Size for Gestational Age and Neonatal Sleep Variables: Behavioral Indices of Risk in Fullterm Twins

Abstract

Neonatal sleep behaviors and behavioral state cycling were observed for 20 pairs of same-sex, fullterm twins in which one twin of the pair was appropriate-for-gestational-age (AGA) and the other twin was small-for-gestational-age (SGA). Time-sampling recordings were made in active sleep of number and vigor of limb movements, body and head movements, and mouth movements. No group differences were observed for time spent in first active sleep, first quiet sleep, or length of first sleep cycle. Examination of specific behaviors indicated a significantly higher incidence of vigorous limb movements and right hand-to-mouth movements, with a trend for more small limb movements and left hand-to-face movements, for AGA twins when compared with SGA twins. SGA twins had significantly more spontaneous smiles and a trend for more spontaneous startles than AGA twins. A stepwise discriminant analysis indicated that a composite of the variables smile, large limb movement, startle, and left hand-to-face significantly discriminated between the two groups, with 90% correct classification of the AGA twins and 75% correct classification of the SGA twins. The results demonstrated the utility of evaluating specific sleep behaviors, rather than state cycling only, to describe differences in neonatal sleep characteristics between AGA and SGA twins.

Co-bedding Twins: A Developmentally Supportive Care Strategy

“…Despite their common intrauterine experience, twins may show differences in activity, irritability, resistance to soothing, and sleeping behavior (Riese, 1993(Riese, ,1994. Such similarities and differences can be partially explained by whether the twins are monozygotic or dizygotic because identical twins presumably share more common behavioral traits than do fraternal twins.…”

Differential effects of perinatal hypoxic risk on early developmental outcome: A twin study.

“…With few exceptions (e.g., Berker, Goldstein, Lorber, Priestley, & Smith, 1992; Hay & O’Brien, 1987; Riese, 1988, 1993), researchers have focused on the role of a single early risk factor—birth weight—in modifying developmental outcome. The findings of several studies revealed that the twin with the higher birth weight tends to fare better intellectually (Churchill, 1965; Marsh, 1980; Matheny & Brown, 1971; Scarr, 1982; Willerman & Churchill, 1967), or that “the bigger the better” (Scarr, 1982, p. 236).…”