Brain tumor development affected by mothers' miscarriage history, birth defects

Children whose mothers have had 2 or more late miscarriages have 3 times the risk of developing central nervous system (CNS) tumors, according to a recent study. Birth defects also correlate with increased risk of CNS tumors.

Because one-third of CNS tumors occur before age 5 and 75% by age 10, awareness of multiple maternal miscarriages and the association of CNS tumors with birth defects may help pediatricians identify at-risk children and detect tumors in earlier stages of development. Primary CNS tumors are the most common solid tumors in children and the third most common type of cancer seen in pediatric populations. In the United States, about 3,000 children are diagnosed with CNS tumors each year.

Researchers identified 3,733 children diagnosed with CNS tumors between 1988 and 2006 and matched each patient to 4 controls, then analyzed the reported presence of a birth defect and the mother’s history of pregnancies previously lost at 20 weeks or later gestation. Children had a 3.13 times greater risk for CNS tumors and a 14 times greater risk for high-grade glioma if their mothers had had 2 or more late fetal losses. Approximately one-third of all CNS tumors are gliomas.

Birth defects also increased the risk of subsequent development of CNS tumors. Children with birth defects were more than 6 times more likely to develop germ cell tumors and 3 times more likely to develop primitive neuroectodermal tumors. They also were at greater risk for developing medulloblastoma.

Researchers concluded that birth defects and multiple late miscarriages might be markers for genetic defects in developmental pathways that trigger development of CNS tumors.

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