Why women often go up a shoe size post childbirth, according to a podiatrist 

By podiatrist, Emily Smith

There are a few unexpected body changes that can occur during pregnancy and postpartum. Some are immediate, and some can sneak up on you.

With your feet directly impacted by weight gain, a 10-fold increase in relaxin (the hormone that relaxes the ligaments in the pelvis and widens the cervix) and swelling, it is no wonder that the very structures that hold us up can crumble under pressure.

Gone up a shoe size?

Yep, it’s a thing, and it’s not uncommon for a whole shoe size differential pre and post pregnancy. Studies have reported increases in foot length, width, flexibility and volume during pregnancy, with significant changes occurring with the first pregnancy and a dose-effect of changes often presenting with each additional pregnancy.

The feet naturally withstand 1.5 -2 x body weight with walking, so a weight gain of 15kg can put up an additional 30kgs through the feet with standing and walking.

This increased force on the feet coupled with the spike in relaxin compromises the integrity of the 30+ foot ligaments, causing a collapse of the medial arch and making the foot splay, widen and lengthen.

Whilst going up a shoe size is not ideal as it usually requires an expensive wardrobe update (after the swelling subsides), the real pain can present with the musculoskeletal injuries associated with the collapse of the foot contributing to excessive strain on the tendons, fascia and joints of the foot and up into the ankles, knees and lower back.

The good news is that the arch collapse and subsequent issues can often be minimised with prophylactic footbeds and well-fitted, supportive footwear.

Make sure you reassess your shoe size regularly, keeping half a thumbs gap between your longest toe and the shoe taken when you’re in a mini squat position (your toenails will appreciate this too!).

Especially towards the end of your pregnancy and in early postpartum days, trying on your shoes before purchase is important to ensure the right fit and to accommodate for transient swelling.

Also monitor the shoe width, making sure the fit is snug, not a tight fit, with no splay over the edges. A simple sign? If a shoe is leaving its mark, it’s probably not right. When a shoe is too small and/or tight, the toes scrunch causing corns, callouses and sore toenails, let alone the myriad of soft tissue injuries and bony deformities such as bunions and hammer toes.

Well-structured shoes and arch supports are key to maintaining the integrity of the foot structure and thus, a happy, healthy body alignment. Investing in good-quality running shoes that have been fitted at a professional running shoe store will be worth their weight in gold for walking, exercise and commuting.

Adding a scientifically engineered off-the shelf insole, such as an Emily Braidwood footbed, will give you the arch support you need to prevent flattening of the foot, without compromising style or space.

Whilst pregnant and in early postpartum days, minimising time spent in super flat shoes, thongs and Ugg boots, as well barefoot, will also give your feet the best chance of surviving maternity leave with arches intact.

If you experience pain or notice any of these changes, seeking early professional advice is key.

Emily Smith is a Sydney-based sports podiatrist with over 16 years clinical experience nested in human mechanics and women’s footwear at www.sportspodiatrists.com.au. Check out Emily Braidwood.