Changes to menstrual cycle following Covid vaccine could be temporary, says expert

 (Getty Images/iStockphoto)
(Getty Images/iStockphoto)

Changes to periods after having a coronavirus vaccine may occur but will quickly return to normal, a leading expert in menstruation has said.

Dr Victoria Male of Imperial College London has cited two recent studies into the matter from the US and Norway, calling them “reassuring”.

In the US, almost 4,000 women monitored their menstrual cycles using an app and found that, after having their second vaccine dose, they experienced a delay in getting their next period.

However, the participants did not report a delay after their first dose.

One in 10 vaccinated women noticed a change in cycle length of more than eight days compared to unvaccinated women.

But after two further cycles, the women reported that their periods had returned to normal.

Similarly, a study in Norway of more than 5,600 people showed how much menstrual cycles vary regardless of vaccines.

Almost 40 per cent of those included in the study noticed one change, with heavier bleeding being the most common, before they were vaccinated.

“Changes to the menstrual cycle do occur following vaccination - but they are small compared with natural variation and quickly reverse,” Dr Male wrote in the British Medical Journal.

She added that concerns regarding fertility that have arisen as a result of the vaccine have come “from misinformation that Covid-19 vaccines cause female infertility”.

The NHS states that there’s no evidence the Covid-19 vaccines have any effect on your chances of becoming pregnant.

Several studies have been published to support this in recent months, including one in New York, published in the journal Obstetrics & Gynecology, that monitored more than 2,000 women undergoing in-vitro fertilisation (IVF) or fertility treatment.

Researchers said that rates of pregnancy were the same among vaccinated and unvaccinated women.

“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,” said lead author, Dr Devora Aharon.