Maternal plasma concentrations of insulin-like growth factor binding protein-1 and placental protein 14 in multifetal pregnancies before and after fetal reduction.

The aim of this study was to investigate the changes in maternal plasma insulin-like growth factor binding protein-1 (IGFBP-1) and placental protein 14 (PP14) in multifetal pregnancies before and after embryo reduction. Maternal plasma IGFBP-1 and PP14 were measured serially in three groups of pregnant women at 8-21 weeks gestation. Groups 1 and 2 were 12 singleton and 12 twin pregnancies achieved after in-vitro fertilization (IVF). Group 3 comprised 26 women with multifetal pregnancies undergoing embryo reduction to twins. In the IVF pregnancies maternal plasma IGFBP-1 and PP14 increased with gestation to reach a peak at 20 and 10 weeks respectively; the mean concentrations in twin pregnancies were significantly higher than in singletons. In multifetal pregnancies the mean plasma concentration of both proteins was similar to that of IVF twin pregnancies before reduction; after reduction, the values fell to less than those of twins. These findings suggest that the maximum secretory capacity of the endometrium is achieved with twin pregnancies. In multifetal pregnancies undergoing iatrogenic reduction to twins, total residual endometrial function was less than in twin conceptions.