As you’ve probably noticed, many things grow during your pregnancy. From your belly to your breasts, you are expanding all over. This increase in size is obviously to be expected, as you have a brand new person growing inside of you. Most of these changes will reverse soon after you’ve delivered, and your body will return almost to its original size and shape. However, one thing might change during your pregnancy that you didn’t expect. If you notice a change in your shoe size, you might first assume that it’s because of the swelling and weight gain. Believe it or not though, there might be more behind the increase than that, and the change could actually be permanent even after you’ve delivered.

The length of your foot’s increase might just be a result of your body’s production of endocrines. During pregnancy, your body will release a hormone that is commonly known as relaxin. Relaxin causes the ligaments in your body to loosen up and relax. Because the arch of the foot contains so many ligaments, the bones spread out as you step on them, and your foot permanently becomes longer. A recent study actually showed that women with a higher BMI are more likely to experience this permanent change. It makes sense, as more weight will induce more stretching in the foot.

Based on the results of the study, women who don’t want to see an increased shoe size after they give birth should try losing weight before their pregnancy. If you weigh a lot and are on your feet during your pregnancy, your body will put more pressure on your loose ligaments, and your feet will stretch to be a bigger size permanently. If you have a pair of Jimmy Choos that you can’t live without, try to minimize your shoe size change by losing weight before you conceive.

If your shoes feel tight and you’re into your second trimester, try reducing any swelling by keeping your feet up and icing them often. You won’t be able to tell whether or not your size increase is based on swelling or the effects of relaxin until after your pregnancy, but you might as well reduce the swelling as much as possible to stay comfortable. If your size is still bigger after a few months post-delivery, your feet probably went through changes caused by relaxin, and its time to buy new shoes.

Source: John Dunn MD et al: Effect of Pregnancy and Obesity on Arch of Foot. Orthopaedic Surgery Volume 4 Issue 2 pp. 101-104 May 2012