Maternity underwear is underwear designed with stretchy fabrics, wider waistbands, and roomier cuts that accommodate a growing belly throughout pregnancy and into postpartum recovery. Unlike regular underwear that simply comes in larger sizes, maternity styles are engineered around the specific shape changes, skin sensitivity, and support needs that pregnancy creates.
How It Differs From Regular Underwear
The most obvious difference is the waistband. Regular underwear has a fixed elastic band that sits at or near the waist. As your belly grows, that band either digs in, rolls down, or both. Maternity underwear solves this with waistbands that either sit low (just under the bump) or stretch up and over it, using soft, wide elastic that moves with your body instead of fighting it.
Beyond the waistband, the construction is different in smaller ways that add up. Leg openings are wider to prevent riding up as your hips spread. Seams are flatter or eliminated entirely to reduce chafing on skin that’s already more sensitive from hormonal changes. The gusset (the fabric panel between the legs) is typically wider to accommodate panty liners, since increased vaginal discharge is a normal part of pregnancy. Some styles incorporate a stretchy belly band woven directly into the fabric, providing a gentle lift to the abdomen that can take pressure off the lower back.
Under-Bump vs. Over-Bump Styles
Most maternity underwear falls into two categories based on where the waistband sits relative to your belly.
Under-bump styles have a low-rise waistband that curves beneath the belly. These are the more popular choice in warmer months because they use less fabric and feel cooler. They work well in the second trimester and early third trimester, and many people prefer them for everyday wear because they feel closest to regular underwear. The tradeoff is that they offer minimal belly support.
Over-bump styles extend a panel of stretchy fabric up and over the entire belly. This panel provides light compression and support, which can feel stabilizing in the third trimester when the weight of your belly pulls on your lower back and pelvis. The extra coverage also keeps the underwear firmly in place without sliding down. Some people find them too warm, but they’re a good option for cooler weather or for anyone who wants that supported, “held together” feeling.
Many people end up owning both types and rotating based on the day, the outfit, and how far along they are.
Materials That Matter During Pregnancy
Pregnancy increases blood flow, raises your baseline body temperature, and makes your skin more reactive to irritation. The fabric of your underwear matters more than it did before.
Cotton is the classic choice for breathability and softness, especially for the gusset. Bamboo-derived fabrics offer similar breathability with a silkier feel. Modal (a type of rayon made from beech trees) is lightweight and resists pilling. For moisture management, some brands use technical cooling fabrics infused with minerals that wick sweat away and dry quickly, blending nylon and spandex in ratios designed to stretch without losing shape. A small percentage of spandex (typically 5 to 10 percent) is standard across most maternity underwear to provide the necessary stretch.
Whatever the outer fabric, look for a cotton or cotton-blend gusset. Synthetic gussets trap moisture and can increase the risk of yeast infections, which pregnancy already makes more common.
When to Make the Switch
Most people transition to maternity underwear between 12 and 16 weeks, roughly the start of the second trimester. That’s when the uterus rises above the pelvic bone and your regular waistbands start to feel noticeably tight.
You don’t need to wait for a specific week, though. The real signals are physical: rolling or tight waistbands, red indentation marks on your skin after wearing underwear, constant adjusting throughout the day, or increased irritation and sensitivity around your hips and lower belly. If you’re experiencing any of those, your body is telling you it’s time regardless of what week you’re in. Some people with bloating or carrying multiples need maternity underwear before 12 weeks.
Sizing and Fit
Sizing for maternity underwear is based on your hip measurement, not your pre-pregnancy clothing size. Measure around the widest point of your hips with a flexible tape. Because pregnancy changes your body significantly and sizing standards vary between brands, your pre-pregnancy size may not translate directly. If you fall between two sizes, go up. Underwear that’s slightly loose is far more comfortable during pregnancy than underwear that’s slightly tight.
Plan to reassess fit as your pregnancy progresses. The pair that fits perfectly at 16 weeks may feel snug by 30 weeks, particularly in over-bump styles where the belly panel needs to stretch further.
Support for Pelvic and Back Pain
Some maternity underwear goes beyond basic comfort and provides targeted support for common pregnancy pain. Pelvic girdle pain, that aching or sharp sensation in the front or back of the pelvis, affects a significant percentage of pregnant people, especially in the third trimester. Specialized support underwear uses built-in bands or criss-cross straps that sit low across the hips, applying gentle pressure to the pelvic area and helping distribute the weight of the belly more evenly.
This type of support can reduce feelings of heaviness and pressure in the vaginal and pelvic region. Because pregnancy pains are often interconnected, pelvic support can also provide some lower back relief even when the product isn’t specifically designed for it. These supportive styles aren’t a replacement for physical therapy or medical treatment, but they can make daily movement more comfortable.
Postpartum Underwear
Maternity underwear doesn’t stop being useful at delivery. Postpartum underwear is a related category designed for the weeks of recovery that follow birth. These styles are high-waisted with a wider gusset to hold thick postpartum pads, since you’ll have lochia (vaginal bleeding) for several weeks regardless of how you delivered.
After a cesarean birth, the needs are more specific. Recovery underwear for C-sections uses dual compression zones: firmer compression in the upper abdominal area to reduce swelling, support weakened core muscles, and stabilize the midsection, with lighter compression over the lower abdomen to gently protect the incision site without pressing on it. Some styles use antimicrobial fibers in the front panel to help keep the incision area clean. Practical details matter too, like no-roll waistbands that stay in place and pull-aside gussets so you don’t have to pull underwear up and down over a tender incision.
Many people buy a few pairs of postpartum underwear in advance and pack them in their hospital bag. The mesh underwear provided by hospitals works fine for the first day or two, but purpose-built postpartum pairs are more comfortable and supportive for the weeks that follow.