Picture and Explanation of How Your Baby is Growing and Developing at 40 Weeks Pregnant (at term)

40 weeks pregnant picture at term internal

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40 weeks pregnant (at term)

Source: The Growing Uterus Charts
© 1985, 2006 Childbirth Connection
This picture shows the usual position of the baby at term, which is 40 weeks of pregnancy, with the head occupying much of the pelvic cavity. The canal of the broad, enlarged cervix is still filled with the plug of mucous. If this is your first pregnancy, the external os, the small opening at the bottom of the cervix, is usually not dilated, whereas if you have given birth before, it will often admit two fingers some time before labor begins. The vagina, which gradually becomes softer, more expandable, and elongated when the uterus rises, seems to shorten when the head enters the pelvis and pushes the cervix into the vagina.

The bladder is compressed between the baby's head and the pubic bones, with no room for expansion except up into the abdominal cavity. The pelvic colon is pushed up out of the pelvis and compressed against the sacrum. Pressure on the blood vessels at the brim of the pelvis interferes with the return circulation from the swollen veins in the vulva, anal region, and lower extremities.

Common discomforts you may experience during the last weeks of pregnancy are frequent urination, increased constipation, edema (water retention), and aching of the legs and vulva, as well as varicose veins in the vulva, rectum, and legs. These can be explained by several factors, including the position of the uterus, the pressure of the baby's head, the loss of muscle tone, the increased vascularity of the tissues, and the added volume of blood distending the vessels in the pelvic cavity, perineal region, and lower extremities.

Most recent page update: 6/4/2013

© 2016 National Partnership for Women & Families. All rights reserved.

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