Early growth patterns of methadone-addicted infants.

The early growth patterns of 15 full-term infants born to mothers on well-controlled, low-dose methadone hydrochloride maintenance were studied. Mean birth weight and length were at the tenth percentile, and mean head circumference was at the fifth percentile. Early withdrawal symptoms persisted for three to four months, and mean growth parameters continued along their respective percentiles. As withdrawal symptoms abated at 4 to 6 months, infants became more responsive, easier to handle, and demonstrated an accelerated growth pattern. This acceleration of growth at 4 to 6 months of age corresponded to patterns found in previous animal studies.