Estimating the Risk of Monochorionic Twins in IVF Pregnancies from the Perspective of a Prenatal Diagnosis Unit

Veronica Sarais, Alessio Paffoni, Giulia Maria Baffero, Fabio Parazzini, Nicola Persico, Edgardo Somigliana

Research output: Contribution to journalArticlepeer-review


The aim of the present work was to estimate the risk of monochorionic twin (MCT) pregnancies in in vitro fertilization (IVF) cycles using data from a prenatal diagnosis unit. This was a retrospective cross-sectional study reporting on the frequency of IVF pregnancies among women attending a prenatal diagnosis service specifically dedicated to the management of monochorionic pregnancies. The observed rate was compared with the local regional rate of IVF births (2.2%). A binomial distribution model was used to calculate the 95% CI of proportions. One hundred and forty-five monochorionic pregnancies were selected. Ten of these were achieved with IVF, corresponding to a rate of 6.9% (95% CI: 3.5-11.8), significantly higher than the background rate in the local population of 2.2%. When considering exclusively monochorionic pregnancies achieving delivery of two viable newborns (n = 132), the number of IVF pregnancies was nine (6.8%, 95% CI: 3.7-12.5). We did not detect major differences in pregnancy outcome between IVF and natural monochorionic pregnancies, with the exception of the proportion of newborns with a neonatal birth <2,500 g (100% vs. 80%, p =.03). In conclusion, data obtained from the perspective of a prenatal diagnosis unit suggest that women undergoing IVF face a 3-to 4-fold increased risk of monochorionic pregnancies.

Original languageEnglish
Pages (from-to)66-71
Number of pages6
JournalTwin Research and Human Genetics
Issue number1
Publication statusPublished - Feb 1 2016


  • in vitro fertilization
  • IVF
  • monochorionic
  • monozygotic
  • twin

ASJC Scopus subject areas

  • Genetics(clinical)
  • Obstetrics and Gynaecology
  • Pediatrics, Perinatology, and Child Health


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