Answers are grounded in this paper and cite their sources.
A study of perinatal mortality in twins has been carried out concurrently in Ibadan, Nigeria, and Aberdeen, Scotland. In both areas perinatal mortality rates have been found to be four times higher in twins than in singletons, reaching up to 310 per 1000 in the monochorionic group in Ibadan. Moreover, rates have been found to increase considerably with maternal age and parity.
No takes yet. Share an insight, caveat, or question.
P. P. S. Nylander (1979) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: