Higher ꞵ-human chorionic gonadotropin and estrogen levels during the first 6 weeks of pregnancy are associated with threatened abortion.

The associations of human chorionic gonadotropin (hCG), estrogen, and progesterone levels with threatened abortion have not been fully studied. Eighty women with threatened abortion were recruited sequentially, and the levels in their pregnancy hormones during the first trimester were compared with that of 160 normal early pregnancy controls. The natural logarithm transformed (Ln) hCG and Lnestrogen of women with threatened abortion and gestational age ≤ 6 weeks were significantly higher than values for the normal controls of the same gestational age (8.6 ± 1.2 vs. 7.4 ± 1.7 mIU/mL and 5.8 ± 0.4 vs. 5.4 ± 0.5 pg/mL); the two hormones reached similar levels in the groups of gestational age > 6 weeks. Among the group with gestational age ≤ 6 weeks, a univariate logistic regression showed that LnhCG and Lnestrogen were associated with threatened abortion, with odds ratios (ORs) of 1.85 [95% confidence interval (CI): 1.30-2.64] and 4.62 (95% CI: 1.67-12.80), respectively. The multivariate logistic regression model revealed that hCG and estrogen were mutually confounding factors, and only hCG was an independent factor for threatened abortion (OR 1.56; 95% CI: 1.06-2.28). None of the variables in the univariate or multivariate logistic regression was a factor associated with threatened abortion after 6 weeks gestational age. In conclusion, β-hCG and estrogen levels in the first half of the first trimester are factors associated with threatened abortion.