Visual outcome in infants born to drug-misusing mothers prescribed methadone in pregnancy.
BACKGROUND
Flash visual evoked potentials (VEPs) were abnormal in a cohort of 100 neonates exposed to maintenance methadone in utero. This prospective cohort study now describes clinical visual and electrophysiological outcomes at 6 months.


METHODS
Visual assessment included modified Atkinson test battery; strabismus, nystagmus, reduced visual acuity, delayed visual maturation or refractive error (>3 dioptres) defined a fail. Pattern-onset VEPs were recorded to 120', 60' and 15' checks.


RESULTS
81 drug-exposed and 26 comparison infants (79% and 52% of the original cohorts) were assessed at a median age of 27 weeks (range 26-30). 90% of drug-exposed infants had been additionally exposed to illicit drugs and 41% to excess alcohol in utero. 40% of the drug-exposed cohort failed clinical visual assessment: the relative risk of abnormal assessment was 5.1 (95% CI 1.3 to 20; p=0.02). Nystagmus was particularly common. VEP peak times were slower and amplitudes smaller in drug-exposed infants, of whom 70% had one or more abnormal VEP parameter. Abnormal visual outcome at 6 months was not associated with the pattern of additional drug exposure or a history of neonatal abstinence.


CONCLUSIONS
Abnormal visual electrophysiology in infants born to drug-misusing mothers prescribed maintenance methadone persists to 6 months of age, and is associated with abnormal clinical visual assessment.
Neonatal Unit, Royal Hospital for Sick Children, , Glasgow, UK.
Laura
L
McGlone
Ruth
R
Hamilton
Daphne L
DL
McCulloch
Jane R
JR
MacKinnon
Michael
M
Bradnam
Helen
H
Mactier
D005074:Evoked Potentials, Visual / Q000187:drug effects*; D005128:Eye Diseases / Q000139:chemically induced* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008691:Methadone / Q000009:adverse effects*; D009294:Narcotics / Q000009:adverse effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced* / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014792:Visual Acuity
D009294:Narcotics; D008691:Methadone
Child Health (Paediatrics); Drugs; Electrophysiology