[Fate of subsequent pregnancies in relation to the outcome of previous pregnancies]

Adverse outcome of the previous pregnancy as a risk factor for the next one has lately been given increased attention. Particular concern has been expressed as to the possible adverse effects of induced abortion on subsequent pregnancy outcome (1, 2, 3, 4, 5, 6). The purpose of the present report was to establish on the basis of population studies whether and to what extent, abnormal outcome of pregnancy increases the risk of abnormal outcome of the next or further pregnancies. Particular attempt was made to evaluate the increased risk of abnormal outcome of pregnancy following spontaneous and induced abortion. A sample of the studied population was originally collected in several Departments of Obstetrics for a study on epidemiology of low birth weight, and its selection was conditioned by that study. The sample included women whose present pregnancy resulted in the delivery of a live born child. This pregnancy was not taken into consideration in the present study except as a basis for selection of 2 study groups of women who previously had at at least 2 pregnancies (except the present one): Group A consisted of 1180 women who gave birth in the recent pregnancy to a full term child weighing over 3000 g and Group B of 1170 women who delivered a low birth weight infant in their previous pregnancy. Mothers of infants weighing between 2500 and 3000 g were also included in this group because the foetal growth tables for Polish newborn infants showed that weight limits at the 5th percentile for full term male infant ranged between 2500-2800 g and below 10th percentile between 2600 and 3000 g. The following outcomes of previous pregnancies were considered: Full term newborn infant (FT) Low birth weight infant (less than or equal to 2500 g) (Pr) Spontaneous abortion (SA) Induced abortion (IA) Other outcomes (O) Contingency tables containing information on the frequency of different outcomes of earlier and later pregnancies were prepared and the effects of the mode of termination of the earlier pregnancy on the later ones were demonstrated. Interrupted pregnancies were not included in the whole number of cases for the calculation of the percent value, as the decision to interrupt is usually arbitrary and very seldom related to the outcome of the previous pregnancy. The differences between the distribution of pregnancy outcomes in various categories of termination of earlier pregnancy were tested by standard Chi square test which was useful also for testing the dependence of the mode of outcome of the preceding and the following pregnancy. The relative risk coefficient was also calculated for two different combinations of outcomes.(ABSTRACT TRUNCATED AT 400 WORDS)