Women with gestational diabetes mellitus often have hypoadiponectinaemia, but it is unknown whether the low levels of adiponectin are causal in the development of gestational diabetes mellitus. Now, researchers have used a mouse model in which the gene that encodes adiponectin is knocked out (Adipoq−/− mice) to demonstrate that adiponectin is involved in regulating the metabolic adaptations to pregnancy. Pregnant Adipoq−/− mice developed glucose intolerance and hyperlipidaemia in the late stages of pregnancy; this effect was not seen in knockout mice that were not pregnant. The fetuses of Adipoq−/− mice also had increased body weight and blood levels of glucose. The lipid profiles and blood glucose levels of Adipoq−/− mice returned to levels seen in wild-type mice after delivery. In addition, administering adiponectin in vivo reversed glucose intolerance and prevented high fetal body weight. The authors of the paper conclude that hypoadiponectinaemia could have an important role in the development of gestational diabetes mellitus.