There is no indication for estrogen therapy during pregnancy or during the immediate postpartum period. Estrogen therapy during pregnancy os associated with an increased risk of congenital defects in the reproductive organs of the fetus, and possibly other birth defects. Estrogens are not indicated for the prevention of partum breast enlargement. The 1985 DES Task Force concluded that use of DES during pregnancy is associated with subsequent increased risk of breast cancer in the mothers, although a casual relationship remains unproven and the observed level of excess risk is similar to that for a number of other breast cancer risk factors. Several reports also suggest an association between intrauterine exposure to progestational drugs in the first trimester of pregnancy and genital abnormalities in male and female fetuses.
Estrogens are ineffective for the prevention or treatment of threatened or habitual abortion.
There is no adequate evidence that progestational agents are effective in preventing habitual abortion when such drugs are given during the first trimester of pregnancy. Furthermore, in the vast majority of women, the cause of abortion is a defective ovum, which progestational agents could not be expected to influence. In addition, the use of progestational agents with their uterine-relaxant properties, in patients with fertilized defective ova, may cause a delay in spontaneous abortion. Premarin is a mixture of sodium estrone sulfate and sodium equilin sulfate. Cycrin contains medroxyprogesterone acetate, a derivative of progesterone.