Psychoactive Substance Use in Pregnancy and Effects on the Fetus

With opioid addiction, methadone substitution treatment is recommended for better control of the addiction as opposed to risking the life of the woman and the fetus with abstinence crises which cause additional stress to both. 

Numerous studies confirm the harmful influence of alcohol and nicotine on fetal development and the potential occurrences of fetal abnormalities, mental or physical disorders, deformities, as well as miscarriages. However, there are very few studies on the effects of illegal psychoactive substances, such as cannabis, opioids and psychostimulants on the fetus during pregnancy, and no studies at all on the harmful effects of new psychoactive substances. Data and potential harms are based on isolated cases and cannot be used to make a generalization on the negative impact. 

Harmful effects are largely dependent on the drug use frequency during pregnancy, particularly if persistent in the first trimester when the pregnancy might remain undetected if unplanned. 

Harmful effects can be heightened with addiction, abstinence or drug injection, all additional risk factors for the pregnant woman and the fetus, simultaneous use of different drugs like alcohol, nicotine, caffeine, cannabis, opioids, psychostimulants etc. Life style, nutrition, stress and socio-economic circumstances should not be disregarded neither, with drug use or in general.  

 Cannabis use during pregnancy

Cannabis use during pregnancy is a controversial topic.

While some doctors suggest that cannabis use can be useful for relieving the first symptoms at the start of the pregnancy, like pain and nausea, an effect supported by personal experiences as well, others warn to the potential harms on fetal development.

Very few studies detail cannabis influence in pregnancy and postnatally, mostly due to legal regulations preventing clinical trials and scientific studies.

D-r Dreher’s study (Prenatal Marijuana Exposure and Neonatal Outcomes in Jamaica) conducted in Jamaica with pregnant women who used cannabis, published in 1994 (American Academy of Paediatrics), resulted with interesting data. Namely, the study examined pregnant women who did not use cannabis and who used cannabis with a different intensity during pregnancy. The goal was to establish cannabis effects on fetuses and postnatal development in the 1st and 4th year. According to previous theories, cannabis had harmful effects on fetal development, resulting with possible weight loss in the pregnant woman and disrupted psychophysical development in the fetus after birth in comparison to pregnant women who did not use cannabis in their pregnancy. The study disproved the thesis, with results showing little difference in development. On the contrary, the study revealed that children born by mothers who smoked cannabis in pregnancy developed faster the first 30 days after birth, although according to the study they all belonged to a higher socio-economic class in comparison to the non-smoking group.

The study Association between Marijuana Use and Adverse Obstetrical and Neonatal Outcomes, conducted by a group of authors and published in the Journal of Perinatology, in December, 2015, offered new data. The findings show that maternal cannabis use does not increase the risk of adverse obstetrical outcomes or fetal anomalies. However, frequent cannabis use is associated with development of a small for gestational age fetus and neonatal intensive care unit admission. Other gynaecological outcomes, including preterm delivery and fetal anomalies were not observed.    

The aim of the study was to find the relation between cannabis exposure and adverse outcomes, and it included women who used several types of drugs during pregnancy, as well as tobacco.  

Opioid use in pregnancy 

Negative influence from heroine use in pregnancy has been confirmed, with possible miscarriages, fetal anomalies, including addiction and withdrawal symptoms in infants after birth.    

With opioid addiction, methadone substitution treatment is recommended for better control of the addiction, as opposed to risking the life of the woman and fetus with abstinence crises which cause additional stress to both. Drug injection always carries additional risk on the health, consequently on the woman in pregnancy and the fetus itself. Overdose, infections such as endocarditis, sepsis and similar risks are always more problematic in injection, particularly with drugs purchased from the black market where composition and purity are always with questionable quality. Consequently, with opioid addiction, methadone substitution treatment, where continuity and dosage are controlled and more convenient, is always recommended in pregnancy.

Heroin detoxification is suggested only in the first trimester of pregnancy, but detoxification after this period can harm the fetus and is not recommended.       
Use of psychostimulants in pregnancy 

Frequent use of amphetamine-type stimulants (MDMA-ecstasy, amphetamine, methamphetamine) increases the risk of miscarriages and preterm deliveries, and leads to significantly increased incidence of malformations in infants. However, the data is based on isolated cases, which prevents us from drawing general conclusions that occasional or rare use of amphetamines might lead to the aforementioned effects. 

Harmful effects of cocaine in pregnancy are described in medical reports from the 1970s. Frequent and long cocaine use increases the risk of miscarriage or preterm delivery. However, as mentioned previously, there is insufficient data on methodical improvement in studies on cocaine harmfulness in pregnancy due to individual case-based results.

Recommendations for drug use in pregnancy

Due to the lack of data and scientific studies, the best recommendation would always be abstinence from drug use in pregnancy (illegal or legal drugs). Very often, in practice, there is use of multiple psychoactive substances, such as nicotine and alcohol, caffeine, cannabis, amphetamine-type stimulants, cocaine or heroin, making detection of the harm caused by each individual drug complex. The influence, such as different degree of harms, frequency of use, tolerance and different addictive capacity of different psychoactive substances should not be disregarded. And, of course, in cases of drug use or addiction in pregnancy, it is best to seek advice and help from professionals and to regularly control the pregnancy and the health condition.    

Davor Smilanov

The author is a doctor of medicine, graduated general medicine at the Faculty of Medicine within the St. Cyril and Methodius University in Skopje, Macedonia. Davor Smilanov, MD is the head of the Medical Service at the Harm Reduction Centre in Kapishtec within HOPS’s Harm Reduction Program. He has participated in numerous national and regional projects, conferences and campaigns on harm reduction. 

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