Brian Hoyle

May 11, 2011

May 11, 2011 (Denver, Colorado) — Analysis of data from a prospective study of more than 25,000 children from birth through 8 years of age has revealed that the length of the umbilical cord as an indirect measure of childhood activity is not an indicator of hyperactivity. However, the data revealed an association between a short umbilical cord and inattentiveness.

The study was presented here at the Pediatric Academic Societies (PAS) and Asian Society for Pediatric Research 2011 Annual Meeting by Andrew Adesman, MD, a pediatrician from the North Shore–Long Island Jewish Health System in New Hyde Park, New York.

"If umbilical cord length is indeed a reliable biometric indicator of fetal activity, then fetal activity level is not likely associated with hyperactivity or impulsivity in later childhood. Mothers who report fetal hyperactivity may be reassured, knowing there is no increased association with impulsivity or hyperactivity," the researchers write in their poster.

Fetal hypoactivity has been linked with a short umbilical cord length, and also with abnormal neurodevelopment, including Down syndrome. However, the influence of cord length on fetal hyperactivity is equivocal, with several small prospective studies finding no association between hyperactivity in the womb and in childhood, whereas a retrospective study did report such an association

Until now, a more definitive large-scale, prospective study has been lacking.

The study analyzed data from the National Collaborative Perinatal Project, a large-scale cohort study of pregnancy and child health with a follow-up of 8 years. The hypothesis driving the study was that a longer umbilical cord allows more movement of the fetus, increasing the likelihood of impulsivity and hyperactivity in childhood.

The analysis involved 25,485 children for whom data on umbilical cord length and at least a follow-up to age 7 years were available.

Increasing umbilical cord length was associated with inattentiveness at both age 7 years (adjusted odds ratio [aOR], 0.979; 95% confidence interval [CI], 0.961 - 0.997) and 8 years (aOR, 0.942; 95% CI, 0.891 - 0.996). Increased umbilical cord length was associated with the behavioral triad of inattentiveness, impulsivity, and hyperactivity at 4 years of age (unadjusted OR, 1.029; 95% CI, 1.000 - 1.058), but the association proved not to be significant when the data were adjusted.

No relationship between umbilical cord length and either impulsivity or hyperactivity was evident at 4, 7, and 8 years of age, "despite the extraordinary statistical power associated with such a large cohort," the researchers write.

"Our study was of greatest relevance to those interested in [attention deficit hyperactivity disorder] and its potential prenatal precursors. First and foremost, it was a negative study with respect to our primary hypothesis variables (hyperactivity and impulsivity)," Dr. Adesman told Medscape Medical News.

"Our secondary hypothesis focused on inattention, and we went to great pains in our poster to understate any clinical significance," stressed Dr. Adesman.

"This study is important. If findings from this study are confirmed in other studies, they can have clinical relevance. . . . Confirmation of these results should encourage clinicians to plan management that would reduce the potential damage as a result of a short umbilical cord, and to be vigilant in supporting these children to mitigate problems," Peter Gichangi, MD, from the University of Nairobi, Kenya, said in an interview with Medscape Medical News.

"At this point, the key take-home message should still be to monitor all patients thoughtfully, assess fully, and intervene appropriately when necessary," Robert Findling, MD, from the University Hospitals Case Medical Center, Cleveland, Ohio, told Medscape Medical News.

The authors, Dr. Gichangi, and Dr. Findling have disclosed no relevant financial relationships.

Pediatric Academic Societies (PAS) and Asian Society for Pediatric Research 2011 Annual Meeting: Abstract 3843.506. Presented May 2, 2011.


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