Excessive Siamese twinning in Southern Africa

Area of Science:

• Medical Science
• Epidemiology
• Environmental Health

Background:

• Since February 1974, twelve sets of conjoined twins have been documented in Southern Africa.
• This observation potentially indicates an increased incidence of Siamese twinning in the region.

Purpose of the Study:

• To investigate a possible increase in the incidence of conjoined twinning in Southern Africa.
• To explore potential links between conjoined twinning and unknown environmental agents.

Main Methods:

• Retrospective case review of conjoined twin births in Southern Africa since 1974.
• Analysis of incidence rates and potential correlations with environmental factors.

Main Results:

• Twelve sets of conjoined twins were recorded since February 1974.
• The observed frequency suggests a possible significant increase in Siamese twinning incidence.
• Antenatal diagnosis was achieved in several cases.

Conclusions:

• The data suggests a potential increase in conjoined twinning incidence in Southern Africa.
• Unknown environmental agents are hypothesized as a possible cause.
• Maternal hydramnios and fetal malpresentation may warrant increased suspicion for conjoined twins.