Effects of chorion type on neonatal temperament differences in monozygotic twin pairs.
Monozygotic (MZ) twins with a known chorion type were assessed in the neonatal period to determine if placentation was related to twin similarity in early temperament development. The sample included 48 pairs with monochorionic placentas and 29 pairs with dichorionic placentas. The assessment focused on irritability, resistance to soothing, activity while awake, activity during sleep, reactivity, and reinforcement value. There were no differences between the monochorionic and the dichorionic twins in any of the temperament ratings. Chorion type was not related to cotwin similarity on any of the temperament ratings. It was concluded that differences in prenatal environment reflected in placentation type did not affect early temperament for MZ twins.
University of Louisville School of Medicine, Child Development Unit, University of Louisville, Kentucky, USA. MLRIESE@GATEKEEPER.LTS.LOUISVILLE.EDU
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D002823:Chorion / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010552:Personality Assessment; D010641:Phenotype; D010929:Placentation / Q000235:genetics*; D011247:Pregnancy; D013694:Temperament; D014430:Twins, Monozygotic / Q000235:genetics*