[Relationship of adverse pregnancy outcomes and a high risk serum screen for Down syndrome in the second trimester].

OBJECTIVE: To investigate the the relationship of a high risk serum screen for Down syndrome in second trimester and adverse pregnancy outcomes, and to evaluate the predictive value for adverse pregnancy outcomes.

METHODS: The tri-marker second trimester maternal serum screening for Down syndrome (alpha-fetoprotein, free beta-hCG and unconjugated estriol) was performed on the pregnant women at Peking Union Medical Hospital from January 2009 to January 2011. The cutoff valvue was 1/270. Pregnancy outcomes were followed up. The general condition and pregnancy complications of the pregnant women with high risk (high-risk group) were compared to that of the pregnant women with low risk (low-risk group); and with 35 years old as a demarcation, the incidences of adverse pregnancy outcomes were calculated in the two groups.

RESULTS: (1) A total of 1935 cases were collected. And 1784 cases were with low risk, and 151 cases were with high risk. The difference of weight and gestational age between the two groups was not statistically significant (P > 0.05); the difference of age between the two groups was statistically significant (P < 0.01). (2) Pregnancy complications were found in 791 cases. In high-risk group, the incidences of gestational diaetes mellitus (GDM, 13.9%), neonatal asphyxia (4.0%) and small for gestational age infant (SGA, 4.6%) were higher than that in low-risk group (8.4%, 1.0%, 1.6%), the difference was statistically significant (P < 0.05). The incidences of gestational hypertension disease, premature labor, oligohydramnios, placenta previa, placenta abruption, fetal macrosomia in the two groups was not statistically different (P > 0.05). (3) In 1705 cases aged less than 35 years, 129 cases (7.6%) were GDM, 43 cases (2.5%) were gestational hypertension disease, 61 cases (3.9%) were premature labor; in 230 cases aged 35 years or more, 41 cases (17.8%) were GDM, 12 cases (5.2%) were gestational hypertension disease, 15 cases (6.5%) were premature labor, and the difference between the two groups was statistically significant (P < 0.05). In < 35 years old group, the incidences of GDM, neonatal asphyxia and SGA (12.3%, 4.4%, 5.3%) were higher in the high-risk group than that (7.2%, 0.9%, 1.6%) in the low-risk group, and the difference was statistically significant (P < 0.05). In ≥ 35 years old group, the incidences of GDM, neonatal asphyxia and SGA (18.9%, 2.7%, 2.7%) were slightly higher in the high-risk group than that (17.6%, 1.6%, 1.6%) in the low-risk group, the difference between the two groups was not statistically significant (P > 0.05).

CONCLUSIONS: The present study revealed apparent increase in the adverse pregnancy outcomes in women with a high risk of Down syndrome screening test. Advanced age is the most important risk factor for a high risk of Down syndrome screening test and adverse pregnancy outcomes. More attention should be attached to the patients whose age were < 35 years old and with a high risk of Down syndrome screening test.