Study Confirms Pregnancy Permanently Changes Foot Size

changes to the body from pregnancy

A study performed by researchers at the University of Iowa confirms there are long-lasting changes to the feet of pregnant women.

New mothers will notice as their pregnancy progresses their shoes will become snug. They hang onto their favorite pairs in the vain hope they’ll fit back into them again. Alas, based on research published in the American Journal of Physical Medicine & Rehabilitation most women will not be able to.

The researchers followed 49 women throughout their pregnancy until five months after child birth. They found for about 70 percent of the women, their feet became longer and wider. The research showed increases in foot length (between 2 and 10 mm) and arch drop.

These permanent alterations to size and shape are especially observed in first time pregnancies, as feet swell and become larger. Subsequent pregnancies did not have as dramatic of a morphological change to the anatomy of the foot.

The physiological and morphological changes which occur to a woman’s body from inception to birth of offspring are significant. Along with the growing belly and stretch marks, a placenta develops. This is the only transient organ in the human body which temporarily forms a porous barrier between mom’s and baby’s blood.

Blood volume increases in the body by 50 percent during pregnancy, accounting for the “glow.” Other extra fluids, which are responsible for 25 percent of weight gain during pregnancy, can pool in the ankles and wrists. This swelling can pinch nerves, causing a tingling sensation.

Several pregnancy hormones are secreted including relaxin. Levels of relaxin are 10 times above normal levels during pregnancy. This particular hormone relaxes the cartilage holding the bones together including the pubic symphysis located anterior to the urinary bladder and superior to the external genitalia. The intent is to make labor easier, but the loosening of the skeletal frame collaterally causes excessive back pain. This hormone is also chiefly responsible for why ligaments slacken, causing feet to enlarge.

Pregnancy related changes to the feet may also lead to arthritis later in life. Flat feet, where the arch of the foot flattens out, is also a common problem for pregnant women. Flat feet are caused by the extra weight and increased laxity of the joints. Arch height and measures of arch rigidity decrease significantly between early pregnancy and five months after childbirth.

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