So I did a bit of googling on how to measure while you are pregnant and every site I hit said to measure your back instead of your belly. Also when I purchased my sling when kensley was born I got a 4 and it ended up being too big. I sent it back without any hassles.
Here are some links
Hotslings Pouches
Hotslings Baby Pouches | Big Mama Slings | Baby Slings, Carriers
sizing
Here is hotslings return policy if you are interested
Exchanges
Since sizing is so important, we have a very easy exchange system. Your sling comes packaged with an exchange form with instructions. Exchanges must be in NEW condition with all original packaging. The exchange must be received by Hotslings within 30 days of the original ship date (or within two weeks of your delivery date if you are pregnant). Please contact
customerservice@hotslings.com to obtain a Return Authorization (RA) number and simply mail in the sling with the form on the back of your packing list filled out and we will send you a new size/fabric as soon as we receive your exchange. RA numbers are void after 45 days.
Returns
Please consider an exchange for sizing concerns before you give up and return the sling altogether. Most people are extremely happy with one size up or down if they are not happy with their original size. No returns will be accepted on sale items; exchanges only.
Returned slings must be in NEW condition with all original packaging. Returns must be received by Hotslings within 20 days of the original ship date. A $5 restocking fee will be charged upon the return of each item. Original shipping will not be refunded. Please contact
customerservice@hotslings.com to obtain a Return Authorization (RA) number and then mail in the sling with the form on the back of your packing list filled out. Your return will be processed as quickly as possible. RA numbers are void after 45 days.