evidence: But the data that speak most clearly to the question of whether the COVID-19 vaccines harm fertility come from the clinical trials themselves4,5,6. Developmental and reproductive toxicity studies show that the vaccines do not prevent female rodents becoming pregnant or harm the pups if given during pregnancy. We also have an idea of how the vaccines affect pregnancy in humans from the volunteers who became pregnant during the clinical trials. Pregnant people were excluded from the trials and participants were asked to avoid becoming pregnant, but, nonetheless, 57 pregnancies occurred across the trials of the three vaccines that have so far been approved in the UK. The outcomes of these pregnancies, so far as they have progressed, are summarized in Table 1. There was no significant difference in the rate of accidental pregnancies in the vaccinated groups compared with the control groups, which indicates that the vaccines do not prevent pregnancy in humans. Similarly, the miscarriage rates are comparable between the groups, indicating no detrimental effect of vaccination on early pregnancy. [...] So, is COVID-19 vaccination safe during pregnancy? The data so far suggest that it is and, given the increased risks associated with COVID-19 in pregnancy, many pregnant people have decided to accept the vaccine. By monitoring the outcomes for these people and their babies, we will soon be able to make evidence-based recommendations on whether the vaccines should be rolled out to pregnant people more widely. In the meantime, those who are planning pregnancies can rest assured that multiple strands of evidence show that vaccination does not harm fertility.