Final answer:
Estrogen is contraindicated in breastfeeding women and/or soon after delivery because it increases the risk of blood clots and may disrupt milk production. It also leads to an amenorrhaeic effect which can affect breastfeeding as a natural contraceptive. Sudden cessation of breastfeeding leads to engorgement and leakage due to continued milk production.
Step-by-step explanation:
Estrogen is contraindicated in breastfeeding women and/or in the first 3 weeks after delivery for several reasons. Initially after childbirth, there is an increased risk of blood clots, and birth control methods containing both estrogen and progestin can further elevate this risk. Women who are breastfeeding should also consider that exogenous hormones may impact milk production and have an amenorrhaeic effect, which can reduce the effectiveness of breastfeeding as a natural contraceptive method.
Breast engorgement and leakage in a woman who has suddenly stopped breastfeeding occur because the physiological process of lactation is still active. Sudden cessation causes the milk that is still being produced to accumulate, resulting in engorgement and leakage. These symptoms are similar to those experienced in the first few weeks of breastfeeding when the milk supply is adjusting to the baby's needs.
The breasts, as accessory sexual organs, engage in lactation for milk production after childbirth. The presence of constant levels of estrogen and progestin from birth control pills provides feedback to suppress the release of FSH and LH from the hypothalamus and pituitary gland, which in turn inhibits ovulation and thereby prevents pregnancy. However, these exogenous hormones may interfere with the contractions of the uterus during childbirth and lactation, potentially causing complications for the mother, as well as affecting milk production.
The increase of prolactin during breastfeeding stimulates milk production for the next feeding, and concurrently, estrogen and progesterone also increase slightly with each spike of prolactin. Nonetheless, the introduction of synthetic hormones can disrupt this natural hormonal balance.