A perusal of the literature and the failure to find the coincidence of intra-uterine and extra-uterine pregnancy mentioned in a number of the latest text-books would indicate that this form of gestation is certainly infrequent.
B. B. Browne1 gives a report of the published cases, 23 in number, dating from 1708 to 1880, and adds a case operated on by H. P. C. Wilson of Baltimore.
Straus2 states that no fewer than 32 instances of tubai pregnancy coexisting with intra-uterine gestation appear in literature. In Straus' table the maternal mortality amounts to 14 in the 32, but 10 of the 14 were in cases dating from 1820 to as far off as 1879. In 13 cases both extra- and intra-uterine pregnancies continued to term; in 4 both fetuses were living, and out of these 4 only 2 were cases in which both fetuses were delivered alive, the one normally, the
HAGENS GJ, MOORHEAD JJ. COMBINED INTRA-UTERINE AND EXTRA-UTERINE PREGNANCY; OPERATION AND RECOVERY.. JAMA. 1903;XL(21):1440. doi:10.1001/jama.1903.92490210032001f