Amniotic fluid human chorionic gonadotropin and alpha-fetoprotein in severe preeclampsia

Park, Kyo Hoon; Park, Koung Mee; Cho, Yong Kyoon; Choi, Hoon; Kim, Bok Rin; Lee, Hong Kyoon

Abstract

OBJECTIVE
Unexplained elevations of midtrimester human chorionic gonadotrophin(hCG) or alpha fetoprotein(AFP) have known to be at increased risk for a variety of third trimester pregnancy complication, such as preeclampsia. The causes of these were thought to be made by impaired placental function, as a reflection of impaired uteroplacental circulation. Our purpose was to determine if amniotic fluid total -hCG and AFP levels are elevated in women with severe preeclampsia and if these levels correlated with other laboratory features of disease severity.
METHODS
Seventeen women with severe preeclampsia were matched with 16 women with the diagnosis of either preterm labor and intact membranes(n=10) or preterm premature rupture of membranes(n=6) who met the following criteria: 1) singleton gestation 2) absence of congenital anomaly 3) absence of active labor 4) confirmed getational age by ultrasonography 5) transabdominal amniocentesis performed to obtain amniotic fluid to assess fetal lung maturity. Amniotic fluid total -hCG and AFP were measured by double antibody radioimmunoassay(RADIM, Italy). Mann-Whitney U test and multiple linear regression analysis were used. RESULTS: 1) Concentrations of amniotic fluid total -hCG but not amniotic fluid AFP, maternal blood total -hCG and AFP were significantly higher in severely preeclamptic women than in their matched controls(amniotic fluid total -hCG; median 28.5, range 4.3-120.3 IU/ml vs. median 9.4, range 2.7-99 IU/ml, p < 0.01). 2) Amniotic fluid total -hCG levels correlated positively with maternal blood BUN(blood urea nitrogen) levels(r= 0.66, regression coefficients 5.57, standard error 2.4021, p< 0.05, multiple linear regression) after correction for known confounding variables(i.e., maternal weight, gestational age at sampling, hematocrit). CONCLUSION: Amniotic fluid total -hCG levels are elevated in women with severe preeclampsia and correlate closely with maternal blood BUN levels. These observation suggest that the pathologic changes of preeclampsia might occur in the placenta and involve in change of a significantly secretory reaction of the placenta.