For the past few weeks, I’ve been researching the effect of COVID-19 infection on fertility. Thankfully, negative effects appear to be temporary in males. But what about the pandemic and female fertility?
Let’s take a closer look at the research.
The importance of ACE2
The information on female fertility and the pandemic isn’t black and white. But it’s important to clearly look at what we do know and how it applies to each unique fertility situation.
Over and over, the studies I reviewed showed that males were more affected by the COVID-19 pandemic than females. This is due to the higher number of ACE2 receptors in the male reproductive system.
In our day-to-day lives, ACE2 is an enzyme that heads an amazing balancing act of hormones in the renin-angiotensin system (RAS).
It produces hormones that regulate inflammation (pro and anti), the constriction and dilation of blood vessels, blood pressure, tissue remodeling, and even metabolic function.
And even though there are more ACE2 enzymes in the male reproductive system, they are present in the ovaries and the uterus (specifically the endometrium, or uterine lining), and also the placenta.
In these areas, ACE2 actions result in effects specific to the reproductive system.
You might be wondering what this has to do with the pandemic!
The novel SARS virus (SARS-CoV-2) gains access to our cells by using the ACE2 enzyme as its docking station.
When it attaches to ACE2 and begins entering our body, it disrupts the balancing act illustrated above. (If you want all the details, click here for one of the most outstanding papers I’ve read about the physiology of the COVID-19 pandemic.)
Unfortunately, the imbalance created by infection with novel SARS is probably a major underlying cause of the extreme inflammation seen in some patients.
And as we’ve learned over the past two years, COVID-19 is more than a respiratory virus.
So, while it’s great news that females have relatively fewer ACE2 receptors in their reproductive system, as I mentioned earlier, there are some in the ovaries and uterus.
The pandemic and female fertility
So what does this mean for fertility and reproduction?
This is the part that isn’t clear.
Many review studies (a study that is like a scientific book report) have examined hypotheticals, meaning they’ve outlined the physiology above and proposed that infection with SARS-CoV-2 might be detrimental to female fertility.
And while these studies are useful, they don’t directly answer the question that is most important—how does infection actually affect female fertility?
Only a handful of studies have given us some answers.
What does the research say?
A study from March of 2021 found connections between decreased levels of anti-Müllerian hormone (AMH) and increased levels of testosterone, prolactin, luteinizing hormones, and follicular stimulating hormone in females infected with SARS-CoV-2 compared to those in a healthy control group.
The authors state that this might indicate ovarian injury and the virus’ influence on the nervous system.
However, they’re also transparent about the limitations of the study. Because it’s an observational study, only correlation, not causation, between viral infection and ovarian function was studied.
And the median age of females in the study was 43 years old. This age and the hormonal shifts that occur as females approach peri-menopause may have influenced the results.
Finally, the study timeline was just over one month. The authors are adamant that longer studies and follow-up studies must be performed to understand the long-term effects of COVID-19 on female fertility.
Another small study explored the effects of infection and vaccination on ovarian function, specifically follicular function (immature egg function).
The researchers found no differences in follicular function or quality between infected, vaccinated, or uninfected/unvaccinated groups.
Notably, the average age of the participants was approximately 10 years younger than in the first study discussed above.
However, the authors state that larger follow-up studies should be conducted.
This study examined the effects of infection with novel SARS on female hormones and the menstrual cycle.
They found that sex hormones and ovarian reserve were not different between infected and uninfected participants.
However, nearly 20% of infected females reported changes to their menstrual cycle. Cycle changes appear to be connected to vaccination, as well.
Finally, studies examining infection and vaccination’s effect on assisted reproductive technology have found mixed results.
This study of those with mild COVID-19 found only slight differences in blastocysts (early stage of an embryo) between infected and uninfected participants.
But there were no differences in pregnancy rates, early miscarriage rates, or implantation rates.
This study also found no differences in live birth rates or pregnancy loss rates in those undergoing ART.
However, a study of 41 females with past COVID-19 infection compared to 41 females with no history of infection or vaccination found that pregnancy rates via frozen embryo transfer were extremely decreased in the infected group.
This was especially true if infection occurred near the time of transfer.
The authors explain that this can happen due to actions of the immune system against the virus or hormonal changes linked to infection.
Similarly, a larger study of over 3,000 females undergoing IVF treatment found a reduced pregnancy rate linked to vaccination against SARS-CoV-2. They recommend embryo transfer be delayed until approximately 61 days after vaccination.
The big takeaways from the pandemic and female fertility
Based on these studies, there is obviously still research that needs to be done.
The inflammatory effects of viral infection and vaccination can, to different degrees, negatively affect female fertility. But we’re not yet sure to what degree or for how long.
This seems to be especially true for those using assisted reproductive technology.
In the meantime, we can do our best to limit damaging inflammation with the healing power of often-forgotten basics:
- Rest
- Work-life balance
- Three nourishing and balanced meals per day
- Time in nature
- Appropriate movement
- Enjoyable and pleasurable activities
- Social and emotional support
- Healthy sex life (whether alone or partnered)
Finally, don’t forget the importance of routine women’s health check-ups. Necessary screening or imaging is crucial for a balanced perspective on reproductive health.
I realize this blog contains a lot of detailed information, and that as time passes, the clinical and anecdotal, and scientific knowledge base will evolve into something vastly different.
And please remember that I’m taking new clients and love to support people with concerns about their reproductive health and fertility.
Click here for a free discovery call if you or someone you know needs more personalized support.