T. Markestad et al., PREDICTION OF FETAL GROWTH BASED ON MATERNAL SERUM CONCENTRATIONS OF HUMAN CHORIONIC-GONADOTROPIN, HUMAN PLACENTAL-LACTOGEN AND ESTRIOL, Acta obstetricia et gynecologica Scandinavica, 76, 1997, pp. 50-55
Background. The purpose was to determine the usefulness of maternal se
rum concentrations of human chorionic gonadotropin (hCG), human placen
tal lactogen (hPL) and estriol as predictors of fetal growth. Method.
From a large cohort serum obtained serially at 17, 25, 33 and 37 weeks
of gestation were analyzed for randomly selected pregnancies resultin
g in small for gestational age (SGA, n = 102) and non-SGA (n = 112) in
fants. Results. There were no significant correlations between birthwe
ight ratio (ratio of birthweight to mean weight for gestational age) a
nd hCG, but between birthweight ratio on one hand and estriol for all
stages of pregnancy (r = 0.19-0.38, p < 0.01 - p < 0.001) and hCL exce
pt at 33 weeks (r = 0.11 - 0.40, p ns - p < 0.001) on the other. There
were statistically significant, but small median differences and subs
tantial overlaps between the SGA and non-SGA infants for hCG at 17 and
37 weeks, for hPL at 17, 33 and 37 weeks, and for estriol at all the
stages of pregnancy. The sensitivity and positive predictive value of
low hormone concentrations (below the 10th percentile) in predicting t
he birth of an SGA infant were in the range of 6 - 26% and 17 - 39%, r
espectively. The corresponding specificity and prediction of a non-SGA
infant from normal levels were 91 - 93% and 85 - 88%. Conclusions. HP
L and estriol, but not hCG concentrations, are positively related to t
he size of the fetus, but the relationships are too weak to be of pred
ictive value in an unselected population.