title: Twins' temperament: early prenatal sonographic assessment and postnatal correlation.
abstract: OBJECTIVE
  To study inter-twin differences in activity during early pregnancy and to examine their relationship to subsequent infant twins' temperament.
  
  
  METHODS
  Measures of fetal motor activity (frequency, duration and number of movements) were collected from 26 twin pairs during ultrasound nuchal translucency scan at late first trimester and early second trimester (11 to 14 weeks gestation). In twenty-two patients, the twins were dizygotic (dichorionic); of them, 13 twin pairs were of different sexes, five were both females and four were both males. Of the four monozygotic twin pregnancies, two were dichorionic and two were monochorionic, three were both females.The more active fetus in each pair was noted according to the position and/or sex without reporting to parents. Reported maternal perception of the more active twin was documented at the mid-trimester anatomical scan. Maternally reported postnatal temperament data of the infants were collected at 3 and 6 months, using Rothbarts' Infant Behavior Questionnaire (IBQ).
  
  
  RESULTS
  After birth, maternal reports on infants' temperament and the more active twin in each pair were in good correlation with prenatal inter-twin differences in activity. The receiver operating characteristic (ROC) curves shows a better performance of ultrasound compared with maternal perception in prediction of the more active twin.
  
  
  CONCLUSIONS
  The features of fetal neurobehavioral activity provide the basis for individual differences in twins' activity in infancy. Differences in activity in early pregnancy even before the emergence of fetal behavioral patterns were followed by temperamental differences postnatally.
authors.affiliation: Department of Obstetrics and Gynecology, Ultrasound Unit, Bnai-Zion Medical Center, Ruth and Baruch Rappaport Faculty of Medicine, Technion Institute of Technology, Haifa, Israel. sdegani@tx.technion.ac.il
authors.forename: S
authors.initials: S
authors.lastname: Degani
authors.forename: Z
authors.initials: Z
authors.lastname: Leibovitz
authors.forename: I
authors.initials: I
authors.lastname: Shapiro
authors.forename: G
authors.initials: G
authors.lastname: Ohel
mesh_terms: D015331:Cohort Studies; D005260:Female; D047109:Fetal Development / Q000502:physiology; D005323:Fetal Monitoring / Q000379:methods; D005324:Fetal Movement; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D018730:Infant Behavior / Q000523:psychology*; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011272:Pregnancy, Multiple; D011336:Probability; D012372:ROC Curve; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D013694:Temperament; D014427:Twins / Q000523:psychology*; D014429:Twins, Dizygotic / Q000523:psychology; D014430:Twins, Monozygotic / Q000523:psychology; D016216:Ultrasonography, Prenatal