By Si Young Lee, PhD
Approximately 131 million births occur each year worldwide, and about 0.5 percent of all births occur before the third trimester of pregnancy. The term periviable birth is used to describe a birth occurring between the start of the 20th week of gestation and the end of the 25th week. Unfortunately, these very early deliveries are a major risk factor for neonatal and infant death. As the survival rate after periviable birth has increased steadily, proper family counseling and adequate management of women with impending periviable birth must be considered.
On February 12, 2016, the quarterly NICHD Exchange Meeting hosted three invited experts in this field to share their opinions and to provide deep insight into the latest issues regarding periviable babies.
Dr. Roberto Romero, chief of the Perinatology Research Branch at Wayne State University and head of the NICHD Program for Perinatal Research and Obstetrics, opened the NICHD Exchange Meeting with his talk “Causes: Intrauterine infection/inflammation as a cause of delivery at periviable gestations.” He started his presentation by explaining why some babies are born so early.
Fundamentally, periviable birth can be the result of spontaneous preterm birth or indicated preterm delivery. In contrast to spontaneous preterm birth, which naturally occurs as a result of intact or ruptured fetal membranes, indicated preterm delivery occurs when labor is initiated by medical intervention due to dangerous pregnancy complications. Even though the two conditions are distinguishable, recent observations suggest that there may be overlap betweeen these conditions. For example, a patient with an indicated preterm birth may also be at risk for spontaneous preterm birth.
Dr. Romero’s work in premature labor has focused on the role of infection and inflammation in spontaneous preterm labor and delivery. At least 40 percent of preterm births involve an intrauterine infection. Recent evidence indicates that infection and the inflammation generated by infection are a major cause of a substantial proportion of preterm births. For example, extrauterine maternal infections (e.g., pyelonephritis and pneumonia) have been linked to premature delivery. Dr. Romero concluded his talk by presenting requirements needed to develop and implement tools for understanding the relationship between the intrauterine environment and periviable birth.
The second speaker was Dr. Rose Higgins, program scientist for the NICHD Neonatal Research Network. Dr. Higgins began her talk by describing the history of periviability. In the 1950’s, infants with birth weights less than one kilogram were still classified as stillborn. The one kilogram limit persisted until the widespread use of mechanical ventilation in the late 1960’s. Then, the wide use of antenatal steroids in the early 1990’s increased survival rate after periviable birth. In the last two decades, technological advances in perinatal and neonatal care have improved the survival rate of an infant at 27 weeks gestation, and weighing only two pounds (900 grams), to 90 percent.
One of the most practical pieces of information in Dr. Higgins’s talk was her introduction to the NICHD Neonatal Research Network (NRN): Extremely Preterm Birth Outcome Data. The NRN was established in 1986 to improve the care and outcomes of neonates, especially for extremely low birth weight infants in neonatal intensive care units (NICUs). On the NICHD NRN website, you can find the predicted outcomes from a periviable birth by entering the parameters of interest. For example, you can learn about survival and neurodevelopmental risk percentages in periviable births with specific gestations, weights, and interventions used. You can find information about the NICHD Neonatal Research Network (NRN) by visiting the following link (https://www.nichd.nih.gov/about/org/der/branches/ppb/programs/epbo/Pages/epbo_case.aspx).
The last speaker, Dr. Tonse Raju, chief of the NICHD Pregnancy and Perinatology Branch, emphasized the importance of counseling women who may deliver extremely premature infants. Counseling is an important, complex, and sensitive issue. Mutual trust and respect have always played a central role in family counseling. Importantly, evidence-based counseling approaches should be followed. Unfortunately, not all doctors are trained in how to manage and counsel families facing the birth of a periviable baby.
Dr. Raju explained how doctors should counsel parents properly. For example, when counseling parents, it is recommended to present the data regarding the rate of survival and long-term disabilities separately, because the parents' perspectives and the importance they give to these may be different. He also mentioned that some phrases, such as “doing everything” or “there is nothing we can do,” must be avoided when counseling a family.
Dr. Tonse Raju closed his talk by listing of some the famous people who were born as periviable babies, including Johannes Kepler, Isaac Newton, Stevie Wonder, and Charles Darwin.
When delivery is anticipated near the limit of viability, families and health care teams must prepare the care for periviable birth. This NICHD Exchange meeting provided considerable knowledge about the efficient management of periviable births based in scientific evidence. A clear understanding about what causes periviable birth is necessary both for families and for health care teams. Complex, ethically challenging decisions also need to be made quickly by families and health care teams, based on individual circumstances.