Body Changes During Pregnancy
The prenatal period is a time of great change for a woman. All systems of the body are affected. Understanding these changes can help you be better prepared as they may occur.
As the fetus grows, the overall musculoskeletal system is challenged by altered posture, shortened muscles, potential muscle imbalances, and changes in spinal mobility. Postural changes include increased spinal curves, rounded shoulders, hyperextended knees, flattened feet, and widened base of support. Because of the postural changes associated with pregnancy, some muscles become tight to support the changing posture, while others are stretched and become weak. This results in muscle imbalance and a potential for decreased stabilization. Fluctuating hormone levels in both the prenatal and postpartum period may cause excessive joint laxity. If not corrected these changes may cause pain and dysfunction.
The postural changes combined with the strain of carrying the fetus and delivering the baby can be especially difficult on both the abdominal and the pelvic floor muscles. As the fetus grows a woman's abdominal muscles are stretched to the limit. Combined with the effects of changing hormonal levels, this may result in a condition called diastasis recti: a separation of the abdominal muscles. Many women may not even be aware they have a diastasis, while others may develop symptoms of low back pain due to lack of abdominal support that helps control the pelvis and low back. This condition can be reversed with corrective exercises. The simple act of bracing the abdominal muscles with your hands while getting up from laying down or standing up from a chair can help to prevent the separation from worsening.
The pelvic floor muscles support the bladder, uterus, and bowel and contribute to continence and normal sexual functioning. They are stressed throughout the pregnancy by the weight of the fetus and can potentially be injured during delivery with tearing and/or incision (episiotomy). Statistically, 20-50% of women will suffer from some degree of incontinence either prenatally or postpartum. Making sure the pelvic floor muscles are functioning well can lessen to potentially detrimental effects of incontinence.
Another area of the body that is affected by the growing fetus is the rib cage and diaphragm. As the fetus grows and starts to take up more space in the abdominal cavity the ribs and diaphragm must accommodate this. There is increased mobility of rib articulations, flaring of the lower ribs, and widening of the subcostal angle. The diameter of the thorax increases by 2 centimeters and the diaphragm is elevated by 4 centimeters. As the pregnancy progresses, women may find that they are short of breath at rest, as a result of their lungs having less room to expand.
The uterus itself goes through significant changes during pregnancy. The uterus increases 5 to 6 times in size and 20 times in weight. Uterine blood flow increases from 50 milliliters per minute at 10 weeks up to 500 milliliters per minute at full-term. Uterine ligaments, which are the major uterine support within the pelvis, along with the pelvic floor muscles, can be stressed by the growing uterus. Stretching of these ligaments, especially the round ligament, may contribute to sudden onset of abdominal pain in a normal pregnant woman. This pain usually resolves on its own.
Edema, or swelling, is a common occurrence especially late in pregnancy as a result of an increase in total body water. Clinically significant edema is present in 40-50% of normal pregnant women. Edema of the ankles is an almost universal finding later in pregnancy. Women might find that wearing support hose or compression stockings may help minimize the swelling. Edema of the hands and wrists may contribute to development of carpal tunnel syndrome as a result of increased compression of the median nerve at the wrist. Symptoms of carpal tunnel syndrome include numbness and tingling in the hand, restriction of finger flexion, and pain. Carpal tunnel syndrome occurs in 1-10% of all pregnancies. Symptoms usually appear in the third trimester and may persist up to 12 weeks post-partum in mothers that breast feed.
Many of the changes discussed are normal physiological changes that do not result in the development of any symptoms, but when symptoms do develop there are specially trained medical providers that can help. Physical therapists are skilled in evaluating and providing patient centered treatment of musculoskeletal problems. Physical therapists trained in the area of women's health have further knowledge about issues directly relating to women as they move through different stages of life, from childbearing years to the post menopausal period. Physical therapists can provide hands on treatment to address spinal and pelvic joint dysfunction, instruct in exercises to address muscle weakness and imbalance, and provide guidance and instruction related to modifications of activities of daily living that may be difficult during the prenatal and postpartum phases.
