2Ballantyne JW. Manual of antenatal pathology and hygiene. Vol 1. Edinburgh, Scotland: William Green & Son,1902.
3Aubry RH, Pennington JC. Identification and evaluation of high - risk pregnancy: The perinatal concept. Clin Obstet Gynecol, 1973,16: 3 -27.
4Eskes TK, Mooij PN, Steegers - Theunissen RP, et al. Prepregnancy care and prevention of birth defects. J Perinat Med ,1992,20: 253 -265.
5Moos MK. Preconceptional health promotion: Progress in changing a prevention paradigm. J Perinat Neonat Nurs, 2004, 18(1) :2 -13.
6Alexander GR, Kotelchuck M. Assessing the role and effectiveness of prenatal care: history, challenges and directions for future research.Public Health Rep ,2001,116 : 306 -316.
7Fiscella K. Does prenatal care improve birth outcomes? A critical review. Obstet Gynecol, 1995,85:468 - 479.
8Strong TH Jr. Expecting Trouble. New York: New York University Press,2002.