Risk factors for gestational trophoblastic disease: a separate analysis of complete and partial hydatidiform moles.

Risk factors for complete and partial hydatidiform mole were analyzed in a case-control study conducted in the greater Milan area on 139 complete moles, 49 partial moles, and 410 obstetric control subjects. Patients tended to be more frequently nulliparous than controls, and the risk of complete mole and partial mole decreased with number of births, although the trend in risk was significant only for partial mole (chi 2(1) trend, P = .05). The risk for both histopathologic subgroups was greater in women reporting spontaneous miscarriages. Compared with women with no previous miscarriage, the estimated odds ratios (as estimators of relative risks) were 3.1 and 1.9, respectively, for complete mole and partial mole for two or more miscarriages. Infertility problems or difficulty in conception were associated with an odds ratio of 2.4 (95% confidence interval 1.3-4.3) and 3.2 (95% confidence interval 1.4-7.0), respectively, for complete mole and partial mole. No association emerged between mole and induced abortions and age at first pregnancy. A personal history of gestational trophoblastic disease increased the risk of both complete mole and partial mole: The odds ratios were 12.0 (95% confidence interval 3.0-38.9) and 18.1 (95% confidence interval 5.0-64.7), respectively. Similarly, a family history of gestational trophoblastic disease was more frequently reported in complete mole cases (five of 128) than in controls (one of 395) (odds ratio 16.0, 95% confidence interval 3.2-80.3). When the mating frequencies by patient/husband blood groups were considered, a nonsignificant increased risk was evident for women with group A married to men of group O in both histopathologic subgroups (odds ratio 1.5 compared with all other combinations).(ABSTRACT TRUNCATED AT 250 WORDS)