Pregnancy outcomes in unselected singleton pregnant women with an increased risk of first-trimester Down's syndrome.

BACKGROUND: The purpose of this study was to assess outcomes in pregnancies with a positive screen of first-trimester combined test (nuchal translucency, pregnancy-associated plasma protein-A and free beta-human chorionic gonadotropin).

METHODS: Using a cut-off level of 1 in 270, 216 (7.1%) women had a positive screen. Among them, 187 delivered their babies in our hospital and the adverse outcomes, such as spontaneous abortion, intrauterine fetal demize, preterm prelabor rupture of the membranes, preterm labor, intrauterine growth restriction, gestational hypertensive disorders, placenta previa, chromosomal abnormalities and fetal structural anomalies, were identified and compared with the 2097 women who screened negative for Down's syndrome.

RESULTS: Pregnancies with a positive screen had a significantly higher risk of adverse outcomes than those with negative screens (30.5% versus 15.3%; odds ratio 2.4; p < 0.001), especially for those complicated by spontaneous abortion (odds ratio 11.4; p < 0.05) and placenta previa (odds ratio 4.3; p < 0.05).

CONCLUSIONS: Besides fetal chromosomal abnormalities and structural abnormalities, pregnancies with a positive screen for Down's syndrome in the first-trimester had a significantly higher incidence of subsequent adverse obstetric outcomes.