Researchers from University of Washington Medicine published a study in the American Journal of Obstetrics and Gynecology on COVID-19 infection rates among pregnant patients in the state of Washington. The study tracked incidence of COVID-19 in pregnant patients from Mar. 1 to Jun. 30, 2020 in 35 hospitals/clinic systems. Their study identified higher rates of COVID-19 infection in pregnant patients compared to patients from similar age groups and COVID-19 affected pregnant patients of color more disproportionately than white pregnant patients.
What Does the Data Show?
Out of 17,233 deliveries in the study period, 240 pregnant patients were diagnosed with COVID-19, resulting in an infection rate of 13.9/1000 deliveries.
Of the 240 diagnosed cases, 45 were asymptomatic. If these 45 cases are excluded from the overall count, the resulting infection rate is 11.3/1000 deliveries. (More on why this could be significant later)
The overall infection rate in pregnant patients is 1.7 times higher than 20-39 year old women, and 1.3 times higher when excluding asymptomatic pregnant patients.
During the same study period, there were 15,238 cases diagnosed out of a population of 2,076,248 20-39 year old women, resulting in an infection rate of 7.3/1000 persons.
Percentage of COVID-19 cases in pregnant patients of color were higher compared to the observed distribution of races and ethnicities in deliveries from 2018. Most notable were Hispanic patients, who accounted for 126 cases, or 52.5% of the cases. In comparison, only 18.6% of deliveries in 2018 were by Hispanic patients.
What Does The Data Mean?
Observed COVID-19 infection rates are higher in pregnant patients than similarly aged adults, up to 70% higher. One could argue that the infection rates among pregnant patients are higher due to more testing. Pregnant patients have to be tested before they're admitted for delivery or earlier in the pregnancy; thus, the likelihood of a pregnant patient being tested for COVID-19 is much higher compared to a healthy 20-39 year-old. That is why researchers also calculated infection rate after excluding asymptomatic pregnant patients. By excluding these cases, the infected pregnant patient population would mimic the population of 20-39 year-olds. During the study period, the US was still struggling with implementing widespread testing solutions and most of the cases tested would have to present symptoms. Regardless of which cut of the infected pregnant patient population is used for the comparison, infection rates are still higher than its comparison group.
The study didn't look at reasons that could explain why this difference in infection rate exists, so it's difficult to say what exactly about pregnancies increases infection rate. There could be behavioral and/or physiological factors associated with pregnancy that affect infection rate. We will have to wait for researchers to look into these factors before we know more. The study also didn't compare severity of disease between pregnant patients and similarly aged adults so there is no information available from this study on how COVID-19 affects pregnant patients and their babies.
Observed COVID-19 infection rates in pregnant patients reflect the same racial/ethnic disparities in the overall population. Pregnant patients of color are disproportionately affected by COVID-19. The main reason for this health disparity is socioeconomic inequality.
What Can I/Should I Do?
Every person's situation is different, and we recommend that you consult your physician and/or prenatal care provider and determine what is best for you. We recommend that you consider the following:
Get vaccinated when you become eligible.
Determine the activities that you do that could put you at risk of exposure. Choose to avoid these activities or find ways to decrease your risk of exposure. You can try to reduce the amount of time spent doing the activity, find a different venue with less risk of exposure, or limit the participants to people in your own household.
Improve your mask fit by double masking or knot and tuck a mask.
Do not wait to contact your physician if you feel sick. Use telemedicine or other tools available for early treatment.
Review CDC guidelines on COVID-19 for Pregnancy, Breastfeeding, and Caring for Newborns.