Usually in the 1st month of pregnancy there is no swelling or pain in the breasts. The first symptom of pregnancy is menopause. If you have not had your period for more than 30 days after your period, you should consider whether there is a pregnancy and then have it checked. After pregnancy, the levels of estrogen, progesterone and chorionic gonadotropin in the body will increase. Generally at 8 weeks after menopause, there will be breast swelling and pain, mainly due to the increase of estrogen and progesterone, resulting in the enlargement of the pregnant woman’s breasts, lobular hyperplasia of the mammary glands, combined with the appearance of nipple pain, and after 6 weeks of pregnancy, the pregnant woman will experience morning sickness and other early pregnancy reactions. So generally in the first month of pregnancy pregnant women will not appear chest pain, this time the increase in hormone levels is not yet obvious, generally in the second month of pregnancy will appear chest pain.