She doesn't "have to" do anything she doesn't wish to. If she thinks the costs outweigh the benefits, she need not get pregnant or she need not carry the pregnancy to term. However, women have the option of conceiving if they think the benefits outweigh the costs, a choice men don't have.
The idea that this is somehow a disadvantage to women is only sensible if you see women as slaves to their biology who are powerless to make sensible choices. I utterly reject that premise.
So there'd be insurances to compensate her temporary inability to carry out a job in the marketplace, insurances that a man would not have to contract. Then what are the (material) benefits anyway? The child owns itself. The emotional factor doesn't mean powerlessness "to make sensible choices", that's exaggerated. The bottom line still is that the market does not incentivize procreation in any form.
Throughout history and across cultures, societies have successfully created collectives to pool resources in support of this indispensable service. They're called "families", and they're perfectly capable of existing in a free market.
There is no guarantee that a guy would stay and form a family, especially in these modern times.
Look, the more primitive a civilization is, the more patriarchal it tends to be. And this is exactly what "progressives" want to get away from.