title: Obstetric outcome of twin pregnancies after in-vitro fertilization: a matched control study in four Dutch university hospitals.
abstract: In singleton pregnancies after in-vitro fertilization (IVF), increased rates of obstetric and perinatal complications have been reported. Studies that compared IVF twin pregnancies with spontaneously conceived twins have yielded conflicting results. We compared 96 IVF twin pregnancies to 96 controls after elaborate matching. The design of our study precluded matching by zygosity. The monozygosity rate was higher in the control group and this implies that beforehand the risk for a less favourable outcome in the control group was higher than in the IVF group. However, the average birthweight of the IVF children was less than that of children in the control group (P = 0.04). This was not due to more intrauterine growth retardation in the IVF group. The mean gestational age at birth was 5 days shorter in IVF than control pregnancies, and although this difference was not significant it might explain the lower birthweight in the IVF group. The discordance rate in the IVF group was significantly increased. We found no difference in perinatal mortality and morbidity. We conclude that this study provides further evidence for a different outcome of IVF twin pregnancies in comparison with spontaneously conceived twin pregnancies.
authors.affiliation: Department of Obstetrics and Gynaecology, University Medical Centre, PO Box 8550, 3508 GA Utrecht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Koudstaal
authors.forename: H W
authors.initials: HW
authors.lastname: Bruinse
authors.forename: F M
authors.initials: FM
authors.lastname: Helmerhorst
authors.forename: J P
authors.initials: JP
authors.lastname: Vermeiden
authors.forename: W N
authors.initials: WN
authors.lastname: Willemsen
authors.forename: G H
authors.initials: GH
authors.lastname: Visser
mesh_terms: D000328:Adult; D001724:Birth Weight; D036861:Delivery, Obstetric; D005260:Female; D005307:Fertilization in Vitro; D005317:Fetal Growth Retardation / Q000209:etiology; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D009017:Morbidity; D009426:Netherlands; D011247:Pregnancy; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D014427:Twins