Clearing the confusion about completed weeks of gestation

摘要

To the Editor,It is important that all providers, including physicians and nurses, have a standard definition for completed weeks of gestation. The definition of the late preterm infant (LPT) varies despite being established in 2005 when the National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health (NIH) recommended that births between 34 completed weeks (34 0/7 weeks or day 239) and fewer than 37 completed weeks (36 6/7 weeks or day 259) gestation be referred to as late preterm (Raju, 2006). However, LPT infants are sometimes defined as infants born between 34 and 36 completed weeks gestation. The definition of completed weeks gestation needs clarification in that 36 weeks gestation is completed at 36 0/7 and not at 36 6/7. The 36th week of gestation is completed when the last day of week 36 (which ranges from 35 0/7-35 6/7) is completed. In other words, week 36 of gestation begins on the first day 35 0/7 and ends on the last day 35 6/7. Week number 37 begins on the next day 36 0/7 and is completed on the last day of the 37th week, 36 6/7. Using the definition as infants born between 34 and 36 completed weeks for LPT infants is erroneous as it excludes the infants born between 36 0/7 and 36 6/7 weeks.