生孩子为什么会疼痛难忍?

Backward Births

逆向生产

That infant head looks mighty large compared to that narrow birth canal. And to add to that, the baby comes out facing down and backwards, which means mothers can do little to assist the birth, or even to untangle the baby from the umbilical cord.

婴儿的头部相对于产道，看起来十分巨大。除此之外，婴儿是按照从头到脚通过产道的顺序，朝着下方出生的，这就意味着母亲在协助产程方面能尽到的协助力很小，甚至无法为婴儿解开缠绕在身的脐带。

According to evolutionary anthropologists, babies of the earliest humans had a 50-50 chance of coming out facing backwards. This was a result of humans learning to walk on two feet. As the pelvis became optimized for walking, the birth canal developed twists and turns that meant the baby had to rotate in order to keep the head and shoulders aligned with the widest part at all times.

根据进化人类学家的说法，最早期人类的婴儿出生时头部先通过产道的几率为50%，这种现象是人类学会用双足直立行走的结果。随着骨盆最优化发育以适应行走，产道中出现了曲折和转弯的部分，这意味着婴儿在通过产道时不得不旋转方向来保持头部和肩膀与产道最宽处相一致。

And then our brains got bigger, which meant more twists and turns and backwards-facing babies.

后来人类脑部体积变得越来越大，这就导致了更多的曲折、转弯和逆向生产。

Special Delivery

特殊的生产方式

Some of the earliest humans learned to compensate for the difficulty of giving birth by receiving assistance during childbirth, and that made a huge difference in terms of survival.

一部分最早期人类学会了通过在生产过程中寻求协助的方式来减小生产的困难，而这种做法在提高存活率方面做出了重大贡献。

Some anthropologists think there might be an evolutionary advantage to having someone help you give birth, and conjecture that human females who gave birth to backwards-facing babies, and females who had assistance because they felt particularly anxious about the birth ended up doing better than females who didn’t. After all, if problems arise during labor, having another person around can mean the difference between life and death.

一些人类学家认为有人协助生产可能是一种进化上的优势，并且设想那些逆向生产婴儿，以及由于对生产感到特别焦虑，从而获得协助的女性，最终比起没有协助的女性所产下的婴儿存活率更高。毕竟，假如产程中出现了问题，有他人在场可能意味着生与死的区别。

Some anthropologists think there might be an evolutionary advantage to having someone help you give birth, and conjecture that human females who gave birth to backwards-facing babies, and females who had assistance because they felt particularly anxious about the birth ended up doing better than females who didn’t. After all, if problems arise during labor, having another person around can mean the difference between life and death.

一些人类学家认为有人协助生产可能是一种进化上的优势，并且设想那些逆向生产婴儿，以及由于对生产感到特别焦虑，从而获得协助的女性，最终比起没有协助的女性所产下的婴儿存活率更高。毕竟，假如产程中出现了问题，有他人在场可能意味着生与死的区别。