Antenatal care provides an opportunity to ask women about substance use. Enquiring in a non-judgemental way may assist women to disclose and enable access to additional support and care, including mental health and drug and alcohol services.
Substance use in pregnancy is an important issue in antenatal care. The use of tobacco and alcohol are common (these are discussed in Sections 12 and 13) but the use of illicit substances and the misuse of prescription medications is also important. The simultaneous use of several substances (polysubstance use) and comorbid mental health problems are also common.
The substances considered in this chapter include cannabis (marijuana), methylenedioxymethamphetamine (MDMA or ecstasy), meth/amphetamines (including powder/pills [speed] and crystals [crystal meth or ice]), cocaine and opioids (including heroin) and misuse of pharmaceuticals.
No information relevant to lysergic acid diethylamide (LSD) was identified.
15.1.1 Prevalence of substance use in Australia
According to the 2013 National Drug Strategy Household Survey, trends in substance use ‘in the last 12 months’ among Australians aged >14 years are as follows AIHW 2014:
- cannabis: use has remained relatively stable since 2004 (10.2% recent use; 35% in their lifetime)
- ecstasy: use has declined (3.0% in 2010 to 2.5% in 2013)
- meth/amphetamine: use has remained stable (2.1% since 2007) but, among meth/amphetamine users, use of ice has almost doubled (22% in 2010 to 50% in 2013) and that of speed has almost halved (51% in 2010 to 29% in 2013)
- cocaine: use has remained stable (2.1% in 2010 and 2013)
- heroin: use has declined (0.8% in 1998 to 0.1% in 2013)
- misuse of pharmaceutical medications: misuse has increased (7.4% in 2010 to 11.4% in 2013).
The type of substance use in the last 12 months varied across jurisdictions. For example AIHW 2014:
- cannabis was most commonly used in the Northern Territory (17.1%); almost double the usage in Victoria (9.1%)
- meth/amphetamines were used more by people in Western Australia (3.8%) than other jurisdictions
- people in New South Wales (2.7%) and the Australian Capital Territory (2.8%) were more likely to use cocaine than people in other jurisdictions
- ecstasy use was most common in the Northern Territory (3.7%)
- people in Western Australia were more likely to misuse pharmaceuticals (5.6%) than those in any other jurisdiction.
The National Drug Strategy Household Survey reported that in Australia in 2013 AIHW 2014:
- regardless of whether women knew they were pregnant or not, 2.2% had used an illicit substance such as marijuana and 0.9% had misused prescription analgesics
- among pregnant women, a small minority had used illicit substances; 2.4% before knowledge of their pregnancy and 1.6% after they knew they were pregnant.
15.1.2 Risks associated with substance use in pregnancy
Systematic reviews of observational studies have identified the following maternal and perinatal risks associated with substance use.
- Marijuana use in pregnancy: One review (n=31) found an association with increased risk of low birth weight (RR 1.43, 95%CI 1.27 to 1.62) and preterm birth (RR 1.32, 95%CI 1.14-1.54) but, when pooled data were adjusted for tobacco use and other confounding factors, there was no statistically significant difference (birth weight RR 1.16, 95%CI 0.98 to 1.37; preterm birth RR 1.08, 95%CI 0.82 to 1.43) Conner et al 2016. Another review that did not adjust for confounders found an increase in risk of low birth weight (OR 1.77; 95%CI 1.04 to 3.01) and maternal anaemia (OR 1.36: 95%CI 1.10 to 1.69) Gunn et al 2016.
- Amphetamine use in pregnancy: Significant increases in unadjusted risks of preterm birth (OR 4.11; 95%CI, 3.05 to 5.55), low birthweight (OR 3.97; 95%CI, 2.45 to 6.43), and small for gestational age (OR 5.79; 95%CI 1.39 to 24.06) were identified and mean birthweight was significantly lower (MD –279 g; 95% CI, –485 to -74 g) Ladhani et al 2011.
- Cocaine use in pregnancy: There was an association with significantly higher risk of preterm birth (OR 3.38; 95%CI 2.72 to 4.21), low birthweight (OR 3.66; 95%CI 2.90 to 4.63), and small-for-gestational-age infants (OR 3.23; 95%CI 2.43 to 4.30), as well as lower gestational age at birth (–1.47 wk; 95%CI –1.97 to –0.98 wk) and reduced birthweight (–492 g; 95%CI –562 to –421 g) Gouin et al 2011.
- Opioid dependence in pregnancy: A review of neurobehavioural function in infants (mean age 14.1 months) found non-significant mean effect sizes in favour of non-opioid exposed controls for cognition (0.24, 95%CI −0.09 to 0.58, Z=1.41, p=0.16), psychomotor function (0.28, 95%CI −0.05 to 0.61, Z=1.67, p=0.09) and behaviour (corrected mean 1.21, 95%CI −0.61 to 3.03, Z=1.30, p=0.19;) Baldacchino et al 2014.
A cohort study found that births associated with maternal opioid abuse or dependence compared with those without opioid abuse or dependence were associated with an increased odds of:
- maternal death during hospitalisation (aOR 4.6; 95%CI 1.8 to 12.1)
- cardiac arrest (aOR 3.6; 95% CI 1.4 to 9.1)
- intrauterine growth restriction (aOR 2.7; 95%CI 2.4 to 2.9)
- placental abruption (aOR 2.4; 95%CI 2.1 to 2.6)
- length of stay >7 days (aOR 2.2; 95%CI 2.0 to 2.5)
- preterm labour (aOR 2.1; 95%CI 2.0 to 2.3)
- oligohydramnios (aOR 1.7; 95%CI 1.6 to 1.9)
- transfusion (aOR 1.7; 95% CI 1.5 to 1.9)
- stillbirth (aOR 1.5; 95%CI 1.3 to 1.8)
- premature rupture of membranes (aOR 1.4; 95%CI 1.3 to 1.6)
- caesarean section (aOR 1.2; 95%CI 1.1 to 1.3) Maeda et al 2014.
No studies were identified that investigated outcomes associated with the use of crystal methamphetamine, LSD or ecstasy in pregnancy.
15.2 Assessing substance use
The World Health Organization (WHO) recommends screening for substance use in pregnancy WHO 2014. Periodic screening for substance use in pregnancy is also recommended in Canada SOGC 2011. In Australia, guidelines developed nationally and revised by NSW Health NSW Health 2014 recommend screening for substance use early in pregnancy. They emphasise the importance of establishing an effective relationship with the woman based on respect and non-judgemental attitudes, of engaging the woman into adequate antenatal care through this relationship, and of maintaining continuity of care and of carers throughout the pregnancy and postnatal period.
Validated screening instruments for substance use are available (see Section 15.5).
Early in pregnancy, assess a woman’s use of illicit substances and misuse of pharmaceuticals and provide advice about the associated harms.
Approved by NHMRC in October 2017; expires October 2022
Asking about substance use at subsequent visits is important as some women are more likely to report sensitive information only after a trusting relationship has been established.
Approved by NHMRC in October 2017; expires October 2022
15.2.1 Referral and intervention
Australian guidelines NSW Health 2014 recommend that pregnant women with significant problematic substance use will benefit from an appropriate referral for specialist drug and alcohol assessment (in addition to midwifery and obstetric care), appointment of a consistent and continuous case manager and care team who use effective communication systems, and specific treatments for their substance use, which may include counselling, pharmacotherapies and relapse prevention strategies.
Cognitive behavioural therapy compared to brief advice for pregnant women with problematic substance use had no clear effect on the risk of low birth weight (RR 0.72, 95%CI 0.36 to 1.43; 1 study; n=160; low quality), preterm birth (RR 0.5; 95%CI 0.23 to 1.09; 1 study; n=163; low quality) or maternal substance use (no significant difference at birth or 3 months postpartum) WHO 2014.
A Cochrane review on treatments for women with opioid dependence in pregnancy Minozzi et al 2013 did not find sufficient significant differences between methadone and buprenorphine or slow-release morphine to allow conclusions to be drawn on whether one treatment is superior to another for all relevant outcomes. While methadone seems superior in terms of retaining women in treatment, buprenorphine seems to lead to less severe neonatal abstinence syndrome Minozzi et al 2013.
15.3 Discussing substance use
Discussions with women identified as using illicit substances or misusing pharmaceuticals may include:
- the harms associated with substance use and the benefits of reducing or ceasing their use
- the availability of local support services, including mental health and drug and alcohol services
- for opioid-dependent women, the benefits and harms of methadone compared to buprenorphine or oral slow-release morphine.
15.4 Practice summary: substance use
Early in pregnancy and at subsequent visits.
- Aboriginal and Torres Strait Islander health worker
- multicultural health worker.
- Explain the purpose of enquiring about substance use
Explain that enquiry about substance use is a routine part of antenatal care and that it aims to identify women who would like assistance.
- Take a holistic approach
If a woman admits that she is using illicit substances or misusing pharmaceuticals (eg prescribed opioids such as codeine, oxycodone, morphine), other considerations include interventions to assist the woman and provide ongoing support. The woman’s emotional well-being, her safety and that of children in her care should be assessed and reporting and/or referral to other services (eg community services, emergency housing, police) made as required or mandated.
- Learn about locally available support services
Available support services for women who are using illicit substances or misusing pharmaceuticals will vary by location.
- Document the discussion
Document in the medical record any evidence of substance use, referrals made and any information the woman provides. If woman-held records are used, the information included in these should be limited and more detailed records kept at the health service.
- Seek support
Depending on your skills and experience in discussing substance use with women and assisting them, seek advice and support through training programs, clinical supervision, mentoring and/or helplines.
- Be aware of relevant legislation
Each state and territory has requirements about reporting the potential for harms from substance use to the unborn child as set out in its legislation.
- NSW Health (2014) NSW Clinical Guidelines for the Management of Substance Use during Pregnancy, Birth and the Postnatal period. Sydney: Ministry of Health NSW. Available at: health.nsw.gov.au
- WHO (2014) Guidelines for the Identification and Management of Substance Use and Substance Use Disorders in Pregnancy. Geneva: World Health Organization.