1. Adams M M, Oakley G P, Marks J S 1982 Maternal age and births in the 1980s. Journal of the American Medical Association 247: 493–4
2. Ales K L, Druzin M L, Santini D L1990 Impact of maternal age on the outcome of pregnancy. Surgery, Gynecology and Obstetrics 171 (171): 3–209
3. Baird P A, Sadovnick A D, Yee I M L 1991 Maternal age and birth defects: a population study. Lancet 337: 527–30
4. Barkan S E, Bracken M B1987 Delayed childbearing: no evidence for increased risk of low birthweight and preterm delivery. American Journal of Epidemiology 125 (125): 1–101
5. Berkowitz G S, Skovron M L, Lapinski R H, Berkowitz R L1990 Delayed childbearing and the outcome of pregnancy. New England Journal of Medicine 322 (322): 10–659