated based upon criteria from the Joanna Briggs Institute and the Johns Hopkins Nursing Evidence-Based Practice Quality Guide. The level of evidence for the majority of studies was non-experimental but they were of good quality with appropriate methods, samples and relevant results. Limited attention and interest in preconception counseling regarding risks of overweight or obesity by health care professionals were noted, which may contribute to women’s unawareness of these risks on preconception health.

Unraveling the Balance between Genes, Microbes, Lifestyle and the Environment to Improve Healthy Reproduction

Humans’ health is the result of a complex and balanced interplay between genetic factors, environmental stimuli, lifestyle habits, and the microbiota composition. The knowledge about their single contributions, as well as the complex network linking each to the others, is pivotal to understand the mechanisms underlying the onset of many diseases and can provide key information for their prevention, diagnosis and therapy. This applies also to reproduction. Reproduction, involving almost 10% of our genetic code, is one of the most critical human’s functions and is a key element to assess the well-being of a population. The last decades revealed a progressive decline of reproductive outcomes worldwide. As a consequence, there is a growing interest in unveiling the role of the different factors involved in human reproduction and great efforts have been carried out to improve its outcomes. As for many other diseases, it is now clear that the interplay between the underlying genetics, our commensal microbiome, the lifestyle habits and the environment we live in can either exacerbate the outcome or mitigate the adverse effects. Here, we aim to analyze how each of these factors contribute to reproduction highlighting their individual contribution and providing supporting evidence of how to modify their impact and overall contribution to a healthy reproductive status.

Adiposity is associated with anovulation independent of serum free testosterone: A prospective cohort study

BACKGROUND

Obesity, a body mass index (BMI) ≥30 kg/m2 , is linked to infertility, potentially through a greater risk of anovulation due to elevated androgens. Yet, previous studies have not directly assessed the impact of adiposity, or body fat, on anovulation in the absence of clinical infertility.

OBJECTIVE

To characterise the associations between adiposity and anovulation among women menstruating on a regular basis.

METHODS

Women from the EAGeR trial (n = 1200), a randomised controlled trial of low-dose aspirin and pregnancy loss among women trying to conceive, were used to estimate associations between adiposity and incident anovulation. Participants completed baseline questionnaires and anthropometry, and provided blood specimens. Women used fertility monitors for up to six consecutive menstrual cycles, with collection of daily first morning voids for hormone analysis in the first two menstrual cycles for prospective assessment of anovulation. Anovulation was assessed by urine pregnanediol glucuronide or luteinising hormone concentration or the fertility monitor. Weighted mixed-effects log-binomial regression was used to estimate associations between measures of adiposity and incident anovulation, adjusted for free (bioavailable) testosterone, anti-Mullerian hormone (AMH), serum lipids, and demographic and life style factors.

RESULTS

343 (28.3%) women experienced at least one anovulatory cycle. Anovulation risk was higher per kg/m2 greater BMI (relative risk [RR] 1.03, 95% confidence interval (CI) 1.01, 1.04), cm waist circumference (RR 1.01, 95% CI 1.00, 1.02), mm subscapular skinfold (RR 1.02, 95% CI 1.01, 1.03), and mm middle upper arm circumference (RR 1.04, 95% CI 1.01, 1.06) adjusted for serum free testosterone, AMH, lipids, and other factors.

CONCLUSIONS

Adiposity may be associated with anovulation through pathways other than testosterone among regularly menstruating women. This may account in part for reported associations between greater adiposity and infertility among women having menstrual cycles regularly. Understanding the association between adiposity and anovulation might lead to targeted interventions for preventing infertility.

Electronic Cigarettes and Fecundability: Results From a Prospective Preconception Cohort Study

Although electronic cigarette (e-cigarette) aerosol contains similar toxicants to combustible cigarettes, few studies have examined their influence on fecundability. We assessed the association between e-cigarette use and fecundability, overall and according to combustible cigarette smoking history, in a cohort of 4,586 North American women (aged 21-45 years) enrolled during 2017-2020 in Pregnancy Study Online, a Web-based prospective preconception study. Women reported current and former e-cigarette use on baseline and follow-up questionnaires, and they completed bimonthly follow-up questionnaires until self-reported pregnancy or censoring. Fecundability ratios and 95% confidence intervals were calculated using proportional probabilities models, controlling for potential confounders. Overall, 17% of women had ever used e-cigarettes and 4% were current users. Compared with never use of e-cigarettes, current e-cigarette use was associated with slightly lower fecundability (fecundability ratio = 0.84, 95% confidence interval (CI): 0.67, 1.06). Compared with current nonusers of e-cigarettes and combustible cigarettes, fecundability ratios were 0.83 (95% CI: 0.54, 1.29) for current dual users of e-cigarettes and combustible cigarettes, 0.91 (95% CI: 0.70, 1.18) for current e-cigarette users who were nonsmokers of combustible cigarettes, and 1.01 (95% CI: 0.85, 1.20) for nonusers of e-cigarettes who were current smokers of combustible cigarettes. Current e-cigarette use was associated with slightly reduced fecundability, but estimates of its independent and joint associations with combustible cigarette smoking were inconsistent and imprecise.

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.

Association Between Male Use of Pain Medication and Fecundability

Administration of pain relievers has been associated with both lower and higher risks of adverse reproductive outcomes in animals. In the sole investigation of male pain-reliever use and human fertility carried out to date, Smarr et al. (Hum Reprod. 2016;31(9):2119-2127) found a 35% reduction in fecundability among males with urinary acetaminophen concentrations in the highest quartile (>73.5 ng/mL) versus the lowest (<5.4 ng/mL). We analyzed data from 1,956 males participating in Pregnancy Study Online, a preconception cohort study of North American couples enrolled between 2013 and 2019. Males and females completed baseline questionnaires on sociodemographic characteristics, lifestyle, medication use, and medical history; females completed bimonthly follow-up questionnaires for up to 12 months. We categorized pain medications by active ingredient (ibuprofen, acetaminophen, naproxen, aspirin) and cumulative monthly dose. We used proportional probabilities models to calculate fecundability ratios and 95% confidence intervals, adjusting for potential confounders. In the 4 weeks before baseline, 51.7% of males used pain medications. Adjusted fecundability ratios were 1.02 for ibuprofen (95% confidence interval (CI): 0.91, 1.13), 0.89 for acetaminophen (95% CI: 0.77, 1.03), 1.07 for naproxen (95% CI: 0.85, 1.35), and 1.05 for aspirin (95% CI: 0.81, 1.35), as compared with nonuse of each medication. In this study, male use of pain medications at low doses was not notably associated with fecundability.

Plasma glycemic measures and fecundability in a Singapore preconception cohort study

OBJECTIVE

To examine the association between plasma glycemia in women attempting to conceive and fecundability, as measured by time to pregnancy.

DESIGN

Prospective preconception population-based study.

SETTING

Hospital.

PATIENT(S)

Asian preconception women, 18-45 years old, attempting conception for ≤12 cycles at study entry.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

We ascertained time to pregnancy within a year of glycemic assessment in menstrual cycles. We estimated fecundability ratios (FRs) and 95% confidence intervals using discrete-time proportional hazards models, adjusting for age, ethnicity, education, body mass index, and cycle regularity and accounting for left truncation and right censoring.

RESULT(S)

We studied a population sample of 766 women from the Singapore Preconception Study of Long-Term Maternal and Child Outcomes prospective cohort. Compared with women with normoglycemia, women with dysglycemia (prediabetes and diabetes, defined by the American Diabetes Association) had a lower FR (0.56). Compared with the respective lowest quintiles, women in the highest quintile of fasting glucose (≥5.1 mmol/L) had an FR of 0.60, while women in the highest 2-hour postload glucose quintile (≥6.9 mmol/L) had an FR of 0.66. Overall, the FRs decreased generally across the range of fasting and 2-hour plasma glucose. Glycated hemoglobin was not associated with fecundability.

CONCLUSION(S)

Increasing preconception plasma glucose is associated with reduced fecundability, even within the normal range of glucose concentrations.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03531658.

Physical Activity and Body Mass Index in Relation to Infertility in Women

BACKGROUND

Infertility is a global social issue, and reproductive health is a priority in global health. This review aimed to study the relation between physical activity (PA) and infertility in non-obese or non-overweight women.

METHODS

We used search strategies in the National Library of Medicine database including the PubMed database to October 2019 to find articles related to women and fertility, infertility, exercise, PA, pregnancy rate, live births, fecundability, and conception. Only cohort studies or randomized controlled trials in English were chosen for review that included outcomes directly related to becoming pregnant. We selected studies in which the participants were categorized by low or high body mass index (BMI).

RESULTS

We found 6 papers meeting our criteria. In the association between PA and outcome, vigorous PA in women with low BMI resulted in both positive and negative effects that were weaker than those in women with high BMI. Among women with low BMI, moderate PA was weakly but positively associated with outcome whereas walking was not.

CONCLUSION

We observed some trends and a slight difference between the outcomes of women with low versus high BMI. There are only a few studies on infertile women with low BMI, and further investigation is warranted.

Changes in Behavior with Increasing Pregnancy Attempt Time: A Prospective Cohort Study

BACKGROUND

The extent to which couples change their behaviors with increasing pregnancy attempt time is not well documented.

METHODS

We examined change in selected behaviors over pregnancy attempt time in a North American preconception cohort study. Eligible females were ages 21-45 years and not using fertility treatment. Participants completed baseline and bimonthly follow-up questionnaires for up to 12 months or until pregnancy.

RESULTS

Among 3,339 females attempting pregnancy for 0-1 cycles at enrollment, 250 contributed 12 months of follow-up without conceiving. Comparing behaviors at 12 months versus baseline, weighted for loss-to-follow-up, we observed small-to-moderate reductions in mean caffeine intake (-19.5 mg/day, CI = -32.7, -6.37), alcohol intake (-0.85 drinks/week, CI = -1.28, -0.43), marijuana use (-3.89 percentage points, CI = -7.33, 0.46), and vigorous exercise (-0.68 hours/week, CI = -1.05, -0.31), and a large increase in activities to improve conception chances (e.g., ovulation testing) (21.7 percentage points, CI = 14.8, 28.6). There was little change in mean cigarette smoking (-0.27 percentage points, CI = -1.58, 1.04), perceived stress scale score (-0.04 units, CI = -0.77, 0.69), or other factors (e.g., sugar-sweetened soda intake, moderate exercise, intercourse frequency, and multivitamin use), but some heterogeneity within subgroups (e.g., 31% increased and 32% decreased their perceived stress scores by ≥2 units; 14% reduced their smoking but none increased their smoking by ≥5 cigarettes/day).

CONCLUSIONS

Although many behaviors changed with increasing pregnancy attempt time, mean changes tended to be modest for most variables. The largest differences were observed for the use of caffeine, alcohol, and marijuana, and methods to improve conception chances.

The Association between Seafood Intake and Fecundability: Analysis from Two Prospective Studies

Background: Seafood is an important source of omega-3 fatty acids, which have been associated with improved oocyte quality and embryo morphology in some studies. However, seafood is also a source of persistent organic pollutants and heavy metals, which may adversely affect fecundity. Previous studies of seafood intake and fecundity have generated inconsistent results. Methods: In two prospective cohort studies of 7836 female pregnancy planners from Denmark (Snart Foraeldre, n = 2709) and North America (PRESTO, n = 5127), we evaluated the association of dietary intake of total seafood and marine-sourced long-chain omega-3 fatty acids (eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid) with fecundability. Participants completed a baseline questionnaire on sociodemographics, behavioral factors, anthropometrics, and medical history, and a food frequency questionnaire. Pregnancy status was updated bimonthly for up to 12 months or until reported conception. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) using proportional probabilities regression models, adjusted for energy intake and other potential confounders. We restricted analyses to women with ≤6 menstrual cycles of attempt time at enrollment. Results: Intake of total seafood or marine-sourced long-chain omega-3 fatty acids was not appreciably associated with fecundability in either cohort (≥200 vs. <50 g/week total seafood: FR = 0.94, 95% CI: 0.79–1.10 in Snart Foraeldre; FR = 1.00, 95% CI: 0.90–1.13 in PRESTO; marine fatty acids: ≥90th vs. <25th percentile: FR = 1.00, 95% CI: 0.85–1.18 in Snart Foraeldre; FR = 0.97, 95% CI: 0.86–1.09 in PRESTO). In PRESTO, where we collected additional data on seafood preparation, we observed an inverse association between fecundability and fried shellfish (≥10 g/week vs. none: FR = 0.77, 95% CI: 0.61–0.98), but not unfried shellfish (≥20 g/week vs. none: FR = 0.98, 95% CI: 0.89–1.07); in Snart Foraeldre, there was no association with total shellfish intake. Conclusions: We found little association between seafood intake and fecundability overall, but greater intake of fried shellfish was associated with reduced fecundability among North American participants.

Taking fertility for granted - a qualitative exploration of fertility awareness among young, childless men in Denmark and Sweden

Most previous studies about fertility knowledge and attitudes among men have been based on quantitative methods using questionnaires with fixed-choice response options. The aims of this qualitative study were to explore childless young men's reflections on fertility and infertility through semi-structured interviews. Danish (n = 17) and Swedish (n = 12) young childless men aged between 20 and 30 years in their last year of education were interviewed. Data were analysed using qualitative content analysis. Few informants had considered their own fertility, and most were positive towards fertility treatment. The young men had inadequate knowledge about factors that can potentially impair male and female fertility. On average, the young men each mentioned three different factors they believed influence male and female fertility: (i) health behaviour; (ii) factors beyond personal control; and (iii) age. None mentioned sexual transmitted infections (STIs) but most appeared aware of the effect of increasing age on fertility. The results of this study highlight the need for educational strategies to improve young men's knowledge about fertility and the factors that influence it, particularly about the potential adverse effect of STIs on fertility.

Coital Frequency and the Probability of Pregnancy in Couples Trying to Conceive Their First Child: A Prospective Cohort Study in Japan

Background: Low fertility persists but remains unexplained in Japan. We examined whether the probability of pregnancy was influenced by coital frequency, age, reproductive age (assessed by antimüllerian hormone, AMH), and BMI. Methods: We established a two-year prospective study with a sample of hormonally monitored Japanese women aged 23-34 years wanting to conceive their first child. For a maximum of 24 weeks participants recorded menstrual bleeding, sexual intercourse, ovulation, and pregnancy. Additional information on pregnancy and infertility treatment was collected one and two years after intake. Results: The natural conception rate and coital frequency were both low in this sample. Among 80 participants, 44% (35) naturally conceived in 24 weeks. After two years, 74% (59) of women had delivered or were currently pregnant, 50% (40) due to natural and 24% (19) due to assisted conception, and 5% (4) were lost to follow-up. By two years, 56% (45) of women had sought fertility treatment. In 18% (58/319) of the observed ovarian cycles across 24 weeks there was no intercourse in a fertile period. Higher coital frequency at intake was associated with increased probability of conception by 24 weeks of follow-up (OR 1.23, 95%CI 1.02, 1.47). Chronological age, reproductive age, and BMI were not associated with the probability of pregnancy at 24 weeks. Conclusions: Our results suggest that first, natural conception rates could potentially increase with more frequent and well timed intercourse, and second that further work is needed to understand why even in a motivated sample of women monitoring their fertile periods, both the conception and coitus rates were low.

A prospective study of treatments for cervical intraepithelial neoplasia and fecundability

BACKGROUND

Treatments for cervical intraepithelial neoplasia remove precancerous cells from the cervix by excising or ablating the transformation zone. Most studies show no association between cervical intraepithelial neoplasia treatments and fertility outcomes. However, only 2 studies have examined time to pregnancy, both using retrospective study designs, with 1 study showing no association and the other showing a 2-fold increased risk of infertility (time to pregnancy >12 months) following excisional or ablative treatment.

OBJECTIVE

We examined the association between cervical intraepithelial neoplasia treatments and fecundability.

MATERIALS AND METHODS

We analyzed data from Pregnancy Study Online (PRESTO), a prospective cohort study of North American pregnancy planners enrolled during 2013-2019. At baseline, women reported whether they ever had an abnormal Papanicolaou test result, the number of abnormal Papanicolaou test results, and their age at first abnormal Papanicolaou test result. They also reported whether they underwent diagnostic (colposcopy) or treatment (excisional or ablative) procedures, and their age at each procedure. We restricted analyses to 8017 women with 6 or fewer cycles of attempt time at enrollment who reported receiving a Papanicolaou test in the previous 3 years. We estimated fecundability ratios and 95% confidence intervals using proportional probabilities models adjusted for sociodemographics, healthcare use, smoking, number of sexual partners, history of sexually transmitted infections, and human papillomavirus vaccination.

RESULTS

A history of abnormal Papanicolaou test results showed little association with fecundability (fecundability ratio, 1.00; 95% confidence interval, 0.95-1.06). Likewise, receipt of colposcopy or treatment procedures, and time since treatment were not materially associated with fecundability. Results were similar when stratified by age and smoking status.

CONCLUSION

We observed no appreciable association of self-reported history of abnormal Papanicolaou test results, colposcopy, treatments for cervical intraepithelial neoplasia, or recency of treatment with fecundability. These results agree with the majority of previous studies in indicating little effect of cervical intraepithelial neoplasia treatments on future fertility.

Maternal preconception body mass index and time-to-pregnancy in Shanghai Women, China

Previous studies suggested an association between female fertility and body size, but most of these studies were from Western countries and focused mainly on obesity. This study investigated the association between preconception body mass index (BMI) and time to pregnancy (TTP) in women planning to conceive from Shanghai, China. A total of 1,182 women aged 24-46 years were recruited from the Shanghai Birth Cohort between 2013 and 2015 and were followed up for 12 months. Preconception BMI was categorized as underweight, normal weight, and overweight/obesity according to the Chinese classification of BMI. Fecundability (FOR) and infertility (IOR) odds ratios were estimated using Cox (n = 1,092) and Logistic (n = 820) regression models, respectively. We found no differences in fecundability between underweight and overweight/obese women and normal-weight women. Furthermore, underweight and overweight/obese women did not have a higher risk of infertility compared with normal-weight women. Our findings suggest that non-optimal preconception BMI does not appear to influence female fecundability and infertility in Chinese women. These results should be interpreted with caution as they may be applicable only to women with demographic and anthropometric characteristics similar to our study population. Our findings need to be confirmed in other populations.

C-reactive protein and ART outcomes: a systematic review

BACKGROUND

A dynamic balance between pro- and anti-inflammatory factors contributes to regulating human female reproduction. Chronic low-grade inflammation has been detected in several female reproductive conditions, from anovulation to embryo implantation failure. C-reactive protein (CRP) is a reliable marker of inflammation that is extensively used in clinical practice. Recent studies quantified CRP in the serum of infertile women undergoing ART and suggested its potential for the prediction of ART reproductive outcomes.

OBJECTIVE AND RATIONALE

The first objective of this systematic review of the available literature was to evaluate the association between pre-implantation circulating CRP concentration and pregnancy rates in women undergoing ART. The second objective was to describe serum CRP concentration changes after early embryo implantation. The changes in circulating CRP throughout the ART cycle, clinical implications of CRP quantification for the management of women undergoing ART, and future therapeutic options will also be discussed.

SEARCH METHODS

The MEDLINE database was systematically searched from inception to March 2019 using the following key words: (C-reactive protein) AND (assisted reproductive techniques OR ovulation induction OR insemination OR in vitro fertilization). Only articles in English were considered. Studies were selected based on title and abstract. The full text of potentially relevant articles was retrieved and assessed for inclusion by two reviewers (S.B. and S.H.). The protocol was registered in the International prospective register of systematic reviews (PROSPERO; registration number: CRD148687).

OUTCOMES

In total, 10 studies were included in this systematic review. Most of these studies reported lower circulating CRP values before the window of implantation and higher circulating CRP values during the peri-implantation period in women with successful ART outcome (biochemical or clinical pregnancy) compared to women without a successful outcome. Several lifestyle factors and/or drugs that reduce the concentration of circulating CRP significantly improve ART outcomes. Subgroup analyses according to female BMI and baseline circulating CRP concentration are highly recommended in future analyses.

WIDER IMPLICATIONS

These findings highlight a possible detrimental impact of preconception high circulating CRP concentration on ART outcomes. However, the biochemical or clinical pregnancy rate endpoints used in the studies examined here are insufficient (there were no data on live birth outcome), and the impact of major variables that can influence CRP and/or ART, for example maternal age, BMI, number of transferred embryos, and use of anti-inflammatory drugs, were not considered in the analyses. CRP quantification may be a potential marker of ART outcome, but its predictive value still needs to be investigated in large prospective studies. In future, the quantification of circulating CRP before starting ART could help to identify patients with a poor ART prognosis, leading to ART cycle cancellation or to preconception treatment to minimize the medical risks and costs.

Pre-pregnancy body mass index and time to pregnancy among couples pregnant within a year: A China cohort study

Background

Extreme pre-pregnancy body mass index (BMI) values have been associated with reduced fecundability and prolonged time to pregnancy in previous studies. However, the effect in fertile couples is unclear.

Objectives

This study aimed to evaluate the association between pre-pregnancy BMI and fecundability, measured as time to pregnancy (TTP), among couples that achieved pregnancy within 1 year.

Methods

This was a retrospective cohort study of 50,927 couples wishing to conceive, enrolled in the National Free Preconception Health Examination Project (NFPHEP) in Chongqing, China, during 2012–2016. Participants’ weight and height were measured by NFPHEP-trained preconception guidance physicians. TTP measured in months was used to determine subfecundity (TTP >6 months). The strength of association between BMI and TTP/subfecundity was measured with fecundability odds ratios (FOR)/odds ratios (OR) and their corresponding 95% confidence intervals (CI), calculated with Cox and logistic regression analysis. We used restricted cubic spline regression (RCS) to test the observed FOR trends.

Results

Compared to women with normal BMI, women with pre-pregnancy overweight/obesity had longer TTP (FOR = 0.96, 95% CI: 0.94–0.99) and increased risk of subfecundity (OR = 1.08, 95% CI: 1.00–1.17). There was no association between TTP and male BMI. RCS trends varied when data were stratified by male pre-pregnancy BMI, with the greatest change detected in pre-pregnancy underweight men.

Conclusions

Pre-pregnancy overweight/obesity was associated with longer TTP and subfecundity among women who became pregnant within 1 year; this effect was likely mediated by their partners’ pre-pregnancy BMI. These findings indicate that BMI could affect fecundability, independently of affecting the risk of sterility. Advice on weight management and maintaining healthy weight should be included in couples’ preconception guidance.

Why does Polycystic Ovary Syndrome (PCOS) Need Long-term Management?

BACKGROUND

Polycystic ovary syndrome (PCOS) is a frequent female reproductive endocrine disease. It has been associated with a number of severe reproductive and metabolic abnormalities. However, there are still open questions especially regarding the best long-term management.

METHODS

We summarized the literature focused on the symptoms and negative long-term consequences of untreated PCOS and the existing options for the treatment. We reviewed the Pubmed and China National Knowledge Infrastructure databases and the relevant literature for the last 20 years. Included in this review also are new results of own (published) research and own experience from treating daily more than 100 PCOS patients.

RESULTS

Obesity is one of the most common findings. It can cause abnormal ovulations which can lead to infertility. Important long-term consequences can be adverse pregnancy outcomes. There is an agreement that the risk of endometrial cancer can be increased. Insulin resistance, important within the pathophysiology of PCOS, predisposes patients to metabolic dysfunction and increased risk of type 2 diabetes mellitus. Lifestyle modifications including dietary changes, exercise and weight loss are first-line interventions for many patients. Well known drug treatments such as metformin, oral contraceptives, etc. should be selected according to the individual situation and patients' needs. Regarding newer methods in the long-term management of PCOS, we found that orlistat may help to achieve weight loss and to improve lipid and glucose metabolism.

CONCLUSION

In addition to pharmacological interventions, long-term standardized individualized management of PCOS patients is needed to achieve fertility and to reduce the risk of metabolic related diseases.

The Risks Associated With Obesity in Pregnancy

BACKGROUND

Approximately one-third of all women of childbearing age are overweight or obese. For these women, pregnancy is associated with increased risks for both mother and child.

METHODS

This review is based on pertinent publications retrieved by a selective search of PubMed, with special attention to current population-based cohort studies, systematic reviews, meta-analyses, and controlled trials.

RESULTS

Obesity in pregnancy is associated with unfavorable clinical outcomes for both mother and child. Many of the risks have been found to depend linearly on the body-mass index (BMI). The probability of conception declines linearly, starting from a BMI of 29 kg/m2, by 4% for each additional 1 kg/m2 of BMI (hazard ratio 0.96, 95% confidence interval: [0.91; 0.99]). A 10% increase of pregravid BMI increases the relative risk of gestational diabetes and that of preeclampsia by approximately 10% each. A 5 kg/m2 increase of BMI elevates the relative risk of intrauterine death to 1.24 [1.18; 1.30]. An estimated 11% of all neonatal deaths can be attributed to the consequences of maternal overweight and obesity. Nonetheless, in most randomized controlled trials, nutritional and lifestyle interventions did not bring about any clinically relevant reduction in the incidence of gestational diabetes and fetal macrosomia.

CONCLUSION

The risks associated with obesity in pregnancy cannot necessarily be influenced by intervention. Preventive measures aimed at normalizing body weight before a woman becomes pregnant are, therefore, all the more important.