Is maternal serum inhibin A a good predictor in preterm labor? - Experience from a community hospital in Taiwan

BACKGROUND: We aimed to determine whether inhibin A could be a reliable and accurate predictor of preterm birth, and discuss the possible pathogenic processes of inhibin A leading to preterm birth. METHODS: A retrospective cohort study was conducted on consecutive singleton pregnant women who underwent the second-trimester quad screen test at a gestational age of 15–20 weeks at Keelung Chang-Gung Memorial Hospital from March 2011 to May 2015. Data including maternal characteristics and pregnancy outcomes were collected from an electric medical record database. Data regarding pregnancy terminations before a gestational age of 24 weeks and regarding pregnancies that involved chromosomal or congenital anomalies were excluded from this analysis. One-way analysis of variance was used to compare second-trimester α-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A in women with preterm deliveries versus those with term deliveries. RESULTS: Although a total of 935 women with singleton pregnancies were enrolled, pregnancy outcome and complete maternal data were obtained from only 770 (82.3%)of them. In total, 687 (89.2%) women delivered at or after 37 weeks of gestation and 83 (10.8%) women delivered before 37 weeks of gestation. The results showed that the inhibin A level was significantly increased in the preterm labor group (p = 0.009). A cutoff inhibin A value above 2.25 was identified statistical significantly in the preterm labor group. CONCLUSIONS: From our results, an inhibin A level above 2.25 multiples of the median in the quad screen test may be associated with preterm labor afterward. Closely monitoring for uterine contractions or cervical length measurement in the second trimester may be indicated in patients with unexplained elevated inhibin A levels.