A pregnant woman with low estrogen levels is treated with hormonal therapy. What teratogenic effect is likely to occur in the newborn?

The correct response highlights that congenital defects of the female reproductive system are likely to occur in the newborn when a pregnant woman is treated with hormonal therapy due to low estrogen levels. This phenomenon can be attributed to the role of estrogen in the development of the genitalia and reproductive organs during fetal growth. Disruption in estrogen levels, particularly during critical periods of development, has been associated with abnormalities in the formation of the female reproductive tract.

Inadequate exposure to estrogen can interfere with the normal differentiation of the reproductive structures, leading to potential congenital anomalies in female offspring, such as abnormalities in the uterus, ovaries, and vagina. The implications of hormonal therapies, particularly concerning the timing and dosage, are crucial in understanding their impact on fetal development.

The other potential teratogenic effects listed, such as neural tube defects, cardiac anomalies, and respiratory complications, are indeed serious concerns in maternal-fetal medicine, but they are more commonly associated with different risk factors or deficiencies rather than specifically linked to low estrogen levels and the administration of estrogen-based hormonal therapy. Thus, the specific teratogenic effect related to low estrogen levels points more directly to issues in the development of the female reproductive system.