Talk to Your Doctor

The PreTRM® Test is a simple blood test performed during the 18th week of your pregnancy through week 20 that provides valuable information on the risk of a premature birth, allowing you to work with your healthcare team to make changes to your medical care if needed.⁹

Because the PreTRM Test is relatively new, not every physician offers it as part of routine pregnancy care. If you are interested in taking this test, talk to your doctor to find out if it is right for you.


Have more questions about the PreTRM Test?


  1. Hamilton BE, et al. Births: Provisional data for 2020. Vital Statistics Rapid Release; no 12. Hyattsville, MD: National Center for Health Statistics. May 2021.
  2. Callaghan WM, et al. The contribution of preterm birth to infant mortality rates in the United States. Pediatrics. 2006 Oct;118(4):1566-73.
  3. Petrini JR, et al. Estimated effect of 17 alpha-hydroxyprogesterone caproate on preterm birth in the United States. Obstet Gynecol. 2005;105:267-72.
  4. Martin JA, et al. Births: Final Data for 2002. Natl Vital Stat Rep. 2003; 52(10):1-113.
  5. Hassan SS, et al. Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial. Ultrasound Obstet Gynecol. 2011;38:18-31. 2.
  6. Martin JA, et al. Births: Final Data for 2009. Natl Vital Stat Rep. 2011; 60(1):1-70.6.
  7. Iams, JD, et al. Prevention of preterm parturition. N Engl J Med. 2014;370:254-61.
  8. Martin JA, et al. National Vital Statistics Report. Births: Final Data for 2018. Centers for Disease Control and Prevention; Vol 68, No November 27, 2019.
  9. A Sera Customer Support team member will help you schedule your blood draw between the first day of your 18th week of pregnancy and the sixth day of your 20th week of pregnancy. That’s a 20-day window between days 126 and 146 of your pregnancy.