A 22-year-old G2P1001 pregnant person with limited prenatal care presented at 27 weeks’ gestation to the emergency department (ED) with persistent shortness of breath and wheezing. Her pregnancy was complicated by a diagnosis of mild intermittent asthma managed with occasional use of albuterol. She had also presented for emergency care 4 days prior with an asthma exacerbation; this exacerbation was treated with albuterol nebulizers and prednisone. At the conclusion of her initial ED visit, she was discharged with a prescription for prednisone. She was unable to obtain this prescription prior to returning to the ED. On re-presentation to the ED, she received multiple courses of combined ipratropium/albuterol nebulizer therapy and was initiated on a high-dose prednisone course. After initial stabilization, she was transferred to obstetric triage for further evaluation and care.In obstetric triage, the patient’s oxygen saturation was 99% in room air. However, she still appeared to have labored breathing with audible wheezing on auscultation. At this point, she denied chest pain, cough, congestion, or fever. The internal medicine consult service recommended scheduled albuterol, budesonide, and ipratropium nebulizers as well as obtaining a chest radiograph (Figure 1) and venous blood gas that were unremarkable. Her breathing continued to be labored, although she continued to demonstrate appropriate oxygen saturations in room air. She had a reactive fetal nonstress test.At 27 weeks and 1 day gestation, the patient developed a new oxygen requirement following a desaturation to 88% in room air. A COVID/influenza/respiratory syncytial virus swab panel returned negative. The patient was transferred to the medical intensive care unit for hypoxic respiratory failure in the setting of an asthma exacerbation. Because the patient was now requiring additional oxygen supplementation and her respiratory status was worsening, a betamethasone course was initiated, given the potential increased likelihood of preterm delivery. Her steroid regimen was increased further to 60 mg methylprednisolone every 6 hours.An expanded respiratory panel returned positive for rhinovirus. She was given high-flow nasal cannula 10 L/.21 fraction of inspired oxygen for administration of continuous albuterol at 3 mL/h. She was continued on ipratropium/albuterol, budesonide, and methylprednisolone.After several rounds of this intensive medical therapy, her respiratory status improved, and she was ultimately successfully weaned to room air. With this improvement, she was transitioned to the obstetric floor to continue prednisone and budesonide-formoterol. She remained on continuous fetal monitoring for intermittent category 2 tracing with irregular spontaneous decelerations, which improved over approximately 24 hours. She was discharged home to complete a prednisone taper and to continue budesonide-formoterol twice daily, which resulted in adequate asthmatic control for the remainder of her pregnancy.The patient was admitted at 41 weeks’ gestation with spontaneous rupture of membranes and regular contractions. She was expectantly managed and progressed to full dilation.The patient had an uncomplicated vaginal delivery. She was discharged on postpartum day 2 in good state of health. She continued to do well on subsequent postpartum follow-up with no acute respiratory issues.A male neonate was born and vigorous at delivery weighing 3820 g (71st percentile) with an Apgar score of 7 and 9 at 1 and 5 minutes, respectively.Asthma is a common condition that complicates approximately 4% to 8% of pregnancies.1 Asthma control can vary during pregnancy, with approximately equal proportions of patients experiencing improvement of symptoms, exacerbation of symptoms, or unchanged symptoms. Typically, mild or well-controlled asthma is associated with near-normal pregnancy outcomes. When exacerbations are encountered, they may require acute ED intervention or hospitalization.2 In those with mild intermittent asthma, approximately 12.6% of individuals will experience an exacerbation in pregnancy, and 2.3% will require hospitalization compared with those with severe asthma, whereas approximately 52% will experience an exacerbation, and 27% will require hospitalization.1 Active management of acute flares of asthma in pregnancy is important to optimize maternal, fetal, and obstetrical complications. Poorly controlled asthma increases risk of preterm delivery, need for cesarean birth, preeclampsia, and fetal growth restriction as well as increased morbidity and mortality to the pregnant person1 (Table 1).Several physiologic accommodations occur during pregnancy that may interact with asthma, including decreased pulmonary functional reserve volume, increased minute ventilation, immune modulation toward T helper 2 allergic response, and pressure on the diaphragm of the gravid uterus in later pregnancy.2Pregnant patients themselves may reduce asthma medication use in pregnancy because of perceived fetal risks with certain medication exposure. Undertreated asthma further predisposes the pregnant person to an asthma exacerbation, which may compound additional socioeconomic barriers or environmental barriers to effective and appropriate maintenance therapy. Additionally, pregnancy poses an elevated risk for decompensation in the setting of respiratory tract infection.3,4 For the above patient, several of these risk factors increased her likelihood of asthma exacerbation.The treatment modalities for asthma exacerbation are similar between patients who are pregnant and the general adult population, with the exception of a higher oxygen saturation goal to promote adequate fetal oxygenation.5,6 One significant challenge in respiratory care for patients who are pregnant is the physiologic hypocapnia and higher baseline arterial pH required in pregnancy, driven by an increased tidal volume and minute ventilation. The relative hypocapnia establishes a favorable gradient for fetal CO2 elimination, which is necessary because the fetus lacks the same capacity as adults for renal or respiratory compensation for acidemia, rendering permissive hypercapnia a less viable management strategy for respiratory management in pregnancy.Mainstay treatments for asthma include avoidance of environmental triggers and monitoring a daily peak flow. A decreasing peak flow is indicative of progressive asthma symptoms and an impending asthma exacerbation.7 Initial rescue therapy should include a short-acting beta-2 agonist such as albuterol; initial rescue therapy should be initiated at home.5 Additionally, either intravenous or oral corticosteroids and intravenous magnesium should be included in treatment of asthma exacerbations in pregnancy.8 Occasionally, chronic steroid therapy is necessary to optimize maternal asthma control; prednisone minimally crosses the placenta, unlike fluorinated steroids such as betamethasone. Benefits of asthma control in pregnancy typically outweigh the potential increased risks of gestational diabetes or low birth weight associated with chronic steroid use.9Typically in asthma exacerbation, the goal is maternal stabilization with consideration of delivery for inability to stabilize the maternal patient or deteriorating fetal testing refractory to maternal stabilization. Preterm delivery typically is not indicated in isolation for treatment of a severe asthma exacerbation. In the third trimester, if there are instances of continued exacerbation refractory to both medical and ventilatory management, there should be consideration of delivery. In these cases, delivery may improve tidal volumes by increasing diaphragmatic excursion and subsequently improving maternal gas exchange, which can be lifesaving. At an earlier gestational age, delivery would have a much smaller influence on respiratory physiologically and is less likely to improve maternal condition.10Pregnant individuals with severe asthma will benefit from multidisciplinary care with obstetrics, pulmonology, critical care specialists, maternal-fetal medicine, and neonatology. If the patient is in acute respiratory distress, they may need escalation of care to the intensive care unit. It is important to remember that intubation in pregnancy can be more challenging compared with nonpregnant individuals because of increased airway edema, decreased reserve volume, and delayed gastric emptying (Figure 2).In the case of this patient, treatment included high-flow nasal cannula, inhaled beta-2 agonists, and corticosteroid administration, and continuous nebulizer treatment successfully managed her asthma exacerbation. Additional betamethasone, a fluorinated steroid, was administered to promote fetal maturity in the event that an indication to deliver was encountered. Ultimately, as was seen in this case, coordinated multidisciplinary care of patients with an asthma exacerbation is critical to achieving optimal pregnancy outcomes for affected pregnant people and their neonates.American Board of Pediatrics Neonatal-Perinatal Content SpecificationKnown maternal medical disorders and medications affecting the fetus and newborn infant.
Hariharan et al. (Wed,) studied this question.