Due to the hormones released during pregnancy, various changes occur in the mother’s body to adapt to pregnancy across all systems. These changes can lead to different interpretations of laboratory measurements taken during pregnancy and the adjustment of medication dosages based on pregnancy. These changes also result in some complaints specific to pregnancy in expectant mothers.
Changes occurring in different systems during pregnancy can be listed as follows:
Cardiovascular System Changes:
The heart shifts upward and to the left due to both the enlargement of the uterus and the upward movement of the diaphragm. The size of the heart increases by 12%. Heart rate increases by 15%, and cardiac output increases by 24%. As a result, during the final trimester of pregnancy, the resting heart rate increases by up to 15 beats per minute compared to non-pregnant individuals. This increase can sometimes lead to palpitations in expectant mothers, and factors such as exercise, stress, and temperature can further exacerbate this sensation.
Additionally, the mother’s position can affect cardiac output. Prolonged lying on the back can reduce blood flow to the heart due to pressure from the uterus, leading to a drop in blood pressure and even fainting in pregnant women. In such cases, the pregnant woman should be immediately placed on her left or right side to normalize blood pressure. Starting from the first three months of pregnancy, there is an increase in blood volume, peaking at the 30th week of pregnancy. The primary reason for this increase in volume is to compensate for the blood loss of approximately 600 mL during vaginal delivery or approximately 1000 mL during cesarean section.
Respiratory System Changes:
As the uterus grows during pregnancy, the diaphragm rises, but this does not lead to any decrease in respiratory function. However, the respiratory rate increases slightly due to the main hormone in pregnancy, progesterone.
Urinary System Changes:
Due to the pressure from the growing uterus and the influence of pregnancy hormones, there is some expansion in the collecting ducts in the kidneys and the ureters. The volume of blood filtered by the kidneys increases. In addition, unlike non-pregnant individuals, there is a slight excretion of glucose and protein in the urine during pregnancy. Especially, the excretion of glucose predisposes the urinary tract to easier infections during pregnancy. Bladder pressure increases due to the growing uterus, so the complaint of frequent urination becomes more common, especially in the later stages of pregnancy.
Digestive System Changes:
Throughout pregnancy, as the uterus enlarges, the stomach shifts upward, while the intestines are pushed backward and to the sides. The gums swell, and gum bleeding occurs in the mouth region due to the effects of the estrogen hormone. Reflux complaints are seen in 30-80% of pregnant women. The main reason for this is the weakening of the valve that separates the stomach from the esophagus due to pregnancy hormones. Additionally, the slower functioning of the digestive system organs and the more acidic release of stomach acid can worsen reflux, especially as pregnancy progresses. During pregnancy, the emptying time of the gallbladder is greatly prolonged. Consequently, there is continuous accumulation of bile and a predisposition to gallstone formation.
Blood Cell Changes:
Although there is an increase in red blood cells during pregnancy, anemia becomes a problem due to a greater increase in the liquid part of the blood called plasma. Thanks to the increase in red blood cell count, the amount of iron used during pregnancy increases compared to normal. Since most women experience iron deficiency before becoming pregnant, pregnancy predisposes to iron deficiency anemia. Therefore, iron treatment is generally started for all pregnant women as a supportive measure. White blood cell count also increases during pregnancy, up to 3-4 times the normal levels. These values are considered normal changes during pregnancy, even though they would suggest a severe infection in non-pregnant individuals.
Platelet counts may drop below normal levels during pregnancy, a condition known as “pregnancy-induced thrombocytopenia.” These values return to normal after childbirth. Coagulation factors increase during pregnancy, and the effectiveness of the fibrinolytic system decreases. As a result, there is an increased tendency for blood to clot during pregnancy.
Skin Changes:
Dark brown streaks known as “linea nigra” that appear in the midline of the abdomen and darkening of the face, called “melasma” or “pregnancy mask,” are some of the major skin changes during pregnancy. Exposure to sunlight can intensify this darkening. Nails become more fragile, and there may be ridges on them. Increased growth of hair follicles during the growth phase leads to thickening of the hair during pregnancy. These changes typically disappear after childbirth.
Due to the pressure of the uterus during pregnancy, especially in the lower legs, buttocks, and genital area, blood flow cannot be adequately provided. This worsens varicose veins in the legs and genital area, and hemorrhoids can also develop.
Please note that this page content is for informational purposes only, and it is essential to consult your doctor for diagnosis and treatment.
Content Update Date: December 26, 2022