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Estimation of the spontaneous abortion risk in the presence of induced abortions
Author(s) -
Hilden J.,
Modvig J.,
Damsgaard M. T.,
Schmidt L.
Publication year - 1991
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4780100211
Subject(s) - abortion , induced abortions , estimation , obstetrics , statistics , medicine , gynecology , pregnancy , research methodology , family planning , population , mathematics , biology , environmental health , economics , management , genetics
We propose a method of estimating the miscarriage risk in a setting where counts of births, miscarriages and induced abortions are available, and also the gestational week of each induced abortion. Unlike previously proposed methods, ours takes into account the fraction of the miscarriage risk to which each interrupted pregnancy has been exposed. For this purpose, we draw on an extraneous standard foetal survival curve and stipulate that the survival curve of the study population is a scaled version thereof. Three such scaling models are discussed, and it is shown that the choice is largely a matter of computational convenience. Separate attention is given to a competing‐risk model of miscarriages and interruptions, and examples are given of reasons why the crucial assumption that these two sources of termination operate independently is unlikely to be met. Finally, it is argued that pregnancy wishes, especially those of habitual aborters, shape the miscarriage rate to the extent that it becomes as much a cultural parameter as a marker of biological hazards.