Novel Influenza A (H1N1) and Pregnancy
Novel influenza A (H1N1) (initially called "swine flu") is a new flu virus that is
believed to spread through the coughs and sneezes (droplet
transmission) of people who are sick with the virus as well as by touching your nose or mouth after touching infected objects. As of July 17 , 2009 there have been 3161 confirmed and probable
cases of influenza A (H1N1) flu infection and 52 deaths attributed to the influenza A (H1N1) virus
in the state of California alone .
Pregnancy is a risk factor for increased illness and death from influenza. At
especially high risk during the
influenza season are pregnant women with underlying medical conditions
such as asthma . The CDC recommends pregnant women with confirmed, probable, or suspected novel influenza A (H1N1) virus infection should receive
antiviral treatment for 5 days. Oseltamivir is the preferred treatment
The incubation period is most likely 1 to 4 days but could range from 1 to 7
days. The duration of shedding with novel influenza A (h1N1)
virus is unknown. However, infected persons should be assumed to be contagious
for up to 7 days from illness
onset. Some infected persons such as young infants or immunosuppressed persons might potentially
be contagious for longer periods . All respiratory secretions and bodily fluids (diarrheal stool) of novel
influenza A (H1N1) cases should be considered potentially infectious. However,
breast milk is not thought to be a potential source of influenza virus
Symptoms H1N1 infection include 
- Fever (temperature of 100°F [37.8°C] or greater)
- Cough and/or Sore throat
- Runny or stuffy nose
- Body aches
Some people may also have
- vomiting and/or diarrhea
Most people with uncomplicated influenza recover in 1-2 weeks
The CDC recommends that "women who have symptoms of
influenza-like-illness (defined as fever (temperature of 100°F [37.8°C] or
greater) and a cough and/or a sore throat in the absence of a KNOWN cause other
than influenza) should be treated as if they had influenza." .
Who to Test
"Not all people with suspected novel influenza (H1N1) infection need to have
the diagnosis confirmed, especially if the person resides in an affected area or
if the illness is mild. Recommendations on who to test may differ by state or
Priority for testing should be given to patients who require
hospitalization or patients at high-risk for severe disease such as:"
- Children younger than 5 years old. The risk for severe complications from
seasonal influenza is highest among children younger than 2 years old.
- Adults 65 years of age and older.
- Persons with the following conditions:
- Chronic pulmonary (including asthma), cardiovascular (except
hypertension), renal, hepatic, hematological (including sickle cell
disease), neurologic, neuromuscular, or metabolic disorders (including
- Immunosuppression, including that caused by medications or by HIV;
- Pregnant women;
- Persons younger than 19 years of age who are receiving long-term aspirin
- Residents of nursing homes and other chronic-care facilities."
As soon as possible after illness onset collect nasopharyngeal swab, nasal aspirate or a combined nasopharyngeal swab with oropharyngeal
swab using swabs with a synthetic tip (e.g. polyester or Dacron®) and an
aluminum or plastic shaft. Specimens should be placed into sterile
viral transport media (VTM) and immediately placed on ice or cold packs or at
4°C (refrigerator) for transport to the laboratory.
"Available rapid tests can distinguish between influenza A and B viruses.
However, these tests may not be sensitive enough to detect the influenza A
(H1N1) virus. A negative result does not exclude a diagnosis of swine influenza
A. A positive result may be helpful, but does not distinguish between seasonal
and swine influenza viruses. Therefore, if a patient tests negative for
influenza by rapid antigen testing, specimens should be sent for further
characterization (including PCR and subtyping) to the local public health
laboratories or VRDL" .
ANY SUSPECT OR LABORATORY-CONFIRMED CASES SHOULD BE
REPORTED TO THE LOCAL HEALTH DEPARTMENT AND THE CALIFORNIA DEPARTMENT OF
PUBLIC HEALTH IMMEDIATELY 
Suspected Novel Influenza A (H1N1) Infection 
A suspected case
of novel influenza A (H1N1) virus
infection in California is any patient with an acute febrile respiratory
illness*, due to the transmission of novel influenza A (H1N1) virus
throughout the state and the presentation of patients with this illness.
*Acute febrile respiratory illness is a measured temperature of ≥37.8°C
(100°F) plus recent onset of at least one of the following: runny nose
or nasal congestion, sore throat, or cough.
Probable Novel Influenza A (H1N1) Infection 
A probable case of novel influenza A (H1N1) virus infection
is defined as a person with an influenza-like-illness who is positive for influenza A
by rapid test, but negative for human H1 and H3 by influenza reverse-transcription polymerase chain reaction (RT-PCR)
Confirmed Novel Influenza A (H1N1) Infection 
A confirmed case of novel influenza A (H1N1) virus infection
is defined as a person with an influenza-like illness with laboratory confirmed
novel influenza A (H1N1) virus infection by real-time RT-PCR and or viral
"Pregnant women with confirmed, probable, or suspected novel influenza A
(H1N1) virus infection should receive antiviral treatment for 5 days.
Oseltamivir is the preferred treatment for pregnant women, and the drug regimen
should be initiated within 48 hours of symptom onset, if possible. Pregnant
women who are in close contact with a person with confirmed, probable, or
suspected novel influenza A (H1N1) infection should receive a 10-day course of
chemoprophylaxis with zanamivir or oseltamivir." [4, 7]
Treatment is also recommended for:
- All hospitalized patients with confirmed, probable or suspected novel
- Patients who are at higher risk for seasonal influenza
complications as noted above.
Antiviral drugs work best if started soon after getting
sick (within 2
days of symptoms). Mothers who are breastfeeding can continue to nurse their babies while being
treated for the flu [8,9].
Oseltamivir (Tamiflu ®)
75-mg capsule orally twice per day for 5 days
75-mg capsule once per day for 10 days after the
last close contact (within 6 feet) with a person who is a confirmed, probable or suspected case
of novel influenza A (H1N1) virus infection during the infectious period of the
Zanamivir (Relenza ®)
Two 5-mg inhalations (10 mg total) twice per day
Two 5-mg inhalations (10 mg total) once per day for 10 days
after the last close contact (within 6 feet) with a person who is a
confirmed, probable or suspected case of novel influenza A (H1N1) virus
infection during the infectious period of the case.
H1N1 Flu Vaccination Resources
Find a Flu Clinic
See also "Is the influenza vaccine safe during pregnancy?"
Preventing Spread of Disease
The California Department of Public Health recommends:
"The patient with symptoms of influenza-like illness should be encouraged
- Self-isolate in their home for 7 days or until their temperature has subsided,
whichever is longer.
- Seek medical care for severe respiratory symptoms such as difficulty breathing
or for dehydration from vomiting and/or diarrhea. They may also need to seek early
medical attention if they have a chronic health condition that puts them at risk
for the complications of influenza.
- If the patient must go into the community (e.g., for medical care), they
should be instructed to wear a mask over their nose and mouth when within six feet of
Obstetric Settings 
The Centers for Disease Control recommends:
In obstetric settings when a pregnant woman has confirmed, probable or
suspected novel H1N1 flu
- Isolate the ill mother from healthy pregnant women .
- Place a surgical mask on the ill mother during labor and delivery, if
tolerable, in order to decrease exposure of the newborn, healthcare personnel,
and other labor and delivery patients to potentially infectious respiratory
- Place the ill mother in isolation after delivery
- The mother should avoid close contact with her infant until she has
received antiviral medications for 48 hours, her fever has fully resolved, and
she can control coughs and secretions.
- In the meantime, the newborn should be cared for in a separate room by
another person who is well, and the mother should be encouraged and assisted
to express her milk.
- After 48 hours of antiviral medications, her fever has fully resolved, and
she can control coughs and secretions the mother should be encouraged to
wear a facemask, change to a clean gown or clothing, adhere to strict hand
hygiene and cough etiquette when in contact with her infant, and begin
breastfeeding (or if not able to breastfeed, bottle feeding).
- She should continue these protective measures, both in the hospital
setting and at home, for at least 7 days after the onset of influenza symptoms
Considerations Regarding Novel H1N1 Flu Virus in Obstetric Settings for full
1. Novel H1N1 Flu Situation Update
2.Rasmussen SA, Jamieson DJ, Bresee JS. Pandemic influenza and pregnant
women. Emerg Infect Dis [serial on the Internet]. 2008 Jan [7-20-2009].
Available from http://www.cdc.gov/EID/content/14/1/95.htm
4. Novel influenza A (H1N1) virus infections in three pregnant women -
United States, April-May 2009. MMWR Morb Mortal Wkly Rep. 2009 May
15;58(18):497-500. PMID: 19444154http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5818a3.htm
5. California Department of Public Health Viral and Rickettsial Disease
Laboratory (VRDL) Swine Influenza A (H1N1) Surveillance
CALIFORNIA DEPARTMENT OF PUBLIC HEALTH NOVEL INFLUENZA A (H1N1) VIRUS (SWINE FLU)INFECTION CONTROL RECOMMENDATIONS IN AN OUTPATIENT SETTING May 19, 2009
7. Tanaka T, et al "Safety of neuraminidase inhibitors against novel influenza
A (H1N1) in pregnant and breastfeeding women" CMAJ 2009;
DOI:10.1503/cmaj.090866. Accessed 7-19-09
8. Interim Guidance on Antiviral Recommendations for
Patients with Novel Influenza A (H1N1) Virus Infection and Their Close Contacts.
http://www.cdc.gov/h1n1flu/recommendations.htm Accessed 7-19-09
9. What Pregnant Women Should Know About H1N1 (formerly called swine flu)
10. Considerations Regarding Novel H1N1 Flu Virus in Obstetric Settings
http://www.cdc.gov/H1n1flu/update.htm Accessed 7-20-09