Second trimester levels of maternal serum total activin A and placental inhibin/activin alpha and betaA subunit messenger ribonucleic acids in Down syndrome pregnancy

Previous data have shown that inhibin A (alpha/betaA) is increased about twofold in maternal serum samples from Down syndrome pregnancy. Our objectives were to determine whether activin A (betaA/betaA) was similarly increased in maternal serum from pregnancies affected with fetal Down syndrome, and to investigate whether increased expression of each inhibin/activin subunit occurred in placental tissue from cases of fetal Down syndrome.