Researchers are investigating how changes during pregnancy may affect the lower extremities in the long term, as well as ways to treat and prevent these issues.
By Lori Roniger
Women’s bodies obviously undergo a lot of changes during pregnancy, including musculoskeletal alterations that affect gait and the lower extremities. Researchers have examined these changes, such as a widened and slowed gait, and interventions that can help improve balance and reduce the risk of falls during pregnancy. However, more recent studies have also considered how lower extremity musculoskeletal changes during pregnancy may continue to affect women after pregnancy.
Lower Extremity Review talked to researchers studying these issues and healthcare practitioners who treat them about these findings and their implications for treatment and prevention.
Neil A. Segal, MD, a professor and director of clinical research in rehabilitation medicine at the University of Kansas Medical Center in Kansas City, is known for his research on knee osteoarthritis (OA), but in recent years has been delving into musculoskeletal issues related to pregnancy and any postpartum issues that remain. He noted that women are more likely than men to experience certain musculoskeletal issues—including anterior cruciate ligament injury, ankle sprain, and knee OA1—and is exploring possible relationships between these gender-specific trends and those seen during and after pregnancy.
“I just want to know if pregnancy has a permanent effect,” Segal said.
He co-edited a book published in 2015 on musculoskeletal health in pregnancy and postpartum, which includes a chapter he coauthored on musculoskeletal anatomic, gait, and balance changes in pregnancy.2 In that chapter, the authors wrote that, while musculoskeletal disorders are common during pregnancy and the postpartum period, these clinically significant changes are poorly understood, and opportunities for prevention, diagnosis, and treatment are often missed, which can lead to undesirable longstanding health effects.
“Pain is not only an issue of maternal comfort but also can contribute to future health risks,” they wrote.2
Changes in foot size and shape
Separately, Segal became curious when he would hear women talk about needing a larger shoe size during or after pregnancies. However, he didn’t see anything in the medical literature on that topic.
He conducted an unpublished survey of 111 women at a pedestrian mall, which found that the women were more likely to have had an increase in shoe size after age 18 years if they had at least one full-term pregnancy (33%) and an even greater likelihood with two pregnancies (68%), compared with 13% of women who said they had never been pregnant.
A follow-up study he and his colleagues published in 2013 compared the feet of 49 women during the first trimester of pregnancy and at 19 weeks postpartum.3 They found lasting changes, including a significant decrease in arch height and rigidity, along with concomitant increases in foot length and arch drop, with the most significant changes occurring during a woman’s first pregnancy.
“A possible mechanism for the changes in arch height and rigidity observed with pregnancy may relate to the combination of increased magnitude and anterior displacement of body mass in the context of a hormonal milieu known to increase collagen extensibility during pregnancy,” the authors wrote.3
The authors concluded these changes could contribute to the increased risk of musculoskeletal disorders in women. And Segal wondered if interventions could be designed to prevent such changes from occurring.
He has since conducted studies (not yet published), in which he randomized pregnant women without severe foot problems to wearing custom insoles that supported their arches in their normal shoes. The authors looked at whether the leg rotates in and how forces affect the knee joint.
“Does the foot change what happens at the knee? Does pregnancy make the knee looser?” Segal posed.
Foot changes and pain
Jean McCrory, PhD, associate professor of exercise physiology at West Virginia University in Morgantown, noted that the structural changes to the foot experienced by pregnant women are similar to those reported in the literature for obese individuals4-6 and even in members of the military who carry heavy loads.7
McCrory has been examining in thus-far unpublished research whether such changes—including lengthening, widening, or arch height asymmetry—have any relationship to foot pain, posterior pelvic pain, or other types of pain.
She and her colleague Kathryn Harrison, MS, a PhD student at Virginia Commonwealth University in Richmond, were unable to confirm any such relationships in pregnant women who were pain free at the time of enrollment. Next, they’ll be recruiting pregnant women who are experiencing pain.
McCrory said she’d like to see if having women wear orthotic devices or supportive shoes during pregnancy would be helpful for avoiding foot pain during or after pregnancy.
Preliminary results presented in 2015 by researchers from the University of Granada at the International Conference of the IEEE Engineering in Medicine and Biology Society in Milan, Italy, indicated a relationship between plantar pressure changes during pregnancy and back pain onset.8 Fifteen pregnant women wore instrumented insoles at weeks 12, 20, and 32 of their pregnancy. The investigators found the center of pressure in both feet was slightly displaced toward the heel at weeks 20 and 32, which coincided with participants’ self-reported onset of back pain.
Sudheer Reddy, MD, an orthopedic surgeon who specializes in foot and ankle conditions at Frederick Memorial Hospital in Maryland, said he’ll often see patients with complaints related to the overall physiological changes of pregnancy, which can include ligamentous laxity that affects not only the pelvis, but also the feet.
“The arch drops and becomes flatter,” Reddy said. “The foot becomes wider. They don’t fit into their shoes. Sometimes that doesn’t change after they deliver.”
He noted gaining weight during pregnancy places added stress on the foot, and women often need bigger and more supportive shoes. His patients complain of foot pain, sometimes along their instep, which can occur with routine activities in regular shoes.
“Initially, I always look at their shoes,” Reddy said.
He recommends that patients buy supportive shoes and sometimes suggests brands that come in multiple widths. If patients need additional support, he may recommend a commercially available foot orthosis. He tries to avoid custom orthotic devices because they’re not always covered by insurance and the condition of feet can continue to change after pregnancy, sometimes reverting to its prepregnancy state.
Ami Sheth, DPM, a podiatrist in Los Gatos, CA, also emphasizes the importance of footwear to her pregnant patients.
“Don’t compromise on your shoe gear,” Sheth said.
She’ll see pregnant women come into her office wearing flip-flops or whatever they can get onto their feet. Many have swelling or flare-ups of previous foot conditions such as plantar fasciitis, and are not wearing supportive shoes. She said heel pain and arch pain in particular are frequent issues, because, as a woman’s base of support during gait widens during pregnancy, she tends to pronate, increasing medial plantar pressures. Sheth will recommend that patients wear more supportive shoes, such as hiking sandals, or even a flip-flop with a built-in arch, and sometimes an over-the-counter orthotic device.
“You have to meet them wherever they’re at and get them through it,” she said.
I am a medical journalist and the mother of two children, but until writing this article I hadn’t heard about the effects the musculoskeletal and hormonal changes of pregnancy can have on the lower extremities both during and long after pregnancy.
I’ve always been physically active, running track throughout high school, though an anterior cruciate ligament (ACL) tear I sustained while skiing when I was in college, plus its consequent repair, slowed me down. However, fairly early on when I was pregnant with my first child, my feet hurt. I needed to take advantage of early aircraft boarding for people with physical disabilities. And during the third trimester, after I had gained about 50 pounds, I had to skip doing some errands if I couldn’t find a parking spot nearby (as I didn’t have a disabled placard) as, at one point, I could hardly walk.
Before the pregnancy, I was already wearing fairly comfortable shoes. Although I managed to get back in shape after pregnancy, with the help of bike commuting and an early-morning boot camp, my feet have never fully recovered and have felt rather sore during and after activity, even after I had lost all of the pregnancy weight and then some.
It wasn’t until perhaps two years after my daughter was born that I was referred to a podiatrist who diagnosed me with plantar fasciitis, prescribed custom foot orthoses, and gave me some footwear recommendations. Nonetheless, I still can’t do everything I want on my feet, finding it hard to take care of my kids, now aged 10 and 6 years, on a weekend day as well as, say, exercise or go for a hike. And I can scarcely do anything around the house unless I’m wearing footwear with arch support.
As someone who used to love the feel of being barefoot but can no longer do so for long, I wonder if some of the interventions that researchers are now studying could have helped me.
Pregnancy and falls
McCrory has been conducting research for years on gait and falls in pregnant women.9-11A significant problem during pregnancy, falls were found to occur in about one-third of pregnancies in a population-based cohort study of 3997 women.12
The study authors said to help decrease falls pregnant women should avoid slippery floors; hold onto stair rails and avoid carrying items or children when climbing up or down stairs; wear shoes that are flat, rubber-soled, and not loose; and try not to hurry. The researchers also advised being careful when carrying children, walking on unlevel surfaces such as grass, or performing any activity involving an obstructed view.
“One of the things that my OB said, and that I echo to pregnant women that I see, is that it’s OK to move slower,” Sheth said.
One of McCrory’s previous studies13 found sedentary women were much more likely to fall than women who exercised.
However, the women in the study who exercised were engaged in a variety of activities, including yoga, swimming, and walking, and that sometimes varied by trimester, so there was no way to determine if results varied by exercise type, McCrory said.
Using data from her previous study, she has more recently reported that pregnant women who didn’t fall may have had greater ankle stiffness compared with pregnant women who fell and controls.14,15 This stiffness may have helped limit center of pressure excursion, which in her study population tended to decrease as pregnancy advanced—a development that appears to contribute to the risk of falling.
“The center of pressure was much smaller in the third trimester and in fallers,” McCrory said. “My theory is that if you’re very stiff, you’re not adapting to your pregnancy and not as familiar with the movement of your body. If you slip or trip or the floor moves under you, you don’t know how to react to it.”
Some intriguing research published in recent years by investigators from the Gaziosmanpasa University School of Medicine in Tokat, Turkey, found women in their third trimester of pregnancy had significantly worse dynamic postural equilibrium than women who weren’t pregnant.16 Fall risk test scores were significantly higher among third-trimester women compared with women in earlier stages of pregnancy or women who weren’t pregnant. The researchers suggested postural stability tests may be useful for detecting pregnant women with a high fall risk.
The same research group conducted another study that found wearing a maternity support belt, which is sometimes used to manage pelvic joint laxity, could help improve balance and prevent falls in pregnant women, especially during the third trimester.17 During each trimester, women who wore a maternity support belt were found to have significantly better anterior-posterior stability index and fall-risk test scores than those who didn’t wear the device.
“The increase in stiffness of the joints by having the belt around the pelvis may change the stability findings,” explained Jill Boissonnault, PhD, PT, WCS, associate professor of physical therapy at George Washington University in Washington, DC.
Getting the word out
Despite the significant problem of falls during pregnancy, pregnant women may not be getting adequate information about fall prevention, according to a study from the University of Massachusetts Lowell in which postpartum women were asked about falls they experienced and fall prevention counseling they received while pregnant.18
“The findings highlight the need for consumer education and the development of fall prevention programs, as 35% of the women reported falling during pregnancy, with only 7% reporting they received fall prevention counseling,” the authors wrote.18
The results also indicated most women were open to using some form of exercise modified for pregnancy and individual fitness levels, such as yoga or Pilates, as a fall-prevention strategy.
Reddy likes to recommend aquatic therapy classes to his pregnant patients. He said the classes can help stabilize their center of mass, while strengthening the core muscles and taking pressure off the joints.
“Part of my teaching includes following the ACOG guidelines for exercise, and the only place that that gets into balance and falls is related to sports and high-risk activities that pregnant women are counseled to avoid,” Boissonault said of the American College of Obstetricians and Gynecologists guidelines that were updated in 2015.19
The guidelines recommend 20 to 30 minutes of exercise on most days, with avoidance of contact sports like soccer and activities with a high risk of falling, like downhill skiing. Other activities were recommended, including walking, swimming, or modified yoga or Pilates.
After pregnancy, Reddy will evaluate whether specific issues remain to be worked on. For example, posterior tibial tendinitis can become a problem in some women several years after pregnancy.
“If left untreated, it can lead to further problems,” he said.
Sheth said she also often sees posterior tibial tendinitis after pregnancy, as well as plantar fasciitis. Achilles tendinitis is another frequent complaint she sees in postpartum women, as well as in grandparents who may be unaccustomed to the frequent bending down that comes with a newborn.
Proper foot care after giving birth is important, too, especially since new moms can be on their feet a lot at home, Sheth said.
“As soon as they have the baby, I put them in orthotics in sneakers at home,” she said.
After pregnancy can be a better time for more aggressive physical therapy, conditioning, or strengthening programs that weren’t possible during pregnancy, Reddy said.
However, Sheth noted new parents may not prioritize their own health.
“People are ignoring themselves because they have better things to do,” she said.
She’ll sometimes brainstorm with patients about how to fit stretching into their regular routine—while they’re nursing the baby, for example.
Preventive care can also be helpful in clients Sheth sees before they’re pregnant, allowing for discussion of the advantages of moving slowly to maintain stability, as well as interventions like stretching, strengthening, supportive shoes, walking, and prenatal yoga before the pregnancy-related changes set in.
“They have an easier time because they already have the tools,” she said.
Lori Roniger is a freelance writer based in San Francisco, CA.
- Wolf JM, Cannada L, Van Heest AE, et al. Male and female differences in musculoskeletal disease. J Am Acad Orthop Surg 2015;23(6):339-347.
- Fitzgerald C, Segal N, eds. Musculoskeletal health in pregnancy and postpartum, an evidence-based guide for clinicians. Cham, Switzerland; Springer: 2015.
- Segal NA, Boyer ER, Teran-Yengle P, et al. Pregnancy leads to lasting changes in foot structure. Am J Phys Med Rehabil 2013;92(3):232-240.
- Price C, Nester C. Foot dimensions and morphology in healthy weight, overweight and obese males. Clin Biomech 2016;37:125-130.
- Dunn J, Dunn C, Habbu R, et al. Effect of pregnancy and obesity on arch of foot. Orthop Surg 2012;4(2):101-104.
- Mueller S, Carlsohn A, Meller J, et al. Influence of obesity on foot loading characteristics in gait for children aged 1 to 12 years. PLoS One 2016;11(2):e0149924.
- Schulze C, Lindner T, Woitge S, et al. Effects of wearing different personal equipment on force distribution at the plantar surface of the foot. ScientificWorldJournal 2013;2013:827671.
- Martinez-Marti F, Martinez-Garcia MS, Carvajal MA et al. A preliminary study of the relation between back-pain and plantar-pressure evolution during pregnancy. Conf Proc IEEE Eng Med Biol Soc 2015;2015:1235-1238.
- McCrory JL, Chambers AJ, Daftary A, Redfern MS. Dynamic postural stability during advancing pregnancy. J Biomech 2010;43(12):2434-2439.
- McCrory JL, Chambers AJ, Daftary A, Redfern MS. Dynamic postural stability in pregnant fallers and non-fallers. BJOG 2010;117(8):954-962.
- Delzell E. Pregnancy and falls. LER 2011;3(9):15-16.
- Dunning K, LeMasters G, Bhattacharya A. A major public health issue: the high incidence of falls during pregnancy. Matern Child Health J 2010;14(5):720-725.
- McCrory JL, Chambers AJ, Daftary A, Redfern MS. Dynamic postural stability in pregnant fallers and non-fallers. BJOG 2010;117(8):954-962.
- Ersal T, McCrory JL, Sienko KH. Theoretical and experimental indicators of falls during pregnancy as assessed by postural perturbations. Gait Posture 2014;39(1):218-223.
- McCrory JL, Chambers AJ, Daftary A, Redfern MS. Ground reaction forces during stair locomotion in pregnancy. Gait Posture 2013;38(4):684-690.
- Inanir A, Cakmak B, Hisim Y, Demirturk F. Evaluation of postural equilibrium and fall risk during pregnancy. Gait Posture 2014;39(4):1122-1125.
- Cakmak B, Inanir A, Nacar MC, Filiz B. The effect of maternity support belts on postural balance in pregnancy. PM R 2014;6(7):624-628.
- Brewin D, Naninni A. Women’s perspectives on falls and fall prevention during pregnancy. MCN Am J Matern Child Nurs 2014;39(5):300-305.
- [No authors listed] ACOG committee opinion no. 650: Physical activity and exercise during pregnancy and the postpartum period. Obstet Gynecol 2015;126(6):1326-1327.