The controversy about whether or not pregnant women should
get flu vaccination is one of the most long-standing discussions that appear to
occur during flu season every year. Now a recent study suggests that pregnant
women and their unborn infant would benefit from flu vaccination. Here we
consider the implications of the study.
Although there have been multiple
studies indicating that there are no significant risks for pregnant women to
get flu vaccinations, many women have been concerned that the vaccination will
go through the placenta and harm the unborn infant. This line of reasoning
mainly stems from other facts about what can pass from the mother to the unborn
infant. A good example of that is cortisol, which is a stress hormone that is
able to pass through the placenta and affect the unborn infant’s health (as the
infant does not have appropriate immune system mechanisms to handle cortisol).
However, there are no reliable studies that have indicated that this would be
the case for flu vaccinations.
The current study, which was
published in Obstetrics and Gynaecology,
analysed data of 74 000 women who at some stage in their pregnancy had received
a flu vaccination. The researchers then compared these outcomes to matched
controls that had not had a flu vaccination but were around the same age and
had similar pregnancy start date. It is also worth noting that the control
sample consisted of 300 000 women. The key findings indicated that there was a
relationship between women who were vaccinated and pre-existing health problems
before pregnancy such as diabetes and high blood pressure. However, upon
following up those women, it appeared that there was no effect on whether they
had any pregnancy complications, vascular problems or urinary tract infections.
A subset of the data also suggested that vaccination was associated with a
decreased risk of gestational diabetes.
One thing that we found
particularly interesting when reading this study was the fact that the
researchers aimed to give explanations behind their findings that did not
patronise women who had considered whether the flu vaccination was necessary.
For instance, although the findings were statistically robust, the researchers
still explained that women who were vaccinated were likely to have had
pre-existing conditions, which led doctors to recommend the vaccinations and
healthy diets (all of which could have affected the development of other conditions).
Having said that, we still feel
like the key take home message from the current study is that there now is
robust evidence that demonstrates the importance of pregnant women getting
vaccinated. As such, it is our hope that this study dissolves the yearly
We would like to point out that we have always supported UK published guidance that has advocated pregnant women to have the seasonal flu vaccination. Here is a link to the NHS page on this matter.