Changes in maternal hemoglobin during pregnancy and birth outcomes

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Perinatal Research

Background:

• Maternal hemoglobin (Hb) levels during pregnancy and their association with birth outcomes remain a subject of debate.
• Understanding how Hb level changes throughout gestation is crucial for predicting perinatal results.

Purpose of the Study:

• To investigate the association between changes in maternal Hb levels from early to mid- or late pregnancy and key birth outcomes.
• To determine if the magnitude of Hb level change influences birth weight, placental characteristics, and fetal growth.

Main Methods:

• A cohort of 1,986 singleton mothers delivering between 34-41 weeks of gestation was analyzed.
• Maternal Hb levels were measured at three trimesters: early (<16 weeks), mid (16-27 weeks), and late (28-36 weeks).
• Multiple regression analysis assessed associations between Hb changes and birth weight, placental weight, and placental ratio, controlling for covariates.

Main Results:

• A smaller reduction in Hb levels from early to mid- or late pregnancy correlated with lower birth weight, Z-score of birth weight, placental weight, and placental ratio.
• Women with the least Hb reduction faced increased risks of low birth weight (LBW) and small-for-gestational-age (SGA) infants.
• Conversely, the greatest Hb reduction was linked to a decreased risk of SGA but an increased risk of a high placental ratio.

Conclusions:

• Changes in maternal hemoglobin levels from early to mid- or late pregnancy demonstrate an inverse association with birth weight, placental weight, and placental ratio.
• These findings highlight the importance of monitoring Hb level dynamics during pregnancy for optimizing birth outcomes.