Abstract STUDY QUESTION Is periconceptional ultra-processed food (UPF) consumption in women and men associated with fertility, embryonic growth, and yolk sac development? SUMMARY ANSWER Higher maternal UPF consumption was associated with smaller embryonic growth and yolk sac volume, and higher paternal UPF consumption was associated with reduced fertility. WHAT IS KNOWN ALREADY The periconceptional period is critical for the probability of conception, pregnancy outcomes, and long-term offspring health, and maternal dietary patterns during this period may influence fertility as well as early embryonic development. No studies have examined the combined influence of maternal and paternal UPF consumption on fertility outcomes and early development. STUDY DESIGN, SIZE, DURATION This study is embedded in a population-based prospective cohort study from preconception onwards, with follow-up into childhood. The present study included 831 women and 651 male partners. PARTICIPANTS/MATERIALS, SETTING, METHODS We assessed periconceptional dietary intake via a food frequency questionnaire at median 12+3 weeks of gestation (95% range 10+6, 18+3). Foods were categorized using NOVA classification, and UPF intake was expressed as a percentage of total food intake (grams per day). Information on time to pregnancy was obtained through questionnaires, with fecundability defined as the probability of conceiving within 1 month and subfertility as time to pregnancy ≥12 months or use of assisted reproductive technology. Crown-rump length (CRL) and yolk sac volume were measured by transvaginal ultrasound examinations at 7, 9, and 11 weeks of gestation. MAIN RESULTS AND THE ROLE OF CHANCE Median UPF intake was 22.0% of total food intake for women and 25.1% for men. UPF intake was not associated with fertility outcomes in women. In fully adjusted continuous models, higher maternal UPF intake was associated with smaller CRL at 7 weeks gestation difference: −0.13 standard deviation score (SDS), 95% CI: −0.25, −0.01, per SDS increase in UPF intake. Higher maternal UPF intake was also associated with smaller yolk sac volume at 7 weeks gestation in fully adjusted continuous models difference: −0.14 SDS, 95% CI: −0.26, −0.02, per SDS increase in UPF intake. These associations attenuated at 9 and 11 weeks gestation. In men, higher UPF intake was associated with decreased fecundability and increased subfertility risk in the continuous models (fecundability ratio: 0.90, 95% CI: 0.83, 0.99, OR: 1.36, 95% CI: 1.11, 1.67, per SDS increase in UPF intake), but not with first trimester development, after adjusting for socio-demographic, lifestyle factors, and female partner’s UPF consumption. LIMITATIONS, REASONS FOR CAUTION The inclusion of a relatively healthy population may limit the generalizability of our findings to broader or higher-risk groups. WIDER IMPLICATIONS OF THE FINDINGS These sex-specific findings underscore the importance of considering UPF intake in preconception and early pregnancy diets to optimize reproductive outcomes, embryonic development, and long-term offspring health. STUDY FUNDING/COMPETING INTEREST(S) The Generation R Study is financially supported by the Erasmus Medical Center, Rotterdam, the Erasmus University Rotterdam, and the Netherlands Organization for Health Research and Development. R.G. received funding from the Netherlands Organization for Health Research and Development (NWO, ZonMw VIDI 09150172110034, and NWO, ZonMW, grant number 05430052110007), from the Dutch Diabetes Foundation (grant no. 2024.28.001), and from the European Union (ERC, OBESE-EMBRYO, ERC-2024-STG-101161004). V.W.V.J received a grant from the Netherlands Organization for Health Research and Development (NWO, ZonMw 05430052110007) and a European Research Council Consolidator Grant (ERC-2014-CoG-648916). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the ERA-NET Cofund action (No. 727565), European Joint Programming Initiative “A Healthy Diet for a Healthy Life” (JPI HDHL), EndObesity, ZonMW Netherlands (No. 529051026). The authors declare that they have no conflict of interest. TRIAL REGISTRATION NUMBER N/A.
Lin et al. (Tue,) studied this question.