The effect of adolescence and advanced maternal age on the incidence of complete and partial molar pregnancy.

OBJECTIVE

To compare the age-specific incidence of complete (CM) and partial molar (PM) pregnancy in a large tertiary care center in the United States.

METHODS

Incidence rates of CM and PM per 10,000 live births were calculated using databases from Brigham and Women's Hospital, between 2000 and 2013. Age-specific rates were calculated for women younger than 20 years old (adolescents), 20-39 years old (average age), and 40 years and older (advanced maternal age). Pearson χ(2) test was used to evaluate potential differences among groups. Rate ratios (RR) and 95% confidence intervals (CI) were used to compare risk of molar pregnancy among average age women with that of adolescents and women of advanced age. Holm-Bonferonni adjustment was used to correct for multiple comparisons.

RESULTS

Between 2000 and 2013, there were 255 molar pregnancies (140 CM and 115 PM) and 105,942 live births, corresponding to a molar pregnancy rate of 24 per 10,000 live births (95% CI 21-27). Rates of CM and PM were 13 (95% CI 11-16) and 11 (95% CI 9-14) per 10,000 live births respectively. The incidence of CM differed significantly among maternal age groups (p<0.001). Compared to average age women, adolescents were 7.0 times as likely to develop CM (95% CI 3.6-8.9, p<0.001), and women with advanced maternal age were nearly twice as likely (1.9, 95% CI 1.8-4.7, p=0.002). The rate of PM did not vary significantly among age groups (p=0.26).

CONCLUSIONS

Adolescence and advanced maternal age were associated with increased risk of complete mole, but not partial mole.