Second-trimester prediction of severe placental complications in women with combined elevations in alpha-fetoprotein and human chorionic gonadotrophin

Objective

The purpose of this study was to determine the ability of uterine artery Doppler and placental ultrasound to identify adverse clinical outcomes attributable to severe placental dysfunction in women with second-trimester unexplained elevated maternal serum screening of alpha-fetoprotein and human chorionic gonadotropin.

Study design

Fifty singleton pregnancies with elevated alpha-fetoprotein (3.5 multiples of median [range 2.1 to 10.5]) and human chorionic gonadotropin (5.3 multiples of median [range 2.5 to 21.7]) and a normal fetal anatomical ultrasound were prospectively evaluated with placental ultrasound and uterine artery Doppler at referral between 19 and 23 weeks' gestation.

Results

Abnormalities in both placental ultrasound and uterine artery Doppler (n = 24) predicted preterm delivery less than 32 weeks from any cause (n = 24) (75% sensitivity, 75% positive predictive value; likelihood ratio positive 3.3 [1.6 to 6.8]), intrauterine fetal death (n = 12) (100% sensitivity, 50% positive predictive value; likelihood ratio positive 3.1 [2.0 to 5.0]), and intrauterine growth restriction with absent/reversed end-diastolic flow (n = 17) (sensitivity 94%, positive predictive value 67%, likelihood ratio positive 3.9 [2.0 to 6.2]) . Ischemic-thrombotic pathology was present in 88% of placentas examined (n = 32).

Conclusion

Uterine artery Doppler and placental morphology identified most pregnancies with combined abnormal maternal serum screening destined to result in extremely premature delivery and/or perinatal death. Abnormal maternal serum screening reports could include a recommendation for placental ultrasound testing when no fetal explanation has been identified.

Key words: Placental dysfunction, Ultrasound, Maternal serum screening, Human chorionic gonadotropin, Alpha-fetoprotein