By Rebecca Bowers

EXECUTIVE SUMMARY

Scientists at Brigham and Women’s Hospital have published early results of an investigative blood test designed to predict which women may be at increased risk and which ones may be at lower-than-average risk for spontaneous preterm delivery. The researchers have identified circulating microparticle proteins found in blood samples taken in the first trimester of pregnancy that may provide clues about the risk of spontaneous preterm birth.

  • Almost 10% of births are preterm and occur before 37 weeks’ gestation. Currently, there is no reliable way to predict which pregnancies will end prematurely. Accurately predicting delivery dates for all types of pregnancies has been a challenge for clinicians, especially those in low-resource settings.

Almost 10% of births are preterm and occur before 37 weeks’ gestation. Scientists at Brigham and Women’s Hospital have published early results of an investigative blood test designed to predict which women may be at increased risk and which ones may be at lower-than-average risk for spontaneous preterm delivery.1

The scientists have identified five circulating microparticle proteins in blood samples taken in the first trimester of pregnancy that may give clues about the risk of spontaneous preterm birth.2 Secreted by cells, the circulating microparticles contain RNAs, proteins, and other molecules that one cell can transmit to another. Although this type of communication between cells has been examined primarily in cancer research, Brigham and Women’s Hospital scientists now are studying its mechanism in placental implantation. Because proteins found in circulating microparticles can be detected in patients’ blood samples, researchers say they may represent a promising biomarker.

For the current paper, the team examined blood samples that were collected near the end of the first trimester of pregnancy. The samples came from three biobanks in Seattle, Boston, and Pittsburgh. Investigators compared samples taken from 87 women who delivered at or before 35 weeks to those from 174 women who were the same age and at the same week of pregnancy at the time of testing as the first group, but who delivered at term.1

The test looked at plasma-derived, exosomal proteins obtained in the first trimester to determine the risk of spontaneous preterm delivery later in pregnancy. The test for first-time mothers correctly identified patients who delivered preterm with 86% specificity and 63% sensitivity levels.1

Researchers plan to validate the findings with a larger national dataset, as well as to make further refinements to the test. They also plan to include additional risk factors, such as maternal characteristics, to improve the accuracy of the test. By using the same testing method, scientists also plan to look for prognostic markers for other conditions related to pregnancy, such as gestational diabetes, to develop a comprehensive test that will offer a detailed look at risk during pregnancy.

“A lot of the issues in pregnancy that result in spontaneous preterm birth begin at the end of the first trimester when the placenta becomes vascularized,” says Thomas McElrath, MD, PhD, a maternal fetal medicine specialist in the Brigham and Women’s Hospital’s Department of Obstetrics and Gynecology and corresponding author. “Our goal is to develop prognostic markers for our patients to help make predictions and, ultimately, help us tailor treatment to the individual and offer highly personalized care to every woman from early on in her pregnancy.”

Problems Come With Preterm Birth

Babies who are born too early have higher rates of death and disability. Data from the Centers for Disease Control and Prevention show that 17% of infant deaths in 2015 were attributed to preterm birth and low birth weight.3 Infants who are born too early may experience trouble with breathing or feeding, developmental delay, cerebral palsy, vision problems, and hearing problems.

Currently, there is not a reliable way to predict which pregnancies will result in premature delivery. Clinicians have been challenged to predict delivery dates accurately for all types of pregnancies, especially in low-resource settings.

Healthcare providers can help pregnant women take steps to help reduce their risk of preterm delivery and take care of their general health. The Centers for Disease Control and Prevention suggests encouraging women to do the following:

  • stop smoking;
  • seek prenatal care promptly as soon as a woman thinks she is pregnant, and then seek routine care throughout pregnancy;
  • seek medical attention for warning symptoms and signs of preterm labor; and
  • discuss with a healthcare provider the use of progesterone treatment if a woman has had a previous preterm birth.

REFERENCES

  1. McElrath TF, Cantonwine DE, Jeyabalan A, et al. Circulating microparticle proteins obtained in the late first trimester predict spontaneous preterm birth at less than 35 weeks’ gestation: A panel validation with specific characterization by parity. Am J Obstet Gynecol 2019 Jan. 25. doi:10.1016/j.ajog.2019.01.220. [Epub ahead of print].
  2. Cantonwine DE, Zhang Z, Rosenblatt K, et al. Evaluation of proteomic biomarkers associated with circulating microparticles as an effective means to stratify the risk of spontaneous preterm birth. Am J Obstet Gynecol 2016;214:631.e1-631.e11.
  3. Xu J, Murphy SL, Kochanek KD, Arias E. Mortality in the United States, 2015. NCHS data brief, no. 267. Hyattsville, MD: National Center for Health Statistics. Available at: https://bit.ly/2icuU9p. Accessed March 21, 2019.