After pregnancy, the secretion of chorionic gonadotropin increases, and progesterone produced by corpus luteum stimulates the formation of endometrial placenta, which in turn produces a large number of estrogen, progesterone and chorionic growth prolactin, which stimulates the development of uterus and breast. At the same time, it can enhance the thyroid function of pregnant women and improve the basic metabolic level. The change of hormones during pregnancy leads to the decrease of the sensitivity of pregnant women to insulin, and about 2% ~ 7% of pregnant women can develop diabetes.

(2) Digestive system

The smooth muscle of the digestive tract of pregnant women is slack, the intestinal peristalsis slows down, and the secretion of digestive juice decreases, so pregnant women are prone to flatulence and constipation, and often have nausea, vomiting and pregnancy reaction in the early pregnancy. However, the absorption rate of iron, calcium, vitamin B 1, folic acid and other nutrients in pregnant women increased.

(3) Renal function

Renal function during pregnancy has obvious physiological regulation, which is manifested by the increase of glomerular filtration level and the obvious increase of urea, uric acid and creatinine excretion. At the same time, compared with pre-pregnancy, urine sugar excretion increased by more than 10 times, folic acid increased by about 1 times, and other water-soluble vitamins also increased greatly. The average amino acid excretion was about 2 grams per day, but urine calcium excretion was less than that before pregnancy.

(4) Blood volume and blood composition

Blood volume increased significantly from the second trimester and increased by 40% in the third trimester. Among them, the plasma volume increased by 50%, while the red blood cells only increased by 20%. Although the total amount of hemoglobin increased, due to the relative dilution of blood, the concentration of hemoglobin in blood decreased, showing physiological anemia.

(5) Weight gain

The average pregnant weight of healthy pregnant women increased 12.5 kg. Too little or too much weight gain is not good for both mother and child. The ideal situation is to gain weight 1.0 ~ 1.5 kg in the first three months of pregnancy, and then gain less than 0.5 kg per week on average.