Substance use during pregnancy is common. In national prevalence surveys, 14% of Canadian women reported using alcohol during their last pregnancy, and 17% reported smoking during pregnancy.

The prevalence of illicit drug use among Canadian women of childbearing age is less but not insignificant. In United States population surveys, around 5% of pregnant women reported illicit drug use during the preceding month.

Marijuana remains the most commonly used illegal drug, followed by cocaine. Women report higher rates than men of prescription drug use, including pain relievers (23.1%), opioid analgesics (2.1%), sleeping pills (1.7%), tranquillisers (1.1%), and antidepressants (2.1%).

The use of alcohol and drugs by pregnant women can result in significant maternal, fetal, and neonatal morbidity. In general, pregnant women with substance use disorders are less likely to seek prenatal care, and they have higher rates of infectious diseases such as HIV, hepatitis, and other sexually transmitted infections.

This clinical practice guideline from the Canadian Society of Obstetricians and Gynaecologists aims to improve awareness and knowledge of problematic substance use in pregnancy and to provide evidence-based recommendations for the management of this challenging clinical issue for all health care providers.

The guideline reviews the use of screening tools, general approach to care, and recommendations for clinical management of problematic substance use in pregnancy.

The authors carried out a systematic search of a range of databases to find English language systematic reviews, randomised controlled trials and observational studies from 1950 onwards. They also searched for grey literature.

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on the Preventive Health Care. Recommendations for practice were ranked according to the method described in that report.

Here are the main recommendations from the guideline:

1. All pregnant women and women of childbearing age should be screened periodically for alcohol, tobacco, and prescription and illicit drug use . (III-A)
2. When testing for substance use is clinically indicated, urine drug screening is the preferred method . (II-2A) Informed consent should be obtained from the woman before maternal drug toxicology testing is ordered . (III-B)
3. Policies and legal requirements with respect to drug testing of newborns may vary by jurisdiction, and caregivers should be familiar with the regulations in their region . (III-A)
4. Health care providers should employ a flexible approach to the care of women who have substance use problems, and they should encourage the use of all available community resources . (II-2B)
5. Women should be counselled about the risks of periconception, antepartum, and postpartum drug use . (III-B)
6. Smoking cessation counselling should be considered as a first-line intervention for pregnant smokers . (I-A) Nicotine replacement therapy and/or pharmacotherapy can be considered if counselling is not successful . (I-A)
7. Methadone maintenance treatment should be standard of care for opioid-dependent women during pregnancy . (II-IA) Other slow-release opioid preparations may be considered if methadone is not available . (II-2B)
8. Opioid detoxification should be reserved for selected women because of the high risk of relapse to opioids . (II-2B)
9. Opiate-dependent women should be informed that neonates exposed to heroin, prescription opioids, methadone, or buprenorphine during pregnancy are monitored closely for symptoms and signs of neonatal withdrawal (neonatal abstinence syndrome) . (II-2B) Hospitals providing obstetric care should develop a protocol for assessment and management of neonates exposed to opiates during pregnancy . (III-B)
10. Antenatal planning for intrapartum and postpartum analgesia may be offered for all women in consultation with appropriate health care providers . (III-B)
11. The risks and benefits of breastfeeding should be weighed on an individual basis because methadone maintenance therapy is not a contraindication to breastfeeding . (II-3B)

Wong S, Ordean A, Kahan M. Substance use in pregnancy (PDF). J Obstet Gynaecol Can. 2011 Apr;33(4):367-84.