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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 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 woman.


Medication Use During Pregnancy

Most women take at least one medication during their pregnancy (average number of two to four, vitamins and minerals excluded).1 The most common types of medications used include vitamins and minerals, allergy medication, analgesics, antacids, antibiotics, antiemetics, laxatives, asthma medication, cold and flu remedies, levothyroxine, and progesterone.1,2

The safety profile of some medications taken during pregnancy is difficult to assess making it difficult to balance risks and benefits of treatment.

Background Risks of Anomalies in Pregnancy

Table 47–1 describes the baseline risks of congenital anomalies and some obstetrical complications observed in the general population—essential information to evaluate risks associated with medication use and to counsel pregnant women.

Table 47–1Occurrence of Some Obstetrical Complications and Risk of Congenital Anomalies in the General Population

Patient Encounter, Part 1

A 30-year-old woman comes to your office after a positive urine pregnancy test. You collect the following data:

Estimated Gestational Age: 5 weeks, regular menstrual cycles of 28 days

PMH: Bipolar disorder, hypothyroidism, one spontaneous abortion

FH: Diabetes, hypothyroidism, hypercholesterolemia

SH: Unemployed; cigarettes, one-half pack daily; no alcohol or illicit substances

Meds: Lithium 900 mg orally at bedtime; quetiapine 50 mg orally at bedtime; levothyroxine 50 mcg orally in the morning; all discontinued 1 week ago

Allergy: Dust mites

ROS: Morning nausea; tiredness

VS: Wt 198 lb (90 kg)/Ht 63 ...

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