On or after January 1, 1990, every group disability contract entered into or renewed that covers hospital, medical, or surgical expenses on a group basis, and which provides benefits for pregnancy, childbirth, or related medical conditions to enrollees of such groups, shall offer benefits for prenatal diagnosis of congenital disorders of the fetus by means of screening and diagnostic procedures during pregnancy to such enrollees when those services are determined to be medically necessary by the disability contractor in accord with standards set in rule by the board of health. Every group disability contractor shall communicate the availability of such coverage to all group disability contract holders and to all groups with whom they are negotiating.