Midtrimester tubal pregnancy with markedly elevated maternal serum alpha-fetoprotein. A case report.
 Elevated maternal serum alpha-fetoprotein levels have been reported to occur in a variety of pathologic conditions, including early tubal pregnancy.
 In this case, markedly elevated maternal serum alpha-fetoprotein was associated with a midtrimester tubal pregnancy.
 The breakdown of the normal fetomaternal circulatory barrier, allowing the transplacental exchange of alpha-fetoprotein, was the likely etiology of the elevation.
