Skip to Main Content

Chapter 48: Pregnancy and Lactation: Therapeutic Considerations

Rebecca H. Stone

LEARNING OBJECTIVES

LEARNING OBJECTIVES

Upon completion of the chapter, the reader will be able to:

  1. Explain the principles of embryology and teratology.

  2. Identify known teratogens and drugs of concern during lactation.

  3. Compare the main sources of drug information relevant to pregnancy and lactation.

  4. Evaluate and communicate the risks of a drug when taken during pregnancy or lactation.

  5. Apply a systematic approach to counseling on the use of drugs during pregnancy and lactation.

  6. Recommend the appropriate dose of folic acid to prevent congenital anomalies.

  7. Describe physiologic changes during pregnancy and their impact on pharmacokinetics.

  8. Choose an appropriate treatment for common conditions in a pregnant or lactating patient.

INTRODUCTION

This chapter will provide the general principles needed to interpret available evidence regarding medication use during pregnancy and lactation, choose an appropriate treatment and dosing strategy for common conditions in pregnancy, and counsel patients in a helpful and supportive way.

EPIDEMIOLOGY AND ETIOLOGY

Background Risks of Anomalies in Pregnancy

Table 48–1 describes the baseline risks of congenital anomalies and some obstetrical complications. This information is essential to evaluate risks associated with medication use and counsel pregnant patients.

Table 48–1Occurrence of Select Obstetrical Complications and Risk of Congenital Anomalies in the General Population1-3
View Table||Download (.pdf)
Table 48–1 Occurrence of Select Obstetrical Complications and Risk of Congenital Anomalies in the General Population1-3
  Risk of Occurrence in Population (%)
Spontaneous abortion/miscarriage (pregnancy loss that occurs after the pregnancy is known and before 20 weeks of GA; risk increases with higher maternal age) 10–15

Congenital anomalies (percentage of live births):

 

14

3

6
Preterm birth (< 37 completed weeks gestation)a 9.9
Low birth weight (< 2500 g)b 8.3

aUnited States data from 2016 to 2018.

bUnited States data from 2018.

GA, gestational age.

Causes of Congenital Anomalies

Although the risk of drug-induced teratogenicity is of concern, the actual risk of birth defects from most drug exposures is small. Medications are associated with less than 1% of all congenital anomalies, although they may also interact with genetic factors.3 It is important to evaluate and optimize drug use in pregnant patients and patients planning a pregnancy.

Other causes of anomalies include genetic causes in 25% of cases (inherited disease, gene mutation, chromosomal disorder), maternal infections (1%), maternal conditions (1%–3%; eg, pregestational diabetes, obesity), multifactorial heredity (23%–50%), and unknown causes (34%–43%).3 Theoretical concerns regarding paternal exposure to genotoxic medication are reported, but currently no medication taken by a man has been proven teratogenic.

PATHOPHYSIOLOGY

Age of Pregnancy

The age of pregnancy can be defined ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.

This site uses cookies to provide, maintain and improve your experience. MH Privacy Center Close