Physical and mental development in 4-6-year-old triplets

A total of 21 families with complete sets of triplets, born within 200 km of Stockholm, were invited to participate in a follow-up study with the aim of assessing the physical and mental development of their triplets at 4-6 years of age. Four families declined to participate in the study and thus the study group consisted of 17 sets of triplets who were born at 33-36 gestational weeks from 1986 to 1989. Mean birth weight was 2104 g (range 1310-2670 g) for the boys and 1882 g (range 1290-2590 g) for the girls. At birth, none of the 51 triplets showed any malformations. No asphyxia or other major complications were noted to have occurred at delivery. The children were examined in their homes with a neurological examination and the Griffiths mental development scales (GMDS). No major physical disabilities were found. In a group of triplets born small for dates, the total GMDS score and most of the subscale scores were significantly lower than for their siblings. In contrast to what has been found in singletons and twins, the differences in mental development between triplet boys and girls were not significant. On the whole, physical and mental development did not differ from what has been found in twins and singletons of the same age and with the same birth weight.