BACKGROUND AND PURPOSE:

• Hillson et al. (The Lancet, 2021) assessed pregnancy outcomes for women who received AstraZeneca’s COVID-19 vaccine during the clinical trials

METHODS:

• Secondary analysis of phase 1, phase 2 and phase 3 clinical vaccine trials | In primary trials, pregnant women were excluded from trials
• Participants
  • ≤49 years
• Interventions
  • Vaccination with AstraZeneca (ChAdOx1)
  • Placebo          
• Study design
  • Pregnancies that occurred during the trial were follow-up until 3 months after birth
• Primary outcomes
  • Fertility rate: Based upon number of pregnancies and number of viable pregnancies
  • Miscarriage: Defined as pregnancy loss <23 weeks

RESULTS:

• 9755 participants included in vaccine trials
  • Pregnancy reported during trial: 1%
  • Fertility outcome analysis: 93 participants
    • Received ChAdOx1: 50
    • Received placebo: 43
  • Pregnancy outcome analysis: 107 participants
    • Received ChAdOx1: 72
    • Received placebo: 35
  • Baseline characteristics were similar between vaccine and control groups
• There was no evidence of reduced fertility with ChAdOx1 vaccination
  • Fertility rate ratio (pregnancies): 1.14 (95% CI, 0.76 to 1.71); P=0.53
  • Fertility rate ratio (viable pregnancies): 1.08 (95% CI, 0.66 to 1.79); P=0.80
• The rate of miscarriage in the vaccine group was no different from that in the control group
  • Miscarriage risk ratio: 0.67; P=0.51

CONCLUSION:

• There is no evidence that the ChAdOx1 COVID-19 vaccine is associated with decreased fertility or increased rate of miscarriage
• The authors state

With increasing availability of misinformation, which continues to affect vaccine uptake, these data, along with published data on mRNA vaccines, can provide evidence to support women in making decisions regarding vaccination

Learn More – Primary Sources:

Fertility rates and birth outcomes after ChAdOx1 nCoV-19 (AZD1222) vaccination

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mRNA COVID-19 Vaccine Safety in Pregnant Women

Do Menstrual Cycle Changes Occur Following SARS-CoV-2 Infection?