May 12, 2009 (CIDRAP News) – Pregnant women who have confirmed, probable, or suspected novel influenza H1N1 infections should receive antiviral treatment for 5 days, the US Centers for Disease Control and Prevention (CDC) said today in a detailed report on three pregnant women who had the disease, one of whom died.
In its surveillance of the novel influenza outbreak, the CDC has been gathering information on infections in pregnant women. As of May 10, 20 cases have been reported, including 15 confirmed and 5 probable cases. The CDC published its findings on the three cases in a Morbidity and Mortality Weekly Report (MMWR) Dispatch.
Anne Schuchat, MD, interim deputy director CDC's science and public health program, said at a media briefing today that the CDC is singling out the cases to remind healthcare providers and the public that pregnant women are at higher risk for flu complications such as pneumonia and dehydration and that the agency is seeing some severe complications in pregnant women who have novel H1N1 infections.
"We want to get the word out about prompt antiviral treatment," she said.
The first of three case reports in today's MMWR Dispatch appears to describe the Texas woman who was recorded as the nation's second novel H1N1 flu death. The 33-year-old woman was 35 weeks pregnant and had a 1-day history of myalgia, dry cough, and low-grade fever when she was seen on Apr 15 by her obstetrician. She had a history of psoriasis and mild asthma, but was not taking medication for the conditions.
Four days later she went to the emergency department with worsening shortness of breath, fever, and cough. During the visit the woman had severe respiratory distress. Chest radiographs showed bilateral nodular infiltrates, and the woman was intubated and placed on mechanical ventilation. Her doctors performed a cesarean delivery, and the healthy baby girl was later discharged home.
On Apr 21 the woman experienced acute respiratory distress syndrome. One week later, she began receiving oseltamivir (Tamiflu) and broad-spectrum antibiotics, but she died on May 4.
During the woman's hospitalization San Antonio health officials detected an untypable influenza A strain in the woman's nasopharyngeal specimen and sent it to the CDC, which on Apr 30 confirmed the novel H1N1 virus.
In the second case report, a previously health 35-year-old woman who was 32 weeks pregnant sought treatment at the emergency department on Apr 20 with a 1-day history of shortness of breath, fever, cough, diarrhea, headache, myalgia, sore throat, and inspiratory chest pain. Chest radiographs were normal and the rapid influenza test was negative. She received parenteral nonsteroidal anti-inflammatory medication, acetaminophen, and an albuterol inhaler, and was sent home.
The next day her obstetrician obtained a nasopharyngeal sample and sent it for testing. She recovered fully and her pregnancy is progressing normally following her treatment with antibiotics, antinausea medication, and an inhaled corticosteroid. Influenza testing revealed an untypable influenza A strain, which was forwarded to the CDC and confirmed as novel H1N1.
She had visited Mexico 3 days before she was seen in the emergency department, and several of her family members on both sides of the border had recently been sick with flu-like illnesses.
The third patient, a 29-year-old woman who was 23 weeks pregnant, visited her family doctor for a 1-day history of cough, sore throat, chills, and subjective fever. She had a history of asthma but was not on medication. Her 7-year-old son was also sick and was also seen during the appointment. Another son, age 10, had been sick with similar symptoms the previous week. The family had not traveled to Mexico recently.
The woman's doctor was 13 weeks pregnant and began oseltamivir prophylaxis and did not get sick.
The woman's rapid influenza test was positive. Her doctor prescribed oseltamivir, her symptoms resolved, and the pregnancy is proceeding normally. The Washington State Public Health Laboratory identified the woman's virus sample as untypable influenza A, and the CDC later confirmed it as novel H1N1.
CDC experts note in the report that research has shown a higher risk for complications in pregnant women during seasonal flu outbreaks and previous pandemics. Cardiovascular, respiratory, and immune system changes during pregnancy are thought to contribute to the higher risk, and health officials have recommended that pregnant women receive annual flu vaccines.
Though little information is available on antiviral use during pregnancy, the CDC says the benefits of treatment for the novel virus outweigh the potential risk to the fetus.
Alongside its recommendation for 5-day antiviral treatment for pregnant women, the CDC recommends that pregnant women who are in close contact with a confirmed, probable, or suspected case-patient receive a 10-day prophylactic course of antivirals.
Though both of the neuraminidase inhibitors can be used to treat or prevent the new virus, the CDC said oseltamivir is the preferred treatment, because its systemic absorption may provide better protection against mother-to-child transmission.
"Beginning treatment as early as possible is critical," the CDC states, adding that treating fevers with acetaminophen is important for preventing maternal hyperthermia, which can lead to adverse pregnancy outcomes.
CDC. Novel influenza A (H1N1) virus infections in three pregnant women, United States, April-May 2009. MMWR Dispatch 2009 May 12;58 [Full text]