Chapter 19: Pregnancy and Preexisting Illness

LEARNING OBJECTIVES

1. Describe the potential effects of prepregnancy chronic health conditions on pregnancy, including an evaluation of preconception readiness and the potential risks for mother and fetus when pregnancy occurs.

2. Compare and contrast the considerations for the use of drug versus nondrug therapies in the treatment of a pregnant patient with asthma, diabetes, seizures, hypertension, and depression.

3. Evaluate the risk versus benefit for appropriate management of chronic conditions during pregnancy in both mother and fetus.

4. List and discuss appropriate monitoring parameters for pregnant patients with asthma, diabetes, seizure disorders, hypertension, and depression.

INTRODUCTION

This chapter summarizes clinical recommendations for drugs used to treat women with medical disorders existing before pregnancy. Because these conditions are diagnosed before pregnancy, this chapter will not discuss the pathology or diagnosis of the conditions. With more women pursuing postsecondary and college education, today’s mother is likely to be older and more likely to have concurrent disease conditions. In 1970, the average age for a first-time mother was about 21. Today she is more likely to be 25 to 29 years old.¹ Furthermore, the birth rate among older women is getting higher, with women older than 35 representing more than 14% of primagravidas.¹ In general, chronic diseases occur more frequently with pregnancy in older patients. Older women may be more likely to have preexisting asthma, diabetes, seizures, hypertension, or other chronic conditions requiring daily treatment with medications. Chronic medical conditions can contribute to the complexity of care of a pregnant patient.

Today women take an average of three to five drugs during pregnancy. As a woman’s body changes throughout her pregnancy, it may affect the dosage required of a particular drug. In addition, preexisting diseases may worsen during pregnancy, altering drug treatment requirements. Questions to consider in this patient population are: How does the disease affect pregnancy, and how does pregnancy affect the disease? Another consideration for chronic condition management is medication use during breast-feeding, potentially exposing her child to the effects of these medications. The safety and use of medications while breast-feeding will be discussed in Chapter 17: Principles of Drug Therapy in Pregnancy and Lactation.

ASTHMA

In the United States, asthma is a prevalent chronic condition, affecting approximately 4% to 9% of all pregnancies.² Approximately one-third of women with asthma maintain control similar to their prepregnancy status, one-third worsen, and one-third improve.³ It has been reported that asthma is undertreated during pregnancy, which is particularly concerning since maternal and fetal complications are associated with poorly controlled maternal asthma, including preterm birth, low birth weight (LBW), increased perinatal mortality, and maternal preeclampsia.^4-8

The 2018 Global Institute for Asthma and the 2007 National Asthma Education and Prevention Program reported “inadequate control of asthma is a greater risk to the fetus than asthma medications are.”^8,9 Common asthma medications, ...