Interpregnancy Weight Change and Adverse Birth Outcomes: Cohort Study Using Brazil's Routine Register-Based Linked...

Area of Science:

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

Background:

• Interpregnancy weight change (IPWC) effects on adverse birth outcomes are unclear, with conflicting data on preterm birth and limited evidence for low birth weight (LBW) or macrosomia, especially in low- and middle-income countries.
• Understanding IPWC is crucial for improving maternal and infant health globally.

Purpose of the Study:

• To evaluate the association between interpregnancy weight change (IPWC) and adverse birth outcomes in subsequent pregnancies.
• To investigate the impact of weight changes between pregnancies on preterm birth, LBW, and macrosomia.

Main Methods:

• A population-based longitudinal study using linked Brazilian register data (2008-2015).
• Analysis of 15,570 live births from 7785 multiparous women.
• Logistic and multinomial logistic regressions to assess associations between IPWC categories (BMI unit change, BMI category change, weight percentage change) and adverse birth outcomes.

Main Results:

• Women reducing BMI between pregnancies had increased odds of preterm birth (OR 1.27).
• Women increasing BMI by ≥4 units had increased odds of macrosomia (OR 1.60) compared to those maintaining BMI.
• Similar associations were found using BMI category and weight percentage changes.

Conclusions:

• Interpregnancy weight change is associated with altered newborn maturity and size in subsequent pregnancies.
• Maternal weight management between pregnancies is critical for improving birth outcomes.
• Further experimental studies are needed to confirm these findings and guide interventions.