Legalizing abortions makes them safer. If they are illegal, women will still seek them when faced with no other choice but to have a child. They will go back to methods that were once used when abortion was still taboo. These methods were brutal and dangerous, posing an increased risk to the mother's health.
This is best illustrated by tracing the number of abortion deaths in the US. In 1972, before abortion was legal, 39 women died from abortion complications. In 1976, after the landmark Roe vs Wade ruling which legalised the practice, just two women died from abortion complications.
Modern abortion methods have eliminated many of the health risks associated with the practice. Less than 0.25% of abortion cases now result in complications.
The risk of dying during an abortion is 14 times lower than the risk of dying during childbirth. It is forced childbirth, not abortion that puts the mother most at risk.
Regarding mental health, it is true that women who receive abortions may be at higher risk of depression than those who don’t, but those that want an abortion but are denied access to them are at higher risk still. Considering this, it would be better to give those that want access to an abortion the ability to terminate the pregnancy.