This is problematic for several reasons.

Firstly, as the article points out, the cost to the employer is significant--having to hire and train someone, only to terminate them 18 months later.  In the meantime, you'll have muddled through with a less-than-stellar staff.  (The pool of people wanting 18-month contracts is small.)

Secondly, many simply won't come back (but of course won't tell you until month 17).

What this all adds up to is, a disincentive to hire women, particularly those in the 25 to 35 age bracket.  The risk of them being gone for 3 of the next five years (because most women don't have just one child) is too high.

From the worker's perspective, they will have been out of the game for so long, that their skills will likely have eroded.  They've become less valuable.

It seems to me that better child care is a better answer.  Help workers have a work AND a home life, rather than helping them to choose one over the other.