'Term’ pregnancy redefined by ACOG, SMFM

Four new definitions of “term pregnancy” have been issued by The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) in a joint Committee Opinion. Published in the November issue of Obstetrics & Gynecology, the terminology is designed to put the focus on preventing deliveries before 39 weeks’ gestation.

In the statement-based on findings from a work group that included representatives from ACOG, SMFM, the Eunice Kennedy Shriver National Institute of Child Health and Human Development and other stakeholder organizations-ACOG and SMFM discouraged the general label “term pregnancy” and replaced it with these specific definitions:

• Early Term: Between 37 weeks 0 days and 38 weeks 6 days

• Full Term: Between 39 weeks 0 days and 40 weeks 6 days

• Late Term: Between 41 weeks 0 days and 41 weeks 6 days

• Postterm: Between 42 weeks 0 days and beyond

The entire period between 37 and 42 weeks’ gestation previously was viewed by ob/gyns as associated with good health outcomes for babies. Research in recent years, however, has documented the best outcomes at 39 weeks 0 days to 40 weeks 6 days gestation.

According to Jeffrey L. Ecker, MD, chair of ACOG’s Committee on Obstetric Practice, planned deliveries before 39 weeks 0 days should occur only when there are significant health risks to a woman and/or the fetus in continuing the pregnancy.  “Each week of gestation up to 39 weeks is important for a fetus to fully develop before delivery and have a healthy start,” he said.

In the Committee Opinion, ACOG and SMFM noted that both organizations endorse and encourage the uniform use of the work group’s recommended new gestational age designations by all clinicians, researchers, and public health officials to facilitate data reporting, delivery of quality health care, and clinical research. Methods for determining gestational age cited by the work group focused on a hierarchy of clinical and ultrasonographic criteria.

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