Field hospitals were deployed by the Israel Defense Forces as part of the international relief efforts after major seismic events, one in Haiti (2010) and one in Japan (2011). The teams treated a total of 44 pregnant and 24 nonpregnant women and performed 16 deliveries and three cesarean deliveries under extreme conditions. Half of all deliveries were complicated by preeclampsia and 31% were preterm (at 30-32 weeks of gestation). It is imperative that obstetrician-gynecologists be included among humanitarian aid delegations sent to sites of natural disasters. The complicated cases we encountered required highly skilled obstetricians and led to a shortage of specific medications for these women. Cases that would have been considered routine under normal conditions created unanticipated ethical and practical issues in the face of very limited resources. The aim of this commentary is to share the experiences and lessons learned by our field hospital obstetrics and gynecology teams after the major earthquakes in Haiti and Japan. We present what we consider to be the 10 most important lessons learned and propose that they serve as guidelines in preparing for essential needs in other natural disaster settings.