Association between maternal pre-pregnancy body mass index, health and socioeconomic factors and neonatal birthweight, preterm birth and onset of delivery, double-center case-control study

Excessive fat deposits in pre-gestational maternal body mass index may lead to adverse pregnancy outcomes, including preterm birth (PB), abnormal birthweight and may influence offspring's future growth and development, contributing to obesity later in life [1].Hyperglycemia and dyslipidemia observed in obese mothers may result in fetal hyperinsulinism leading to fetal overgrowth and delivery of large for gestational age (LGA) neonates, while chronic inflammation and oxidative stress increase the probability of small for gestational age (SGA) neonates and PB.External factors, including maternal socioeconomic status (SES), concomitant diseases and lifestyle, can also affect the offspring's birthweight and modulate the risk of PB [2][3][4].We explore how maternal pre-pregnancy body mass index (BMI), health and SES are associated with neonatal birthweight and the risk of PB and we analyze their relation to onset of delivery.Methods.This prospective case-control study was conducted from March 2023 to February 2024 among mothers hospitalized in the postpartum wards of two hospitals: a university tertiary perinatal care center and a secondary care unit.Maternal and neonatal data were obtained from two combined sources: a questionnaire completed by mothers and hospital records.The questionnaire was printed on a paper form in the Polish language, included questions about pre-pregnancy weight and height, previous obstetric history, parity, fertilization, maternal smoking, alcohol consumption, education level, employment, SES and place of residence.Study participants.The inclusion criteria were: residence in our region, singleton delivery, Polish language proficiency, and signing an informed consent form.Incomplete questionnaires with missing pre-pregnancy body weight, medical and obstetric history were excluded.Of 285 mothers who delivered prematurely and were eligible to complete the questionnaire, 36 were excluded: twelve refused to participate in the study or data were incomplete, two lived in another province, 16 did not speak the Polish language and six neonates presented with severe congenital defects.Results from 249 questionnaires were analyzed.The control group of 311 full-term newborns was selected from patients hospital-