Jon Matthew Farber, MD

A milestone-related assessment of early psychomotor development of preterm (PT) twins compared with PT singletons found that twins born between 32 and 33 weeks’ gestational age (GA) have an early neuro- development advantage over their singleton peers. Italian investigators conducted developmental assessments in 73 PT twins and 207 PT singletons throughout the first 18 months of life. 

Assessments, using standardized tests and parental observation, included primary gross motor milestones, beginning of babbling, early visual fixation, and being able to follow a moving object. Investigators divided participants into 3 groups according to GA: 17 born at less than 31 weeks (group 1), 30 born between 32 and 33 weeks (group 2), and 26 born between 34 and 36 weeks (group 3). 

Twins in group 1 not only spoke their first single word significantly earlier than singletons in the group did but also demonstrated persistent superior language skill achievement at long-term follow-up together with better oculomanual abilities. 

Compared with singletons, group 2 twins also spoke their first single words at a younger age and achieved standing, walking, and pointing earlier. No significant differences emerged between group 3 twins and singletons except that twins demonstrated worse personal and social skills than singletons at long-term follow-up. 

Overall, investigators concluded that the differences in twins compared with singletons in the 3 groups were independently related to their gemellarity (“twinness”).

This is an interesting finding. An earlier study showed that firstborn twins above 28 weeks’ gestation were less likely to have respiratory distress syndrome than singletons. I wonder whether better lungs account for some of the difference. Unfortunately, many of the children, twins or not, had developmental delays at 25 to 36 months of corrected age.

1. Turriziani L, Cafeo A, Pino G, Vetrano N, Alibrandi A, Di Rosa G. Early psychomotor advantage in moderately preterm twins born between 32 and 33 weeks. 

 2021;19(4):240-246. doi:10.1055/s-0040-1709719

This article was originally published on Contemporary Pedatrics®. 

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A recent study indicates that when born prematurely, twins may have some gains over singleton babies.

Developmental advantages of premature twins

Children born at a gestational age (GA) of 22 to 27 weeks are at significant risk of cognitive impairment at age 6.5 years, as are a substantial proportion of children born at a GA of 28-31 weeks. However, whereas neonatal conditions affect the prevalence of cognitive impairment of the former group (extremely preterm), these associations are not as evident in those in the latter group (very pre-term), according to a recent study.

Swedish investigators divided pre- term infants into 2 groups—those born extremely preterm (EPT) and those born very preterm (VPT). They assessed both groups for neurodevelopment at age 2.5 years and for cognitive outcomes at 6.5 years. Both assessments revealed mild-to-severe neurodevelopmental impairment. At 6.5 years, 8 of 91 children tested were diagnosed with cerebral palsy (4 VPT and4EPT)and6(4VPTand2EPT) with autism. Three of these 14 children had both cerebral palsy and autism. Neonatal factors independently related to 6.5-year outcomes were GA, retinopathy of prematurity, and treated persistent ductus arteriosus. But cognitive test scores at 2.5 years explained only 44% of intelligence score variance at 6.5 years. Given these results, the authors recommend following up into school age all children born before 32 weeks’ GA.

The test results at 2.5 years were corrected for prematurity. Although correction may be valid for younger children, I have always been leery that it is misleading by 2.5 years, presenting an overly optimistic picture. Unless the cognitive development of an extremely preterm child is solidly normal at 2.5 years, he or she still needs to be monitored closely.

This article was originally published on Contemporary Pediatrics®.

1. Kaul YF, Naseh N, Brodd KS, Böhm B, Holmström G, Hellström-Westas L. Average 2.5-year neurodevelop- mental test results in children born very preterm did not rule out cognitive deficits at 6.5 years of age. 

. 2021;110(3):846-854. doi:10.1111/apa.15586

A recent study highlights the need to continually monitor the cognitive development of children who were born very preterm.

Jon Matthew Farber, MD

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Developmental advantages of premature twins

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