Dynamic changes in the levels of maternal serum squamous cell carcinoma antigen, a potential biomarker of amniotic fluid embolism, before and after delivery in relation to the mode of delivery

Abstract

Amniotic fluid embolism (AFE) is a serious disease in which amniotic fluid components enter the maternal systemic circulation, causing cardiopulmonary collapse in pregnant women. It has been previously reported that amniotic fluid contains extremely high levels of squamous cell carcinoma antigen (SCCA), and that pregnant women who do not survive due to AFE have high blood SCCA levels. The aim of the present study was to determine the possible mechanisms through which SCCA in amniotic fluid enters the maternal blood, as well as the potential origin of SCCA. The prospective study included a cohort of 464 women (339 normal vaginal deliveries, 97 cesarean deliveries without labor, and 28 cesarean deliveries with labor). The dynamic changes in maternal serum SCCA levels were determined before and after delivery in relation to the mode of delivery, and SCCA levels were measured in the placenta, fetal skin, amniotic fluid cell components, amniotic fluid and neonatal urine. Serial serum samples collected at the time of admission, at 2 h postpartum, and on postpartum day 3 were quantitatively measured for SCCA by enzyme-linked immunosorbent assay. Amniotic fluid and neonatal urine SCCA levels were also measured. The protein expression of SCCA in the placenta and fetal skin was assessed by immunohistochemistry. In vaginal deliveries, there was a significant increase in serum SCCA levels from admission to 2 h postpartum, and SCCA levels decreased on postpartum day 3. In cesarean deliveries, the SCCA levels at the time of admission and 2 h postpartum did not differ. The SCCA levels were significantly higher in women who underwent vaginal deliveries compared to those that underwent cesarean deliveries without labor (P= 0.033). Immunohistochemical staining revealed no SCCA expression in the placenta and fetal skin. The SCCA levels in neonatal urine immediately after birth were as high as those in the amniotic fluid, suggesting that SCCA may originate from fetal urine. The present study thus suggests that amniotic fluid SCCA levels, which may be derived from fetal urine, can enter the maternal circulation during vaginal delivery. The onset of labor and full cervical dilatation are the main causes of entry of amniotic fluid components into the maternal circulation.