Taking birth control pills during pregnancy causes the mother’s milk to decrease and the fetus to mature prematurely. Since birth control pills are hormonal drugs, they contain progesterone and estrogen, which will be secreted to the baby through the mother’s milk after taking them, which is not good for the health. It also reduces the nutritional content of breast milk, making the supply of nutrients to the baby insufficient and affecting normal growth and development, and can easily cause side effects such as nausea and vomiting. When the pill reaches the baby’s body through breast milk, it can cause premature maturation of the child, thickening of the vaginal epithelium and abnormalities in the sex characteristics of the baby girl, such as thickening of the labia. If you are breastfeeding, you need to wean your baby for about a week after taking the pill, so that the components of the pill in your body can be metabolized before breastfeeding your baby. It is recommended that breastfeeding women take other methods of contraception, such as condoms, intrauterine devices, etc. In addition, women who take other medications while breastfeeding can easily affect their children, so it is recommended to ask your doctor before taking them.