As someone currently on maternity leave and a former union rep, I actually think that the maternity leave law needs to be rebalanced in order to be fair towards all women, including those who can't or don't want to have children, who are lumped in together with all other women of childbearing age and discriminated against accordingly.
Maybe we should have the current (or even better) maternity leave/pay for the first child, then maybe just leave/no pay for the second, and on your own for the third. At least employers could anticipate and financially plan for 1 period of maternity leave/pay, but to employ someone who then has 3 pregnancies 2 years apart, could really damage a company.
In my role, due to health and safety, as soon as a women is pregnant they have to be found alternative duties, then if a years maternity leave is taken, your up to 19/20" months out of position, plus any accumulated annual leave, then 3 weeks refresher training, so your getting close to 2 years, and that's just for 1 pregnancy!!!
Might also help deal with over population!!