OS009. Second trimester serum hyperglycosylated human chorionic gonadotrophin and preeclampsia

Hyperglycosylated human chorionic gonadotrophin (hCG-h), produced by the placental trophoblast cells, is involved in placental development in early pregnancy. Decreased second trimester urine hCG-h is associated with later preeclampsia, which may be a sign of impaired trophoblastic invasion preceding symptoms of the disease.

To study whether maternal second trimester serum hCG-h concentrations predict later development of preeclampsia.

Fifty-five women with subsequent preeclampsia, 21 women with gestational hypertension, 30 normotensive women with small-for-gestational-age (SGA) infants and 83 controls with uneventful pregnancies were included in the study. Their serum hCG and hCG-h concentrations were analyzed by fluoroimmunoassay at 14-17weeks of gestation. The proportion of hCG-h of total hCG (%hCG-h) was calculated and converted to multiples of the median (MoMs) of the controls. MoMs of the groups were compared by Mann-Whitney U test. Pearson's correlation was used to analyze correlations between clinical characteristics and serum marker concentrations. The results are given as medians with 95% confidence intervals (95% CI). A two-tailed P<0.05 was considered significant.

The concentrations of hCG-h and %hCG-h decreased with advancing gestational weeks in women with subsequent preeclampsia (r=-0.289, p=0.032 and r=-0.464, p<0.001), but not in women in the other groups. There was a tendency towards lower concentrations of hCG-h and %hCG-h in women with subsequent preeclampsia than in controls. The median MoMs of %hCG-h were 0.89 (95% CI,0.79-1.00) in women with subsequent preeclampsia and 1.00 (0.91-1.11) in controls. The corresponding values for women with subsequent gestational hypertension were 1.00 (0.86-1.16), for those with subsequent SGA infants they were 1.09 (0.89-1.23). The difference between preeclampsia and the other groups together was significant (p=0.029).

Earlier studies suggest that decreased urine hCG-h concentrations reflect changes in placental function that precede the development of preeclampsia. At 14-17weeks of gestation, the serum concentrations of hCG-h showed moderate validity to predict later development of preeclampsia. Further studies on the utility of hCG-h for prediction of subsequent preeclampsia are warranted.