Whatever happened to Pfizer's covid vaccine trial in pregnant women?

When covid-19 vaccines were granted emergency authorization in Dec 2020, there was consternation over whether pregnant women should be vaccinated. 

Pregnant and breastfeeding women were excluded from the original Pfizer and Moderna phase III clinical trials, so any recommendation to vaccinate them was a gamble.

The world was dealing with a novel vaccine technology, tested under ‘warp speed’ conditions, and no long-term safety data to speak of. 

For this reason, the WHO did not widely recommend the covid-19 vaccine during pregnancy because of insufficient safety data. But not everyone agreed.

In January 2021, soon after the vaccine roll-out commenced, US Centers for Disease Control and Prevention (CDC) updated its website saying that the mRNA vaccines were “unlikely to pose a specific risk for people who are pregnant.”

Professional societies such as the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) both advised that covid-19 vaccines not be withheld from pregnant or lactating women.

Similarly, the UK’s Royal College of Obstetricians and Gynaecologists (RCOG) released a statement saying that “COVID-19 vaccines are strongly recommended in pregnancy.”

So, as the months passed, hundreds of thousands of pregnant women globally, rolled up their sleeves to receive the vaccine, despite the absence of any clinical trials.

The message from authorities was clear - the harm from covid-19 infection outweighed any harms from the mRNA vaccine – but in truth, they couldn’t possibly have known.