Pregnancy-specific pulmonary complications

Uncommon pulmonary conditions which may complicate pregnancy include amniotic fluid embolism and pulmonary edema secondary to preeclampsia.

  1. Amniotic fluid embolism: This is a rare obstetric complication (between 1/8000 and 1/80,000 live births) with catastrophic consequences, that may account for 10% of maternal deaths. Amniotic fluid embolism is usually associated with labor and delivery, but may also occur with uterine manipulations or uterine trauma. The mechanism involves amniotic fluid entering the vascular circulation which produces acute pulmonary hypertension as well as myocardial dysfunction. The diagnosis is by exclusion of other conditions (eg. pulmonary embolism, acute coronary event, septic shock) and several blood tests have been evaluated but have not been validated. Treatment is supportive (inotropes, mechanical ventilation) and many patients develop ARDS and a coagulopathy. Some authorities suggest treatment with steroids.
  2. Pulmonary edema due to preeclampsia: Pulmonary edema may complicate preeclampsia, in about 3% of these patients. The mechanism relates to reduced serum albumin, elevated left ventricular afterload, and systolic and diastolic myocardial dysfunction as well as aggressive, intrapartum fluid replacement.  Management requires ventilatory support and careful diuresis, in addition to the usual management of preeclampsia.

   Acute respiratory distress in pregnancy


 Distinguishing Features

Amniotic fluid embolism

 Cardiorespiratory collapse, seizures, disseminated  intravascular coagulopathy

Pulmonary edema caused by  preeclampsia

 Hypertension, proteinuria

Tocolytic pulmonary edema

 Tocolytic administration, rapid improvement with  discontinuation

Aspiration pneumonitis

 Vomiting, aspiration

Peripartum cardiomyopathy

 Gradual onset, signs of heart failure

Venous thromboembolism

 Evidence of deep venous thrombosis; radiologic investigations


 Occurs during delivery, subcutaneous emphysema


Knight M, Berg C, Brocklehurst P, Kramer M, Lewis G, Oats J, Roberts CL, Spong C, Sullivan E, van Roosmalen J, Zwart J. Amniotic fluid embolism incidence, risk factors and outcomes: a review and recommendations. BMC Pregnancy Childbirth. 12:7, 2012

Clark SL, Hankins GD, Dudley DA, et al: Amniotic fluid embolism: Analysis of the national registry. Am J Obstet Gynecol 172:1158–1169, 1995.

Scisciore AC, Ivester T, Largoza M, et al: Acute pulmonary edema in pregnancy. Obstet Gynecol 101:511–515, 2003

Lapinsky SE. Concise Definitive Reviews in Critical Care: Cardiopulmonary Complications of Pregnancy. Crit Care Med 2005; 33:1616.

Special Pregnancy Program

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Fetal Medicine: 416-586-4800 x 7756
Fax: 416-586-3216

Maternal Medicine: 416-586-4800 x 7000
Fax: 416-586-5109

Main clinic hours: Monday to Friday, 8am to 4pm

Prenatal Diagnosis & Medical Genetics

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phone: 416-586-4800 x 4523
fax numbers:
416-586-4723 or 416-586-8384

Perinatal Mental Health

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Phone: 416-586-4800 x 8325
Fax: 416-586-8596