"BIRTH: Around 40 weeks after that drunken night at the cabin, the adult (hopefully) female’s uterus began contracting. This forced the fetus onto the cervix, thinning and dilating it, and rupturing the amniotic sac. As the painful contractions increased in frequency and intensity (8 to 14 hours), the 8 pound, 22-inch infant journeyed down the birth canal towards the vagina. The baby’s head passed under the pubic bone and began to stress the perineum (it’s the tissue between the vagina and rectum), often tearing it. Through a storm of screams, amniotic fluid, mucus and blood, the final pushes introduced the bundle of joy to the outside world. He/she wailing uncontrollably. And with that, the easy part was over."
— Earth: The Book