BACKGROUND: Cases of abdominal pregnancy, in the form of intra-abdominal mummified fetuses, have been described in nonhuman primates. Gestational diabetes and pre-eclampsia are common pregnancy complications in women. METHODS: Two timed-bred rhesus monkeys had high-risk pregnancies, an abdominal pregnancy with delivery of a live term infant, and a case of gestational diabetes that later developed pre-eclampsia. RESULTS: The monkey that had abdominal pregnancy later died from septic peritonitis. The monkey had a colonic adenocarcinoma that may have allowed leakage of intestinal contents into the abdomen. Her infant was fostered to another female and survived. The monkey with gestational diabetes and pre-eclampsia was treated with a regimen similar to that used in women, and a live infant was delivered at day 157 of gestation by Caesarian section. CONCLUSION: These cases underscore the value of timed-breeding and the similarities between pregnancy complications in women and in nonhuman primates.