It is coming up to a year since the first mRNA vaccines were approved for use against Covid-19, and almost seven months since they were approved for expectant mothers. The initial government advice was was that they should hold off getting a jab, but since more data has become available, medical experts have been encouraging women to get vaccinated. But there has been no big government awareness campaign, despite pregnant women being identified as a vulnerable group. I knew the proportion of fully vaccinated pregnant women in the UK would be low, but I did not expect it to be as low as 15% (in the US, it is more than twice that, at 33.8%).

That such a small porportion of pregnant women are fully vaccinated in the UK, seven months after vaccines were approved for them, is nothing short of a scandal. And more women and their babies are at risk of dying because of it. Recent figures for England show that one in six critically ill patients are unvaccinated pregnant women with Covid. Of the 20 pregnant women requiring the highest level of life-saving care, 19 were unvaccinated and one had received one dose.

These are frightening statistics, but on their own they do not seem to be enough to persuade pregnant women to get vaccinated. In order to do that, it’s important to understand why we are seeing such high levels of hesitancy.

Women are used to being told to avoid certain foods and medication when they are pregnant. In the absence of data that can be ethically collected, patients become accustomed to a “better not, just in case” philosophy. Conflicting opinions abound, and vary from country to country. Can you have a glass of wine? Eat feta? Take medication? Use sun lotion? In this way, pregnant women are primed to always take what they believe is a risk-averse approach.

In February, at the very beginning of the vaccine rollout, a pregnant friend of mine, a doctor who worked in ICU, had her first dose of an mRNA vaccine to protect her and her baby against Covid-19. At the time, this went against government advice, as there was not much data available. However, she did her own literature review and rightly concluded that there would be no conceivable reason that the vaccine’s ingredients would cross the placenta or harm her baby, and got her jab.

Most pregnant women do not have the scientific grounding that my friend has. But at various points this year, I have reflected how easy it would have been to have furnished them with a factsheet or a leaflet explaining the science and how it works, making clear that, despite the initial absence of data, there was no scientific reason to suggest the vaccine would harm their baby, and laying out the risks to pregnant women of staying unvaccinated.

Instead, pregnant women have been left to do their own research. Government agencies have created a vacuum that has been filled by disinformation. There has been little information given about the risks to pregnant women, short of saying that they are at increased risk of severe illness, and minimal comment on the risk that even a mild case of Covid might pose to a baby. When you are pregnant your immune system is suppressed. Your uterus is expanding, putting pressure on your lungs. Having Covid at around the time of birth makes a woman twice as likely to have a premature delivery or stillbirth, and more likely to need an emergency caesarean. We have known this since May. My doctor friend concluded that the risks from having Covid and low oxygen levels while pregnant were far greater than any unfeasible, theoretical risk from the vaccines.

There has been mixed messaging, even from medical professionals. Another pregnant friend of mine, who also works in the NHS, held off having the vaccine earlier this year, but, deciding the risks were too great for her and her baby, went on to have both doses in the second trimester.

“NHS staff haven’t helped,” she says. “I had to take my husband with me for moral support because they kept telling me that I had to weigh up risks and benefits and there was no evidence it wouldn’t harm my pregnancy. It was terrifying!”

Several friends of hers had the same experience and also went ahead, and all have since had their babies. But they shouldn’t have needed to fight in order to access crucial medical care, and they should have received information and encouragement about the vaccine – just as pregnant women do for flu and whooping cough vaccinations. Instead, pregnant women describe receiving no prompts or messages, and some say they have had to seek out the factsheets and bring it up themselves with doctors and midwives.

More than 100,000 pregnant women in England and Scotland have received a Covid-19 vaccine with no adverse effects recorded. More than 160,000 pregnant women in the US have had a Covid-19 vaccine (Pfizer/BioNTech or Moderna) with no safety concerns being raised. Early data from three US safety monitoring systems did not find any safety concerns for pregnant people who received an mRNA Covid-19 vaccine late in pregnancy or for their babies. No increased risk of miscarriage was found among people who received a vaccine just before and during early pregnancy (before 20 weeks of pregnancy). No safety concerns were found in animal studies. And the antibodies produced may well help to protect your baby (research is ongoing on this).

The low take-up of vaccines among pregnant women makes me despair. It is an outrage, and increased pressure on maternity services will not help. Some women are not seeing a single medical professional for the first 12 weeks of their pregnancies – surely a giant missed opportunity for a conversation about vaccination. The tone towards the pregnant population has been one of blame, but we should not be blaming women who have been left without clear messaging. Why has this group been so neglected when other vulnerable groups have not?

Now that England has ditched masks and loosened other restrictions, some of these women will have essentially become shut-ins for the duration of their pregnancies. If they do mix, in waiting rooms, at NCT classes and other in-person groups, they put vaccinated pregnant women and their babies at risk. But it is not their fault: they have been failed, and more women and babies are at risk of dying as a result.

• Rhiannon Lucy Cosslett is a Guardian columnist and author