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 Centre for Addictionand Mental Health |
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Properties, Effects and Recommendations - Introductory issuesFrom: Exposure to Psychotropic Medications and Other Substances during Pregnancy and Lactation: A Handbook for Health Care Providers On this page:
Ideally, all pregnancies would be planned, in order to ensure that a woman feels positive about her pregnancy and has the support and resources she needs to care for herself and her child. Planned pregnancies also help to ensure that the fetus is not exposed to harmful substances that may cause adverse effects. However, it is well known that 50 per cent of all pregnancies are unplanned.1 Consequently a fetus may be exposed to harmful substances that a woman would not have taken had she known she was pregnant. While current research suggests that some illegal drugs pose less of a direct harm to a fetus or infant than originally thought, these results should be seen as neither an endorsement of the safety of these substances nor an endorsement of their use. Associated environmental factors (e.g., child neglect, poor nutrition, criminal activity, unsafe housing) contribute to an unhealthy and potentially harmful environment. The mental health of a mother is key to the health of her baby. Women are often told—by well-meaning friends and family, the media and even health care providers—to stop taking psychiatric medications in pregnancy, and/or to choose between breastfeeding or their medication. However, this advice does not take into account the negative effects that untreated illness or abrupt withdrawal can have on both the mother and the baby. In fact, the American Academy of Pediatrics considers most medications to be compatible with breastfeeding. For women with untreated or undertreated mental illness, substance use often becomes a coping mechanism. Although there is little literature on this topic, proper treatment of mental illness, which may include being stabilized on medications, can help decrease a woman’s substance use during pregnancy. Pharmacokinetics of the maternal-fetal-placental unitThe free fraction of almost all drugs has been shown to cross the placenta and enter the fetal circulation in measurable quantities. Several models have been used to explain the pharmacokinetics of the maternal-fetal-placental unit. The majority of these models suggest two main factors that contribute to pharmacokinetic changes due to pregnancy:
These factors can affect any or all of drug absorption, distribution, metabolism and elimination. Therefore, the degree and nature of the changes in the pharmacokinetic profile of a given drug due to pregnancy depend on the changes in metabolic pathways to which the agent is susceptible. Teratogenicity and fetal toxicityTeratogenesis is the structural or functional dysgenesis of fetal organs and/or skeletal structures. The typical manifestations include fetal growth restriction or death, carcinogenesis and physical malformations, and they may be of varying severity, requiring surgery in extreme cases. Some drugs are not considered teratogenic but, rather, fetotoxic. These agents are not considered to cause physical birth defects per se but are known to have harmful health effects on the fetus and child following long-term exposure in utero. A prime example of a substance that is both teratogenic and fetotoxic is alcohol, which can cause physical defects when used in early pregnancy and adverse long-term neurodevelopmental effects when used heavily throughout pregnancy. Breastfeeding recommendationsMany drugs can be taken while breastfeeding without harm to the infant. The American Academy of Pediatrics considers excretion of less than 10 per cent of a drug into the breast milk to be compatible with breastfeeding.2 The recommendations in this handbook are based on how a substance would affect a full-term newborn healthy baby of average weight. It is unknown how even a small amount of drug excreted into the breast milk may affect a premature, low-weight baby. Maternal and neonatal withdrawalPrevention and treatment of withdrawal from some psychotropic medications and other substances may require both medical intervention and psychosocial supports. Medical treatment focuses on relieving withdrawal symptoms and preventing complications for the mother and her baby. Psychosocial supports focus on helping the mother overcome cravings and dysphoria. Psychosocial support, including counselling, can also facilitate a woman’s entry into treatment for withdrawal and any other potential substance use issue. In other words, withdrawal can present an important opportunity for intervention, for providing information and for educating women about use of prescription medications and other substances. Women whose withdrawal symptoms are treated inadequately or without compassion are more likely to relapse. To best support women withdrawing from substance use, issues such as housing, poverty, nutrition, prenatal care, relationships and mental health should be addressed with an individualized long-term treatment plan. Treating and dealing with the withdrawal experience in the absence of these and other issues in the woman’s life will rarely lead to her long-term substance use reduction and/or recovery. Information about withdrawal symptoms, risks and complications in the mother and withdrawal symptoms in the newborn is included in some of the individual drug sections that follow.
References
General issues and background
Psychotropic medications and other substances: Properties, effects and recommendations |
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Last updated: Apr 17, 2008 4:20 PM Published: Jul 04, 2008 12:13 PM ID#P35819 |