Olsen J, Bønnelykke B, Nielsen J
Institute of Social Medicine, University of Aarhus, Denmark.
Acta Med Scand. 1988;224(5):491-4. doi: 10.1111/j.0954-6820.1988.tb19616.x.
In a case-control study an association was found between mothers' smoking habits and the frequency of dizygotic twinning. As cases were included all twins born in Denmark in 1984 and 1985. A random sample of 1.5% of mothers to singletons, born in the same period were selected as controls. Only live-borns, conceived after no hormonal treatment, were included in the study. The finding may be due to the well-known anti-estrogen effect of smoking.
