Does the COVID-19 vaccine affect fertility?
No, there's no evidence that the COVID vaccine (or any vaccine) causes fertility problems for women or men. It's important to get your COVID vaccination and booster whether you're pregnant, trying to get pregnant, or planning to get pregnant in the future. And there's no need to delay conception after getting a COVID vaccine.
If you're concerned about fertility after receiving a COVID shot, consider:
- Loss of fertility hasn't been reported among participants in any of the COVID vaccine trials. In fact, about two dozen people in the Pfizer vaccine trials became pregnant while participating in the studies.
- Animal studies show no signs of infertility after COVID vaccination.
- A report tallying data from the CDC's v-safe safety monitoring system found that 4,800 people had a positive pregnancy test after receiving their first dose of the COVID-19 vaccine.
- There's no evidence that the pandemic has changed fertility patterns.
- One study found no differences in pregnancy rates among women who had COVID-19 antibodies (from vaccination or infection) and those who didn't have antibodies. It confirmed that COVID vaccination or infection doesn't prevent embryo implantation or early pregnancy development and concluded that neither COVID nor antibodies made from vaccination will cause sterility.
The American College of Obstetricians and Gynecologists (ACOG), the American Society for Reproductive Medicine (ASRM) and the Society for Maternal-Fetal Medicine (SMFM) released a joint statement in February 2021 asserting that COVID vaccines do not impact fertility.
Will getting COVID-19 or the COVID-19 vaccine affect my menstrual cycle in any way?
COVID-19 infection and your cycle
Some people have reported changes in their menstrual cycle after having a COVID-19 infection. More research is needed, but it's possible that when the body launches a fight against the illness, hormonal function may be affected, resulting in a change to the menstrual cycle. (We know that many factors – including stress – can affect your period.)
In one small study of COVID patients, nearly one-fifth of them had a menstrual volume decrease or longer cycle (time between periods). Those with severe COVID illness reported longer cycles than those with mild illness. The researchers tested levels of sex hormones and found no significant difference between those with COVID-19 and those without.
In another small study, 16 percent of participants with COVID reported a change in their period. Those who reported changes were more likely to have COVID symptoms such as fatigue, headache, body aches and pains, and shortness of breath than those who didn't report menstrual change. The change most often reported was irregular menstruation (60 percent), followed by an increase in premenstrual syndrome symptoms (45 percent) and infrequent menstruation (35 percent). The researchers underlined that the study was limited because of the small size and possible confounding factors that they didn't adjust for.
Data so far shows that most people return to their normal menstrual cycle in a month or two after their COVID-19 infection.
The COVID-19 vaccine and your cycle
Menstrual cycle information wasn't collected during the COVID-19 vaccine trials (as is unfortunately standard for any vaccine trial). More studies are needed to determine if the vaccine might affect your menstrual period in any way.
One study of almost 4,000 people who received the COVID-19 vaccine (Moderna, Pfizer, or Johnson & Johnson) concluded that the vaccine was associated with a very small and temporary (0.7 days) change in cycle length (the time between periods) but not in menses length (the total time the period lasts).
It's common for menstrual cycles to vary slightly from month to month, and they can be affected by stress. We also don't know if other vaccines might affect a menstrual cycle. (Most vaccinations are given in childhood or during pregnancy, which makes this harder to determine.)
Why do some people think the COVID vaccine affects fertility?
There's no plausible explanation for how the COVID vaccine would affect fertility.
The widespread myth stems from the idea that the vaccine would cause the body to attack a protein (called syncytin-1) that's crucial to the formation of the placenta. Proponents of this myth, mostly discussing the topic on social media platforms, claimed that there were significant similarities between syncytin-1 and the spike protein of the COVID virus. But the proteins are not remotely similar. And serum from vaccinated women (thus with antibodies) does not react with the syncytin-1 protein in lab studies.
Although there's no evidence to support a link between the COVID vaccine and fertility, many people cite it as a reason for not getting vaccinated. According to one study, 58 percent of unvaccinated survey respondents were worried about unknown long-term adverse effects, and 41 percent of those believed that the vaccine can negatively impact reproductive health and/or fertility.
Is the COVID vaccine safe if I'm going through fertility treatments?
Yes, the COVID-19 vaccine is safe while you're getting fertility treatment, such as in vitro fertilization (IVF) or intrauterine insemination (IUI). According to ASRM, there's no evidence that vaccination before or during fertility treatment will affect the treatment in any way.
One recent study of over 2,000 patients who received IVF treatment compared the results of fully vaccinated patients with those of patients who did not receive the COVID-19 vaccine. The researchers found no differences in the number of quality eggs produced for fertilization, the rates of fertilization, or pregnancy outcomes (such as the risk of miscarriage) between the patients who were vaccinated and those who weren't.
Because you may have some minor side effects after the vaccine, however, you might want to time your vaccine so that it's not within a few days of any of your procedures so that symptoms of one and the other can be distinguished and so that you feel your best during treatment. You can talk with your reproductive endocrinologist throughout the process to determine what's best for you.
Can male fertility be affected by COVID vaccination?
There's no evidence that the COVID vaccine affects male fertility. One small study of men who received the COVID-19 vaccine found that there were no changes to sperm, such as their number or their movement , before and after vaccination.
Having COVID may negatively affect male fertility, however, including sperm production. Researchers are looking into this. One review of the medical literature on COVID-19 and male fertility, for example, concluded that COVID-19 infection can cause a temporary reduction in testosterone production.
More studies are needed, but at this point it looks like if you're concerned about fertility, it's most important to get a COVID vaccine and booster and avoid a COVID-19 infection.
When should I get the COVID vaccine if I'm trying to conceive?
You should get the COVID vaccine right away if you're trying to conceive. Getting vaccinated now will help protect you from becoming ill with the virus while you're pregnant. Pregnant women who get COVID are at increased risk of preterm birth and perhaps other pregnancy complications, such as preeclampsia and stillbirth. They're also at higher risk of severe illness – including intensive care admission, mechanical ventilation, and death.
Be sure to follow up with your booster at the scheduled time, too. It's safe to receive both your vaccine and your booster shot at any time during pregnancy.