Cases of whooping cough have risen in the last six months. Despite a vaccination now being available to pregnant women, figures suggest that only half of mothers to be are being immunised.
Whooping cough can be deadly and newborns are highly susceptible to the infection until they start vaccination at two months old. Three years ago, a vaccine for pregnant women was introduced.
According to Public Health England (PHE) 56.4% of pregnant women were vaccinated in 2014-15. During that period were seven baby deaths from whooping cough.
Dr Mary Ramsay, PHE's head of immunisation, told BBC News: "It's important that pregnant women visit their GP surgery or midwife to get vaccinated, ideally between weeks 28 and 32 of their pregnancy. Being vaccinated against whooping cough while you're pregnant is a highly effective way to protect your baby in the first few weeks of their life."
Vaccination reduced the risk of a newborn developing whooping cough by 91%.
Prof Alan Cameron, from the Royal College of Obstetricians and Gynecologists, said: "We understand some women may have concerns about receiving vaccinations during their pregnancy, but we can provide reassurance that the whooping cough vaccine is safe for use during pregnancy, with no known adverse side effects for mother or baby."