Abstract
Pulmonary assessment during pregnancy is similar to that of the non-pregnant patient. During pregnancy, there are a number of new symptoms, many of which are physiological, but others may be of more concern. The anatomical and physiological changes can result in changes which overlap with those seen in disease. Respiratory symptoms may arise from pregnancy-specific conditions such as pre-eclampsia or peripartum cardiomyopathy. Pregnancy can also increase the risk of conditions like thromboembolism and exacerbate pre-existing conditions like asthma.
Pulmonary assessment during pregnancy is similar to that of the non-pregnant patient. During pregnancy, there are a number of new symptoms, many of which are physiological, but others may be of more concern. The anatomical and physiological changes can result in changes which overlap with those seen in disease. Respiratory symptoms may arise from pregnancy-specific conditions such as pre-eclampsia or peripartum cardiomyopathy. Pregnancy can also increase the risk of conditions like thromboembolism and exacerbate pre-existing conditions like asthma.
The clinician needs to be able to discern benign symptoms and signs and reassure women appropriately whilst recognizing abnormal findings, which may indicate underlying disease and warrant further investigation. A systematic approach including a relevant history, physical exam and appropriate investigations can help the clinician to make the diagnosis.
History
A careful history is the initial step in the assessment of the obstetric patient. Three particularly common symptoms bring the patient to the clinician for pulmonary assessment: dyspnoea, cough and chest pain. Each of these three symptoms may result from both pulmonary and non-pulmonary disorders. In addition, women may have more than one condition present at the same time. For example, a woman with a pre-existing history of asthma may develop pneumonia.
The history can be helpful in distinguishing between causes. The history is also critical to differentiating between normal or expected symptoms in pregnancy and pulmonary disease. Dyspnoea or shortness of breath is perhaps the most common complaint in pregnancy, yet it can be physiologic. Chapter 16 discusses this further.
Timing of symptom onset, precipitating circumstances and associated symptoms can characterize each of these symptoms further and provide clues to distinguish between causes.
Timing of Symptom Onset
Pregnancy-specific conditions that can lead to dyspnoea, like pre-eclampsia or peripartum cardiomyopathy, usually present in the late second or third trimester, whereas physiologic dyspnoea of pregnancy can begin as early as the late first trimester. Conditions exacerbated by pregnancy such as valvular heart disease or arrhythmias are more likely to present in the third trimester when blood volume reaches its peak.
Sudden-onset dyspnoea has more ominous causes; some examples are pulmonary oedema, pulmonary embolism, pneumothorax and cardiac disease. A benign condition like physiologic dyspnoea typically has a gradual onset.
Precipitating Circumstances
The circumstances that precipitate a symptom can provide useful information. In normal pregnancy, actual exercise tolerance is not greatly affected, despite dyspnoea. Physiologic dyspnoea of pregnancy is usually present with exertion although a small number of women complain of breathlessness at rest. With cardiac disease, dyspnoea may be present at rest, especially when lying flat (orthopnoea). Pleuritic chest pain, which can be seen with pulmonary conditions like pulmonary embolism or pneumonia, is unaffected by position, whereas pleuritic chest pain from pericarditis worsens with lying down, but improves with sitting up.
Associated Symptoms
The patient should be carefully evaluated for associated symptoms when assessing pulmonary complaints. Physiologic dyspnoea of pregnancy, for example, does not present with other associated symptoms. The presence of other symptoms such as wheezing, orthopnoea or paroxysmal nocturnal dyspnoea might indicate a possible cardiopulmonary cause of dyspnoea. A pregnancy-specific condition like pre-eclampsia may present with a constellation of symptoms like headache, visual disturbance, chest pain and epigastric pain, in addition to dyspnoea. Fever or sputum production with cough or chest pain might steer the clinician towards a pneumonia. Worrisome or red flag symptoms are outlined in Table 2.1.
To complete the history, medications should be reviewed and a social and family history should be taken. Some common medications can cause pulmonary complaints or even be associated with pulmonary toxicity, and therefore, it is important to ensure that the patient is not on one of the many medications that can lead to respiratory complications. Some examples of such medications include nitrofurantoin, and amiodarone. At the same time, it is also important to confirm that the pregnant woman has not discontinued essential medications, due to inappropriate concerns for fetal toxicity.
The social history can provide information on smoking, and housing or working conditions, both of which can be helpful for understanding asthma triggers. A family history is important for hereditary conditions like cystic fibrosis. The family history can also be useful in evaluating risk for venous thromboembolism.
Along with the history, simple, patient-based questionnaires may be used to diagnose or assess disease severity of specific pulmonary disorders. For example, the National Asthma Education and Prevention Program recommends using validated questionnaires to assess asthma control including the Asthma Control Test (ACT). The ACT has been found to be reliable in discriminating between levels of asthma control in pregnant women and therefore can be a useful tool for the clinical management of asthma during pregnancy.1 Another common scenario that the obstetrician might encounter is obstructive sleep apnoea. However, unlike asthma, questionnaires for sleep apnoea (Berlin and Epworth Sleepiness Scale) showed poor performance during pregnancy.2
Physical Examination
A complete physical examination, like a carefully taken history, is likely to lead the clinician toward the proper diagnosis. The physical exam begins with the general appearance of the patient. Respiratory distress may present with laboured breathing, difficulty speaking in full sentences and audible wheezing or stridor. Heart rate, blood pressure, respiratory rate, oxygen saturations and temperature are key vital signs used to assess clinical status. When evaluating vital signs, it is important to distinguish between expected (normal) physiological changes of pregnancy and abnormal findings. However, what we know as normal ranges do not account for the different stages of pregnancy. A study is underway to determine gestational-age-specific vital signs.3 Table 2.2 gives a brief outline of the expected changes in pregnancy.
| Blood pressure4 | Heart rate5 | Respiratory rate | Temperature | Oxygen saturation6 |
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