Low maternal serum concentrations of human chorionic gonadotropin as part of the triple test screening: a follow-up study.

Objective: To determine whether low maternal serum concentrations of human chorionic gonadotropin (hCG) were associated with poor pregnancy outcome.

Methods: Between 1999 and 2000, 20,880 women underwent triple test screening in our hospital. The levels of hCG were detected by fluorescent immunoassay. Low hCG levels (< or = 0.20 MoM in our center) were considered to be a marker for increased risk for trisomy 18 or adverse pregnancy outcome. Each patient completed a questionnaire regarding fetal karyotype, complications of pregnancy and pregnancy outcome.

Results: Low maternal serum concentrations of hCG were detected in 119 pregnancies (0.57%). Of these, 19 (16%) were found to be missed abortions. The distribution of the remaining 100 cases was as follows: 72% had an isolated low hCG level, 24% had a low hCG level and a combination of hCG + alpha-fetoprotein < 0.80 MoM, and 4% had a low hCG level and a combination of hCG + unconjugated estriol < 0.80 MoM. No trisomy 18 or other chromosomal abnormalities were detected in our patient population. However, there were perinatal complications.

Conclusion: Based on our screened population, a combination of multiple analytes seemed to be a better marker than an isolated finding of low maternal serum concentrations of hCG with regards to abnormal fetal karyotype, specifically trisomy 18, although it did determine a high-risk group in terms of complications of pregnancy.