It is diicult to summarize the current practices of obstetrical care in the management of the periviable pregnancy given its rapid evolution. For example, since January 2016, the American College of Obstetricians and Gynecologists has penned three iterations of its Practice Bulletin "Management of Preterm Labor," and three versions of the "Obstetric Care Consensus" document have been published since November 2015. In this uncertain environment, individualized, patientcentered care with a multidisciplinary team remain as bedrock for the clinician.
While we do not have the answers, we describe our strategies from Parkland Hospital as one approach to management. Our policies were developed in conjunction with the Division of Neonatal Medicine. Importantly, the decision not to perform cesarean delivery does not necessarily imply that care for the fetus is discounted. Neonatologists are consulted before delivery, and a trilateral discussion of survival and morbidity rates ensues with the woman and her family. A neonatologist attends each delivery and determines subsequent management.
In our institution, traditional fetal indications for cesarean delivery are practiced in women at 25°/7 weeks or beyond. Cesarean delivery is not ofered for fetal indications before 24°/7 weeks. At 240r weeks, cesarean delivery is not ofered unless fetal weight is estimated at 750 g or greater. Aggressive obstetrical management is practiced in cases of growth restriction, wherein gestational age is used to guide management rather than fetal size.
Neonates born between 34 and 36 weeks account for more than 70 percent of all preterm births (Fig. 42-4). This group has been the fastest rising proportion of singleton preterm births in the United States (Raju, 2006). Nationally, the late-preterm 32-33 weeks (12.1%) 34-36 weeks (71e.3%) (late preterm)
FIGURE 42-4 Distribution of preterm births by gestational age in the United States in 201o5. (Data from Martin JA, Hamilton BE, Osterman MJ: Births: final data for 2015. Natl Vital Stat Rep 66(1):1, 2017.)
Spontaneous rupture ofPlacental abruption, 1 % membranes Placenta previa, 1 % 35%
Fetalcomplications, 2%
Other, 3%
FIGURE 42-5 Obstetrical complications associated with 21,771 late-preterm births at Parkland Hospital. (Data from Mcintire DO, Leveno J: Neonatal mortality and morbidity rates in later preterm births compared with births at term, Obstet Gynecol. 2008 Jan;loll (1 ):35-41o.) birth rate rose from 6.82 percent to 6.87 percent from 2014 to 2015 (Martin, 2017).
To estimate the risks associated with late-preterm births, investigators analyzed neonatal mortality and morbidity rates at 34, 35, and 36 weeks compared with those of births at term between 1988 and 2005 at Parkland Hospital (McIntire, 2008). Approximately 3 percent of all births during the study period were between 24 and 32 weeks, and 9 percent were during the late-preterm weeks. hus, and similar to the national rates, late-preterm births accounted for three fourths of all preterm births. Approximately 80 percent of these resulted from 1.6 1.5a 1.4 1.2 1.0 0.8 0.6 0.4 0.2