Key points are not available for this paper at this time.
Lois A. Fingerhut, Diane Makuc, Joel C. Kleinman, Delayed Prenatal Care and Place of First Visit: Differences by Health Insurance and Education, Family Planning Perspectives, Vol. 19, No. 5 (Sep. - Oct., 1987), pp. 212-214+234
Fingerhut et al. (Tue,) studied this question.