Maternal pregnancy loss, birth characteristics, and childhood leukemia (United States)

Objective: The authors evaluated the relation between maternal pregnancy loss, birth characteristics, and childhood leukemia in the Northern California Childhood Leukemia Study. Methods: Incident cases of childhood leukemia (age 0-14 years) were rapidly ascertained, and controls were randomly selected from birth records and individually matched to cases. A total of 366 cases [313 acute lymphoblastic leukemia (ALL) and 53 acute myeloid leukemia (AML)] and 460 controls were included in this analysis. The biological mothers of all subjects provided detailed reproductive history and birth characteristics of the index children during a personal interview. Odds ratio (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. Data on maternal pregnancy loss and birth characteristics were also available from the birth certificates of 96.3% of all subjects. Results: History of miscarriage was associated with a significantly increased risk of AML (OR = 2.94, 95% CI: 1.03, 8.34), but not ALL. Neither birth weight, birth order, or parental ages appeared to be an important predictor of the risk of ALL or AML. A comparison between data from two different sources (interview versus birth certificate) indicated good reproducibility and offered some evidence against recall bias. Conclusion: Maternal history of miscarriage is associated with an increased risk of childhood AML.