Check the portfolio: Each maternity photographer has a variant style and creative skills. An overview of the photographer's portfolio will let you know the type of results you will be getting. If you are not impressed with the portfolio, you must check the next photographer in your list.
Experience: When it comes to maternity photography, it is vital to understand that the photographer for maternity pictures is entirely different from other photographers. It is the requirement of pictures, quality and concept that makes it different. The variety of poses in the pictures and other factors will help you know the past experience of the photographer.
Expertise: This is important because his professional guidance is important for selecting the best pictures and cropping and finishing them. If this is not taken care of properly, you might not be happy with the end result.
Referrals: Do ask for referrals to be sure of your decision. Call them and ask them about the service and the final result they got. If their previous clients tell you that they were satisfied, it will help you take your final decision.