Early motor behaviour in infants born to mothers in opioid replacement therapy during pregnancy: a prospective cohort study

There is a strong recommendation for opioid replacement therapy (ORT) in pregnant women dependent on opioids. Using drugs and alcohol in pregnancy is a well-documented risk factor for later neurodevelopmental impairment, and the infants have reduced quality of their early motor behaviour at the age of 3-4 months corrected age (CA). Growing evidence indicates that ORT exposure in utero has negative long-term effects on the child but whether ORT-exposed infants have reduced quality of early motor behaviour has never been studied. The primary aim of this study was to examine early motor behaviour at 3-4 months CA in infants born to mothers in ORT during pregnancy, infants exposed to alcohol and/or drugs and unexposed infants. Secondary, we aimed to estimate odds for reduced motor behaviour in the three groups.

In this prospective cohort study, Children Exposed to Alcohol and/or Drugs in Intrauterine Life (CEADIL), we used cross-sectional data to compare a group of infants exposed to ORT during pregnancy (ORT group, n = 15), a group of infants exposed to alcohol and/or drugs during pregnancy (CEADIL group, n = 99) and a group of healthy unexposed infants (control group, n = 105). Outcome measures were Motor Optimality Score-Revised (MOS-R) and the Alberta Infant Motor Scale (AIMS) at 3-4 months CA.

The median MOS-R score was 26 (IQR 22-28) in the ORT group and 26 (IQR 24-28) in the CEADIL group, compared with 28 (IQR 26-28) in the unexposed control group (p < 0.001). The ORT and the CEADIL group had higher odds for a MOS-R total score ≤ 24, a higher frequency of aberrant fidgety movements, reduced or absent age-adequate movement repertoire, abnormal observed postural patterns, and abnormal movement character, compared with the unexposed control group. The AIMS total score was 8.0 (IQR 7.0-11.5) in the ORT group and 9.0 (IQR 8.0-10.0) in the CEADIL group, compared with 11.8 (IQR 11.0-13.0) in the unexposed control group (p < 0.001).

Similar to the CEADIL group, the ORT group had reduced quality of early motor behaviour compared with the control group. Hence, ORT-exposed infants may be at risk for neurodevelopmental impairment.

Not applicable.