It's not the expectation that women have to work that makes having children difficult, it's that they are expected to work and still do the majority of the childcare that is making having children difficult. Historical remember so many children died, in Ancient Roman times, for example it would take 6 to 9 children per household to keep the population rate stable, with wealthier houses having fewer children, not just because of child survival rates but also because childbirth was so damn risky for the mother. With a 1 in 50 chance of dying, that increased with each subsequent child. Half of all children born would be dead by age 10 so they needed to have so many children.