Current Status and Future Diagnostic Trends of Prenatal Illicit Drug Exposure in the Neonate

With regards to opiate abuse, heroin has become the mostcommon illicit drug in Taiwan. In pregnant women, opiateabuse contributes to adverse effects, such as low birth bodyweight, premature delivery, and life-long developmentalconsequences in the neonate.Clinical characteristics foropiate or poly-drug exposurein utero, resulted in neonatalwithdrawal syndrome, which required clinical observationand treatment for days or even weeks in hospital. TheAmerican Academy of Pediatrics published guidelineswhich include the monitoring and treatment of neonatalabstinence syndrome (NAS) followingin uteroopiate orpoly-drug exposure. Among these patients, NAS was themost observed clinical finding, and included dysfunction ofthe central nervous system, autonomic nervous system,gastrointestinal tract, and respiratory system.1In somesevere cases, NAS led to deleterious outcomes, such asdiarrhea, fever, seizure, feeding intolerance, poor weightgain and even death. Moreover, poly-drug abusers, whoused multiple illicit substances during pregnancy, declined;this obscured the clinical situation with regards to thetreatment of their offspring.Thus, the identification ofillicit drugs, while the patient suffers during the perinatalperiod, could provide an imperative basis for clinical diagnosis and potential management. Practically speaking, thisidentification should be assessed in both mothers and theirnewborn. Samples used in newborn drug testing includedurine, meconium, hair, and umbilical cord segment. Urinetesting of the neonate for illicit drugs, revealed a low biological sensitivity, as this procedure can only detect recentdrug exposure. In addition, since the earliest collection ofthe newborn’s urine with the highest concentration of ananalyzed substance was often missed, due to practicalclinical difficulties, meconium drug testing was more biologically sensitive and easier to perform.However, meconium passage in a newborn may take several days; thisoften delayed the clinical diagnosis. Su et almeasuredhairs of neonates; this method was potentially more biologically sensitive and more rapid in the identification ofpoly-drug use. Indeed, it has been reported that hairanalysis was costly and good at detecting chronic exposure,but, although it exerted a high biological sensitivity foropiate, amphetamine, and cocaine, it showed a low biological sensitivity for marijuana exposure.In addition, hairanalysis provided a possible duration of illicit drug exposure, by the measurement of the hair segment. Althoughthis technique is not widely available at present, it isa potential survey tool for use in important aspects ofclinical needs. It is worth considering for unsolved issuesunderlying illicit drug exposure in the neonate prenatally,such as the occurrence and severity of NAS, and neonatalpsychomotor behavior after poly-drug exposure.

Treatment of prenatal substance use or abuse should bestarted before delivery. Since the 1970s, methadone,a synthetic opiate, has been recommended for opioiddependence in pregnant women, to improve maternalhealth and neonatal outcomes, such as lower birth weightand NAS.6Buprenorphine, a partial agonist of the mu-opioidreceptor and a partial antagonist of the kappa-opioidreceptor, was first introduced in 1996 and is increasinglybeing used for opioid addiction treatment, due to fewerautonomic side effects, in non-pregnant women. Buprenorphine was also thought to be a better treatment foropioid abuse in pregnant women, due to the need for lessmorphine, shorter duration of treatment for NAS, anda shorter hospital stay of neonates with perinatal morphineexposure.7The reason for the high attrition rate remains tobe addressed in future research. Prospectively, there willbe a trend to use buprenorphine as the first line medicationfor opioid dependence in pregnant women. Therefore, hairanalysis in neonates forin uteroillicit drug exposure shouldinclude buprenorphine as a future candidate.

The prevalence of illicit drug abuse has increased inpregnant and non-pregnant women recently. Althoughcurrent medical technology and environment can providea better treatment, decreasing drug abuse in pregnantwomen is more efficient. Thus, more attention and studiesshould be focused on a rapidly, widely available, cheap,and accurate survey for neonates with prenatal poly-drugexposure, in order to develop a suitable clinical and therapeutic strategy.