Shero Michelle R
Biology Department, Woods Hole Oceanographic Institution, Falmouth, Massachusetts.
F S Rep. 2025 Apr 15;6(Suppl 1):24-31. doi: 10.1016/j.xfre.2025.02.004. eCollection 2025 Apr.
Trends in modern society show an increase in maternal age due to deferred childbearing, and assisted reproductive technologies often make this possible. However, there are still numerous challenges in the field of reproductive health, ranging from conception to delivery and beyond. Wild animals may provide answers to some of the field's pressing problems because these species have acquired adaptations to maximize reproductive output under some of the world's most extreme conditions. Here, I focus on 3 key aspects of marine mammal life history that could provide significant insight into reproductive physiology and function for future study. First, marine mammals are fasting-adapted species that cease feeding activities during portions of their reproductive cycle. Strong selective pressures for lipid mobilization to support energetic demands during fasts result in reversible insulin resistance, similar to gestational diabetes mellitus. Second, marine mammals extensively forage as they recover from fasts, engaging in repeated, long-duration dives. This exposes the females and their pregnancies to prolonged hypoxia, extending far past the limits that human fetuses could withstand during delivery without hypoxic ischemic encephalopathy or asphyxiation. Finally, pinnipeds and polar bears use embryonic diapause to time birth with optimal conditions for successful offspring rearing. The ability to "pause" pregnancy until conditions improve could substantially enhance successful outcomes for assisted reproductive technologies in humans. Lessons learned from marine mammal physiology highlight the value in applying comparative studies toward a One Health approach in reproductive medicine.
现代社会的趋势表明，由于生育推迟，产妇年龄有所增加，而辅助生殖技术常常使之成为可能。然而，生殖健康领域仍然存在众多挑战，从受孕到分娩以及产后皆是如此。野生动物或许能为该领域的一些紧迫问题提供答案，因为这些物种已经进化出了适应性，以便在世界上一些最为极端的条件下实现生殖产出最大化。在此，我聚焦于海洋哺乳动物生活史的三个关键方面，它们能够为未来关于生殖生理和功能的研究提供重要洞见。其一，海洋哺乳动物是适应禁食的物种，在其生殖周期的某些阶段会停止进食活动。在禁食期间，为支持能量需求而进行脂质动员的强大选择压力会导致可逆性胰岛素抵抗，这类似于妊娠期糖尿病。其二，海洋哺乳动物在从禁食状态恢复时会大量觅食，进行反复的长时间潜水。这使得雌性及其孕期暴露于长时间的缺氧环境中，远远超出了人类胎儿在分娩时不发生缺氧缺血性脑病或窒息所能承受的极限。最后，鳍足类动物和北极熊利用胚胎滞育来选择在最有利于成功养育后代的条件下分娩。“暂停”妊娠直至条件改善的能力可能会显著提高人类辅助生殖技术的成功率。从海洋哺乳动物生理学中汲取的经验教训凸显了在生殖医学中采用比较研究以实现“同一健康”方法的价值。
