Heterogeneity between women who received prenatal care in the third trimester and those who received no prenatal care.
OBJECTIVE
To determine whether women who received prenatal care in the third trimester differed from those who received no prenatal care.


METHODS
We analyzed US birth certificates from 1990 through 1992, computing the distribution of live births for women who received prenatal care in the third trimester and for those who received no prenatal care according to eight demographic and pregnancy-related characteristics (age, race, marital status, residence, country of birth, education, interbirth interval, and parity). We used the Cochran-Mantel-Haenszel statistic to test the significance of the differences between the distributions for each characteristic, adjusting simultaneously for the other seven characteristics.


RESULTS
Women who received no prenatal care differed from women who received prenatal care in the third trimester for each of the demographic and pregnancy-related characteristics we examined. Among black and unmarried women, the two categories of prenatal care differed by more than 10%.


CONCLUSIONS
The characteristics of women who received no prenatal care and those of women who received prenatal care in the third trimester were heterogeneous. Strategies to promote earlier prenatal care should be specific and sensitive to women at risk for each category of late entry to prenatal care.
D000293:Adolescent; D000328:Adult; D001723:Birth Rate; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D011295:Prenatal Care / Q000592:standards*; D016016:Proportional Hazards Models; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D016387:Women's Health