Morning sickness-like changes during pregnancy in non-human primates and rodents

Nausea and vomiting of pregnancy (NVP), commonly referred to as “morning sickness,” causes a range of symptoms including nausea, vomiting, weight loss, anorexia, and malaise in pregnant women during early pregnancy. Although NVP highly affects the quality of life of pregnant women, the absence of model animals has prevented us from revealing the underlying mechanisms. Here, to identify whether non-human animals may serve as models for studying NVP, we analyzed metabolic changes during pregnancy in common marmosets and mice. Marmosets exhibited a transient weight decrease during the period of placental development in approximately 22% of pregnancies. Some marmosets repeatedly showed transient weight loss across multiple pregnancies, suggesting individual variations in the likelihood of NVP-like symptoms. Although mice did not show apparent alteration in body weight, they exhibited a slowdown in food intake and alterations in locomotor activity during the corresponding phase. These shared alterations suggest that marmosets and mice may exhibit phenomena analogous to human NVP and could serve as useful models for investigating its biological basis.