Picture and Explanation of How Your Body and Baby are Growing and Developing at 20 Weeks Pregnant
The enlargement of the uterus during this week is greatest at the site of the placental attachment (usually on the front or back wall), so the uterus has an asymmetrical bulge. The wall of the uterus, which lengthens and thickens early in pregnancy, stretches as the fetus grows, and becomes thinner now, only 3 to 5 millimeters thick. The bladder ascends but not as much as the uterus, which straightens as it ascends.
Your ascending uterus rests against the lower portion of the front of the abdominal wall, causing it to bulge forward noticeably by your 20th week. The amount of the bulge is influenced by the tone of the abdominal muscles. If they are firm, the uterus may be pressed against the spinal column, and there will be no noticeable bulge; if they are weak, the pressure of the uterus against the interior wall produces a sizeable bulge.
The position of the uterus during this week explains why you may feel more comfortable at this stage than earlier in your pregnancy. Pressure within the pelvic cavity, which during the earlier weeks may cause weariness and frequent urination, is relieved when the uterus ascends into the abdominal cavity.
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Childbirth Connection is a national not-for-profit organization founded in 1918 as Maternity Center Association. Our mission is to improve the quality of maternity care through research, education, advocacy and policy. Childbirth Connection promotes safe, effective and satisfying evidence-based maternity care and is a voice for the needs and interests of childbearing families.
Most recent page update: 11/7/2007