Over 60,000 pregnant women have signed up for the v-safe program which monitors people who received a COVID-19 vaccine, and no safety concerns have been flagged. Studies are underway that assess the safety and efficacy of vaccination during pregnancy.
A recent study that included 131 mRNA vaccine recipients found that vaccines generated robust humoral immunity in pregnant and lactating participants, and vaccine-induced immune responses were significantly greater than the response to natural infection. Immune transfer to neonates occurred via placenta and breastmilk.
While emerging data on efficacy are very promising, many are still concerned about safety - particularly in the first trimester of pregnancy. The concern arises because one possible side effect of vaccination is fever (regardless of whether you're pregnant), and persistent high fever in the first trimester can raise the risk of birth defects and miscarriage. As such, some clinicians have told their patients to delay vaccination until after 12 weeks of gestation.
Fever has been reported in approximately 10-15% of people after the second dose of the Pfizer or Moderna shot (only about 1% experienced a fever over 102 F). Fever is the least common side effect of the J&J vaccine and, if it occurs, typically lasts a day or so.
The American College of Obstetricians and Gynecologists does NOT specify timing for vaccination and says no trimester is better (or worse) than others when it comes to getting vaccinated. Fever can be treated with acetaminophen which has been shown to be safe for use in pregnancy and does not appear to impact immune response.
If you do choose to delay vaccination during pregnancy, it is best to get both doses (if you’re getting a two-dose vaccine) before you deliver to optimize protection for yourself and your baby. If you contract COVID-19 while pregnant, the risks of illness - which include persistent high fever - are far greater than the risks of vaccination.
https://www.ajog.org/article/S0002-9378(21)00187-3/fulltext
