Reviewed by The Mom Store editorial team, October 2026. See our editorial policy.
In most maternity ranges you buy the size you wore before pregnancy, not one or two sizes up. Maternity clothes are cut with the extra room built in where your body changes, around the bump, bust and hips, while the shoulders and sleeves stay close to your usual fit. If you wore a medium before, a medium maternity top or dress will usually fit.
That is a starting point, not a rule. Sizing is not standard between brands, so your current measurements and the brand's own size chart matter more than the letter on the label.
Measure yourself now, not from memory
Use a soft measuring tape and keep it snug but not tight. Depending on the garment, you may need:
- Bust: around the fullest part.
- Waist: follow the brand's instructions. Some ask for your natural waist, others for a measurement around the bump.
- Hips: around the widest part.
- Inseam and thigh for trousers and jeans, and shoulder width for structured kurtas and blouses.
Write the numbers down and compare them with the size chart on the product page each time. A medium at one brand can be quite different from a medium at another, and this matters most for jeans, trousers, bras, fitted dresses and structured ethnic wear. Loose tops and kaftans are more forgiving.
How a good maternity fit feels
The garment should give you room to change without swamping the parts of you that have not changed. Before you keep something, check that you can sit, bend, walk, raise your arms and breathe comfortably, and that you could wear it for several hours. If you find yourself tugging at it all the time, it is the wrong size or the wrong cut.
Bottoms: choose by waistband
Trousers and jeans usually stop fitting first, so this is where maternity sizing helps most. The waistband style matters more than going up a size:
- Over the bump panels stretch up over your belly and give more coverage.
- Under the bump bands sit below your stomach, which some women find cooler and less fussy.
- Adjustable waists with buttons, elastic or side tabs let you loosen the fit as the months go by.
You can compare these styles in maternity pants and jeans.
Why sizing up backfires
A larger size gives you room at the bump, but it also gives you room everywhere else. Tops slide off the shoulders, sleeves get too long and dresses lose their shape. Since maternity clothing already allows for a growing bump, check whether the garment has enough room for the months ahead before you reach for a bigger size.
Think about which trimester you are buying for
In the first trimester many women still wear their usual clothes. The bump tends to show more in the second trimester, which is when maternity pieces start to earn their place, and by the third trimester comfort usually wins over everything else. If you are buying early, stretch fabrics, adjustable waists, side gathers and relaxed cuts will keep the same piece wearable for longer.
Fabric
Cotton, modal and blends with a little elastane or spandex move with your body far better than rigid fabric, which is useful for leggings, lounge pants, tees, nightwear and casual dresses. In Indian summers, breathable cotton is easier to live in than synthetic stretch. Stretch is not a reason to buy something that is already tight, though.
Tops need length as well as width
Regular tops often still fit at the shoulders but ride up over the bump. Maternity tops add length and fabric at the front, so check the fit from the side and make sure the hem covers your bump when you sit. If you plan to breastfeed, tops with nursing openings carry on being useful after delivery; the maternity and nursing tops range includes both.
Dresses
Dresses are often the easiest thing to size because there is no separate waistband, but the bust, shoulders and hips still need to fit. A line and empire waist cuts, side gathers, stretch fabric and adjustable ties all give the bump room to grow. Avoid a dress that fits your stomach perfectly today, because it will not in two months.
Bras
Your band and cup size can both change during pregnancy, sometimes more than once. Rather than buying several bras early, buy one or two and check the fit every few weeks. You need a new size if the band digs in, the cups spill over, the straps keep slipping, or you struggle to fasten it on the loosest hook. A good maternity or nursing bra should feel supportive without pressing.
If you are between two sizes
Look at the garment before you decide. For a stretchy, relaxed top you can usually take either. For structured pieces like fitted trousers or a bra, accurate sizing matters more, so go by the chart. If you are early in pregnancy and expect to grow a lot, a flexible design is more useful than a rigid one in a bigger size. When in doubt, ask the brand or store for the garment measurements.
Common mistakes
- Buying two sizes up "to be safe" and ending up with clothes that hang off you.
- Going by your usual size instead of measuring.
- Buying a whole wardrobe at once. Start with a few basics and add as your shape changes.
- Choosing something that looks good but feels restrictive. You will not wear it.
- Forgetting about after the birth. Nursing access and flexible fits stretch your money further.
