Timing of insurance coverage and use of prenatal care among low-income women.

Objectives: This study examined the relationship between timing of insurance coverage and prenatal care among low-income women.

Methods: Timeliness of prenatal care initiation and adequacy of number of visits were studied among 5455 low-income participants in a larger cross-sectional statewide survey of postpartum women in California during 1994-1995.

Results: Although only 2% of women remained uninsured throughout pregnancy, one fifth lacked coverage during the first trimester. Rates of untimely care were highest (> or =64%) among women who were uninsured throughout their pregnancy or whose coverage began after the first trimester; rates were lowest (about 10%) among women who obtained coverage during the first trimester. Women who first obtained Medi-Cal coverage during pregnancy were at low risk of having too few visits.

Conclusions: Timing of prenatal coverage should be considered in research on the relationship between coverage and care use among low-income women. Earlier studies that relied solely on principal payer information, without data on when coverage began, may have led to inaccurate inferences about lack of coverage as a barrier to prenatal care.