Human placental growth hormone is increased in maternal serum in pregnancies affected by Down syndrome.

Objective: To evaluate the relationship between maternal serum levels of human placental growth hormone (hPGH) and fetal Down syndrome at gestational midtrimester.

Methods: We retrospectively analyzed samples of serum from 21 women with Down syndrome pregnancies detected at gestational midtrimester. The samples were obtained at 16-23 weeks' gestation during amniocentesis for fetal karyotyping. Sixty-two serum samples were used as controls, which were obtained at 16-23 weeks' gestation from women with singleton, uncomplicated pregnancies, who gave birth to healthy neonates with a birth weight appropriate for gestational age. The hPGH levels were measured by a solid-phase immunoradiometric assay using 2 different epitopes.

Results: The median hPGH values in the serum of the Down-syndrome-affected pregnancies were significantly higher (p < 0.05) than those of the normal pregnancies at 16-23 weeks' gestation: the median value in the serum was 9.4 ng/ml (5th to 95th percentiles = 1.49-39.03) versus 4.7 ng/ml (0.53-7.88).

Conclusion: The hPGH levels in maternal serum were found to be higher at 16-23 weeks' gestation in pregnancies affected by fetal Down syndrome. Further investigation is needed to examine if maternal serum hPGH could be used as an additional marker in prenatal screening of Down syndrome at gestational midtrimester.