Monochorionic (MC) twins share a placenta, which leads to a heightened risk of developing medical complications. This study explored the impact of adverse intrauterine circumstances on the...Show moreMonochorionic (MC) twins share a placenta, which leads to a heightened risk of developing medical complications. This study explored the impact of adverse intrauterine circumstances on the temperament development of 6-month-old infants, focused on Twin-to-Twin Transfusion Syndrome (TTTS), Twin Anemia-Polycythemia Sequence (TAPS), and selective Fetal Growth Restriction (sFGR). The investigation measured temperament in terms of positive and negative affectivity. It was hypothesized that MC twins affected by TAPS and sFGR would display differential affectivity, with donors and smaller twins exhibiting lower positive affectivity and higher negative affectivity compared to their co-twins. For TTTS, no significant long-term temperamental differences between twins were anticipated. Additionally, it was expected that MC twins from uncomplicated pregnancies would show higher positive affectivity and lower negative affectivity compared to those with medical complications. Conducted as part of the TwinLIFE study, this research examined 103 MC twin pairs, a group naturally controlling for genetic and environmental confounders, thereby exploring the effects of these specific prenatal circumstances. The Infant Behavior Questionnaire-Revised Very Short Form (IBQ-R-VSF) was administered to assess temperament for each individual twin at 6 months of age. Results indicated no significant within-pair differences in temperamental development among medically complicated twins, as expected for TTTS, but contrary to expectations regarding TAPS and sFGR. These results indicate a sense of relief for parents with twins from complicated pregnancies, as they suggest no need for additional intervention to promote healthy development. Contrary to expectations, comparisons between twins from uncomplicated and complicated pregnancies revealed lower positive affectivity in the uncomplicated group. These findings could be explained by a potential influence of parental focus on positive reinforcement in children with complications in the context of the child's survival and well-being. These results highlight that intrauterine circumstances do not necessarily cause any substantial differences but suggest a complex interplay between parental interactions and temperamental expression, warranting further investigation into the long-term outcomes and support programs.Show less
