Check it there:
Why Are French Women Killing Their Babies?
The obvious answer to the enigma: motherhood is seen as a stigma in our so called culture where professional "career" is the ultimate goal, as if giving life wasn't the very finest destiny one could aspire to. Being inescapable does not make it less valuable.
As a lady very dear to me said to her daughter, when she was, or rather, felt confronted with the motherhood/career dilemma "by definition, the exercise of freedom requires you to abandon all of possible choices offered to you but the one". Coelho made a very similar comment recently.