Not enough evidence to link Covid vaccine to menstrual changes, say experts

While the Commission for Gender Equality (CGE) is pressing against mandatory Covid vaccines due to a recent study that found a link between menstrual cycle length and the jab, doctors say there is nothing to worry about.

The reason for this, say experts, is the cycle returned to normal in two to three months and there was no direct evidence linking this solely to the vaccine.

An American study published in the Obstetrics and Gynecology journal this month found that of nearly 4,000 people whose menstrual cycles were tracked, 2,400 people experienced a less than one-day change in cycle length after receiving two doses of the Covid vaccine.

More than half of the vaccinated respondents had received the Pfizer jab.

But back in South Africa, Thato Penya, 33, said she started experiencing a difference in her menstruation after getting her first Pfizer dose in September last year. Instead of a longer menstrual cycle, she suffered a much heavier flow.

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“I had no side effects after taking it, until I got my periods. I realised that my flow is very heavy and started wondering what was wrong. My hormones also seemed to change. My face started to break-out. What made me realise it could be the Pfizer vaccine is when I spoke to my colleague who said she is experiencing weird side effects ever since she took the same jab. Her side effects were similar to mine but she was spotting non-stop,” she said.

Experts, however, emphasise that a direct link to the Covid vaccine needs to be probed further.

Specialist obstetrician and gynaecologist Dr Emmanuel Moagi says there is insufficient evidence to attribute menstrual change to the vaccine as there could be a “co-founder” associated with such an effect.

“We can’t say the vaccine is behind it. The evidence shows that… it is on an individual basis. We can’t base this on one or two people and say the vaccine affects the menstrual cycle. It depends on other issues. The vaccine (alone) should not do that,” said Moagi.

While previous studies found similar results, such as research published in September last year by the British Medical Journal, these reports were low compared to the number of vaccines administered, said Professor Glenda Davison, head of the biometric sciences department at Cape Peninsula University.

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The reason for the slight change in the cycle was initially speculated to be caused by the immune response, but this still needs to be studied, she said.

“Hormones which control the menstrual cycle can be influenced by the immune response. This is one reason. Another could be that the vaccine may influence the immune cells which are in the lining of the uterus and which also play a role in regulating the menstrual cycle,” said Davison.

Evidence suggested that everything returns to normal by the second cycle, she said.

“Therefore, there is no need to fear anything worse. Fertility is not affected and the cycle returns to normal. Women receiving the vaccine have been able to fall pregnant quite easily.”

The CGE, however, said such scientific evidence between the Covid vaccine and women’s reproductive health may leave many women uncomfortable with getting vaccinated. The Chapter 9 institution said those who wish to delay getting the vaccine should be respected and not forced.

“While health experts believe this finding is not clinically significant, the commission would like to caution businesses and various institutions against forcing employees to vaccinate and imposing harsh sanctions on them if they do not.”

“The commission has long taken a commitment to promote and protect the sexual and reproductive health rights of girls, women, and men. It must be acknowledged that Covid-19 is a relatively new pandemic, and that scientists in South Africa and around the world are still working to assess long-term effects of vaccines. This is more critical for women, who have to manage menstrual health, contraception, and sexual reproduction, as part of their reproductive health,” said CGE spokesperson Javu Baloyi.

The Obstetrics and Gynecology report, led by Alison Edelman, lacked the population-level to obtain sufficient evidence.

“Social media reports suggest menstrual disturbances are much more common but that these disturbances appear to be temporary. The lack of population-level, prospective evidence about relationship to Covid-19 vaccination and menstrual cycles limits our ability to sufficiently address these concerns and to counsel individuals who menstruate about what to expect with vaccination,” said the report.

rorisangk@citizen.co.za