Abnormal levels of maternal serum human chorionic gonadotropin and alpha‐fetoprotein in the second trimester: Relation to fetal weight and preterm delivery

Abstract

The aim of this prospective descriptive cross-sectional study was to examine the clinical significance of abnormal maternal serum human chorionic gonadotropin (MShCG) and alpha-fetoprotein (MSAFP) in the second trimester of pregnancy. The study group comprised 8892 women with a singleton pregnancy, who were screened for a neural tube defect and Down's syndrome. Exclusion criteria were unknown pregnancy outcome, a congenital anomaly, delivery before 25 weeks of amenorrhoea, or known insulin-dependent diabetes. MSAFP and MShCG were determined between 15 and 20 weeks' amenorrhoea. An abnormal result was defined as (a) MSAFP or MShCG ≥ 2·5 MOM, (b) MSAFP or MShCG ≥ 0·5 MOM, and (c) MSAFP and MShCG ≥ 2·5 MOM. Birth weight percentiles and the duration of amenorrhoea at the time of delivery were employed as outcome parameters. Of the women with an abnormally elevated MSAFP, 9·4 per cent had an extremely small-for-gestational age (SGA) infant (PPPPPPPPP<0·01, relative risk 3·0). Isolated or combined elevation of the MSAFP and MShCG levels in the second trimester of pregnancy is an indication for extra vigilance during further prenatal care. This applies to a lesser extent to a low MShCG level.