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What Maternity Size To Buy?

Are your jeans starting to feel a bit snug around the waist? Have your boobs jumped a cup size overnight? Welcome to the early stages of pregnancy! 

With so many changes in your body and many more yet to come, it’s difficult to know how to plan your wardrobe over the coming months. And while it may seem unimportant today, knowing you have cosy, flattering clothing to wear can be an absolute game-changer down the line, especially on those days when you’re feeling uncomfortable in your own skin. 

But how do you plan ahead for a body that seems to change shape in the blink of an eye? We’re here to talk you through what maternity size to buy and things to keep in mind when shopping.

What week do you need maternity clothes?

Most first-time mums tend to feel their tummy growing at around the 14-week mark, although it may still not be visible (for second pregnancies, it can be much sooner). By week 20, most women will either be wearing maternity clothes or at least sizing up their regular wardrobe. 

Learn more in our blog, When Should You Start Buying Maternity Clothes?

By pregnancy week 20, most women will either be wearing maternity clothes or at least sizing up their regular wardrobe.
Round the 20 week scan, most women will find their pre-pregnancy clothes uncomfortable or ill-fitting.  
Learn more in our blog, When should you start buying Maternity clothes?

Should I buy maternity clothes or just bigger sizes?

Whether to invest in maternity clothes or just buy regular clothing in a larger size is entirely personal preference, but there are definitely benefits to dedicated maternity clothing. 

Clothing specifically for pregnancy is designed to better adapt to your shape, using either stretch or cut. This is part of the reason maternity clothing is so much more flattering than simply wearing bigger sizes. If you’re on a super tight budget, you can certainly get through a pregnancy without maternity clothing, but if comfort, style and fit are important to you, you’re much better off investing in a few maternity pieces to see you through. 

NINE+QUARTER Lipstick maternity t-shirt with side seams

Maternity clothing is designed specifically to adapt to your changing shape. 

Do you buy a size bigger in maternity clothes?

Because maternity clothing has been designed with your changing body in mind, you should purchase your regular size for the best fit. If you're a U.K. size 12 you should opt for a size 12 in maternity clothes. If you were a size 10 pre-pregnancy and have gone up to a size 12, opt for a size 12 in maternity clothes. 

Essentially you can ignore the size of your bump when shopping maternity clothes as maternity wear have been tailored to fit a growing bump, throughout all stages of pregnancy, and also a somewhat bigger bust.

How many sizes do you go up during pregnancy?

This is such a great question, but one that doesn’t have an easy answer. While some women will stay in their regular size throughout pregnancy, simply moving from a regular 12 to a maternity 12, other women will have bigger weight fluctuations. 

Personally, I gained slightly over 30kg in my last pregnancy; although my craving for cheeseburgers had a lot do to with that! My advice would be to buy your usual size when purchasing maternity clothes, but size up if you’re sitting between sizes. You’ll find the majority of clothing has been cleverly designed with stretch in all the right places so that it fits well even as your belly grows. 

Why is some maternity clothing more expensive?

What’s the difference between a £5 maternity tee and a £35 maternity tee? A lot more than you’d think. We discuss this in more detail in the recent blog, How Maternity Clothes Work, but to give you a brief overview:

Cheaper maternity clothes are usually:

  • Cut from poor-quality fabric that quickly loses its shape
  • Made in factories that exploit their workers
  • Fast fashion, only designed to be worn for short periods.

Compare that to NINE+QUARTER, where we use sustainable 100% organic cotton, design our clothing to last not just through your pregnancy but even into breastfeeding and over multiple pregnancies, and have a great relationship with a family-owned factory in Portugal that produces our garments. 

Looking for more information on finding clothes you can wear beyond pregnancy? Check out Multi-Wear Maternity Clothing.



Originally from New Zealand, Sarah is a mother to two boys and has lived in the UK for the past 10 years. She is a home educator, freelance writer, Netflix-binger and has a penchant for strong black coffee.

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