How to cite this article: Hoekstra C, Willemsen G, van Beijsterveldt TCEM, Montgomery GW, Boomsma DI. 2008. Familial twinning and fertility in Dutch mothers of twins. Am J Med Genet Part A 146A:3147–3156.
Familial twinning and fertility in Dutch mothers of twins†
Version of Record online: 14 NOV 2008
Copyright © 2008 Wiley-Liss, Inc.
American Journal of Medical Genetics Part A
Volume 146A, Issue 24, pages 3147–3156, 15 December 2008
How to Cite
Hoekstra, C., Willemsen, G., van Beijsterveldt, T. C.E.M., Montgomery, G. W. and Boomsma, D. I. (2008), Familial twinning and fertility in Dutch mothers of twins. Am. J. Med. Genet., 146A: 3147–3156. doi: 10.1002/ajmg.a.32585
- Issue online: 21 NOV 2008
- Version of Record online: 14 NOV 2008
- Manuscript Accepted: 30 SEP 2008
- Manuscript Received: 7 DEC 2007
- National Institute of Child Health and Human Development. Grant Number: HD042157
- Center for Neurogenomics and Cognition Research (CNCR) of the VU University Amsterdam
- Twin-Family Database for Behavior Genetics and Genomics Studies. Grant Number: NWO-MagW 480-04-004
- Spinozapremie. Grant Number: NWO/SPI 56-464-14192
- spontaneous DZ twinning;
- iatrogenic twins;
- familial twinning;
We studied twinning and fertility indices in mothers with spontaneous monozygotic (MZ) and dizygotic (DZ) twins and in mothers who conceived their twins after the use of assisted reproduction techniques (ART). Participants in this study consisted of 8,222 and 5,505 women with spontaneous DZ and MZ offspring and 4,164 and 250 women with ART DZ and MZ twin pairs, respectively. Women were compared with respect to the number of sibs and offspring, the presence of other relatives with twins and the time it took to conceive the twins. We also compared familial twinning between a younger and an older age group. Women with spontaneous DZ twins more often reported female relatives with twins than those with spontaneous MZ twins. The proportion of DZ versus MZ twin offspring in relatives was also larger in women with spontaneous DZ offspring than in women with MZ offspring. The first group of women reported a shorter time to conceive. Women with ART twins had fewer sibs and offspring and less often reported relatives with twins. We did not observe that DZ twinning was more familial in women who had their twins before age 36 years compared to older women. Familial DZ twinning is clearly present in mothers of spontaneous DZ twins. The mechanisms underlying spontaneous and non-spontaneous DZ twinning are different and fertility treatment should be taken into account in any study of twinning. Twinning is not more familial in women who have their twins at a younger age. © 2008 Wiley-Liss, Inc.