[Prevalence of drugs in meconium]

The number of newborn infants with symptoms suggesting drug withdrawal is increasing. As only part of prenatally exposed infants show typical drug withdrawal, and drug-use reported by addicted mothers is often unreliable the prevalence of neonates that were exposed to illicit drugs before birth is unknown. The purpose of this study was to evaluate prospectively the prevalence of drugs in meconium and to define risk factors for intrauterine drug exposure.

During a period of 4 months meconium was collected twice in 420 nonselected newborn infants. Meconium was analysed with a modified test developed for toxicology screening in urine. Information on pre- and postnatal risk factors including drug-use during pregnancy was obtained.

Among 415 mothers four reported illicit drug use and ten licit drug use during late pregnancy. In all these infants meconium drug test was positive. After exclusion of these infants and of five second twins 401 infants with negative drug history remained. 45 of them (11%) had one or two drugs in the meconium: opiate 17x, amphetamine 16x, barbiturate 15x, benzodiazepine 3x, cannabinoid 2x, cocaine 1x (in 9 infants two substances were detected). None was positive for LSD or phencyclidine. The infants with positive drug tests had the following risks compared to those with negative tests: prematurity (odds ratio 2.3, 95% confidence interval 1.3-4.3). Microcephaly or macrocephaly (2.0:1.01-4.1), Apgar-Score below 5 at 1 min (2.4:1.5-5.4), Apgar score below 7 at 10 min (4.0: 1.6-9.9), mother academic (2.8:1.2-6.2).

Newborn infants may have been exposed to illicit drugs in utero even if their mothers deny drug use and even if they do not show withdrawal symptoms. Prematurely born infants and infants with problems in postnatal adaptation have an increased risk of having been exposed to drugs.