5Huang L, Sauve R, Birkett N, et al. Maternal age and risk of stillbirth : a systematic review. CMAJ,2008,178 : 165-172.
6Tough SC, Newbum-Cook C, Johnston DW, et al. Delayed childbearing and its impact on population rate changes in lower birth weight, multiple birth, and preterm delivery. Pediatrics, 2002,109:399-403.
7Luke B, Brown MB. Elevated risks of pregnancy complications and adverse outcomes with increasing maternal age. Hum Reprod, 2007,22 : 1264-1272.
8Jahromi BN, Husseini Z. Pregnancy outcome at maternal age 40 and older. Taiwan J Obstet Gynecol,2008 ,47 :318-321.
9Montan S. Increased risk in the elderly parturient. Curr Opin Obstet Gyneco1,2007,19 : 110-112.
10Cnattingius S, Stephansson O. The epidemiology of stillbirth. Semin Perinatol, 2002,26 : 25 -30.