This is a summary, written by members of the CITF Secretariat, of:
Fell DB, Dimanlig-Cruz S, Török E, Håberg SE, Regan AK, Kaufman JS, Platt RW, Gravel CA, Bruce L, Shah PS, Wilson K, Sprague AE, Alton GD, Dhinsa T, El-Chaâr D, Buchan SA, Kwong JC, Wilson SE, Dunn SI, MacDonald SE, Barrett J, Okun N, Walker MC. Pregnancy, fetal, and neonatal outcomes following a first booster dose of COVID-19 vaccine during pregnancy in Ontario, Canada: a population-based retrospective cohort study. BMJ Medicine.2023 Jul 11;2(1):e000632. doi: http://dx.doi.org/10.1136/bmjmed-2023-000632.
The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.
A CITF-funded study, published in BMJ Medicine, reported that pregnant individuals who received a third COVID-19 vaccine dose (first booster dose) during pregnancy had no increased risk of adverse pregnancy, fetal, and neonatal outcomes compared to those who did not receive a third dose. This study was led by Dr. Deshayne Fell (University of Ottawa and CHEO Research Institute).
- Individuals who received a third dose (first booster dose) of COVID-19 vaccine during pregnancy had no increased risks of adverse pregnancy outcomes — including placental damage, chorioamnionitis (infection of the placenta and membrane that surrounds the baby), postpartum hemorrhage (excessive bleeding after giving birth), and caesarean delivery (surgical delivery of the baby) – compared to eligible individuals who did not receive a third dose during pregnancy.
- Pregnant individuals who received a third COVID-19 vaccine dose (first booster dose) during pregnancy had no increased risks of stillbirth, preterm birth (before 37 weeks), very preterm birth (28 to 32 weeks), neonatal intensive care unit admission, newborn 5-minute Apgar scoreMeasurements made by the health professional at birth to assess a newborn’s health. <7, and small-for-gestational age at birth (smaller newborn size than expected for the number of weeks of pregnancy) compared to those who did not receive a third dose during pregnancy.
- Individuals who received a third dose (first booster dose) of COVID-19 vaccine during pregnancy were more likely to be older (30-34 years old), have pre-existing medical conditions, and live in neighbourhoods with higher household incomes.
This population-based study found no evidence of increased risks for adverse pregnancy, fetal, and neonatal outcomes associated with receiving a third dose (first booster dose) of an mRNA COVID-19 vaccine during pregnancy. Considering the potential risks associated with COVID-19 illness during pregnancy, and evidence that vaccination during pregnancy protects both the pregnant individual as well as the newborn from COVID-19 during the first few months of life, these findings can contribute to evidence-based decision making about the risks and benefits of COVID-19 booster doses during pregnancy.
Using Ontario’s birth registry Better Outcomes Registry & Network (BORN), this study included over 18,000 pregnant individuals with an expected date of delivery from December 20, 2021 (start date of third dose eligibility for everyone 18 years and older) to August 31, 2022, who had completed the two doses of their primary COVID-19 vaccine series before pregnancy and became eligible for a third dose (6 months or more since dose two) before the end of pregnancy.