There are several rumours going around about Covid-19 vaccines and pregnancy, periods, and fertility.
So let’s be clear about this: any claims that vaccination can cause infertility are baseless.
For starters, the Royal Australian and New Zealand College of Obstetrics and Gynecology has recommended those who are pregnant are offered the Pfizer-BioNTech vaccine — that's the vaccine currently being rolled out across the country — at any stage of pregnancy.
The Pfizer vaccine is an mRNA vaccine (so is the one made by Moderna). These vaccines don't contain any live virus. They use a chemical messenger — the mRNA, or messenger ribonucleic acid — to help teach our immune system to recognise and attack the virus.
The mRNA never enters the nucleus of cells, where our genetic material is kept.
Data from large numbers of pregnant women around the world have not identified any safety concerns with mRNA Covid-19 vaccines.
Plus, there's evidence the breastmilk of vaccinated mothers contains antibodies that can help protect infants against Covid-19.
Declining the vaccine, however, comes with many risks. This is because pregnancy significantly increases the risk of severe outcomes from Covid-19.
We've covered this subject in more detail in another post, as part of The Whole Truth: Covid-19 Vaccination.
People trying to conceive should also have the vaccine as soon as they’re eligible, says Dr Andrew Murray, medical director at Fertility Associates Wellington.
One study involving 32 women undergoing in vitro fertilisation found Covid-19 vaccination with the Pfizer vaccine had no effect on the health of the ovarian follicles or egg quality. Another that looked at IVF outcomes among vaccinated people found vaccination before conception doesn't affect embryo implantation.
Recently, rapper Nicki Minaj said her cousin's friend in Trinidad and Tobago "became impotent" after receiving the vaccine. These claims have been widely rejected — studies have shown the mRNA Covid-19 vaccines appear safe for the male reproductive system.
Contracting Covid-19, on the other hand, has been associated with male infertility and sexual dysfunction.
Experts agree, there's no plausible mechanism by which the leading Covid-19 vaccines could cause infertility or damage a pregnancy.
“There are no known mechanisms by which the vaccine could impact reproductive tissues or functions,” says Associate Professor Rebecca Campbell from Otago University's Centre for Neuroendocrinology.
After it has done its job, the mRNA from the vaccine is broken down by our immune cells. Professor Graham Le Gros, director of the Malaghan Institute, says the body's immune system is "all about localisation".
Our reproductive organs are “exquisitely designed to be protected from foreign substances including infections”, he says.
That's why some people will experience temporary swelling and pain near the injection site after getting the jab.
Some people have asked whether menstrual cycle changes can be a side effect of getting the jab. So far, these reports are anecdotal (although there's a survey underway).
In Aotearoa, reports of "menstrual disorders and unexpected vaginal bleeding" have been reviewed by the Covid-19 Vaccine Independent Safety Monitoring Board. The number of reports is low compared to the number of women who have been vaccinated, and how common these experiences are generally, Medsafe said.
The board found current evidence doesn’t support a link between menstrual changes and vaccination, but it will continue to monitor reports.
We know there's a long list of triggers that can cause changes to someone's cycle, including stress, nutrition, illnesses and inflammation. So — while unlikely — even if there is a connection, any changes will be short-term, seen only during the cycle in which the vaccine was given.
Reporting disclosure statement: This post was written with expert advice from Professor Graham Le Gros, director of the Malaghan Institute of Medical Research and programme director of Vaccine Alliance Aotearoa New Zealand, and Associate Professor Rebecca Campbell, from Otago University’s Centre for Neuroendocrinology. It was reviewed by The Whole Truth: Covid-19 Vaccination expert panel member Dr Dianne Sika-Paotonu, immunologist and senior lecturer in pathology and molecular medicine.
