Effect of race/ethnicity on risk of complete and partial molar pregnancy after adjustment for age.

OBJECTIVE: To quantify the effect of race/ethnicity on risk of complete and partial molar pregnancy.

METHODS: We conducted a cross-sectional study including women who were followed for complete or partial mole and those who had a live singleton birth in a teaching hospital in the northeastern United States between 2000 and 2013. We calculated race/ethnicity-specific risk of complete and partial mole per 10,000 live births, and used logistic regression to estimate crude and age-adjusted relative risks (RR) of complete and partial mole.

RESULTS: We identified 140 cases of complete mole, 115 cases of partial mole, and 105,942 live births. The risk of complete mole was 13 cases per 10,000 live births (95% confidence interval [CI] 11-16) and that of partial mole was 11 cases per 10,000 live births (95% CI 9-13). After age-adjustment, Asians were more likely to develop complete mole (RR 2.3 95% CI 1.4-3.8, p<0.001) but less likely to develop partial mole (RR 0.2; 95% CI 0.04-0.7, p=0.02) than whites. Blacks were significantly less likely than whites to develop partial mole (RR 0.4; 95% CI 0.2-0.8, p=0.01) but only marginally less likely to develop complete mole (RR 0.6; 95% CI 0.3-1.0, p=0.07). Hispanics were less likely than whites to develop complete mole (RR 0.4; 95% CI 0.2-0.7, p=0.002) and partial mole (RR 0.4; 95% CI 0.2-0.9, p=0.02).

CONCLUSION: Race/ethnicity is a significant risk factor for both complete and partial molar pregnancy in the northeastern United States.