Best Medical Practices in Pregnancy

"Both Canadian and World Health Organization guidelines now recommend routine seasonal influenza vaccination of all pregnant women in any trimester."
Alexandra Legge, Dalhousie University, Halifax; study published in Canadian Medical Association Journal

During the 2009 H1N1 pandemic resulting from a particularly virulent strain of influenza, vaccination rates in pregnancy were fairly high. Government of Canada data revealed that about 64% of pregnant women in Nova Scotia alone received the H1N1 vaccine at that time. The flu inoculation takeup since then has reduced considerably. And, write the authors of a new study published in the Canadian Medical Association Journal, experts are concerned that higher rates of flu vaccination haven't resulted since that 2009 scare.

In fact, of the 12,233 women who delivered a live or stillborn infant between November 2010 and March 2012, 16% took the precautionary recommendation of availing themselves of flu inoculation during pregnancy, a "disappointingly low" number. When pregnant women approach nearer to their due dates, their immune systems undergo change. This makes them more susceptible to serious illness from flu and other infections, a condition that places stress on the developing fetus.

Earlier study results found that women in Nova Scotia admitted to hospital with respiratory illness during flu season are likelier to deliver babies small for their gestational age. Or they will deliver with a low birth weight. Flu shots, according to the conclusions reached in this new study,  help to prevent premature labour. Urinary tract infections are known triggers for pre-term labour. Infection with influenza viruses increases the production of cytokines, chemicals secreted by immune cells.

Elevated levels of circulating cytokines increase the production of prostaglandins, hormones that are naturally occurring, which cause the muscles in the uterus to contract "and that are widely known to play a key role in the initiation of labour", explains Ms. Legge. The odds of preterm birth (defined as deliveries taking place at less than 37 weeks' gestation) and lower-birth-weight babies were fewer among babies of pregnant women who were vaccinated.

Born prematurely, babies are at elevated risk of respiratory and heart abnormalities, intracranial hemorrhage (bleeding within the brain), and infections, any of which increase death risk. Low-birth-weight infants are as well at higher risk of dying in their infancy than are normal-weight babies. Many women are anxious about the presumed safety of acquiring flu shots in pregnancy, even while the vaccine comprised of inactive or killed influenza virus particles is considered scientifically safe.

"Another reason I think is that a lot of pregnant women aren't aware of the risks of influenza itself in pregnancy. If there was more awareness of the evidence we have for the potential consequences, maybe pregnant women would be more willing to accept the vaccine", Ms. Legge explained. Which leads to the role that doctors and other pre-natal care providers can play in this critical issue: recommending and offering the annual flu shot to pregnant women during routine pre-natal visits.

Of course, there's another issue involved in this discussion as well. And it is that despite scientific medical evidence testifying to the safety and better outcomes with the use of approved vaccines there will always be a demographic in any community that will spurn inoculations of any kind, attributing to them the worrying concern of being a disease vector in and of themselves.