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Nausea & Vomiting of Pregnancy

For further information, see CMDT Part 19-07: Vomiting of Pregnancy & Hyperemesis Gravidarum

Key Features

  • "Morning sickness"

  • Up to 75% of women complain of nausea and vomiting during early pregnancy

  • Vast majority of symptomatic patients note nausea throughout the day

  • Symptoms are particularly common with multiple pregnancy and hydatidiform mole

  • Exerts no adverse effects on the pregnancy and does not presage complications

Clinical Findings

  • Morning or evening nausea and vomiting usually begin soon after the first missed period and ceases after the fifth month

  • Persistent, severe vomiting is hyperemesis gravidarum, a distinct entity (see Hyperemesis Gravidarum)

Diagnosis

  • Clinical

Treatment

  • Reassurance and dietary advice are adequate in most cases

  • Vitamin B6, 50–100 mg orally once daily, is nontoxic and may help some patients

  • Pyridoxine alone or in combination with doxylamine (10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride, two tablets at bedtime) is first-line pharmacotherapy

  • To limit the risk of teratogenicity, drug use in the first half of pregnancy should be limited to those of major importance to life and health (Tables 19–1 and 19–2)

Table 19–1.Common drugs that are teratogenic or fetotoxic.1
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Table 19–1. Common drugs that are teratogenic or fetotoxic.1

ACE inhibitors

Alcohol

Androgens

Angiotensin-II receptor blockers

Antiepileptics (phenytoin, valproic acid, carbamazepine)

Benzodiazepines

Cyclophosphamide

Diazoxide

Diethylstilbestrol

Disulfiram

Ergotamine

Estrogens

Griseofulvin

Isotretinoin

Lithium

Methotrexate

Misoprostol

NSAIDs (third trimester)

Opioids (prolonged use)

Radioiodine (antithyroid)

Reserpine

Ribavirin

Sulfonamides (second and third trimesters)

Tetracycline (third trimester)

Thalidomide

Tobacco smoking

Warfarin and other coumarin anticoagulants

1Many other drugs are also contraindicated during pregnancy. Evaluate any drug for its need versus its potential adverse effects. Further information can be obtained from the manufacturer or from any of several teratogenic registries around the country.

Go to https://www.fda.gov/ScienceResearch/SpecialTopics/WomensHealthResearch/ucm134848.htm for more information.

ACE, angiotensin-converting enzyme; NSAIDs, nonsteroidal anti-inflammatory drugs.

Table 19–2.Drugs and substances that require a careful assessment of risk before they are prescribed for breastfeeding women.1
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Table 19–2. Drugs and substances that require a careful assessment of risk before they are prescribed for breastfeeding women.1
Drugs Concern
Atenolol Hypotension and bradycardia in the infant. Metoprolol and propranolol are preferred.
Ciprofloxacin Adverse effects on fetal cartilage and bone. Must weigh risks versus benefits.
Codeine, oxycodone CNS depression. Unpredictable metabolism.
Cyclophosphamide Neonatal neutropenia. No breastfeeding.
Diphenhydramine Present in very small quantities in milk; sources are conflicting with regard to its safety.
Fluoxetine Present in breast milk in higher levels than other SSRIs. Watch for adverse effects like an infant’s fussiness and crying.
Lisinopril Unknown effects. Captopril or enalapril is preferred if an ACE inhibitor is needed.
Lithium Circulating levels in the neonate are variable. Follow infant’s serum ...

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