Examining the Study
This prospective cohort study focused on couples residing in the United States and Canada and relied on internet-based data collection. The research included 1,815 female participants who conceived between December 2020 and November 2022, with data on 1,570 couples that also provided information on male partner vaccination. Eligible female participants were aged 21 to 45 and were actively trying to conceive without the use of fertility treatment. They completed questionnaires at various points, sharing details about their COVID-19 vaccination status, brand, and date of doses, along with their pregnancy status and other potential confounding factors.
The study categorized vaccination status into four groups: never vaccinated, vaccinated at any time before conception, having a full primary vaccination sequence before conception, and completing the full primary sequence less than three months before conception. Participants were followed up from their first positive pregnancy test until a miscarriage or other censoring events occurred, such as induced abortion, ectopic pregnancy, or reaching 20 weeks' gestation.

Reassuring Findings
The results of this study offer comfort and reassurance to couples seeking to start a family. Among the 1,815 eligible female participants, a significant 75% had received at least one dose of a COVID-19 vaccine by the time of conception.
Crucially, the study found that COVID-19 vaccination was not associated with an increased risk of early miscarriage (occurring before 8 weeks' gestation) or late miscarriage (between 8 and 19 weeks' gestation). In essence, receiving a COVID-19 vaccine before conception did not raise the risk of miscarriage. The study also delved into the role of male partner vaccination, and again, no increased risk of miscarriage was observed. The findings provide an encouraging perspective on the safety of COVID-19 vaccinations concerning pregnancy.

Considerations
It's important to note that this study relied on self-reported vaccination status and clinic history, which could introduce some degree of misclassification. However, the design of the study, which focused on the preconception period and included a high prevalence of home pregnancy testing, helped reduce the potential under-ascertainment of miscarriages. As with any observational study, the possibility of residual or unmeasured confounding factors remains.

Implications for Planning a Pregnancy

The implications of this study are significant. It offers the first prospective evaluation of the relationship between preconception COVID-19 vaccination in both partners and miscarriage. The findings provide valuable insights for individuals planning to start a family and for healthcare providers assisting them in their journey.
As the world navigates the ongoing challenges of the pandemic, prospective parents can take some solace in the knowledge that preconception COVID-19 vaccination is not associated with an increased risk of miscarriage. It's an important step toward understanding the interplay between vaccination and reproductive health, providing much-needed reassurance for those embarking on the path to parenthood.

A prospective cohort study of preconception COVID-19 vaccination and miscarriage