Background: The Rh-negative gene is a well known cause of perinatalmortality especially before there were any eﬀective treatment. The Rh disease, that is caused by a Rh positive foetus carried by a Rh negativemother, leads to typical patterns of perinatal mortality with an increaseof mortality with parity and mortality clustered in families. This eﬀecthas been largely neglected in earlier papers trying to explain mortalitypatterns in historic data.
Objectives: This paper highlights the role of this gene in causing these patterns and tries to quantify the eﬀect in a society with a large group of Rh-negative persons and no access to treatment.
Methods: The risks of the Rh disease is approximately known from the medical literature. Knowing family sizes and the approximate share of Rh negative genes the ”theoretical” patterns of perinatal mortality can becalculated and simulated. Comparing these ﬁgures with observed patterns of perinatal deaths the relative importance of Rh factor can be estimated.We have used data from 1840-1900 in the Swedish parish of Skellefteå where we have data on all births and their outcomes as well as good estimates of the Rh negative gene frequency.
Results: The results show that the Rh gene is likely to have had an important role in perinatal mortality and the patterns with more dead at high parities and clustering explaining a relatively large part of these phenomenon in high Rh negative gene societies.
Conclusions: The paper shows that the Rh-disease is an important fac-tor in understanding mortality patterns. Its great eﬀect on the patterns makes it necessary to take it into account when analysing other factors that can aﬀect perinatal mortality patterns.
Umeå: Umeå universitet, Centrum för befolkningsstudier , 2010.