IMPACT OF CONTINUOUS MATERNAL ENROLLMENT ON STILLBIRTH GESTATIONAL AGE DISTRIBUTIONS AND MATERNAL CHARACTERISTICS AMONG MEDICAID ENROLLEES.

Abstract

Stillbirths are defined as intrauterine fetal deaths occurring at ≥20 weeks of gestation. While uncommon (1), late pregnancy loss is tragic and therefore an important focus for research. The Medicaid program covers health care for nearly half of all US pregnancies (2), and Medicaid administrative claims provide an important data source for pregnancy studies. Typically, maternal enrollment from the date of the last menstrual period (LMP) onward is required in order to capture fetal exposures incurred during early gestation. However, because of Medicaid eligibility restrictions focusing on low-income families, qualified pregnant persons and children, and individuals with disabilities (3), a sizable proportion of women become eligible for Medicaid only after their pregnancy is recognized, while those already enrolled before the LMP date are likely to already have children and to qualify under the low-income family criterion or due to disability. Thus, selection of pregnancies on the basis of time of Medicaid enrollment (before or after LMP) results in different populations of women and potentially different risk levels for adverse pregnancy outcomes. Because the date of LMP is not directly recorded in Medicaid claims data and LMP estimation for stillbirth based on claims has been elusive, enrollment requirements imposed to ensure complete claims records for a desired look-back period are typically based on a fixed gestational age (e.g., 20 weeks or 45 weeks as a minimum or maximum gestational age of stillbirth). It is unknown how imposing different enrollment requirements affects the selection of stillbirths in the Medicaid population.