Association between maternal serum alpha-fetoprotein and adverse outcomes in pregnancies with placenta previa.

OBJECTIVE

To determine whether increased maternal serum alpha-fetoprotein (MSAFP) level at 15-20 weeks' gestation is a marker of adverse outcomes in women with placenta previa at delivery.

METHODS

We conducted a retrospective cohort study of singleton pregnancies complicated by placenta previa, diagnosed sonographically, and confirmed at delivery. All women had MSAFP screening at 15-20 weeks' gestation and delivered nonanomalous live-born infants at or after 24 weeks' gestation.

RESULTS

One hundred seven women with placenta previa delivered during the study. Fourteen (13%, 95% CI 7%, 21%) had MSAFP at least 2.0 multiples of the median (MoM). They were significantly more likely than those with lower MSAFP levels to have one or more of the following outcomes: hospitalization for antepartum bleeding before 30 weeks' gestation (50% versus 15%), delivery before 30 weeks' gestation (29% versus 5%), or preterm delivery for pregnancy-associated hypertension before 34 weeks' gestation (14% versus none). The MSAFP cutoff of 2.0 MoM provided the best combination of sensitivity and specificity for those outcomes, using receiver operating characteristic curves.

CONCLUSION

Women with placenta previa who also have high MSAFP levels are at increased risk of bleeding in the early third trimester and preterm birth. We did not find women who required cesarean hysterectomy, including those with placenta accreta, to consistently have elevated MSAFP.