Department of Obstetrics and Gynecology, Division of Obstetrics and Feto-Maternal Medicine, Medical University of Vienna, Vienna A-1090, Austria.
Department of Evolutionary Anthropology, University of Vienna, Vienna A-1030, Austria.
Proc Natl Acad Sci U S A. 2024 Oct 15;121(42):e2316189121. doi: 10.1073/pnas.2316189121. Epub 2024 Oct 7.
Human fetuses at term are large relative to the dimensions of the maternal birth canal, implying that their birth can be associated with difficulties. The tight passage through the human birth canal can lead to devastating outcomes if birth becomes obstructed, including maternal and fetal death. Although macaques have to accommodate similarly large fetuses, relative to their maternal birth canals, it was not known whether macaque mothers face birth difficulties similar to humans. Based on 27 y of demographic data from a semi-free-ranging, closely monitored population of Japanese macaques (), we found no birth-associated mortality in macaques. This differs from the situation in many human populations. We suggest three nonmutually exclusive hypotheses to explain these observations. i) The macaque fetal skull is similarly flexible as the human fetal skull. ii) The macaque pelvis and connective tissue show greater flexibility during birth. iii) The interplay between macaque pelvic shape and birth dynamics is smoother and incurs fewer complications than in humans.
足月的人类胎儿相对于母体产道的尺寸较大，这意味着他们的出生可能会带来困难。如果分娩受阻，胎儿通过人类产道时的紧密通道可能会导致灾难性的后果，包括母婴死亡。尽管猕猴的胎儿相对于其母体产道来说也很大，但人们并不知道猕猴母亲是否面临与人类相似的分娩困难。基于对一个半自由放养、密切监测的日本猕猴种群（）长达 27 年的人口数据，我们发现猕猴在分娩过程中没有与分娩相关的死亡。这与许多人类群体的情况不同。我们提出了三个非互斥的假设来解释这些观察结果。i）猕猴的胎儿头骨与人类胎儿头骨一样具有柔韧性。ii）猕猴的骨盆和结缔组织在分娩过程中具有更大的灵活性。iii）猕猴骨盆形状与分娩动力学的相互作用比人类更顺畅，并发症更少。
