Do coronavirus vaccinations affect the cycle?

and Christiane Fux, medical editor

Maximilian Reindl studied chemistry and biochemistry at the LMU in Munich and has been a member of the editorial team since December 2020. He will familiarize himself with medical, scientific and health policy topics for you in order to make them understandable and comprehensible.

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Christiane Fux studied journalism and psychology in Hamburg. The experienced medical editor has been writing magazine articles, news and factual texts on all conceivable health topics since 2001. In addition to her work for, Christiane Fux is also active in prose. Her first crime novel was published in 2012, and she also writes, designs and publishes her own crime plays.

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There are currently increasing reports of menstrual disorders, which have occurred in rare cases after a coronavirus vaccination. Is there a connection? Read what is known about it here.

Before a Covid-19 vaccination, doctors inform the vaccinated about possible side effects. Typical vaccine reactions that can be expected are pain at the injection site, fatigue or slight febrile reactions. There is usually no mention of irregularities in the menstrual cycle.

Increased reports from vaccinated women now indicate that these could occur. Those affected report heavy or premature menstrual bleeding following a vaccination. There are as yet no reliable figures on how often such possible side effects actually occur. The officially reported number of cases is currently low.

However, such a connection is not implausible: there have been similar observations with regard to other vaccines from previous years - for example after flu vaccinations or HPV vaccinations. These vaccines sometimes affected the woman's menstrual cycle. Afterwards, however, it usually leveled off again soon.

Do coronavirus vaccines increase the risk of bleeding?

The UK's Medicines and Healthcare Products Regulatory Agency (MHRA) reported 958 documented cases of menstrual disorders following vaccination as of April 5, 2021.

These cases are distributed in a ratio of 2: 1 between the vaccines VaxZevria from the manufacturer AstraZeneca (643 cases) and Comirnaty from BioNTech / Pfizer (315 cases). According to a statement from the British Medical Journal, the actual number of cases could also be higher.

Menstrual cycle disorders reported in Germany

The Paul Ehrlich Institute (PEI) also lists a number of cases in its 11th safety report (as of May 31, 2021) in which bleeding events occurred after a coronavirus vaccination. As in Great Britain, the risk of bleeding after vaccination with VaxZevria is higher in Germany than after vaccination with mRNA vaccines.

However, the institute summarizes all minor bleeding events. This means that it does not differentiate between bruises, nosebleeds, bleeding gums, bloody urine and a disturbed menstrual bleeding.

Usually harmless and rare

In concrete terms, this means a reporting rate of 76.2 bleeds per million vaccinated people for the vector vaccine VaxZevria in Germany. For Comirnaty, the PEI puts the cases at 7.5 per million people and with the Moderna vaccine at 10.4 bleeding events per million people.

However, the informative value of these figures reported so far is limited. The PEI points out that the increased media attention may have led to higher reporting rates.

What is known about possible causes?

At present, one can only speculate about the causes of a possible connection. There is still a lack of relevant studies. But there are different hypotheses:

Coagulation disorder: It is known that vector vaccines can, in rare cases, cause certain coagulation disorders. It is therefore possible that the reported bleeding could be related to a vaccine-related platelet disorder.

Activated immune system: The strong activation of the immune system could also explain an early onset of the period after a vaccination. It goes hand in hand with an increased release of inflammatory messenger substances and an increased activity of immune cells.

Immune influence on the cycle: Immune cells, in turn, are themselves significantly involved in building, maintaining and breaking down the uterine lining. It is therefore conceivable that a vaccination could temporarily influence the cycle in this way and bring it out of step.

However, the irregularities observed could also be the result of a complex interplay of several influencing factors - such as persistent stress or psychological challenges from the stresses of everyday life in a pandemic.

Further studies must clarify whether and if so, how the vaccinations disrupt the cycle.

Does vaccination affect pregnancy?

Although vaccinations may have a temporary effect on the menstrual cycle, as far as we know today, this does not mean an increased risk of bleeding during pregnancy.

No general STIKO recommendation for pregnant women

The Standing Vaccination Commission (STIKO) in Germany does not currently recommend that pregnant women be vaccinated against the Sars-CoV-2 pathogen during pregnancy. Vaccination is recommended for pregnant women with previous illnesses and pregnant women with a high risk of getting sick.

In these cases, you should seek medical advice as a victim. After weighing up the risks and benefits, you can receive a vaccination with an mRNA vaccine from the second trimester. If the vaccination is given as part of a pregnancy that has not yet been recognized, the STIKO sees no relevant risk for mother and child.

When should you see a doctor?

If you notice an irregular cycle after a coronavirus vaccination, there is nothing to worry about at first. In most cases, the cycle will quickly level off again.

However, if your cycle is repeatedly irregular, you should definitely consult a doctor you trust in order to receive the best possible care. This is especially true if you are in severe pain or lose large amounts of blood.

Tags:  Diseases elderly care magazine