In this section, I'll take you step by step through the process of making something out of nothing. Guiding your model into her pose step by step may be a lot easier for her and for you. It also means you are interacting rather than trying to start at the end — a finished photograph.
Let's begin with our basic good posture and put a hand under the belly:
Then, we will have her raise one leg up, as described earlier, so that her nearer foot is on tip-toe. Notice how it creates an S-curve through the frame.
In the next photo her left hand is now placed on top of her belly, counterpoint to her right, which is a much more loving gesture. Rather than simply holding her belly, she is cradling her baby. By changing the position of the hands, we get not only a different line, but a different mood. There are few photographs more potent in meaning than a maternity portrait — so while we can talk about line and composition, we can't ignore the emotional meaning in the photographs.
The cradled belly (below, far left) is warm and shows the connection between mother and child...
...while the proud belly (above, far right) is more about pride in her changing body. These two poses will be covered in the next section, but hopefully this will give you a sense of how you can incorporate specific poses into your photo session. There are all sorts of stages and iterations between that can be experimented with, and, if you are lucky enough to work with many clients, you will find that these types of subtle changes help bring out your client's personality.
Taking the last pose and having the mom-to-be arch her back creates a strong, proud, sexy portrait. Having her bring her arm down changes the mood and line again, creating a pose that is almost purely about the strength and beauty of the pregnant form.
And if you would like to have a look at just what a difference in line and form that leg up makes here is the same pose, leg up and then leg down:
Which brings me around to an interesting observation about poses, line and meaning. If we look at that last photo with the leg down, we end up nearly back at our starting point.
But notice how much more dynamic the feel is at the end (right) than at the start (left). Instead of standing and waiting for a photo, she has been active. She has been thinking about movement, about the baby, and she looks more vibrant and present. The two poses are nearly the same, but the ending pose on the left is significantly more engaging.