Influence of increased paternal BMI on pregnancy and child health outcomes independent of maternal effects: A systematic review and C meta-analysis

Objectives: The influence of maternal body mass index (BMI) on pregnancy and child health outcomes is well characterised, however less is known about paternal BMI. This systematic review investigated the independent effects of increased paternal BMI on conception and pregnancy as well as neonatal and childhood outcomes. Methods: Our systematic search (Sept. 2018) of PubMed, Embase, Cinahl, Web of Science, ProQuest, and OpenThesis resulted in 11,045 hits from which 17 studies met the inclusion criteria (Participants: men Exposure: BMI or waist circumferences Outcomes: associations with time to pregnancy, incidence of infertility, pregnancy loss, pregnancy complications, birthweight and length, childhood weight and height, or incidence of any childhood disease). Studies had to adjust for maternal age and BMI. Results: Meta-analysis was only possible for infertility which was significantly more prevalent in obese (OR= 1.49 95%CI 1.30-1.70) and overweight (OR= 1.18 95%CI 1.11-1.26) men. Individual studies showed increased likelihoods of small for gestational age and macrosomia in fathers who had increased BMI possibly accounting for the general finding of no effect on mean birthweight in other studies. Most studies found increased BMI in fathers correlated with altered growth curves and increased BMI in childhood, while one study found a higher likelihood of autism spectrum disorder. Conclusion: Our findings support increased paternal BMI negatively affecting pregnancy and child health outcomes. Future studies must include or adjust for paternal contributions, as the longstanding assumption that only maternal factors are relevant is likely to have considerably confounded prior work. (C) 2019 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.