Maternal Diet, Lifestyle Factors, and Gestational Weight Gain: A Single-Center Case-Control Study in Hungary

Preterm birth (PTB) is a major public health concern worldwide, which may lead to detrimental maternal and neonatal outcomes. Maternal nutritional status, gestational weight gain (GWG), and lifestyle factors are potentially modifiable determinants of adverse pregnancy outcomes. This study examined the association between PTB and maternal GWG and assessed whether maternal dietary habits and lifestyle factors were related to GWG in women delivering preterm versus at term.

A retrospective case-control study was conducted at a tertiary center in Hungary (MANOR Study, 2019). The case group included n = 100 women with PTB, while n = 200 matched term deliveries served as controls (1:2 ratio). Data were collected using a self-administered questionnaire and medical records. Pre-pregnancy body mass index (BMI) was categorized using standard definitions, while GWG was classified as inadequate, recommended, or excessive according to the US 2009 Institute of Medicine guidelines. A 7-item dietary index score was calculated based on gestational dietary habits.

Pre-pregnancy BMI distribution did not considerably differ between groups (p > 0.05); over one-third of women in both groups were overweight or had obesity (38.7% vs. 36.7%). Previous PTB (p < 0.001) and gestational hypertension (GHT) (p = 0.003) were more common among current PTB cases, while smoking, alcohol consumption, and gestational diabetes mellitus (GDM) showed negligible differences (p > 0.05)-28.0% of cases, and 34.5% of controls were classified as having healthy dietary habits, based on the dietary index score calculated. Inadequate GWG was more prevalent among PTB cases (49.0% vs. 26.8%), whereas excessive GWG was less frequent among cases (21.9% vs. 38.4%). Being within the recommended GWG range and the manifestation of gestational hypertension were associated with lower (aOR: 0.39; 95% CI: 0.18-0.87; p = 0.020) and higher (aOR: 3.43; 95% CI: 1.44-8.19; p = 0.005) odds of PTB, respectively.

Inadequate GWG was more common in PTB, while excessive GWG was more frequent in term pregnancies. Fast-food consumption was associated with excessive GWG among term births. Optimizing GWG and improving maternal diet quality should be included as key, cross-cutting interventions targeting the improvement of antenatal care.