Morris · F&S reports 2021 · controlled cohort study · n=?

SARS-CoV-2 spike protein seropositivity from vaccination or infection does not cause sterility.

Cited 90 times in the scientific literature.

Level 3 - non-randomized controlled study

Non-randomized comparative cohort study evaluating implantation rates across serostatus groups.

PubMed 34095871 · doi:10.1016/j.xfre.2021.05.010 · record verified 2026-08-31

What was done

Researchers evaluated whether SARS-CoV-2 spike protein antibodies impact female fertility using a frozen embryo transfer clinical model. Implantation rates documented by serum hCG and sustained implantation rates were compared across three groups: vaccine-seropositive women, infection-seropositive women, and seronegative control women.

What was found

No difference was found in serum hCG-documented implantation rates or sustained implantation rates between the three groups. The abstract reports no numerical values, percentages, sample sizes, or p-values.

Why it matters

This study provides clinical evidence against claims that SARS-CoV-2 spike protein antibodies cross-react with syncytin-1 to cause female sterility.

Limits

The abstract reports no sample sizes, numerical implantation rates, confidence intervals, or demographic details. The cohort is restricted to women undergoing frozen embryo transfer, which may not capture all factors involved in unassisted conception.

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