Objective: To estimate the incidence of gestational trophoblastic disease in Nova Scotia and to evaluate the effect of time and maternal age on these rates.
Methods: Information on women with a pathologically confirmed diagnosis of gestational trophoblastic disease was extracted from the Nova Scotia Gestational Trophoblastic Disease Registry between 1990 and 2005. The total numbers of deliveries and pregnancies were determined from the Nova Scotia Atlee Perinatal Database and consensus data derived from Statistics Canada.
Results: Four-hundred twenty-eight women were identified with gestational trophoblastic disease. Hydatidiform moles showed rates of 220/100,000 pregnancies, 264/100,000 total births, and 266/100,000 live births. Rates of partial mole were twofold higher than complete mole (P<.001). The rates of hydatidiform mole were highest in both younger (younger than 20 years old, P=.02) and older age groups (30-34 years old, P=.04, and at least 35 years old, P=.02). The rates of hydatidiform mole were highest in both younger (less than 20 years old, P=.02) and older age groups (30-34 years old, P .04, and 35 or more years old P=.02). The rates of partial moles were significantly higher in women older than 20 years of age (P<.001) and increased with increasing age (P<.001); the reverse trend was seen in complete mole (P<.001). There was no temporal change in rates or average age of hydatidiform mole during the study period.
Conclusion: The rates of hydatidiform mole in Nova Scotia estimated by this population-based study using comprehensive validated information, are higher than most previously reported. Maternal age was a significant factor in the risk for molar pregnancies.