Upon completion of the chapter, the reader will be able to:
Explain the principles of embryology and teratology.
Identify known teratogens and drugs of concern during lactation.
Compare the main sources of drug information relevant to pregnancy and lactation.
Evaluate the risks of a drug when taken during pregnancy or lactation.
Apply a systematic approach to counseling on the use of drugs during pregnancy and lactation.
Recommend the appropriate dose of folic acid to prevent congenital anomalies.
Describe physiologic changes during pregnancy and their impact on pharmacokinetics.
Choose an appropriate treatment for common conditions in a pregnant or lactating woman.
EPIDEMIOLOGY AND ETIOLOGY
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 |Favorite Table|Download (.pdf) Table 47–1 Occurrence of Some Obstetrical Complications and Risk of Congenital Anomalies in the General Population
| ||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):
• Minor malformations
• Major malformations at birth
• Major malformations at 2 years old
|Preterm birth (< 37 completed weeks gestation)* ||11.5 |
|Low birth weight (< 2500 g)a ||8.0 |
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 in (160 cm), BP 110/72 mm Hg, P 70 beats/min, RR 12 breaths/min; slight enlargement of thyroid
How will you confirm gestational age?...
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