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A clinical worker administers a COVID-19 vaccine to a pregnant person.
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Study Shows COVID-19 Vaccines Are Safe for Pregnant and Lactating Individuals

The results suggest that the earlier a vaccine is received during pregnancy, the more antibodies are transferred to the fetus

A recent systematic review published in the International Journal of Gynecology & Obstetrics strongly supports that COVID-19 vaccines are safe and effective during pregnancy and lactation. The results may alleviate the hesitancy some mothers have about the risk of complications from COVID-19 vaccines.

The researchers identified 13 peer-reviewed studies, plus 10 preprint and in-press articles, from September 1, 2020, to June 29, 2021. In these studies, vaccines were administered to pregnant and lactating women in high income countries. Across all these studies, the rate of side effects was the same for pregnant and lactating women when compared to the general population. The studies also reported that the antibodies produced by the vaccines were present in the mother, child, and breast milk. Meanwhile, no ill effects on the developing child or birth were reported. 

These studies varied the time of injection during pregnancy and measured the antibody levels in the mothers and neonates. Among the vaccines tested were vaccines from Pfizer, Moderna, Johnson and Johnson, and AstraZeneca/Oxford. The researchers found that increasing the time between the first dose and birth was correlated with antibody transfer. This suggests that the earlier a first dose is received during pregnancy, the more antibodies are transferred to the fetus. None of these studies measured how much immunity is transferred through breast milk alone for lactating mothers who receive a vaccine.

While the authors suggest further studies with increased sample size and diversity will be necessary, these results provide evidence that COVID-19 vaccines are safe and effective for mother and child. In the authors' own words, “These results support current recommendations from WHO and various obstetrical and gynecologic societies that COVID-19 vaccines can and should be used during pregnancy and lactation.”