There is accumulating evidence that pregnant women might be at increased risk for complications from pandemic swine influenza A (H1N1) virus infection, the novel influenza A virus, or as it is more commonly known, the SWINE FLU. Evidence that influenza can be more severe in pregnant women comes from observations during previous pandemics of 1918 -1919 and 1957 – 1958, and from studies among pregnant women who had seasonal influenza.

The majority of pregnant women infected with the H1N1 virus will invariably have a typical course of uncomplicated respiratory influenza-like illness including cough, sore throat, rhinorrhoea, fatigue, myalgia and in some cases nausea and vomiting. Typically, pregnant patients should recover without any major adverse events. However, for some pregnant women, illness might progress rapidly and might be complicated by secondary bacterial infections, including pneumonia, leading to significant respiratory compromise and possibly even death. Of the eighteen cases that have died from the infection in South Africa, nine were in pregnant women, six of which were in the third trimester of pregnancy and two of which were in late second trimester.

Be it through the natural immune suppression of pregnancy or the restrictive impact of the enlarging uterus on lung capacity, especially during the third trimester of pregnancy, pregnant women are more likely than the general population to develop severe disease and are four times more likely to be hospitalized, with an unusually high death rate compared to the general population.

In the current Swine flu pandemic, it is still too soon to definitively know much about fetal outcome, although infected pregnant women seem to be at high risk at premature delivery. Increased rates of spontaneous abortions and stillbirths, preterm birth, especially in mothers with pneumonia have been described following infection with the H1N1 virus. The infection, however, has its greatest impact on the wellbeing of the pregnant patient where in some cases the course of the disease is particularly virulent and lead to significant respiratory compromise and ultimately to death. Pregnant women must be considered high risk necessitating that antiviral treatment should be provided as soon as their infection is suspected or confirmed in order to minimise the complications of the disease.

The risk of acquiring the virus in general, and amongst pregnant women, can be dramatically reduced by taking some precautionary steps. Pregnant women are advised to practice good hand hygiene by washing hands frequently with soap and water. Tissues should be used to cover the mouth and nose when sneezing and coughing and used tissues should be disposed of promptly. If a tissue is not available, then coughing onto one's sleeve is advised. Pregnant women are advised to avoid crowded places where possible, practice social distancing by keeping at least six feet from groups or crowded environments and staying away from areas of H1N1 infectious outbreak exposure. If used correctly, face masks and respirators may help reduce risk, but they should be used along with other preventative measures, namely avoiding close contact with ill persons and maintaining good hand hygiene. Once ill, the pregnant mother should stay at home, except to seek medical care. Women without flu-like symptoms are advised to attend their usual antenatal appointments unless different arrangements have been made by their local maternity service or providers.

TREATMENT AND CHEMOPROPHYLAXIS.

Pregnant women who present with influenza-like symptoms should receive empiric antiviral treatment. Health care providers need not wait for test results to document the viral infection, or indeed perform diagnostic tests, before introducing antiviral therapy. Treatment should be initiated as soon as possible after the onset of influenza symptoms, with benefits expected to be greatest if the antiviral medication is started within 48 hours of onset of symptoms, although there still is benefit for hospitalized patients even if the treatment is started after 48 hours. The H1N1 virus is known to be susceptible to the neuraminidase inhibitor antiviral drugs, oseltamivir (Tamiflu) or zanamivir (Relenza). Tamiflu is administered orally and is absorbed systemically, whilst Relenza is inhaled, which minimises systemic absorption. Pregnant women who are close contacts with persons with suspected, probable or confirmed cases of H1N1 virus infection should receive antiviral chemoprophylaxis. Recommended duration of TREATMENT is five days and the dose is 75mg twice per day for Tamiflu and two 5 mg inhalations twice per day for Relenza.

Duration of CHEMOPROPHYLAXIS is 10 days and the dose is 75 mg daily for Tamiflu and two 5mg inhalations per day for Relenza. No clinical studies have been conducted to adequately assess the safety of these antiviral drugs, although to date there have been obviously adverse effects among women or among infants born to women using them. Pregnant women appear to be at higher risk on developing severe complications from swine influenza and the benefits of treatment or chemoprophylaxis with oseltamivir or zanamivir are likely to outweigh the theoretical risks of antiviral use. Although there is still no finite data, it may be prudent to use oseltamivir (Tamiflu) as the preferred option for TREATMENT of pregnant women because of its systemic absorption, and zanamivir (Relenza) as the drug of choice for PROPHYLAXIS, because of its limited systemic absorption. It must be remembered however that zanamivir can cause or aggravate respiratory complications because it is an inhalant. Tamiflu then becomes the drug of choice. Of note the United Kingdom has recommended zanamivir as the preferred drug for TREATMENT and PROPHYLAXIS, whilst the Centre for Diseases Control in USA has recommended oseltamivir (Tamiflu) for treatment and zanamivir for PROPHYLAXIS.

Although the H1N1 virus can have disastrous consequences in healthy pregnant women, factors that appear to be associated with poor outcome include commencing the antiviral therapy beyond the 48 hours of onset of the influenza-like symptoms, immune suppression due to HIV or steroids, morbid obesity, other associated underlying medical conditions including chronic pulmonary disease, diabetes mellitus, cardiac disease and being in the third trimester of pregnancy when getting the disease.

HYPERTHERMIA OR PYREXIA

Hyperthermia or pyrexia not uncommonly may occur as a result of the infection. Studies have revealed that hyperthermia or pyrexia especially during first trimester doubles the risk of neural tube defects, developmental problems of the foetal central nervous system and could be responsible for other birth defects and unfavourable birth results. Limited data suggest that antipyretics and / or folic acid may minimise the risk of these occurring. Maternal fever during labour has been shown to be a risk factor for adverse neonatal and developmental outcomes, including neonatal seizures, encephalopathy, cerebral palsy and neonatal death. Fever in pregnant women should be treated because of the risk that hyperthermia appears to pose to the foetus. Paracetamol or aspirin seem to be the most appropriate options for fever control in pregnancy.

BREAST FEEDING

Breast feeding does reduce infant vulnerability to infection and their possible hospitalization for severe respiratory illness. After delivery, mothers who have recovered from the influenza infection and are no longer ill should be encouraged to commence breast feeding early and continue to do so. Infants seem to be at higher risk for severe illness from H1N1 viral infection and the mother who is not ill with the disease should make breast feeding a priority as transmission of virus through breast milk is unlikely whilst the infant does receive protection by getting maternal antibodies secreted in the breast milk. Mothers who are ill should be encouraged to express their milk for bottle feeding. The expression of the breast milk can also be performed by a healthy family member. Antiviral medication to mother for either treatment or prophylaxis is not a contraindication to breastfeeding.

Precautionary hygienic measures are very important for women who are caring for their infants while infected with H1N1 virus. Ideally when ill there should be someone else to assist with the infant children. Women who are infected should also wear a face mask when feeding and caring for their infants to reduce the transmission of the virus. Other measures include frequent washing of hands, practising cough etiquette as described previously, ensuring social distancing of children and keeping them away from crowds, preventing sharing of toys or other personal items which may have been in a child's mouth and clean with soap and water if these items have been touched orally.

WHERE TO LOOK FOR MORE DETAILS.

NICD Website .www.nicd.ac.za
Department of Health Website .www.doh.gov.za/swineflu/swineflu-f.html
World Health Organisation Website .www.who.int/csr/disease/swineflu/en/
Centres for Disease Control and Prevention.www.cdc.gov/h1n1flu/