The preterm prediction study: the value of new vs standard risk factors in predicting early and all spontaneous preterm births. NICHD MFMU Network.

TLDR

The study aimed to evaluate how fetal fibronectin, short cervix, bacterial vaginosis, and other traditional risk factors predict spontaneous preterm birth. Researchers screened 2,929 pregnant women between 22 and 24 weeks of gestation from 1992 to 1994. Fetal fibronectin and short cervix were the strongest predictors of spontaneous preterm birth, especially early births, with bacterial vaginosis being a stronger predictor in Black women and responsible for 40 % of the risk before 32 weeks, while a history of preterm birth was linked to subsequent spontaneous preterm birth through a short cervix.

Abstract

OBJECTIVES: This study was undertaken to determine the relationship between fetal fibronectin, short cervix, bacterial vaginosis, other traditional risk factors, and spontaneous preterm birth. METHODS: From 1992 through 1994, 2929 women were screened at the gestational age 22 to 24 weeks. RESULTS: The odds ratios for spontaneous preterm birth were highest for fetal fibronectin, followed by a short cervix and history of preterm birth. These factors, as well as bacterial vaginosis, were more strongly associated with early than with late spontaneous preterm birth. Bacterial vaginosis was more common--and a stronger predictor of spontaneous preterm birth--in Black women, while body mass index less than 19.8 was a stronger predictor in non-Black women. This analysis suggests a pathway leading from Black race through bacterial vaginosis and fetal fibronectin to spontaneous preterm birth. Prior preterm birth is associated with spontaneous preterm birth through a short cervix. CONCLUSIONS: Fetal fibronectin and a short cervix are stronger predictors of spontaneous preterm birth than traditional risk factors. Bacterial vaginosis was found more often in Black than in non-Black women and accounted for 40% of the attributable risk for spontaneous preterm birth at less than 32 weeks.