Epidemiology

Despite the fact that the first postpartum visit is generally scheduled at 6 weeks, most life-threatening complications arise within the first 3 weeks following delivery and are thus likely to be seen in the emergency department (ED). These complications are primarily related to infection, hemorrhage, pregnancy-induced hypertension, and embolic events.^1,2 Infection is one of the top five causes of mortality, with approximately 13% of pregnancy-related deaths between 1991 and 1999 being due to infection.² In the general population, the incidence of pregnancy-induced venous thromboembolism (VTE) is approximately 0.49 to 1.72 per 1000 deliveries.³ The risk for VTE is five times higher in a pregnant than in a nonpregnant patient. When compared with pregnancy, the risk for VTE is even higher postpartum: a postpartum woman’s risk for VTE is 20- to 80-fold higher in the first 6 weeks, and in the first postpartum week the risk is 100-fold higher.^3,4 The majority of deaths from VTE occur during the first 2 weeks of the puerperium, but a significant number of nonfatal events occur 2 to 6 weeks after delivery.⁴ Approximately 75% of cases of pregnancy-associated VTE are deep vein thrombosis (DVT) and approximately 25% are pulmonary embolism (PE).³

Additionally, there is a high frequency of late maternal morbidity from a variety of causes; up to 87% of women note problems in the first 6 weeks postpartum, and as many as 76% of these patients continue to have these problems for as long as 18 months following delivery.

Pathophysiology: the Puerperium

Originally, the puerperium was defined as the period of confinement during and just after birth; it is now generally accepted to mean the 6 weeks after delivery. The puerperium has also been referred to as “the fourth trimester.” This period is marked by multiple physiologic changes (Table 123.1) as the woman returns to the prepregnant state, including healing physically from any trauma during delivery, and adjusts to the many physiologic and psychologic demands involved in caring for a newborn. Just as in pregnancy, when there are so many physiologic changes, the potential exists for the normal healing process to go awry and emergencies to occur.

Table 123.1 Physiologic Changes in the Puerperium

GFR, Glomerular filtration rate; T₃, triiodothyronine; T₄, thyroxine; TSH, thyroid-stimulating hormone;

^* Approximate time.

Certain significant changes in the physiology of the coagulation system during pregnancy persist past delivery and into the puerperium, including major changes in the coagulation and fibrinolytic system, as well as a reduction in venous blood flow in the deep venous system. Combined, these alterations increase the thrombotic potential in near-term and immediate postpartum patients.

A pregnant patient around term and immediately postpartum has significant increases in factors I, V, VII, IX, X, and XII; von Willebrand factor antigen; and ristocetin cofactor activity. The endogenous anticoagulants protein C and antithrombin remain unchanged throughout pregnancy, but levels of protein S are reduced. Fibrinolytic activity is impaired during pregnancy as a result of placentally derived plasminogen activator inhibitor type II and pregnancy-induced increases (approximately threefold) in endothelial and hepatic-derived inhibitor of plasminogen activator type I. These changes rapidly return to normal following delivery.

During normal pregnancy there is a significant reduction in blood flow to the deep venous system, as well as an increase in diameter of the major leg veins. These changes do not occur evenly in both legs. Studies of patients in the puerperium have reported greater diameter and slower blood flow in the left common femoral vein than in the right. These differences are manifested clinically; in nonpregnant patients, the left leg was affected in 55% of cases of DVT, whereas in pregnancy the rate was 85%. The mode of delivery also affects the deep venous system. Women who delivered by cesarean section had a lower mean velocity of blood flow in the common femoral vein during the puerperium than did those who had delivered vaginally. These changes in flow velocity and diameter take approximately 6 weeks to return to baseline. Another significant clinical difference observed in pregnant and immediate postpartum patients is that the majority of DVT events seen during this time occur in the iliofemoral segments rather than in the calf veins and are therefore more likely to result in PE. Additional underlying risk factors that increase the likelihood for thrombotic complications are age older than 35 years, delivery by cesarean section, weight greater than 175 lb, and a family or personal history of thrombosis and thrombophilia (protein C or S deficiency, factor V Leiden).

Presenting Signs and Symptoms

The most common complaints in the postpartum period are fatigue (56%), breast problems (20%), backache (20%), depression (17%), hemorrhoids (15%), and headache (15%).⁵

The signs and symptoms of metritis are fever, uterine tenderness, abdominal pain, and either purulent lochia or a positive culture of endometrial fluid or tissue usually between the second and seventh days postpartum. Fever (>38° C [100.4° F]) is the most important criterion for the diagnosis of metritis. Lochia may be foul smelling or have no odor.

Peritonitis is manifested as severe abdominal pain but may be misdiagnosed because abdominal rigidity, guarding, or rebound tenderness are often not present on physical examination as a result of laxity of the rectus abdominus muscles. Commonly, an adynamic ileus is the first sign.

Symptoms of toxic shock syndrome (TSS) include fever with a temperature of 39° C (102.2° F) or higher; erythematous diffuse rash; headache, photophobia, myalgias, and altered sensorium; gastrointestinal complaints, including nausea, vomiting, and watery diarrhea; and rapid progression to renal failure, hepatic failure, disseminated intravascular coagulation, and circulatory collapse.

Clinical signs and symptoms associated with cardiopulmonary complications may include fatigue, dyspnea, cough, orthopnea, hemoptysis, chest pain, palpitations, abdominal pain, tachycardia, elevated blood pressure, pulmonary rales, third heart sound, mitral regurgitant murmur, and peripheral edema.

Symptoms of postpartum mood disturbance include mild depression, irritability, confusion, mood instability, anxiety, headache, fatigue, and forgetfulness. Usually, the postpartum blues appear in the first 2 weeks after delivery and last from a few hours to a few days. More severe symptoms may include delusions, hallucinations, rapid mood swings, sleep disturbances, and obsessive thoughts about the baby.

Differential Diagnosis and Medical Decision Making