In order to become a maternity photographer, you will first need to learn as much as possible about portrait photography and the different lighting techniques commonly used for such portraits. Not everyone can become a maternity photographer just by purchasing a camera and snapping photos; professional photographers spend years practicing the craft, building their reputations, and marketing to expectant parents who want such photos taken. It may be helpful to take a position as a photographer's assistant or apprentice to learn what it takes to become a maternity photographer before making the significant investment of time and money into the trade.
As a photographer, you will need to know the technical aspects of photography in order to become a maternity photographer. It may be helpful to experiment with lighting techniques with friends or family before trying to book maternity clients. Photography schools and programs are a great way to learn more about lighting and posing techniques, and such programs often give you access to studio space stocked with the proper equipment. Purchasing such equipment can be extremely expensive, so you may want to consider researching rental options or other studio space options in your area. Not all portraits need to be shot indoors, but the lighting equipment and enclosed space offers privacy and controlled lighting that make the process much easier.
Develop a marketing strategy to become a maternity photographer in your area. Consider printing up flyers and business cards to advertise your work, and develop a rapport with local midwives, maternity clothing stores, local child birthing classes, and so on to make sure you get your name out to expectant mothers. Advertising on the Internet is another great way to gain more customers in your area; if possible, develop a website with your best work displayed on it, as well as your pricing structure and contact information.
Many maternity photographers start in other areas of photography and develop a niche as a maternity photographer later on. Many wedding photographers, for example, get the opportunity to develop a relationship with a husband and wife through the engagement photos and wedding photos, and if that couple decides to have maternity photos taken, they are more likely to call up the photographer they know and trust already. Consider working in other areas of photography to become a maternity photographer, and don't be afraid to advertise yourself as a multi-purpose photographer. Offering package discounts will help ensure past clients come back to you for more work down the road.