The mid-gestation triple test profile among women diagnosed with vasa previa.

PURPOSE: To assess the mid-trimester triple test biomarkers among women diagnosed with vasa previa (VP). METHODS: The study included 43 singleton pregnancies diagnosed with vasa previa between the years 1988 and 2011. The mid-gestation screening test for Down syndrome was calculated from the combination of triple serum markers and maternal age, and expressed as a multiple of the gestation specific normal mean (MoM). Reference MoM values were calculated from the local population. The levels of mid-gestation maternal serum alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) of patients with VP were compared with control reference group. RESULTS: The mean hCG and αFP levels of women diagnosed with VP was significantly higher compared to control reference group (1.42 versus 0.99 MoM; p < .002 and 1.24 versus1.01 MoM; p < .001, respectively). In contrast, there was no significant difference in uE3 levels between these two groups (0.99 versus 0.98 MoM; p = .71). CONCLUSIONS: Our findings suggest that increased mid-gestation hCG and AFP were found among pregnancies complicated with VP. Clinicians should consider targeted scanning of pregnant women with risk factors for VP, including unexplained high maternal levels of hCG and αFP of the triple test, while conducting mid-gestation anomaly scan.

Evaluation of the impact of vasa previa on feto-placental hormonal synthesis and fetal growth.

INTRODUCTION: A vasa previa (VP) refers to aberrant chorionic vessels which can either connect the chorionic plate to a velamentous cord (type I) or a succenturiate or accessory lobe to the main placental mass (type II). METHODS: We performed retrospective cohort study of 32 singleton pregnancies diagnosed with VP. The levels of maternal serum alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and unconjugated estriol (uE3) were measured at 15-18 weeks as part of the triple test screening for Trisomy 21. The data were subdivided according to the type of VP and compared with those of a control group with central cord insertion and no succenturiate or accessory placental lobe. RESULTS: Twenty one (65.6%) parturient women presented with VP type I and 11 (34.4%) with VP type II. The mean birthweight and placental weight was significantly higher in pregnancies with VP type II than in pregnancies with VP with VP type I (3037.3±400.9 gr vs 2493.5±491.6 gr; p=0.004 and 511.0±47.2 gr vs 367.1±64.3 gr; p<0.0001; respectively). The mean hCG level in VP type II was significantly (p<0.001) higher than those with type I (2.38MoM vs 1.17MoM) and compared to controls (2.38MoM vs 0.99MoM). CONCLUSIONS: There is no obvious impact on both placental and fetal growth in VP type II. By contrast, VP type I is associated with slower feto-placental growth secondary to impaired development and biological functions of the placenta during the first half of pregnancy.