Look at Van Eyck The Arnolfini Wedding, you will see the woman is in a similar pose. This picture is generally believed to be a form of marriage contract, the style of dressing, popular at the time giving the impression of a pregnancy; or else, as noted in the paragraph starting Although many viewers presume....... that this gesture, the hand over her stomach that you mention, might merely have been a way of showing the couple's desire to have children. So, no this pose may not be an indicationof newly pregnant ladies but of the wish of a couple to prove fertile.
