The inhibin A test is done on a sample to measure the amount of this hormone in a pregnant woman's blood to check a if the down syndrome in the baby. This hormone is produced by the placenta during pregnancy. Generally done between 15 and 20 weeks, this test checks the levels of four substances in a pregnant woman's blood: 1.alpha-fetoprotein(AFP)
2.human chorionic gonadotropin(hCG),
3.a type of estrogen
4.hormone inhibin A.
The level of this hormone is used to determine various birth defects to the child during the pregnancy of a mother.