Undertreatment a problem in pregnant asthmatics

OB/GYN News, March 1, 2003 by Sharon Worcester

SARASOTA, FLA. -- The biggest problem with asthma in pregnancy is undertreatment, Dr. Felice Baron said at a pennatal symposium sponsored by Symposia Medicus.

Patients, and often their physicians, tend to fear that asthma medications could be harmful to the fetus, so they discontinue them and go through pregnancy with poorly controlled asthma, said Dr. Baron, director of the Perinatal Center at Sarasota Memorial Hospital.

"Chronic hypoxia is going to hurt the baby far more than anything that any pharmaceutical company is going to create," she said.

In fact, poorly controlled and! or severe asthma are associated with increased risk for intrauterine growth restriction, low birth weight, preeclampsia, preterm labor, and neonatal morbidity due to hypoxia.

Approximately 4% of pregnancies are complicated by asthma, and status asthmaticus complicates 0.2% of pregnancies. A third of asthmatic pregnant patients' asthma will improve during pregnancy, one-third will worsen, and one-third will stay the same. While it is difficult to predict the impact of pregnancy on asthma, generally, the more severe and poorly controlled the asthma is before pregnancy, the worse it will be during pregnancy.

Most patients with mild asthma will do well during pregnancy Outcomes in those with mild, well-controlled asthma are not very different from those in nonasthmatic patients.

Mild intermittent patients--those with fewer than two exacerbations weekly--can continue to use rescue medications, such as an albuterol inhaler, to treat the exacerbations. Those with mild persistent asthma (more than two attacks weekly) will probably require a steroid inhalant. Don't take patients off this, or they will likely develop moderate asthma, Dr. Baron warned.

Patients with moderate asthma (more than three attacks per week), require more medications for asthma control. The pulmonologist or primary care physician usually prescribes an anti-inflammatory and [[beta].sub.2]-agonist, and these drugs can be continued in pregnancy These patients usually do very well and can be treated with oral steroids for flares.

Those with severe asthma, who are well known at the emergency room and the pulmonologist's office, usually are on three medications: an anti-inflammatory; a [[beta].sub.2]-agonist; and oral steroids, either daily or every other day. While these patients may be at increased risk for gestational diabetes and should be closely monitored, medical treatment should not be discontinued. Consider prescribing extra calcium supplementation to reduce the increased risk of osteoporosis associated with the steroid use, Dr. Baron suggested.

Advise asthmatic patients to head to the emergency room if an acute exacerbation fails to respond to the first medication tried. If the attack is not easily abated in the emergency room, the patient should be admitted. Advise your pulmonology and emergency medicine colleagnes to treat pregnant asthma patients as they would any other asthma patient; the immediate goal is to "break" the attack and protect the fetus. Oxygen administration and improvement in maternal partial pressure of oxygen are imperative, Dr. Baron said.

Fetal assessment in those with moderate or severe asthma should include serial ultrasound evaluation in the third trimester and fetal movement counts beginning at 28 weeks' gestation. Prepartum testing may also be useful.

Considerations during labor and delivery when the risk of asthma exacerbations is further increased, include avoiding the use of 15-methyl prostaglandin F2[alpha] (Hemabate), which is a "very, very very potent bronchoconstrictor" that could cause a "rip-roaring" attack. Before using this drug, always ask the nurse and patient about asthma history Dr. Baron said, noting that prostaglandin [E.sub.2] is safe to use because it is a bronchodilator.

Narcotics can also be a mild bronchoconstrictor and should be used during labor and delivery with care; epidural anesthesia, which is safe in asthmatics, is preferable. Vaginal deliveries are preferred when possible because they are associated with fewer attacks than cesarean deliveries.

As for the long-term effect of pregnancy on asthma, most patients return to their baseline status within 3 months following delivery; pregnancy does not appear to worsen or improve asthma in the long term, Dr. Baron noted.

RELATED ARTICLE: Risk Factors for Rapid Progression

In assessment of lung function in pregnant patients with asthma, a careful history and physical examination can provide clues about the risk of rapid progression of asthma during pregnancy Dr. Baron said.

The following characteristics are considered indications of such risk:

* Previous intubation.

* At least two hospitalizations for asthma in the past year.

* At least three emergency room visits for asthma exacerbations in the past year.

* Recent use of systemic corticosteroids.

* Presence of central cyanosis.

* Use of accessory muscles during respiration.

* Presence of pulsus paradoxus.

* Positional changes in severity.