Abstract

PIP: The frequency of women with demonstrable "pregnancy zone" protein (assumed to be a steroid-induced alpha-2-globulin) at term of pregnancy was determined in order to investigate whether lack of this protein in maternal serum was in any way related to maternal age, parity, abortion history, or some factors reflecting fetal maturity (birth weight, placental weight, and gestational age). 311 (88.9%) out of 350 pregnant women demonstrated "pregnancy zone" protein in their sera. Birth weight was significantly lower (p less than .05) among infants of women lacking this protein. No apparent correlation was found between lack of "pregnancy zone" protein in maternal serum and maternal age, parity, previous abortion, placental age, or gestational age. The results indicated that lack of or low levels of this protein in the maternal circulation at term is a phenomenon compatible with normal pregnancy, although some slight effect on fetal development cannot be excluded.