Unexplained elevated maternal serum free beta-human chorionic gonadotrophin concentrations and adverse pregnancy outcome

Abstract

The objective of this study was to investigate the association between unexplained very highly elevated maternal serum beta-human chorionic gonadotrophin (hCG) in the second trimester of pregnancy and adverse outcome of pregnancy. In a case–controlled study of 3463 women who opted for second trimester serum screening for Down's syndrome, 124 were found to have an unexplained elevated serum beta-hCG of greater than 3.5 multiples of the median (MoM), 40 of whom had a serum beta-hCG of greater than 5.0 MoM. For a large number of adverse outcomes, these women were compared to a control group of women with serum beta-hCG of around the median. In the elevated beta-hCG group statistically significantly more babies required admission to the special care baby unit (P = 0.02) or were small for gestational age (SGA) (P = 0.03). The mean birth weight was also statistically significantly lower in the elevated beta-hCG group. Women with a serum beta-hCG of ≥5, ≥6, ≥7 or ≥ 8 MoM were associated with SGA in 40%, 44%, 64% and 86%, respectively. All six babies born to women with beta-hCG of 8.75–24.1 MoM were small for gestational age.