I hope nobody is basing their opinion of pain tolerance on Hollywood birth scenes. According to doctor and women's issues author Esther Villar, women have learned to play a gender role in which they exaggerate the pain in order to play on the emotions of the men who have traditionally been their providers. If it hurt that much, why are so many so eager to get pregnant?
I've read the opposite about pain tolerance of acute physical pain. A paper published in Nature or something similar a couple years ago looked at tolerance to pain using several tests, hands in a bucket of ice, chemical pain, and some others. The men did better in the test than the women.
Another measure of toughness might be endurance athletes. Do as many women compete in ultramarathons as men? It's not a question of who would win based on equal training, that's well-established, but just how many women versus men can even do it?