Both drowsiness during pregnancy and drowsiness during menstruation can be caused by changes in hormone levels, but the specific causes can be somewhat different, and the accompanying symptoms and time of appearance of the two can also be different. Common causes and differences 1, pregnancy drowsiness: drowsiness is mainly caused by the rise of hormone levels in the body to a certain extent, but also due to the increase in the basal body temperature of pregnant women, increased metabolism resulting in excessive calorie consumption in the body, usually about 2 weeks after the cessation of menstruation, lasting until about 3 months of pregnancy disappeared, generally do not need to worry too much. In addition to drowsiness, nausea, vomiting and other symptoms of early pregnancy reaction may also appear when pregnant; 2. Menstrual drowsiness: drowsiness during menstruation may be caused by changes in hormone levels, or due to blood loss, abdominal pain and other reasons resulting in poor mental state, fatigue, and drowsiness symptoms, mainly on the second day of menstruation. If you are pregnant and drowsy, you need to develop regular habits, avoid staying up late and working hard, and relax to improve the quality of sleep, and you need to strengthen nutrition in your diet, so you can consume lean meat, eggs and other foods. If women experience drowsiness during menstruation, they should take proper rest and avoid eating cold foods, such as ice cream.