title: A computer model of antenatal care: relationship between the distribution of obstetric risk factors in simulated cases and in a real population.
abstract: The main purpose of antenatal care is to identify risk factors for the fetus. A number of systems have been described in which positive factors are summed to produce an overall risk score for the individual woman. In the present study a computer simulation of a population of pregnant women has been used to examine the use of Bayes theorem to calculate obstetric risk scores. The findings of the computer simulation have been compared with those in a real obstetric population (774 primigravidae; 930 multigravidae). A number of observations have been made which may be of considerable practical significance: (1) in the population as a whole the distribution of risk scores is skewed; most women have a low score while relatively few subjects have high scores; (2) a minimum number of risk factors must be present simultaneously for the risk in an individual to consistently exceed the overall population risk; this number is 4 in primigravidae and 5 in multigravidae; (3) the relationship between the number of risk factors and overall risk does not follow a straight line. The computer simulation provides a test bed in which various assumptions can be examined, such as the effect of removing or redefining given risk factors.
authors.affiliation: Department of Obstetrics & Gynaecology, St. Bartholomew's Hospital Medical College, London, U.K.
authors.forename: T
authors.initials: T
authors.lastname: Chard
authors.forename: S
authors.initials: S
authors.lastname: Carroll
mesh_terms: D001499:Bayes Theorem; D003198:Computer Simulation; D005260:Female; D006801:Humans; D011247:Pregnancy; D011295:Prenatal Care; D012307:Risk Factors; D011795:Surveys and Questionnaires