A poll of more than 3,000 women for the charity Group B Strep Support found only one in three feel well informed about the risks of Group B Strep (GBS), which is the UK's most common cause of life-threatening infection in newborn babies.
GBS can cause a range of serious problems, including meningitis, septicaemia and pneumonia.
Two newborns every day develop the infection. While many recover, one baby a week does not survive and one baby a week is left disabled.
The NHS does not currently recommend screening for GBS.
Women living in other countries - including the US, Canada, France, Germany and Slovenia - are routinely offered a test.
In the new poll, carried out by Bounty for Group B Strep Support, two thirds of expectant or new mothers said they were not properly informed about GBS.
Personal experience or hearing about GBS from a friend remain the most common ways women become aware of the infection.
Around one in five pregnant women in the UK carries GBS in their digestive system or their vagina and some babies become infected during birth.
Symptoms of GBS in babies include being floppy and unresponsive, not feeding well, grunting, having a high or low temperature, and fast or slow breathing or heart rate.
Women who test positive for GBS can be offered antibiotics in labour to reduce the chance of passing on the infection to their baby.
Group B Strep Support chief executive Jane Plumb said she was pleased that the survey showed that, on the whole, awareness of GBS among women was increasing.
But she added: "In too many cases, this awareness is the result of either tragic personal experience or that of a friend.
"It must be the responsibility of all health professionals to inform their new and expectant mums of the risks of Group B Strep. Too many women are being let down at present."
The charity is working with the Royal College of Obstetricians and Gynaecologists to provide a patient information leaflet that will be available in maternity units.
Ms Plumb is also calling for all women to be screened.
She said the Department of Health has committed to undertaking a trial that will compare the testing of all pregnant women for GBS with the current approach, but this will not finish until 2021.
The charity also wants the NHS, when it does test pregnant women, to use enriched culture medium (ECM) testing, which costs around £11 per test.
It said the current NHS test is inadequate and misses around half of women carrying GBS.
ECM is available privately for about £40.
GBS caused the death of one-day-old Pippa Griffiths last year while under the care of Shrewsbury and Telford Hospital NHS Trust.
A coroner ruled her death could have been prevented if GBS had been spotted earlier.
A post-mortem showed that GBS was also a factor in the death of Jack Burn, who died at the trust in 2015.
Health Secretary Jeremy Hunt has ordered an investigation into at least seven avoidable baby deaths that occurred within two years at the trust.
A Department of Health spokeswoman said: "Providing women and their babies safe care is our priority which is why, based on the independent UK National Screening Committee's recommendation, we have not approved screening for Group B Strep - in part because this would have led to about 100,000 screened women being prescribed antibiotics unnecessarily during labour.
"However, as the committee recognises, better quality evidence is needed to assess the clinical effectiveness and impact of a screening programme. That's why this August, we invited people to apply for a trial to compare universal screening for Group B Strep against usual risk based care."