The epidemiology of conjoined twinning in Southern Africa.
Thirty-one sets of conjoined twins were born in Southern Africa during the period February 1974 to May 1982 with a striking increase in incidence in 1974 and 1975. There was no ethnic or social predilection, but clustering of cases occurred in a remote area of Zimbabwe. No aetiological agent was discovered, and there was no seasonal variation in the time of conception. Female conjoined twins accounted for 62% of cases, and twenty sets were of the thoracopagus type. Four pairs were separated, three of which were of the xiphopagus subtype and have survived.
D000353:Africa, Southern; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013029:Space-Time Clustering; D014428:Twins, Conjoined