Determination of gestational age by beta-subunit HCG measurement.

The accurate knowledge of gestational age is important in most Obstetric decisions near term. Gestational age estimation by a single measurement of beta-subunit HCG in early pregnancy was assessed in 164 Nigerian Women attending the antenatal clinic of Jos University Teaching Hospital. The mean difference between estimated gestational age by HCG concentrations and by recorded dates of last menstrual period was 2.8 +/- 1.6 days (mean +/- SD). This relationship was valid only for samples randomly selected between 35 and 56 days of gestation. We conclude that single measurement of HCG in early pregnancy provides accurate estimation of gestational age.