Adverse pregnancy outcome after a false-positive screen for Down syndrome using multiple markers

Area of Science:

• Maternal-fetal medicine
• Prenatal screening
• Pregnancy outcomes

Background:

• Multiple-marker screening (MMS) uses maternal serum alpha-fetoprotein (MSAFP), unconjugated estriol (E3), hCG, and maternal age to assess Down syndrome risk.
• False-positive MMS results can cause patient anxiety and lead to unnecessary invasive procedures like amniocentesis.

Purpose of the Study:

• To evaluate the risk of adverse pregnancy outcomes in women with a false-positive Down syndrome screen.
• To determine if MSAFP, E3, or hCG levels predict adverse pregnancy outcomes in these cases.

Main Methods:

• A case-control study matched 58 women with false-positive Down syndrome screens to 116 controls with low-risk screens.
• Pregnancy outcomes were compared, and the predictive value of specific markers (MSAFP, E3, hCG) for adverse outcomes was analyzed.

Main Results:

• Women with false-positive screens had significantly higher rates of preterm delivery (20.6% vs. 8.6%), preeclampsia (6.9% vs. 0%), small for gestational age newborns (5.2% vs. 0%), and fetal demise (5.2% vs. 0%).
• Overall adverse pregnancy outcomes occurred in 32.8% of the study group versus 12% in controls (OR 3.5).
• Unconjugated E3 ≤ 0.75 multiples of the mean (MoM) was a significant predictor of adverse outcomes (OR 2.5).

Conclusions:

• Approximately one in three women with a false-positive Down syndrome screen experienced an adverse pregnancy outcome.
• Low unconjugated E3 levels appear to be a stronger predictor of adverse pregnancy outcomes than MSAFP or hCG in this population.