Risk of previous very low birth weight and very preterm infants among women delivering a very low birth weight and very preterm infant

OBJECTIVE: To examine the relationship of the birth of a very low birth weight (VLBW, < 1500 gm) and very preterm (VPT, ≤ 32 week) infant to previous occurrences of VLBW-VPT infants among women who had two to five pregnancies. STUDY DESIGN: This was a case-control study using data from the 1988 National Maternal and Infant Health Survey (NMIHS). A case was defined as a singleton live birth weighing 500 to 1499 gm with a gestational age of ≤32 weeks. Control infants were defined as singleton births weighing >2500 gm with gestational ages of ≥38 weeks. RESULTS: There were 128 non-black cases and 864 non-black controls, and 241 black cases and 1205 black controls available for analysis. Logistic regression was used to adjust for a history of previous stillbirth, mother's birth weight, pre-pregnancy weight, pregnancy interval, and sociodemographic risk factors. The adjusted odds ratio for the occurrence of a previous VLBW-VPT birth for non-black cases versus controls was 21.24 (6.87, 65.7) and for black cases versus controls, 6.87 (3.82,12.34). CONCLUSION: These results confirm the substantial risk of previous VLBW-VPT infants among women giving birth to such an infant, independent of sociodemographic factors and other prior pregnancy outcomes.