Malformations and deformations in abdominal pregnancy.

Abdominal gestation is a relatively uncommon complication of pregnancy. Previous reports describe a high incidence of fetal deformations and mortality as well as maternal mortality. A case of twin abdominal gestation is presented and the literature concerning abdominal pregnancy since 1809 is reviewed. The survival rate of liveborn infants of 30 or more weeks gestation was 63%. The maternal mortality rate since 1809 was 18.2%, but this has decreased to 4.5% during the last 20 years. The combined rate of malformations and deformations in the infants was 21.4%. The most common deformations observed were facial and/or cranial asymmetry and various joint abnormalities. Among the most common malformations were limb deficiency and central nervous system malformations. Proposed mechanisms of compression and vascular disruption are discussed.