A pulmonary embolism (PE) is a sudden blockage of a major blood vessel in the lungs, typically caused by a blood clot that travels from another part of the body. In obstetric and midwifery practice, PE remains one of the leading direct causes of maternal mortality worldwide. Pregnancy naturally increases the risk of blood clots because the body prepares for childbirth by altering its clotting factors to prevent excessive bleeding during delivery. When these protective mechanisms work overtime or combine with other risk factors, clots can form inside the maternal blood vessels. Midwives must remain vigilant because the physiological changes of a normal pregnancy—such as mild breathlessness and an elevated heart rate—can easily mimic the early warning signs of a life-threatening clot. Recognizing this condition early saves maternal lives.
The journey of a pulmonary embolism almost always begins in the deep veins of the pelvis or lower extremities, a condition known as deep vein thrombosis (DVT). When a thrombus forms in these slow-moving venous pools, a piece of the clot can break free, becoming an embolus. This loose clot travels upward through the inferior vena cava, passes through the right side of the heart, and enters the pulmonary arterial circulation. As the blood vessels branch and become progressively smaller, the embolus wedges tightly inside a pulmonary artery. This blockage immediately halts blood flow to that section of the lung, creating a ventilation-perfusion mismatch where air enters the alveoli, but no blood is available to pick up the oxygen. The resulting strain on the right ventricle can rapidly lead to acute right heart failure and cardiovascular collapse.
Certain expectant and postnatal mothers carry a significantly higher chance of experiencing a thromboembolic event. Midwives must screen for these risk factors during every antenatal booking visit.
The clinical picture of a pulmonary embolism can range from mild discomfort to sudden cardiovascular collapse. Midwives should never ignore a complaining mother who presents with unexplained symptoms.
Confirming a diagnosis of pulmonary embolism requires specialized investigations, especially because the symptoms overlap with normal pregnancy complaints. Midwives play a key coordinating role in emergency diagnostic workflows. An initial electrocardiogram (ECG) helps rule out cardiac events and may show signs of right heart strain. A chest X-ray is usually performed first to exclude other pulmonary conditions like pneumonia or heart failure, even though it often appears normal during a PE. Blood tests, particularly D-dimer assays, measure clot breakdown products, though normal pregnancy naturally elevates D-dimer levels, limiting its usefulness in maternity care. Definitive imaging is often achieved through a computed tomography pulmonary angiography (CTPA) or a ventilation-perfusion (V/Q) scan, both of which provide clear visualization of blood flow within the lungs while carefully balancing radiation exposure to the fetus.
A suspected or confirmed pulmonary embolism is a medical emergency requiring swift, multi-disciplinary action. The immediate priority is stabilizing the mother's airway, breathing, and circulation. Administer high-flow oxygen immediately via a face mask to correct hypoxemia, regardless of pulse oximetry readings. Secure intravenous access for fluid resuscitation and emergency medications. Anticoagulant therapy, typically using low-molecular-weight heparin, is started promptly unless absolute contraindications exist, as it prevents the clot from enlarging and allows the body's natural fibrinolytic system to dissolve it. In massive PEs with hemodynamic instability, thrombolytic therapy or surgical embolectomy may be required. Continuous monitoring of vital signs, oxygen saturation, and urine output remains vital throughout the acute phase.
Preventing a pulmonary embolism starts with identifying high-risk women early and implementing targeted prophylactic measures. Encouraging early postpartum mobilization after both vaginal deliveries and Cesarean sections helps keep blood circulating through the lower limbs. Midwives should instruct postpartum women on simple leg exercises, such as ankle rotations and calf stretching, while confined to bed. Graduated compression stockings or intermittent pneumatic compression devices are helpful mechanical methods for immobile high-risk patients. For women with significant risk factors, pharmacological prophylaxis with low-molecular-weight heparin is prescribed during antenatal or postnatal periods. Hydration is equally critical, as dehydration increases blood viscosity and promotes clot formation in vulnerable vessels.