During pregnancy, the mammary gland prepares for feeding the baby in advance; from about the third month of pregnancy, the production of colostrum (a thick yellowish liquid) begins.
During sexual arousal, the hormone oxytocin is released. This is the same hormone that is released when you breastfeed your baby. The “love hormone,” which is responsible for sexual desire, also ensures milk production. Therefore, it is natural that a small amount of colostrum may be released during sexual intercourse.