Factors influencing twins and zygosity

Gary V.D. Hankins, George R. Saade

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Zygosity is influenced by many factors. Monozygotic twins occur spontaneously in approximately 1 in 250 births and are felt to increase twofold with ovulation induction techniques. Monozygotic twinning also increases in proportion to the number of blastocysts transferred during in vitro fertilisation. In contrast, dizygotic twinning appears to be influenced by race, genetic factors, maternal age, fertility enhancing drugs, folic acid supplementation, and maternal nutritional status.

Original languageEnglish (US)
Pages (from-to)8-9
Number of pages2
JournalPaediatric and Perinatal Epidemiology
Issue numberSUPPL. 1
StatePublished - Jan 2005
Externally publishedYes

ASJC Scopus subject areas

  • Epidemiology
  • Pediatrics, Perinatology, and Child Health


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