1. Abortion and premature labor;Hellman,1971
2. Incidence of early pregnancy loss;Wilcox;N Engl J Med,1988
3. A cytogenetic study of spontaneous abortions with direct analysis of chorionic villi;Ohno;Obstet Gynecol,1991
4. Embryonic demise in early pregnancy: A new look at the first trimester;Goldstein;Obstet Gynecol,1994
5. Embryonic ultrasonographic measurements: Crown-rump length revisited;Goldstein;Am J Obstet Gynecol,1991