1. Assuming your size has not changed
Relaxin softens the ligaments in the arch, so the foot spreads and flattens under the extra weight. Most mothers go up half to a full size, and many do not go back down after delivery. Measure your feet in the second trimester and again in the third, in the evening when swelling is greatest.
2. Living in flat flip-flops
Completely flat chappals with no arch support force the plantar fascia to do the work the shoe should be doing, which is why heel pain on first standing in the morning is so common in the third trimester. A slight heel of one to three centimetres and a supportive footbed spread the load far better.
3. Keeping the heels on "just for the function"
Heels above four centimetres push your already forward-shifted centre of gravity further forward, increasing the arch in your lower back and, with it, back pain. They also narrow your base of support at the point when your balance is least reliable. Keep a supportive dressy flat or a low block heel for occasions.
4. Ignoring the sole's grip
Falls are the leading cause of injury in pregnancy, and wet bathroom and kitchen floors are where they happen. Smooth leather and worn-out rubber soles are the problem. Choose a textured rubber sole, and add a rubber-backed bath mat.
5. Shoes you have to bend over to fasten
Lace-ups become genuinely hard to manage by the third trimester, and bending forward at the waist is uncomfortable and unsteady. Slip-ons with a closed heel, or velcro straps you can adjust seated, work better. Avoid backless mules — they make you grip with your toes to keep them on.
6. Non-adjustable uppers
Feet swell through the day and more in the heat. A fixed-width upper that fits at 9 am will compress by 6 pm, worsening swelling and numbness. Velcro, buckles and stretch panels let you loosen as needed.
7. Wearing out the same single pair
Cushioning compresses within a few months of daily wear, and pregnancy adds weight and walking. Rotate two supportive pairs and replace either once the tread flattens.
8. Dismissing new foot pain as normal
Arch and heel pain usually respond to better footwear and calf stretching. But sudden, marked swelling of one leg with pain or warmth needs urgent assessment for a clot, and swelling of the face and hands alongside headache or visual changes needs urgent blood pressure review. Symmetrical ankle swelling that improves overnight is the normal kind.
A simple test before you buy
Stand in the shoe. You should be able to rise on your toes without wobbling, feel a firm sole that does not twist easily when wrung, and have a thumb's width of space in front of your longest toe. If you cannot get it on and off while seated without help, it is not the right shoe for the next six months.