Make Your One-Piece Swimsuit Pattern Maternity Friendly

The new Annette swimsuit just released and I’m loving all the details that make this suit unique!  When testing time came, I knew there had to be a way to make it fit my ever growing belly comfortably.  So that’s what I’m here to show you – how to hack the Annette One-Piece Swimsuit Sewing Pattern to work throughout your pregnancy! (Psssst! This hack works for pretty much every one-piece swimsuit if you have another favorite)

The best part – this hack doesn’t have to be just for maternity. It can work for everyone as well (you know, to help hide the extra piece of pizza you had or something like that).

Can’t read this now? Pin this image to save this tutorial for later!

A visibly pregnant woman sitting on a dock with her toes in the water. She is wearing a one-piece swimsuit  and sunglasses.

The first thing you want to do is grade your pattern based on your measurements. Don’t know what grading is? Read our article explaining how to grade patterns here. This can be intimidating/tricky so I highly advise you to make a quick muslin of the bodice pieces (without lining) before you cut into your good swim fabric to make sure you get the fit perfect!

Here is a table summarizing my measurements so you can understand why I did what I did.

Pre-preggars DIBY Size 15 Weeks Preggars
Full Bust 35.5 6 8 36.5
Waist 29 9 10 30.5
High Hip 33.5 6 8 34.75
Hip 38 8 8 38

Because I want to make sure to account for my stomach, I am going to grade ONLY the front piece a little bigger at the waist. Here is a photo of my graded front bodice. I went up two sizes at my waist. Note: if you are not pregnant and just want to add the stomach ruching, do not grade bigger at the waist. Just cut out your normal size.

Paper pattern piece of the Annette Swimsuit. The piece has been graded to a larger waist.
For the back bodice, there is no belly to account for, so I used my pre-pregnancy measurements for this.  Below is my graded back bodice.
Back bodice pattern piece from the Annette swimsuit pattern with grading marks.

Now that your pieces are graded for your belly, let’s cut out the pieces so we can make some adjustments for the ruching!

This pattern is drafted for a height of 5’5”.  I originally adjusted for my height (5’8”) but found that it was too long and ended up taking everything back out that I added.  Again – here is where a muslin really helps. Once you adjust for your height we are going to add length to the front bodice ONLY so we can ruch/gather the stomach area. The amount of length is kind of up to you depending on how much ruching you would like. I added 4-inches of length.

 Annette Swimsuit pattern piece showing where to add the length in the middle of the piece. Text on the image reads "Add 4-inches for gathering/ruching by slashing and spreading your front bodice piece."

Once you’ve added this length you will need to smooth out the side seam curve just as you would if you were grading the pattern. It doesn’t have to be a perfect, smooth line, as this will be gathered into a really small length.

Now we are ready to cut out our fabric! We will use our lengthened front bodice piece for the main and the lining (and any other power mesh you are adding). While cutting out your front bodice, you are going to want to mark on your main and lining fabric where you added the ruching length.

Photo of the pattern piece sitting on top of the swim fabric. Arrows are point to the two locations to be marked on the fabric.

The next step is gathering the front bodice pieces.  You are going to want to gather your fabric about half an inch past each of your markings (in my case, I sewed about 5-inches of a gathering stitch).

Don’t know how to gather fabric? No problem! We have a full tutorial here for different techniques.

We need to gather more than the 4 inches we marked. If we only gathered the 4 inches, it would gather down to about an inch and our front bodice side seam will be an inch longer than our back bodice side seam. So if you gather a little more, your side seams will match up better! We are going to gather the main fabric AND the lining fabric.  With a long straight basting stitch, I sewed two parallel rows of gathering stitches.

A photo of the bodice piece in a sewing machine which is stitching the gathering lines.

Gather the fabric as much as you possibly can – but don’t break those threads!

Photo of the bodice on a cutting mat being gathered.

Repeat this for the other side seam and for the front lining piece.

Photo of the gathered lining piece.

Your front lining piece should look like this too.

Now you can continue construction of your suit just as the tutorial states.  When you get to sewing the side seams, you will catch your gathers and can remove your basting stitch.

Front bodice of Annette Swimsuit with both sides gathered.

A pregnant smiling woman wearing the Annette swimsuit that was created for this tutorial. She is sitting on a dock in the sun.

A woman wearing the swimsuit, standing on the dock with her back to the viewer.

Picture of a woman in the swimsuit standing next to a lake.


Want some patterns that are maternity or nursing friendly straight out the box? Check out the Cecilia Crisscross Sweater. View more maternity and nursing pattern hack packs here.

This article is a guest post originally contributed by Jenn Williams.

Back to blog