You have time…
While your Newborn Session should usually take place within the first week of baby’s life, scheduling your Maternity Session offers much more flexibility. It is ultimately your personal choice when you would like your Maternity Portraits to be taken, and depends on the style of maternity portraits that you are looking to achieve.
It is quite common to have multiple sessions throughout the pregnancy, in order to capture its progress, but many choose to capture the most prominent phase of their pregnancy. First time moms should plan on a photo shoot between weeks 28 and 36 (aim for weeks 30-33) when the belly is is nice and defined and while mom can still walk and move around :).
Moms with twins or those with additional children should aim for a photo shoot between 24 and 32 weeks simply because the belly will most likely be more prominent sooner.
Whatever your plan is, you will find it less stressful to plan ahead, so go ahead and book your session at least a month in advance. Doing so will help you think through all of the details with your photographer. It will also allow you to have some time to spare in case labor comes a bit earlier than anticipated.