Common, rising later in pregnancy, and mostly mildEmerging evidence
In 419 women in Brisbane, 44% had had foot pain by 24 weeks and 56% by 36 weeks; at 36 weeks, 8.4% called it moderate and none called it severe, and 9.0% had at least moderate difficulty with everyday activities. In one Turkish hospital, where 184 women were asked at each trimester visit, ankle and foot pain rose from 6.5% in the first trimester to 9.2% in the second and 19.6% in the third.
In a US clinic, foot pain was commoner in women who had just given birth than in women who had never been pregnant (31% against 22%), and most of the leg and foot pain began in the second and third trimesters. That study asked women to remember, so its figures are rougher.
Sources 1, 2, 3
Why feet swell, and how common it isStrong evidence
"It's normal to get some swelling in pregnancy, particularly in your legs, ankles, feet and fingers", the NHS says, and it's often worse at the end of the day and further into pregnancy. The body holds more water than usual, the water gathers in the lowest parts of the body, especially in hot weather or after a lot of standing, and the growing womb presses on the veins of the legs.
About 4 in 10 women had foot swelling in late pregnancy in one study of 88 women in Taiwan; there is no large study of how common it is.
Sources 4, 5, 6, 7
Feet get fuller, wider and a little flatterEmerging evidence
About 8 small studies agree that feet get fuller, a little wider and roll in more during pregnancy, and that many women's arches drop a little: about 1 mm on average in one study, a few millimetres in some women. Foot shape changes weren't linked with when pain started in one study of 62 women; pain and function went more with swelling.
Relaxin, the hormone often blamed, wasn't measured in these studies, and one put the changes down to fluid and soft tissue rather than looser ligaments.
Sources 8, 6, 9, 10, 11, 12, 13, 14, 15
Do feet go back to normal? Often, but not alwaysMixed evidence
About 19 weeks after the birth, 30 of 49 women had slightly longer feet than early in pregnancy (mostly 2 to 10 mm) and 35 had a little more arch drop (about 0.7 mm and 0.9 mm on average), most of the change coming with a first pregnancy. Another small study found foot length back to normal by 4 to 6 weeks, but a flatter arch. In older women, the link between the number of births and rolled-in feet disappeared once age and weight were counted.
Swelling settles slowly: in one study only a small part of the extra foot volume had gone by 8 weeks. No study follows women for longer than about 19 weeks, and whether these changes matter for foot pain later is unknown.
Sources 8, 16, 17, 15
Swelling that isn't normal: pre-eclampsia and clotsStrong evidence
"A sudden increase in swelling can be a sign of pre-eclampsia or a type of blood clot called deep vein thrombosis (DVT) and needs to be checked immediately", the NHS says. Pre-eclampsia affects 2% to 8% of pregnancies worldwide, is most likely from 20 weeks, and can start in the days or weeks after the birth. Swelling isn't part of how the National Institute for Health and Care Excellence (NICE) defines it: it is mostly found by the blood pressure and urine checks at every antenatal appointment.
Clots affect about 1 to 2 in 1,000 pregnancies and the weeks after the birth, most often just after delivery, the Royal College of Obstetricians and Gynaecologists (RCOG) says. In pregnancy they are usually in the left leg (88% of the 96 women whose side was known, in a review of 6 studies) and often high in the leg, so the whole leg may swell. Rarely, swollen legs with breathlessness come from the heart.
Sources 18, 19, 20, 21, 22, 23, 24, 25, 26
Heels, arches, cramps, tingling and restless legsEmerging evidence
Heel pain that is worst on the first steps after rest and eases as you move is usually plantar fasciitis. No study shows how often it happens in pregnancy or that pregnancy causes it, though the band under the foot was thicker and more elastic in pregnant women in small studies.
Leg cramps affected 75% of 184 women in the Turkish study, mostly at night in the third trimester, and 58% of 205 women in the third trimester in Jordan, more often with swollen legs; blood magnesium and calcium were the same with or without cramps. Restless legs affects about 1 in 5 women in the third trimester (22.9% across 10 studies) and usually goes after the birth. Tingling, numbness or pain in the sole was reported by 24.5% of the Turkish women; those were symptoms, not diagnoses. A flat foot that is new and on one side only needs a GP.
Sources 27, 28, 29, 2, 30, 31, 32, 33
With diabetes, look after your feetStrong evidence
NICE's diabetes in pregnancy guideline has no foot checks, and the NHS gestational diabetes page doesn't mention the feet; one small study found slightly reduced heel sensation and balance with gestational diabetes. With diabetes that has already affected the feet, any new wound, infection or hot, swollen foot needs a specialist foot service within 1 working day, NICE says, and the NHS asks you to see a GP or diabetes nurse for blisters, cracked skin, or pain, tingling or numbness that could be nerve damage.
Sources 34, 35, 36, 37, 38
When a scan or test helpsStrong evidence
Most foot pain in pregnancy needs no tests. Blood pressure and urine checks at every antenatal appointment pick up pre-eclampsia. "If a doctor thinks you have DVT ... you should be referred to hospital within 24 hours for an ultrasound scan", the NHS says; a D-dimer blood test isn't used to rule out a clot in pregnancy.
A foot X-ray for a suspected break or stress fracture can be done when it's needed: UK guidance asks about pregnancy for X-rays between the diaphragm and the knees, so the foot lies outside that area (our reading), but tell the radiographer you're pregnant. With diabetes and a suspected Charcot foot, NICE asks for a weight-bearing X-ray, and a magnetic resonance imaging (MRI) scan if it's normal. MRI showed a very rare thinning of the ankle bones in pregnancy in a case report.
Sources 21, 19, 25, 39, 40, 41, 37, 42
How it usually goesEmerging evidence
Foot pain and swelling build towards the third trimester. Swelling "is usually temporary and settles after your baby's born", NHS inform says, though slowly. Cramps in pregnancy "should pass after the baby is born", and restless legs "usually go away after giving birth". Foot length and arch changes may last at least 19 weeks. No one can promise a timescale.
Sources 1, 2, 6, 5, 15, 43, 32, 8
