Coronavirus jabs do not affect a woman’s ability to conceive a child, another study suggests.
Researchers in New York monitored more than 2,000 women undergoing in-vitro fertilisation (IVF) or fertility treatment.
Rates of pregnancy were ‘the same’ among unvaccinated women and those double-jabbed with Pfizer or Moderna.
The researchers said the findings add to ‘ever-increasing evidence’ the jabs do not interfere with fertility, despite misinformation being common online.
Lead author Dr Devora Aharon added that there was no difference in ‘egg quality or embryo development’ between women who were jabbed and un-jabbed.
She said: ‘Our findings that vaccination had no impact on these outcomes should be reassuring to those who are trying to conceive or are in early pregnancy.’
Vaccine hesitancy has been common among young women and expectant mothers due to concerns about fertility that were preyed upon by anti-vaxx groups.
But despite billions of women vaccinated around the world, there has not been any uptick in miscarriages or significant dips in birthrates.
And a growing number of studies have failed to spot a mechanism for the vaccines to interfere with fertility or pregnancy.
Researchers at Reproductive Medicine Associates in New York found 59.5 per cent of vaccinated and 63.7 per cent of unvaccinated women undergoing frozen-thawed embryo transfer became clinically pregnant (meaning that their positive test was confirmed by an ultrasound). They said ‘no significant differences were seen’ between vaccinated and unvaccinated patients in the secondary outcomes of pregnancy rate (a positive pregnancy test), ongoing pregnancy rate, biochemical loss rate (when a pregnancy is lost after a positive test), or clinical pregnancy loss rate (when a pregnancy is lost after a positive test and ultrasound scan detected early development of the embryo)
Researchers who monitored more than 2,000 women undergoing fertility treatment said rates of fertilisation and pregnancy were ‘the same’ among the unvaccinated and those jabbed with Pfizer or Moderna
The Royal College of Obstetricians and Gynaecologists — which is made up of the top fertility doctors in the UK — says there is ‘no biologically plausible mechanism by which current vaccines would cause any impact on a woman’s fertility’.
‘Evidence has not been presented that women who have been vaccinated have gone on to have fertility problems,’ it says on its website.
For the latest study, published in the journal Obstetrics & Gynecology, scientists from the Reproductive Medicine Associates of New York looked at 2,152 women, of which just 20 per cent were double-jabbed.
They had an average age of 37 and were given fertility treatment between February and September last year.
A group of around 950 women underwent IVF, which saw their eggs fertilised in a lab then transferred into their womb.
The second group of around 1,200 women were given drugs that increased their chance of conceiving naturally.
In the IVF group, 73.8 per cent of those vaccinated had a positive pregnancy test, compared to 74.9 per cent of the unvaccinated group.
And 59.5 per cent of vaccinated people and 63.7 per cent of unvaccinated people became clinically pregnant, meaning their positive pregnancy test was confirmed via an ultrasound.
Among those who were prescribed ovarian stimulation drugs, eggs became fertilised among 80.7 per cent of the vaccinated group and 78.7 per cent of the unvaccinated.
The team said these rates were not statistically different.
IVF success rates vary due to multiple factors, which may explain why the overall pregnancy rates were lower in those groups.
Dr Aharon, an expert in reproductive endocrinology and infertility at medical school Icahn Mount Sinai in New York and RMA, said: ‘This is one of the largest studies to review fertility and IVF cycle outcomes in patients who received Covid vaccinations.
‘The study found no significant differences in response to ovarian hyperstimulation, egg quality, embryo development, or pregnancy outcomes between the vaccinated compared to unvaccinated patients.’
As well as among women trying to conceive, jabs have also been shown to be safe in women currently pregnant.
More than 100,000 women in the UK have been vaccinated while carrying a child, largely with Pfizer or Moderna, according to the Joint Committee on Vaccination and Immunisation.
Research shows the vaccines do not increase the risk of miscarriage, preterm birth, stillbirth, a baby being born too small or having birth defects.
Data from the UK Health Security Agency shows the stillbirth rate for vaccinated women was 3.4 per 1,000, compared to 3.6 per 1,000 unvaccinated women between January and August 2021.
And one in 20 babies were born with a low birth rate among both jabbed and unjabbed mothers, according to UKHSA figures.
The premature birth rate was 6.5 per cent for vaccinated mothers and 6 per cent for unjabbed mothers.
Senior author Dr Alan Copperman said: ‘By leveraging science and big data, we can help reassure patients of reproductive age and enable them to make the best decisions for themselves.
‘It will give people comfort to know that the Covid vaccine does not affect their reproductive potential.’
Around one in 50 babies born in the UK and US are through IVF, with more than 70,000 IVF cycles recorded among Britons in 2019, compared to more than 300,000 among Americans.
Despite Covid jabs being safe in pregnant women and lowering their risk of becoming severely unwell, just one in five pregnant women in the US and UK are vaccinated, official figures show.
Q&A: Everything you need to know about Covid vaccines in pregnancy
Are vaccines safe for pregnant women?
There is no evidence the vaccines cause a different reaction in pregnant women.
Side effects reported by expectant mothers are similar to those seen among non-pregnant women.
Real-world data does, however, show mothers-to-be face a greater risk from Covid, especially if they get infected in their third trimester or have underlying health conditions.
The Royal College of Obstetricians and Gynaecologists warn pregnant women are slightly more likely to give birth prematurely or suffer a stillbirth if they catch Covid.
And NHS chiefs last month revealed one in five Covid patients on ventilators were expectant mothers who had not been jabbed.
Could vaccines harm babies in the womb?
Experts have uncovered no proof that the jabs can harm babies in the womb — and insist there’s no reason to suspect they would either.
Covid vaccines do not contain ingredients that are known to be harmful to pregnant women or to a developing baby.
Nor do they contain organisms that can multiply in the body, so they cannot infect an unborn baby in the womb.
Studies of the vaccines in animals to look at the effects on pregnancy have shown no evidence jabs cause harm.
Research from six studies involving 40,000 women show the vaccines don’t raise the risk of miscarriage, preterm birth, stillbirth, or the baby being born smaller than usual or with birth defects.
Miscarriages occur in 20 to 25 per cent of pregnancies in the UK, while stillbirths happen in one in every 200 pregnancies in Britain.
Can vaccines make it harder to get pregnant?
There is also no evidence the Covid vaccines hamper a woman’s chances of getting pregnant.
The Association of Reproductive and Clinical Scientists and the British Fertility Society says there is ‘absolutely no evidence, and no theoretical reason, that any of the vaccines can affect the fertility of women or men’.
But some concerns have been raised because thousands of women have recorded disrupted period after getting the jabs.
By October 27, the UK medicines watchdog, the Medicines and Healthcare Products Regulatory Agency (MHRA), had received 41,332 reports of menstrual cycle side effects after first, second or third doses of the Covid jabs.
Nearly 50million Covid vaccines had been administered to women up to the same date.
The side effects included heavier or lighter bleeding than usual, as well as more painful periods. But the MHRA said the changes are ‘transient in nature’ — meaning they are short-lived.
Period problems are very common — with up to a quarter of women of childbearing age reporting them at any one time — and are often triggered by stress.
Why were vaccines not initially offered to pregnant women?
Like other vaccines and medicines, clinical trials of the Covid jabs did not include pregnant women.
This meant the UK’s vaccine advisers, the Joint Committee on Vaccination and Immunisation (JCVI), did not have enough evidence to recommend pregnant women should get vaccinated when jabs were initially rolled out last winter.
But real-world data from the US — where 90,000 pregnant were given doses of Pfizer or Moderna — did not reveal any safety concerns.
So the JCVI advised that these jabs should be offered in the UK.
And subsequent studies show the jabs were just as effective in pregnant women as those who were not pregnant.