A preliminary case-control study was conducted on Saudi women to detect possible risk factors for spontaneous abortion (SA). Two hundred and twenty six consecutive women hospitalised for SA and 226 women admitted for normal delivery and used as controls, were studied. Women with SA were significantly older at menarche (Relative Risk (RR) = 3.2), more frequently married to blood-related husbands (RR = 2.1) and husbands older than 50 years (RR = 2.4). Number of previous abortions related linearly to the risk of aborting spontaneously in the next pregnancy. Compared to primigravidas, the RR was 3.2 if the outcome of the most recent pregnancy was SA, and 0.8 if it was a livebirth. A family history of SA was more common among cases (RR = 4.6). Spontaneous abortion was also associated with daily consumption of more than 150 mg of caffeine, abdominal trauma, infection and fever during pregnancy. No significant association, however, emerged with maternal age, social class, education, exposure to video display terminals, parity, use of contraception, diabetes or obesity. The application of these data in clinical practice and future research needs are discussed.