Prepregnancy adherence to plant-based diet indices and exploratory dietary patterns in relation to fecundability

Abstract

Background: Modest associations have been reported between specific food groups or nutrients and fecundability [measured by time to pregnancy (TTP)]. Examining overall diets provides a more holistic approach towards understanding their associations with fecundability. It is not known whether plant-based diets indices or exploratory dietary patterns are associated with fecundability.

Objectives: We examine the associations between adherence to 1) plant-based diet indices; and 2) exploratory dietary patterns and fecundability among women planning pregnancy.

Methods: Data were analyzed from the Singapore Preconception Study of Long-Term Maternal and Child Outcomes (S-PRESTO) study. Prepregnancy diet was assessed using a semi-quantitative FFQ from which the overall, healthful, and unhealthful plant-based diet indices (oPDI, hPDI, and uPDI, respectively) were calculated. Exploratory dietary patterns were derived using factor analysis based on 44 predefined food groups. Participants were categorized into quintiles based on their dietary pattern scores. TTP (expressed in menstrual cycles) was ascertained within a year from the prepregnancy dietary assessment. Discrete-time proportional hazard models, adjusted for confounders, were used to estimate fecundability ratios (FRs) and 95% CIs, with FR > 1 indicating a shorter TTP.

Results: Among 805 women, 383 pregnancies were confirmed by ultrasound scans. Compared with women in the lowest quintile, those in the highest quintile of the uPDI had reduced fecundability (FR of Q5 compared with Q1, 0.65; 95% CI, 0.46-0.91; P trend, 0.009). Conversely, greater adherence to the hPDI was associated with increased fecundability (1.46; 95% CI, 1.02-2.07; P trend, 0.036). The oPDI was not associated with fecundability. Among the 3 exploratory dietary patterns, only greater adherence to the Fast Food and Sweetened Beverages (FFSB) pattern was associated with reduced fecundability (0.61; 95% CI, 0.40-0.91; P trend, 0.018).

Conclusions: Greater adherence to the uPDI or the FFSB dietary pattern was associated with reduced fecundability among Asian women. Greater adherence to the hPDI may be beneficial for fecundability, though this requires confirmation by future studies.

Trial registration: ClinicalTrials.gov NCT03531658.

Keywords: diet indices; dietary patterns; fecundability; plant-based diet; preconception; time-to-pregnancy.

Conflict of interest statement

Conflict of interest: YSC has received reimbursement for speaking at conferences sponsored by Abbott Nutrition, Nestle, and Danone. KMG and YSL has received reimbursement for speaking at conferences sponsored by Nestle and has received reimbursement for speaking at conferences sponsored by Danone and Nestle and consulting for Mead Johnson and Nestle. KMG, YSC and SYC are part of an academic consortium that has received research funding from Abbot Nutrition, Nestle and Danone. LP-CS has received research funding from Danone. SYC received reimbursement from Nestle for speaking at a scientific conference. SXL, SLL, MTC, JSL, KHT, FY, JGE, JKYC and MFFC do not have any conflict of interests.

© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.