1. VenturaSJ. Trends and variations in first births to older mothers, 1970-86. Vital Health Star [21] 1989;47:1-27. 2. Population changes 1990. Official statistics of Sweden. Stockholm, Sweden: Statistics, Sweden, 1992.
2. Relation of the mother's age to obstetric performance;Israel;Obstet Gynecol,1964
3. The elderly primigravida;Morrison;Am J Obstet Gynecol,1975
4. Delayed childbearing in Sweden;Forman;JAMA,1984
5. The problem of the older primipara;Kessler;Obstet Gynecol,1980