For pregnant women with regular menstrual periods, the earliest appearance of nausea and other reactions to pregnancy is around 6 weeks after menopause. In most pregnant women, chorionic gonadotropin levels rise significantly after 6 weeks of menopause, and peak at 8-10 weeks of menopause, before dropping significantly after 12 weeks of menopause. After the chorionic gonadotropin level decreases, the nausea and vomiting of pregnant women will be significantly reduced. For pregnant women with irregular menstruation, there may be delayed ovulation and delayed conception, in which case the rise in chorionic gonadotropin levels will also be delayed, so the date of early pregnancy reaction will be pushed back accordingly. Pregnant women with regular or irregular menstruation need to check the expected date of labor and the week of pregnancy after the ultrasound examination. After checking the expected date of labor, we can take the checkups on time and observe whether the baby’s growth and development are in accordance with the gestational week. Most pregnant women experience nausea and vomiting during early pregnancy, which occurs around 6 weeks after menopause.