Relation of obstetric parameters to the concentrations of four pregnancy-associated plasma proteins at term in normal gestation.

The relations between normal obstetric parameters and the maternal levels of four pregnancy-associated plasma proteins (PAPP) were studied, with the use of plasma samples taken from 187 normal pregnant women within seven days before delivery. PAPP-A levels were correlated with placental and newborn weights. The levels of this pregnancy protein was higher in primigravid women and in groups with higher diastolic blood pressure than in other groups. Women with extremely high PAPP-A concentrations were likely to have extremely large placental weight was not necessarily associated with a high PAPP-A level. PAPP-C was not correlated with placental or newborn weight. The relationship between PAPP-C and maternal age, as well as maternal weight, was significant by one but not in the other three statistical analyses employed. The pregnancy zone protein was found to be correlated with parity. In primigravid women, this protein additionally showed an inverse correlation with the placental weight. Human chorionic somatomammotropin was significantly related to placental weight and inversely related to maternal weight. Its relationship with newborn weight was best seen in primigravid subjects. Other parameters (systolic blood pressure, one- and five-minute Apgar scores, weeks of gestation, days before delivery, newborn sex, and newborn bilirubin level) were not related to any of these pregnancy proteins.