Faculty Bibliography

Importance/UNASSIGNED:Preterm and postterm deliveries have declined since 2005 in the United States, but the association between these changes and neonatal mortality remains unknown. Objective/UNASSIGNED:To estimate changes in the gestational age distribution among spontaneous and clinician-initiated deliveries between 2006 and 2013 and associated changes in neonatal mortality. Design, Setting, and Participants/UNASSIGNED:A retrospective cohort analysis was conducted of 22 million singleton live births without major malformations in the United States from 2006 to 2013. Data analysis was performed from August to October 2017. Main Outcomes and Measures/UNASSIGNED:Changes in gestational age distribution among spontaneous and clinician-initiated deliveries at extremely preterm (20-27 weeks), very preterm (28-31 weeks), moderately preterm (32-33 weeks), late preterm (34-36 weeks), early term (37-38 weeks), term (39-40), late term (41 weeks), and postterm (42-44 weeks) gestations and changes in neonatal mortality rates at less than 28 days between 2006 and 2013. These changes were estimated from log-linear Poisson regression models with robust variance, adjusted for confounders. Results/UNASSIGNED:Among 22 million births, 12 493 531 (56.7%) were spontaneous and 9 557 815 (43.3%) were clinician-initiated deliveries. Among spontaneous deliveries, the proportion of births at 20 to 27, 28 to 31, 32 to 33, 34 to 36, and 37 to 38 weeks declined. Among clinician-initiated deliveries, the proportion of births at 34 to 36 and 37 to 38 weeks declined and the proportion at 39 to 40 weeks increased. Among spontaneous deliveries, overall neonatal mortality rates declined from 1.8 to 1.3 per 1000 live births, mainly at 20 to 27 weeks (adjusted annual decline, 1%; 95% CI, -2% to -1%) and 28 to 31 weeks (adjusted annual decline, 6%; 95% CI, -8% to -5%). Among clinician-initiated deliveries, overall mortality rates remained unchanged (2.1 to 2.2 per 1000 live births). However, mortality rates declined (0.6 to 0.5 per 1000 live births) at 39 to 40 weeks by 1% (95% CI, -3% to -0.4%) annually, adjusted for confounders. Conclusions and Relevance/UNASSIGNED:In the United States, there was a decline in spontaneous deliveries associated with an overall decline in neonatal mortality. Although clinician-initiated deliveries increased at 39 to 40 weeks, neonatal mortality at that gestation declined.

BACKGROUND:During labor, maintenance of maternal euglycemia is critical to decrease the risk of neonatal hypoglycemia and associated morbidities. When continuous intravenous insulin infusion is needed, standardized insulin dosing charts have been used for titration of insulin to maintain glucose in target range. The GlucoStabilizer software program (Indiana University Health Inc, Indianapolis, IN) is a software-guided insulin dosing system that calculates the dose of intravenous insulin that is needed based on metabolic parameters, target glucose concentration, and an individual's response to insulin. Although this tool has been validated and shown to reduce both hypoglycemia and errors in critical care settings, the utility of this software has not been examined in obstetrics. OBJECTIVE:The purpose of this study was to determine whether the use of intravenous insulin dosing software in women with pregestational or gestational diabetes mellitus that requires intrapartum insulin infusion can improve the rate of glucose concentration in target range (70-100 mg/dL; 3.9-5.5 mmol/L) at the time delivery. STUDY DESIGN/METHODS:We performed a retrospective cohort study comparing laboring patients with diabetes mellitus that required insulin infusion who were dosed by standard insulin dosing chart vs the GlucoStabilizer software program from January 2012 to December 2017. The GlucoStabilizer software program, which was implemented in May 2016, replaced the standard intravenous insulin dosing chart. Inclusion criteria were women with pregestational or gestational diabetes mellitus who were treated with an intravenous insulin infusion intrapartum for at least 2 hours. Maternal characteristics, glucose values in labor, and neonatal outcomes were extracted from delivery and neonatal records. The primary outcome was the percentage of women who achieved the target glucose range (defined as a blood glucose between 70-100 mg/dL; 3.9-5.5 mmol/L) before delivery. Parametric and nonparametric statistics were used to compare both groups; a probability value of <.05 was considered statistically significant. RESULTS:We identified 22 patients who were dosed by a standard insulin dosing chart and 11 patients who were dosed by the GlucoStabilizer software program during intrapartum management. The GlucoStabilizer software program was superior in achieving glucose values in target range at delivery (81.8% vs 9.1%; P<.001) compared with standard insulin dosing without increasing maternal hypoglycemia (0% vs 4.3%; P=.99). Patients whose insulin dosing was managed by the GlucoStabilizer software program also had lower mean capillary blood glucose values compared with the standard insulin infusion (102.9±5.9 mg/dL [5.7±0.33 mmol/L] vs 121.7±5.9 mg/dL [6.8±0.33 mmol/L]; P=.02). Before the initiation of the infusion, both groups demonstrated mean capillary blood glucose values outside of target range (122.6±8.8 mg/dL [6.7±0.49 mmol/L] for the GlucoStabilizer software program vs 131.9±10.1 mg/dL [7.3±0.56 mmol/L] for standard insulin treatment group; P=not significant). There were no significant differences in baseline maternal characteristics between the groups or neonatal outcomes. CONCLUSION/CONCLUSIONS:This study is the first to demonstrate that the use of software-guided intravenous insulin dosing in obstetrics can improve intrapartum glycemic management without increasing hypoglycemia in women with both pregestational and gestational diabetes mellitus that is treated with an insulin infusion.

Importance/UNASSIGNED:Whether the changing gestational age distribution in the United States since 2005 has affected perinatal mortality remains unknown. Objective/UNASSIGNED:To examine changes in gestational age distribution and gestational age-specific perinatal mortality. Design, Setting, and Participants/UNASSIGNED:This retrospective cohort study examined trends in US perinatal mortality by linking live birth and infant death data among more than 35 million singleton births from January 1, 2007, through December 31, 2015. Exposures/UNASSIGNED:Year of birth and changes in gestational age distribution. Main Outcomes and Measures/UNASSIGNED:Changes in the proportion of births at gestational ages 20 to 27, 28 to 31, 32 to 33, 34 to 36, 37 to 38, 39 to 40, 41, and 42 to 44 weeks; changes in perinatal mortality (stillbirth at ≥20 weeks, and neonatal deaths at <28 days) rates; and contribution of gestational age changes to perinatal mortality. Trends were estimated from log-linear regression models adjusted for confounders. Results/UNASSIGNED:Among the 34 236 577 singleton live births during the study period, the proportion of births at all gestational ages declined, except at 39 to 40 weeks, which increased (54.5% in 2007 to 60.2% in 2015). Overall perinatal mortality declined from 9.0 to 8.6 per 1000 births (P < .001). Stillbirths declined from 5.7 to 5.6 per 1000 births (P < .001), and neonatal mortality declined from 3.3 to 3.0 per 1000 births (P < .001). Although the proportion of births at gestational ages 34 to 36, 37 to 38, and 42 to 44 weeks declined, perinatal mortality rates at these gestational ages showed annual adjusted relative increases of 1.0% (95% CI, 0.6%-1.4%), 2.3% (95% CI, 1.9%-2.8%), and 4.2% (95% CI, 1.5%-7.0%), respectively. Neonatal mortality rates at gestational ages 34 to 36 and 37 to 38 weeks showed a relative adjusted annual increase of 0.9% (95% CI, 0.2%-1.6%) and 3.1% (95% CI, 2.1%-4.1%), respectively. Although the proportion of births at gestational age 39 to 40 weeks increased, perinatal mortality showed an annual relative adjusted decline of -1.3% (95% CI, -1.8% to -0.9%). The decline in neonatal mortality rate was largely attributable to changes in the gestational age distribution than to gestational age-specific mortality. Conclusions and Relevance/UNASSIGNED:Although the proportion of births at gestational age 39 to 40 weeks increased, perinatal mortality at this gestational age declined. This finding may be owing to pregnancies delivered at 39 to 40 weeks that previously would have been unnecessarily delivered earlier, leaving fetuses at higher risk for mortality at other gestational ages.