This research examined the safety of the whooping cough (pertussis) vaccination in pregnant women, using GP data from around 12.5 million women. In 2012, the UK targeted a vaccination programme at pregnant women to tackle an increasing rate of whooping cough, a very dangerous condition for newborns. This study found that the vaccine didn't increase the risk of stillbirth.

Why was this work needed?

Whooping cough can be a dangerous disease, in particular among children under three months old. In response to an increase in whooping cough, in 2012 the Government started a campaign to vaccinate pregnant women. Although the vaccine was known to have only mild side effects, in children and non-pregnant adults, and was deemed safe to implement, it had not been systematically checked in pregnancy. Therefore, it was very important that its safety was carefully monitored from the beginning of the campaign, just in case there were any adverse effects.

What happened?

The Medicines and Healthcare products Regulatory Agency (MHRA) wanted to check the safety of giving the whooping cough vaccine to pregnant women. The MHRA looked at the GP records of women who were given the vaccine for six months afterwards, checking for any health problems, particularly stillbirth. They compared the rates of stillbirth among vaccinated mothers with those who hadn’t been vaccinated to check whether there was any difference between the two groups.

What were the benefits?

This study found that the vaccination did not increase the rates of stillbirth, or other difficulties in pregnancy. This means that the campaign to vaccinate pregnant women can be continued, protecting unborn children from a potentially deadly disease.

What type of data was involved?

This research was conducted using the Clinical Practice Research Datalink (CPRD), a database of GP records.

GP practices agree to allow their data to be uploaded to the CPRD. Linkage for this study was carried out within the CPRD and researchers were then given access to the data, which was de-personalised.

Who funded and collaborated on this work?

This work was carried out by the MHRA, with data provided by the CPRD.

Where can I go for more information?

Safety of pertussis vaccination in pregnant women in UK: observational study