AS GLOBAL vaccination against covid-19 ramps up, women who are pregnant, breastfeeding or trying to conceive have been left uncertain as to whether they should join in.
Advice has been slow to develop, and is often contradictory. Initially, the UK’s Joint Committee on Vaccination and Immunisation said people shouldn’t get a coronavirus vaccination if they were pregnant or planning to conceive in the next three months. But the pregnant women who are likely to be exposed to the coronavirus because they work in healthcare, for instance, may wish to consider getting vaccinated after discussing it with a healthcare professional. It also says there is no need to delay conception or avoid breastfeeding.
The and the have similar advice. Israel, in contrast, has , after several pregnant women were hospitalised with covid-19.
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Israel’s health ministry advises those who are pregnant to wait until their second trimester to get a vaccine unless they have other risk factors. “This would seem a reasonable approach if vaccination during pregnancy is indicated,” says Adam Balen at Leeds Fertility in the UK. “The very early developing embryo is undergoing dramatic changes even before a pregnancy test is positive.”
It isn’t clear how pregnancy affects covid-19 risk. There is no evidence that pregnant women are more likely to get severely ill, but they are classed as being at moderate risk because they can get more sick from viruses like flu, according to .
“From basic principles, there is no reason to think the vaccine would be unsafe in pregnancy”
It may be possible for pregnant women to pass the coronavirus to a baby before it is born, but when this has happened, the baby has recovered. There is no evidence that the coronavirus causes miscarriage or affects a fetus’s development.
When it comes to weighing up vaccination options, those who are pregnant have little safety data to go on. All the trials completed so far aimed to exclude pregnant women, as is standard in medical research. However, in the trial of the vaccine created by Pfizer and its partner BioNTech, 23 women discovered they were pregnant after getting the vaccine and no problems have been reported.
Trials in pregnant women are usually carried out after a few years of data have accrued from women who take a new medicine without realising they are pregnant. But in the case of covid-19, “we don’t want to wait because it can be such a serious illness”, says Pat O’Brien, vice-president at the UK’s Royal College of Obstetricians and Gynaecologists.
From basic principles, there is no reason to think a covid-19 vaccine would be unsafe for pregnant women, says O’Brien. While vaccines based on live viruses are avoided in case they infect the fetus and cause harm, none of the available covid-19 vaccines are based on live virus that can reproduce. Pregnant women are offered other non-live vaccines, such as those against flu.
More information will emerge this year. Pfizer is starting a vaccine trial in pregnant women, and there are plans to create registries of people who receive the covid-19 vaccine while pregnant.
In the meantime, healthcare providers need to help people weigh up the risks and benefits, says O’Brien. “It’s an individual’s decision, with support from a professional. It might sound like a cop-out, but that happens all the time in maternity care.”
