A study, conducted in women who underwent in vitro fertilisation, claims that there is absolutely no difference between vaccinated and unvaccinated pregnant women in terms of several key fertility markers: egg quality, embryo development, pregnancy rates or early miscarriage.

Veronica Fuentes 26/1/2022 10:12 CEST

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In pregnant women, SARS-CoV-2 infection substantially increases the risk of severe illness and death. However, a major concern since the start of the pandemic has been how vaccines to deal with the virus might affect these women and their future children.

In the early months, positions on the impact and need for vaccination in children and pregnant women were mixed. However, clinical trials published so far confirm its safety and health authorities recommend its use.

Fertilisation, pregnancy and miscarriage rates in IVF patients who had received two doses of vaccines manufactured by Pfizer or Moderna were the same as in unvaccinated patients.

Previous research has shown that vaccination against covid-19 helps protect pregnant women, confers antibodies to their babies and does not increase the risk of preterm birth or foetal growth problems.

Now, a new study, published in the journal Obstetrics & Gynecology – the largest to date on fertility and early pregnancy following coronavirus vaccination – reveals that the vaccine does not affect fertility outcomes in patients undergoing in vitro fertilisation (IVF).

Researchers from the Icahn School of Medicine at Mount Sinai and the Clinics for Reproductive Medicine of New York (RMA) compared fertility, pregnancy and early miscarriage rates in IVF patients who had received two doses of vaccines manufactured by Pfizer or Moderna – mRNA vaccines – with the same outcomes in unvaccinated patients.

“These findings show absolutely no difference between vaccinated and unvaccinated patients in ovarian stimulation, egg quality, embryo development, pregnancy rates and miscarriages,” says Christopher M. Zahn, vice president for practice activities at the American College of Obstetricians and Gynecologists (ACOG).

This study did not look at the booster vaccine, as it was approved later and data are still being collected. “We suspect that the booster is just as safe as receiving the original two doses of vaccine. We want to look at this systematically and, once we have more data, publish that as well,” Alan B. Copperman, professor of obstetrics, gynaecology and reproductive sciences at Icahn Mount Sinai and author of the study, tells SINC.

No impact on fertility
The study involved women whose eggs were retrieved and fertilised by sperm in a laboratory between February and September 2021, creating embryos that were frozen and then thawed and transferred to the uterus and patients who underwent medical treatment to stimulate egg development.

The two groups that underwent embryo transfer – 214 vaccinated and 733 unvaccinated – had similar pregnancy and early pregnancy loss rates. Likewise, the two groups that underwent ovarian stimulation – 22 vaccinated and 983 unvaccinated – had similar rates of egg retrieval, fertilisation and embryos with normal chromosome number, among other measures.
“The data available since the start of mass vaccination programmes have always pointed to no harm to fertility. However, it is important to continue studying, as unfortunately there is still some resistance to vaccination among those who are considering pregnancy or are already pregnant,” Rita Vassena, scientific director of the Eugin Group, told the COVID-19 Vaccine Media Hub.

“This reluctance is due to several factors, such as the lack of inclusion of pregnant women in clinical trials of vaccines – which has been replaced by real-world data – and the presence of transient menstrual cycle alterations in many women after receiving the doses,” Vassena stresses. “This study adds to the positive evidence we have and strengthens the case for vaccination.
Questions about vaccination and fertility
Should I get the vaccine or booster during pregnancy or should I wait?

For Alan B. Copperman and Devora A. Aharon, authors of this research, the best time to receive the vaccine or booster dose is “when it is available. All the evidence indicates that vaccination is completely safe during pregnancy and poses no harm to the woman or the developing foetus. This is true during the first trimester as well, and there is no reason to wait”.

Can I get the vaccine or booster during my reproductive treatment?

“We have no reason to believe that there is any detrimental effect on the cycle. It is possible to receive the vaccine or booster dose during IVF stimulation or embryo transfer,” the experts continue. “However, it is advisable to avoid receiving it two days before or after your procedure, if possible.

What to do if I have a fever after vaccination?

Fever from any cause during the early stages of pregnancy can theoretically pose some risk to the foetus, “although it is very rare for it to have any harmful effect. It is advised that if you have a fever above 38°C as a side effect of the vaccination, or from any other cause, you should take paracetamol to bring your temperature down. But, to be clear, this is not a harmful effect of the vaccine itself, but a precaution against fever that may be a side effect of vaccination,” they point out.

Reference:

Devora Aharon, M, et al. “In Vitro Fertilization and Early Pregnancy Outcomes After Coronavirus Disease 2019 (COVID-19) Vaccination.” Obstetrics and Gynecology 2022.