Almost 4,000 women have reportedly suffered period problems shortly after getting their Covid jab, Britain's vaccines watchdog has confirmed. 

The issues, which have typically involved 'heavier than usual' bleeding or a delayed period, have primarily affected women aged between 30 and 49.

The Medicines and Healthcare products Regulatory Agency (MHRA) claimed it had received 2,734 reports linked to the AstraZeneca jab up to May 17. Another 1,158 reported menstrual changes after receiving Pfizer's and a further 66 were linked to the recently deployed Moderna jab.

Experts said the number of women suffering from period problems will 'definitely' be higher because many don't take the time to report them through official channels. 

The figures, obtained by the Sunday Times, have raised questions about why menstrual changes are not included on the MHRA's list of potential Covid jab side effects.  

However, the regulator said a review into the issue concluded that the symptoms were not happening more frequently in newly vaccinated women than the general population. It said it would continue to 'closely monitor' the situation.

MHRA chief executive Dr June Raine said: 'Alongside the independent experts of the Commission on Human Medicines and members of its Medicines for Women's Health Expert Advisory Group, we have reviewed reports of menstrual disorders and unexpected vaginal bleeding, suspected as adverse reactions to vaccination. 

'The current evidence does not suggest an increased risk, following vaccination, with the UK's three Covid vaccines.

'The number of reports is low in relation to the number of women who have had the vaccine to date and the background rate of menstrual disorders generally. 

'We continue to closely monitor these reports for potential signals.' 

Up to a quarter of women of childbearing age experience menstrual irregularities, which can include heavier or lighter than usual bleeding, delayed or early periods and cramps. 

They are often triggered by hormonal changes and stress, as well as certain medical conditions and medications.

Similar issues after vaccination have been reported in the US, but scientists say it is too early to confirm a link. 

However, GAVI, an international alliance dedicated to ensuring the world has fair access to Covid jabs has said it could be possible.