Covid vaccine and menstrual disorders: what symptoms?

More than 10,000 cases of menstrual disorders (very long, very abundant, on the contrary non-existent periods…) have been reported after the injection of a RNA vaccine against Covid in France. Disorders that may arise during 1st, 2nd or booster dose with an mRNA vaccine like those of Pfizer or Moderna. In this context, the National Medicines Agency (ANSM) sent a state of knowledge on menstrual disorders after vaccination against Covid-19 and sent recommendations for affected women and for healthcare professionals, June 23, 2022. In addition, a declaration assistance guide has been developed with representatives of patient and healthcare professional associations to support these women. How many cases in France? With the vaccine Pfizer? From Moderna ? What are the symptoms ? The avenues considered? The behaviour to have for women with these symptoms? Status to date.

How many women have had menstrual disorders after being vaccinated in France?

According to the regional pharmacovigilance centers (CRPV), as of April 28, 2022:

• 9,381 reports of cycle disorders reported with the Comirnaty vaccine (Pfizer), that is 0.02% of total injections.
• 1,557 reports of cycle disorders reported with the Spikevax vaccine (Moderna), that is 0.01% of total injections.

The majority of these declarations were made by the patients directly. By the same date, 58 million people of all sexes had been vaccinated with the Comirnaty vaccine and 12 million people with the Spikevax vaccine.

What are the symptoms of these menstrual disorders?

Cycle disorders (also called cycle abnormalities) are menstrual cycle irregularities. They can affect both the frequency and intensity of bleedingrecalls the ANSM in its press release of June 23, 2022. During a meeting between representatives of patient associations and health professionals on menstrual disorders declared after vaccination, the menstrual disorders most frequently described in these testimonies have been :

• Rules irregular
• Rules painful (dysmenorrhea)
• Rules too abundant or too prolonged (menorrhagia) or absent for several months (amenorrhea).
• Bleeding between two cycles (metrorrhagia).
• Significant pelvic painor abdominal
• In women with endometriosis : a reactivation of their painful symptoms when the disease was well controlled until now;
• In postmenopausal womenabnormal bleeding
• In some cases, abnormal bleeding in quantity and duration has led to hysterectomies.

Are these menstrual disorders after vaccination serious?

The ANSM indicates that health professionals explained that they saw in practice few serious cases of menstrual disorders and that it was difficult to analyze them because they were often poorly documented. In their experience, the majority of menstrual disorders observed were generally non-serious, of short duration and self-limiting.

What are the possible causes of these menstrual disorders?

To date, the available data do not make it possible to describe the mechanism of occurrence of these menstrual cycle disorders.

Menstrual disorders have occurred as well after the first injection than after the second or booster dose. In parallel, the pharmacovigilance committee (PRAC) of the EMA is currently reassessing the link between these menstrual disorders and the Spikevax and Comirnaty vaccines. In its first conclusions issued in June 2022, the PRAC concluded that the evidence was insufficient at this stage to establish the link between RNA vaccines and cases of missed menstruation. Nevertheless, the committee is continuing to monitor this adverse effect. Regarding heavy menstrual bleeding, the committee concluded that the need for further evaluation. To date, the available data do not make it possible to describe the mechanism of occurrence of these menstrual cycle disorders. However, several assumptions are made:

• Reactogenicity (fever, headache, nausea, etc.) caused by vaccination. This could indeed, as during an infection, affect hormones involved in the menstrual cycle ;
• Significant stress or anxiety, generated by the act of vaccination and/or the context of a pandemic. Indeed, stress and anxiety are known factors of disturbance of the hypothalamic-pituitary-ovarian axis which regulates the smooth running of the menstrual cycle;
• Other factors: underlying gynecological disease, pregnancy, contraceptive treatment…

What to do and what is the course of action for the women concerned?

If you experience unusual effects, abnormal pain, your menstrual cycle is upset, and these disorders persist, the ANSM invites these women:

• to consult the doctor. He will be able to listen to you and, if necessary, carry out additional examinations.
• to be declared on the portal of the Ministry of Health : signalement.social-sante.gouv.fr or contact a healthcare professional.

On July 19, 2022, the ANSM indicated the provision of a declaration assistance guide. In other words, if you wish to declare menstrual disorders that appeared after vaccination against Covid-19, it is necessary to provide the most detailed information possible in the declaration form. These elements will enable the regional pharmacovigilance centers (CRPV) to conduct their assessment of reported cases as efficiently as possible. The purpose of this document is to guide you in this declaration by specifying the information to be provided. This information is not mandatory, but will be useful to the CRPVs for their analysis.

What should be done for healthcare professionals?

Faced with any symptom of menstrual disorders mentioned by your patient and according to your knowledge of her medical history:

► If the patient is taking hormonal treatment: check that there has been no poor compliance or vomiting which could be the cause of an interruption in taking the treatment

► If the patient is not taking hormone treatment or if treatment has not been interrupted:

• check that it is not an acute symptomatology
• check the absence of pregnancy (delayed period, repeated bleeding)
• keep in mind the possibility that the patient develops a gynecological disease (polycystic ovary syndrome, hyperprolactinemia, adenomyosis, etc.) concomitantly with the vaccination. If the symptoms persist the following month, it is necessary to launch investigations and consider such an underlying pathology.

► If you observe serious or unexpected adverse effects: declare on the portal of the Ministry of Health: signalement.social-sante.gouv.fr.

Source: Menstrual disorders after vaccination against Covid-19: state of knowledge and advice for women concerned, ANSM, June 23, 2022.