Data from the CDC isn't enough because only about 28% of 360,000 women of reproductive age in the US. researchers found that pregnant or immediately postpartum women with COVID-19 were nearly six times as likely to land in ICUs as their nonpregnant, COVID-19–infected peers. During the H1N1 flu epidemic of 2009, pregnant women accounted for 5% of U.S. deaths, although they constituted about 1% of the population. One study found pregnant women with severe acute respiratory syndrome (SARS), which is caused by a virus that’s a close cousin of SARS-CoV-2, were significantly more likely to be admitted to the ICU and to die than nonpregnant peers. The immune system is critical at this time because the mother has to compromise her immune system to protect the baby.