Hair Analysis for Drug Abuse among Postpartum Women with a Comparison of Neonatal Birthweights:
Results from an Exploratory Study in Pinellas County, Florida.

Richard Newel, Operation PAR, St. Petersburg, FL
Tom Mieczkowski, Ph.D., University of South Florida
Raul Montenegro, MD, All Children's Hospital, St. Petersburg, FL

Introduction

One of the most serious issues in the field of drug abuse treatment is that some women abuse psychoactive drugs during their pregnancy, causing harm to themselves and to their unborn children. We have recently conducted an exploratory study to examine the suitability of using radioimmunoassay-based hair analysis as a potential tool for increasing the accuracy in the determination of drug abuse among postpartum mothers.

Zuckerman and his colleagues (1989) utilized urinalysis as a new assay procedure in the determination of the effects on infants of the mother's use of marijuana and cocaine. Based on the urine assay results they found that 16 percent of the subjects had used marijuana with 9 percent having used cocaine. Also, infants born to drug-using mothers were found to have significantly lower birthweights than infants born to drug-free women. This association was not found when they analyzed their data using only self-reported drug use, illustrating the importance of using bioassays to accurately determine drug exposure.

Other researchers have also documented the link between drug use and poor pregnancy outcomes including pre-term births and intrauterine growth retardation (Bateman, 1993; Petitti, 1990; MacGregor, 1987; Oro, 1987; Chouteau, 1988; Cherukuri, 1988 and Little 1989). Exceptions to this conclusion have included a study by Chasnoff and his colleagues (1989), however the lack of significant results over their 23 subjects may have been due to problems with their statistical approach.

Graham and her colleagues (1989) utilized the radioimmunoassay of hair specimens obtained from mothers and their infants to determine exposure to cocaine during the mother's pregnancy. Results suggested that hair analysis may help identify intrauterine exposure to cocaine in babies when a maternal drug history is either not available or is considered to be of low veracity. Graham also concluded that the hair analysis technique is "...better able to detect previous cocaine use than is the standard urinalysis...(and the)...misclassifying of cocaine users as nonusers in a pregnant population may profoundly bias the results of any study on the reproductive hazards of cocaine" (Graham 1989, p.3330).

The hair assays used in this study provide the capability of reliably looking at drug exposure retrospectively for as long as 90 days, and are especially suitable for detecting rapidly excreted drugs of abuse, such as cocaine and heroin. Its potential has been recently recognized by the U.S. government General Accounting Office (GAO, 1993) which has stated that ". . . we endorse its field trial use in community drug prevalence measurement studies" (GAO, 1993, p.59] and recommended that all national drug abuse surveys based on self-report begin validation studies that focus on using "objective techniques such as hair analysis." [GAO, 1993, p.61]

The primary advantages of hair analysis relative to urine, blood, saliva, and other traditional testing media is an expanded retrospective "window of detection", and the potential for providing quantitative or semi-quantitative assay values which can be used to interpret the relative degree of exposure. For example, where cocaine and its metabolites can only be reliably detected in urine for 48 to 72 hours, hair samples can reveal exposure for several months prior to the time a specimen is collected.

Studies have shown hair assays are more effective measures of cocaine exposure during pregnancy than either medical histories, urine, or infant meconium, when assessing individual patients (Callahan, 1992; Grant, 1994; Welch, 1990). Furthermore, several studies have shown a significant correlation between qualitative detection of cocaine in maternal and neonatal hair samples, and have also shown significant correlations between the quantitative values in maternal and neonatal samples (Graham, 1989; Marques, 1993). An additional appealing aspect of hair sample analysis is the more convenient collection and handling of hair specimens as opposed to urine or blood specimens.

This study was an attempt to extend the work of Zuckerman (1989) and others using the bioassay technique utilized by Graham (1989) in order to explore the general utility of the radioimmunoassay of hair specimens within an obstetrical setting and any relationships that might exist between drug use (as determined by hair testing) and birthweights.

Method

Postpartum women at a Tampa-Bay area hospital were asked to voluntarily participate in an exploratory drug use study. A female registered nurse employed at the hospital (but not working in the birthing/obstetrics unit) functioned as the sample collector. The women were approached at times deemed convenient and unobtrusive by the nurse, and offered a small monetary incentive to participate in the research. At the request of the hospital review board no information of any kind was recorded about the volunteers, other than their child's birthweight. A small ($10) incentive was offered for their participation. Their participation was consensual, anonymous, confidential, and untraceable. The nurse collected approximately 40-50 strands of hair from the vertex of the scalp, cut at scalp level with surgical scissors. Each sample was packed in a special collection kit to maintain hair alignment and root-tip orientation. Specimens were sectioned from the root outward to 2.54 cm (an average 60 day growth length) and analyzed for cocaine, cannabinoids, opiates, methamphetamine, and phencyclidine or, as appropriate, their metabolites. The analysis was performed by the Psychemedics Corporation (Culver City, CA) and included washing and wash kinetic analysis to differentiate external contamination from internally bound drug.

Results

One-Hundred-and-Two patients provided hair samples for analysis. Three classes of drugs were detected in these samples: cocaine/benzoylecognine, cannabinoids, and opiates. There were no detections of methamphetamine or phencyclidine. Of the 102 patients providing samples, 34 were positive for at least one of these three drugs, and several were positive for multiple drugs. The Venn diagram (see Figure 1) reports the overall configuration of outcomes for these 34 patients.

There were 14 patients positive for cocaine. Of these 14, 6 were positive for cocaine only, 7 were positive for cocaine and cannabinoids, and 1 for cocaine and opiates. There were 26 patients positive for cannabinoids, of whom 18 were positive for cannabinoids only, while the remainder were positive for cannabinoids in combination with either cocaine (7) or opiates (1). One patient was positive for opiates only. No cases had more than two drugs detected in the hair. The mean concentration for detected drugs was as follows: Opiates had a mean value of 15.4 ng/10 mg of specimen (SD=13.55, Range=6.5-31.0); Cocaine had a mean value of 326.84 ng/10 mg of sample (SD=717, Range=5.3-2431). Cannabinoids cannot be reliably quantified when using radioimmunoassay, so they are reported only as dichotomous (+)/(-) outcomes.

The median birthweights for five groups of women are shown in Figure 2. The "No Use" conditions was comprised of women who obtained a drug-negative result from their hair assay. Likewise, the "Marijuana", and "Cocaine" use groups were comprised of women who had either only marijuana or cocaine detected with a hair analysis. The "Any Use" condition includes women who were found to be positive for any one drug or combination of drugs. The "Poly Drug Use" group was comprised of women found to be hair-positive for multiple drugs only.

The median birthweights were found to be: "No Use"=118.5 oz.; "Marijuana Only"=112.5 oz.; "Any Use"=107.5 oz.; "Cocaine Only"=101.0 oz.; "Poly Drug Use"=100.0 oz. The non-parametric Mann-Whitney test was utilized to test whether the data were from the same population as the distributions were highly skewed. All comparisons were statistically significant (Mann-Whitney U; p<.05) with the exception of the "Cocaine Only" and "Poly Drug Use" comparison.

Discussion

These results are consistent with the conjectures of other researchers that maternal substance abuse is probably better detected by bioassays than medical history (Grant, 1994; Marques, 1993; Welch, 1990). The high percentage of women identified as substance abusers in this study may be due to hair assay's expanded retrospective "window of detection" for illicit drugs. This conclusion is consistent with past research conducted with other populations which have consistently shown that hair assays are a particularly suitable analysis matrix for rapidly excreted drugs such as cocaine (Callahan, 1992; Marques, 1993; Mieczkowski, 1993). The results of the comparisons of birthweights suggest that hair assays may be a more sensitive detection mechanism than either self-reported drug use or urinalysis as for the first time the differential effects for marijuana, cocaine, any drug use and poly drug use on an infant's birthweight have been observed. Further work on the epidemiological utility of hair assays for the detection of rapidly cleared drugs, especially cocaine, in obstetrical settings is, we believe, justified by these results.

References

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