Do pregnant women have different reactions to COVID vaccines?

A study involving more than 17,000 women in the US has found that mRNA COVID-19 vaccines are ‘well tolerated’ in pregnant and breastfeeding women.
 
The peer-reviewed article, published this week in JAMA Network, concludes both Pfizer and Moderna cause reactions among pregnant women that are comparable to the wider population.
 
Researchers say they found no increased risk of side effects.
 
Dr Alex Polyakov, an obstetrician and senior clinical lecturer at the University of Melbourne, said the findings reinforce the broad benefits of vaccination for most pregnant women. 
 
‘It must also be stressed that COVID-19 infection in pregnancy is associated with an increased risk of severe clinical symptoms which may adversely affect the health of the mother and the wellbeing of the fetus,’ Dr Polyakov said.
 
‘On the other hand, there is no evidence to suggest that vaccination either during pregnancy or breastfeeding is associated with a higher risk of either long- or short-term complications, compared to the general population. The balance of risks clearly favours vaccination in these at-risk groups.’
 
Three groups were involved in the University of Washington study, which began in January this year and included 7809 pregnant women, 6815 breastfeeding women and 2901 women planning pregnancy in the near future.
 
Researchers said a strength of the study was to allow a comparison between pregnant and breastfeeding women compared to non-pregnant women of a similar age.
 
Of those who took part, the majority received the Pfizer vaccine (61.9%) with the remainder having Moderna. Most of the participants worked in healthcare, with 15,055 of the total cohort reportedly having two vaccine doses.
 
The most common reported side effect was pain at the injection site (91.4%), followed by fatigue (31.3%), while muscle pain, headaches, chills and fever were also observed in smaller numbers.
 
Side effects were reported more frequently following a second dose of both the Pfizer and the Moderna vaccines compared to the first dose.
 
Interrupted breastfeeding after vaccination was reported by just over 2% of individuals, with a decrease in milk observed for less than 24 hours afterwards by 339 individuals after the first dose (5%) and 434 after the second dose (7.2%).
 
Study authors said their work was limited by only covering only the first wave of vaccination and by relying on self-reporting of reactions. However, they say the results reinforce previously reported findings about the safety of the vaccine for pregnant women.
 
In Australia, vaccination against COVID-19 is recommended by the Australian Technical Advisory Group on Immunisation (ATAGI) for women at any stage of their pregnancy as well as when breastfeeding.
 
‘Global surveillance data from large numbers of pregnant women have not identified any significant safety concerns with mRNA COVID-19 vaccines given at any stage of pregnancy,’ a joint statement released in June by ATAGI and the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) stated.
 
‘Furthermore, there is also evidence of antibody in cord blood and breastmilk, which may offer protection to infants through passive immunity.’
 
Last week, RACGP President Dr Karen Price backed calls to ensure COVID-19 vaccination is widely available for pregnant women.
 
‘The data are clear – COVID-19 infection in pregnancy is high risk,’ Dr Price told newsGP. ‘COVID-19 vaccination is very safe and provides strong protection against the virus.’
 
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