During a normal pregnancy, a variety of physiological changes occur, both to support the developing fetus and to prepare the mother for labor and delivery. It is important to be able to distinguish normal changes to your body from abnormal ones. Read on to learn more about different ways your body changes during pregnancy.
Hormonal changes
- The rise in estrogen and progesterone levels during pregnancy lead to many bodily changes.
- High levels of estrogen during pregnancy enable the uterus and placenta to improve the formation of blood vessels, transfer nutrients, and support the developing baby. The rapid rise in estrogen during the first trimester is thought to cause some of the nausea associated with pregnancy. During the second semester, estrogen plays a role in the development of the milk ducts, which enlarges the breasts.
- High levels of progesterone during pregnancy affect ligaments and joints throughout the body, which can make pregnant women at great risk for ankle or knee sprains and strains. Progesterone will also help your uterus adapt to the growing fetus.
- Larger breasts and a concave abdomen both lead to an increase in back curvature, which can affect posture and sense of balance.
Weight gain, fluid retention and physical activity
- Pregnant women retain fluids and experience swelling of the face and limbs, usually starting during the second semester and continuing into the third trimester.
- This increase in fluid retention is responsible for a significant amount of weight gain associated with pregnancy. Weight gain, combined with ligament strain and increased size of the uterus may lead to increased discomfort during exercise.
Sensory changes
- Some women experience vision changes during pregnancy, such as increased nearsightedness, blurriness, discomfort with contact lenses, or an increase in intraocular pressure. Women with preeclampsia or gestational diabetes may face a higher risk of developing rare eye problems like retinal detachment or vision loss.
- Many women experience changes in their sense of taste during pregnancy, such as a preference for saltier and sweet foods. Some women may experience a decrease in the ability to taste during the first trimester of pregnancy. Other women also report a heightened awareness and sensitivity to certain odors.
Breast and cervical changes
- Hormonal changes during pregnancy lead to many physiological changes that affect women’s breasts and cervix.
- Significant changes to pregnant women’s breasts occur as the body prepares for breastfeeding. These include darkening of the areola, tenderness or sensitivity of the breasts, darker veins and increased protrusion of the nipples. It is common to begin producing and even “leaking” small amounts of a thick yellowish substance during the second trimester.
- As milk ducts expand for producing and storing milk, some women may notice small lumps in breast tissue, which usually disappear after a few days of massaging and warming the breast.
- The cervix, which is the entry of the uterus, thickens and becomes firm and glandular. In early pregnancy, it produces a thick mucus “plug” to seal off the uterus.
- Up to a few weeks before childbirth, the cervix may dilate slightly and soften. Prior to delivery, it dilats significantly to allow the baby to pass through the birth canal.
Hair, skin, and nail changes
- Changes in hair and nail growth are common during pregnancy, and include hair growth and thickening, or excessive hair shedding or hair loss. Faster nail growth can also be experienced during pregnancy.
- Most women will experience some type of skin hyperpigmentation during pregnancy, in areas such as the areolas, genitals, scars, and the linea alba (dark line down the middle of the abdomen). Darkening of the skin on the face can also occur, which is why it is particularly important to use a broad-spectrum sunscreen daily during pregnancy.
- Stretch marks are a well-known skin change of pregnancy, often on the breast and abdomen, most of which fade and shrink postpartum.
- Hyperpigmentation can also cause darkening of moles, freckles and birthmarks. While often these changes are harmless, it is always safe to see a dermatologist if you notice any significant changes.
Circulatory system changes
- During pregnancy, the mother’s heart at rest is working 30-50% harder, with a heart rate that may increase up to 15-20%. Blood volume also increases progressively during pregnancy.
- During exercise, pregnancy hormones can suddenly affect tone in blood vessels which can lead to dizziness. Another form of dizziness can be caused by lying flat on the back, which causes decreased blood flow to and from the heart, and is more common after 24 weeks. After the first trimester, it is not recommended to lie on the back, and lying on the left side may help relieve dizziness.
Respiratory and metabolic changes
- During pregnancy, women experience increased demand for blood, which leads to an increase of air moved in and out of the lungs. Due to the enlargement of the uterus, and less room for movement for the diaphragm, some women report shortness of breath and increased difficulty in taking deep breaths.
- The amount of energy the body expends while at rest also increases significantly during pregnancy, which is why it slowly increases its energy requirements as the fetus grows.
- An increase in basal body temperature is maintained throughout pregnancy, and pregnant women can be at a higher risk of hyperthermia and dehydration, which stresses the importance of maintaining a proper hydration, especially during exercise.
