Elevated maternal second-trimester serum alpha-fetoprotein as a risk factor for placental abruption

To analyze the association of second-trimester maternal serum alpha-fetoprotein (MSAFP) and free beta human chorionic gonadotrophin (MSbeta-hCG) levels to placental abruption.

Fifty-seven women with placental abruption and 108 control women without placental abruption were tested for second-trimester MSAFP and MSbeta-hCG levels as a part of a trisomy 21 screening program. Discriminatory cutoff levels for MSAFP were sought to predict placental abruption.

The median of the MSAFP multiples of median (MoM) (1.21) was significantly higher in the abruption group than in the control group (1.07) (p = 0.004). In multivariate analysis, elevated MSAFP remained an independent risk factor for placental abruption when adjusting for other risk factors (parity >/= 3, smoking, previous placental abruption, preeclampsia, bleeding in II or III trimester, and placenta previa). MSAFP >/= 1.5 MoM had a sensitivity of 29% and a false-positive rate of 10%. The levels of the MSbeta-hCG MoM did not differ between the cases and the controls.

Although second-trimester MSAFP levels are higher in women with subsequent placental abruption, the clinical usefulness of this test is limited due to low sensitivity and high false-positive rate.