Short-term reproductive prognosis when no cause can be found for recurrent miscarriage

The short-term reproductive prognosis of recurrent miscarriage for which no cause was found has been evaluated in 95 couples investigated between 1980 and 1986 at the First Obstetric and Gynaecological Clinic of the University of Milan. The actuarial overall 3-year livebirth delivery rate was 64%, increasing constantly with time. The reproductive success rate decreased with the number of previous miscarriages from 80% in women with two, to 60% with three and 46% with four or more miscarriages. No effect of age and socio-economic status emerged. There was a positive association between the number of previous miscarriages and the risk of miscarriage in the next pregnancy. Compared with women with two miscarriages the relative risk of another miscarriage was 2.3 for those with three previous miscarriages and 5.0 for those with four or more (chi 2 1 for trend adjusted for age = 5.2, P = 0.02).