Both studies confirm the same outcome, the safety of the vaccination for young women. Very interestigly both studies analyzed the entire cohort of women in their reproductive age: the first one is in fact focused on the fertile couples, while the second one on the infertile couple undergoing the two most used techniques: ovarian stimulation and frozen embryo transfers. Looking at the whole cohort of women investigated in both studies we have an holistic view on the safety for every woman at any level of the reproductive process (spontaneous or medicalized).

Both studies are well designed, the statistical analysis is rigorous, the results reliable and the discussion offers a clear view on the possible explanations of the outcomes registered.

I consider this kind of evidence strong enough to pass the message: get vaccinated regardless your family project.

‍A prospective cohort study of COVID-19 vaccination, SARS-CoV-2 infection, and fertility is a very large prospective cohort study where the possible association between COVID-19 vaccination and SARS-CoV-2 infection with fertility was investigated among couples trying to conceive spontaneously using data from an internet-based preconception cohort study (PRESTO). Results of the study showed that COVID-19 vaccination was not appreciably associated with fecundability in either partner. Furthermore, SARS-CoV-2 infection among male partners was associated with a short-term decline in fertility that may be avoidable by vaccination. Therefore, given the known risks of SARS-CoV-2 infection during pregnancy to maternal and fetal health, and the evidence presented of no harmful association with fertility, the results support the promotion of COVID-19 vaccination during the preconception period.  

In Vitro Fertilization and Early Pregnancy Outcomes After Coronavirus Disease 2019 (COVID-19) Vaccination is a  retrospective cohort study with the aim to determine whether COVID 19 mRNA vaccination is associated with ovarian stimulation and early pregnancy outcomes. the comparison was between fully vaccinated patients and unvaccinated patients who cycled during the same time period. primary outcome were fertilization rate (for ovarian stimulation) and clinical pregnancy rate (for frozen-thawed embryo transfer). Among the vaccinated and unvaccinated women there was no association on adjusted analysis between COVID-19 vaccination and fertilization rate (nor any of the secondary outcomes investigated) and no association between COVID-19 vaccination and clinical pregnancy or any of the secondary outcomes analyzed. Therefore, the results of the present study contribute to the growing body of evidence concerning the safety of COVID-19 vaccination in young women in their reproductive years.

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Data on natural pregnancies among participants in vaccine clinical trials have been very reassuring from the outset, as pregnancies have been found to occur with the same frequency in both the vaccine and control groups. Moreover, no relevant deviations between pregnancies in vaccinated and non-vaccinated populations have been reported. This suggests that the vaccine does not negatively affect fertility. 

However, pregnancies resulting from assisted reproduction techniques allow us to analyse reproductive details that are beyond the scope of epidemiological studies, such as how the ovary responds to reproductive hormones, if there are alterations in egg quality, if there are very early gestational losses (these losses go unnoticed in population-based studies because the pregnancy is interrupted in the first 2-3 weeks, before it is even recognised as such).

These details, which are discussed in the study by Aharon and colleagues, confirm and extend the evidence already available: there is no evidence that the vaccine has negative effects on fertility, even in a reproductively fragile population such as assisted reproduction patients.

The data available to the medical and scientific community since the beginning of mass vaccination programmes have always pointed to the fact that the vaccine does not affect fertility. However, it is important to continue to study this issue and confirm the data, as unfortunately there is still some resistance among those who are considering pregnancy, or who arealready pregnant, to be vaccinated.

This reluctance is due to several factors, such as the lack of inclusion of pregnant women in vaccine clinical trials (which has been filled by real-world data once vaccination has become widespread), and the presence of transient menstrual cycle disturbances in many women after vaccination. This study adds to the evidence we have, and reinforces the indication to vaccinate.

It is worth remembering that while the vaccine does not affect fertility or pregnancy outcomes, developing covid-19 does carry an increased risk of hospitalisation in pregnant women, as well as a more severe course of the disease. New evidence indicates that covid-19 is also associated with ongoing pregnancy loss.

In summary, we see no adverse effects of the vaccine on the reproductive function of women, and it is important to be vaccinated to protect both mother and baby from severe forms of the disease.

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