Maternity Sewing offers patterns by a variety of designers. Each pattern designer uses her own pattern block and size chart. Therefore, the sizing and fit that you get from one designer’s pattern may be different than another designer’s pattern. Each pattern’s size chart is included in the product listing so you can ensure that the pattern includes your size.
Many maternity pattern designers suggest that you pick a size based on your pre-pregnancy measurements and account for an “average” pregnancy weight gain in their finished maternity patterns. Knowing that women gain different amounts of weight at different times in their pregnancy, Maternity Sewing Exclusive patterns use a size chart that is based on your current size. “Maternity friendly” patterns (or patterns not specifically designed for maternity) may not account for any pregnancy weight gain and so you will probably get the best fit from going up 1-3 sizes.
To make it easier to browse for patterns that include your size, we have annotated all patterns in the Maternity Sewing shop as to how they best fit on the above size chart. So if you wear a size 18 on the chart above then patterns marked as including size 18 will have a size with similar measurements included in the pattern. Again, each designer uses her own size chart so it may not include the exact measurements as the chart above. Note that the size chart uses high bust NOT full bust for size selection. This accounts for the fact that different patterns are designed with different cup sizes. (Read more about selecting a cup size).
Surprisingly, you may find it easier to pick a size and fit a maternity pattern than a non-maternity pattern. Maternity patterns generally aren’t fitted (meaning they have lots of ease) through the waist and the hips since those are areas that change greatly over the course of pregnancy. Therefore, you can pretty confidently pick a maternity size by your high bust (representing your frame size) and not worry about waist or hip measurements (as long as the pattern is large enough in the cup size).

Maternity Sewing was founded by Lisa Kievits and Erin Weisbart. They created Maternity Sewing to help you love your body and your wardrobe while pregnant and after. Read more about Erin & Lisa.