Maternity clothes usually match your pre-pregnancy size, but measuring your bust, hips, and bump against each brand’s chart is the only reliable way to get the right fit.
Pregnancy changes your body faster than your wardrobe can keep up, and sizing rules that worked before simply don’t apply the same way. The good news: most brands size maternity wear to your pre-pregnancy number, so if you wore a size 8 before pregnancy, you’ll typically fit a size 8 maternity garment. The catch is that every brand measures differently, which is why a tape measure beats a guess every time.
Does Your Pre-Pregnancy Size Still Work?
For most shoppers, yes. Mothercare states plainly that maternity sizing follows “the same as standard clothing sizes”—a pre-pregnancy size 8 maps to a maternity size 8. Kohl’s a:glow™ chart does the same, translating your regular size directly into maternity sizes from XS through XXL and plus sizes.
That consistency exists because maternity garments build in room for your growing bump rather than asking you to size up. You’re not buying bigger clothes; you’re buying differently cut ones. Still, treat your pre-pregnancy size as a starting point, not a guarantee.
What Measurements Actually Matter?
Skip the scale and reach for a fabric tape measure. The cited size guides agree on four key points:
- Bust/chest: measure across the fullest part, keeping the tape level.
- Waist or bump: measure where the garment will sit—some brands use your natural waist, others the over-bump or under-bump fit.
- Hips/seat: measure around the fullest part of your hips.
- Inseam: for pants, measure from the inner thigh to the hem when the brand’s chart asks for it.
Kohl’s a:glow™ treats bust and hip as the primary measurements for sizing. Mothercare’s guide points to the same areas. Take your numbers, then compare them against that specific brand’s maternity chart—don’t assume one brand’s medium equals another’s.
Reading Size Charts: What the Numbers Mean
Charts translate your measurements into a size, but the translations vary. Kohl’s a:glow™ maternity, for instance, lists XS as pre-pregnancy size 2 with a 34″–35″ bust and 37″–38″ hip, while M maps to pre-pregnancy 8/10 with a 37″–39″ bust and 40″–43″ hip. Mothercare’s guide runs broader: S equals 4–6, M equals 8–10, L equals 12–14, XL equals 16–18, and XXL equals 20.
Notice the ranges. A size M at one store might fit a 37-inch bust, while another store’s M tops out at 39 inches. That gap is exactly why checking the chart matters more than memorizing your number.
Two sizing traps trip up most shoppers. First, don’t buy on your regular size alone without glancing at the brand chart—the sizing usually holds, but not always. Second, check whether the item is bump-friendly, under-bump, or over-bump; that choice changes which measurements matter most. A pair of over-bump jeans needs accurate hip and waist numbers, while an under-bump style depends far more on your hips.
Also confirm which sizing system the brand uses. US, UK, EU, and dual-size charts don’t line up neatly, and a UK 10 is not a US 10. When you find a maternity brand that fits well, stick with it—consistency across one label’s cuts makes future orders simpler.
If you’re shopping for a specific occasion rather than building a full maternity wardrobe, our roundup of the most attractive maternity clothes can point you toward styles worth measuring for.
Common Sizing Mistakes to Skip
Even experienced shoppers trip on these three errors:
- Guessing from weight gain. The cited guides size by body measurements, not pounds. Two women at the same weight can wear different sizes depending on where they carry.
- Ignoring the garment’s fit style. Maternity tops, pants, dresses, and support wear each use different measurement priorities. A dress that fits over the bump may need a different size than a pair of under-bump leggings.
- Assuming universal sizing. Charts differ across US, UK, EU, and dual systems, and some guides apply only to maternity wear—nursing-specific styles can fit differently.
When in doubt between two sizes, order both and return the one that doesn’t work. Your body will keep changing through the trimester, and a little extra room in the bust or hips often buys you another month of wear.
FAQs
Should I size up in maternity clothes?
Usually not. Most maternity brands size garments to your pre-pregnancy measurements, building in room for your bump rather than requiring a larger size. Size up only if a specific brand’s chart or a particular garment’s cut runs small, which is why checking each chart matters.
What if I’m between two maternity sizes?
Choose the larger size when you’re between measurements, especially for pants and dresses. Your bust, hips, and bump will continue growing through pregnancy, and a bit of extra room extends how long the garment stays comfortable. For tops, consider the fit style—over-bump styles tolerate more ease than fitted ones.
Do maternity size charts use US or UK sizes?
It depends on the brand. US, UK, EU, and dual-size systems all appear on maternity charts, and they don’t convert cleanly—a UK size 10 is not a US size 10. Check the chart’s labeling before ordering, and when a brand lists both systems, use the one matching your country’s standard sizes.
References & Sources
- BabyCenter. “How do maternity clothing sizes work?” Explains that maternity sizes generally match pre-pregnancy sizes.
- Kohl’s. “a:glow™ Women’s Maternity Clothing Size Chart.” Maps maternity sizes to pre-pregnancy sizes with bust and hip measurements.
- Mothercare. “Maternity Size Guide.” Provides size examples and measurement guidance for maternity wear.