Prepregnancy weight, weight gain, and birth weight

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Public Health Nutrition

Background:

• Maternal weight gain during pregnancy is a critical factor influencing fetal development and birth outcomes.
• Existing guidelines on recommended maternal weight gain vary, particularly for women with different prepregnancy body mass index (BMI) categories.
• Understanding the precise relationship between maternal weight gain and birth weight across diverse BMI strata is essential for optimizing prenatal care.

Purpose of the Study:

• To investigate the association between maternal weight gain and infant birth weight.
• To determine if this association differs based on prepregnancy maternal body mass index.
• To evaluate the necessity of current minimum weight gain recommendations for obese pregnant women.

Main Methods:

• A retrospective cohort study of 2946 live births delivered after 37 weeks' gestation.
• Maternal prepregnancy weight for height was categorized using body mass index (BMI).
• Multiple regression analysis was employed to assess the influence of maternal weight gain on birth weight, controlling for covariates.

Main Results:

• Both prepregnancy BMI and maternal weight gain were significant determinants of infant birth weight in the overall sample.
• Each kilogram of maternal weight gain was associated with a significant increase in birth weight for underweight, ideal weight, and moderately overweight women (BMI ≤ 135% of ideal).
• The association between maternal weight gain and increased birth weight was not significant for women with higher prepregnancy BMI.

Conclusions:

• Maternal weight gain positively influences birth weight, particularly in non-obese women.
• Current recommendations for minimum maternal weight gain may not be universally applicable and might be unnecessary for obese women.
• Further research could refine individualized weight gain recommendations based on prepregnancy BMI and other maternal factors.