Increased risk of adverse neurological development for late preterm infants.

OBJECTIVE: To assess the risks of moderate prematurity for cerebral palsy (CP), developmental delay/mental retardation (DD/MR), and seizure disorders in early childhood. STUDY DESIGN: Retrospective cohort study using hospitalization and outpatient databases from the Northern California Kaiser Permanente Medical Care Program. Data covered 141 321 children > or =30 weeks born between Jan 1, 2000, and June 30, 2004, with follow-up through June 30, 2005. Presence of CP, DD/MR, and seizures was based on International Classification of Diseases, Ninth Revision codes identified in the encounter data. Separate Cox proportional hazard models were used for each of the outcomes, with crude and adjusted hazard ratios calculated for each gestational age group. RESULTS: Decreasing gestational age was associated with increased incidence of CP and DD/MR, even for those born at 34 to 36 weeks gestation. Children born late preterm were >3 times as likely (hazard ratio, 3.39; 95% CI, 2.54-4.52) as children born at term to be diagnosed with CP. A modest association with DD/MR was found for children born at 34 to 36 weeks (hazard ratio, 1.25; 95% CI, 1.01-1.54), but not for children in whom seizures were diagnosed. CONCLUSIONS: Prematurity is associated with long-term neurodevelopmental consequences, with risks increasing as gestation decreases, even in infants born at 34 to 36 weeks.

The relationship between cesarean delivery and gestational age among US singleton births.

The increasing trend of delivering at earlier gestational ages has raised concerns of the impact on maternal and infant health. The delicate balance of the risks and benefits associated with continuing a pregnancy versus delivering early remains challenging. Among singleton live births in the United States, the proportion of preterm births increased from 9.7% to 10.7% between 1996 and 2004. The increase in singleton preterm births occurred primarily among those delivered by cesarean section, with the largest percentage increase in late preterm births. For all maternal racial/ethnic groups, singleton cesarean section rates increased for each gestational age group. Singleton cesarean section rates for non-Hispanic black women increased at a faster pace among all preterm gestational age groups compared with non-Hispanic white and Hispanic women. Further research is needed to understand the underlying reasons for the increase in cesarean section deliveries resulting in preterm birth.

Impact of the recent randomized trials on the use of progesterone to prevent preterm birth: a 2005 follow-up survey.

OBJECTIVE: The purpose of this study was to determine whether current attitudes regarding the use of progesterone to prevent preterm birth have changed since our last survey in 2003. STUDY DESIGN: We mailed a 20 question survey to 1264 board certified Maternal-Fetal Medicine specialists in the United States between February and March of 2005 asking about their use and attitudes regarding progesterone to prevent preterm birth. RESULTS: Five hundred and seventy-two surveys were returned (response rate of 45%). In 2005, 67% of respondents used progesterone to prevent SPTB, compared to 38% in 2003 (P < .001). Among users, 38% recommended progesterone for indications other than previous SPTB. Users were more concerned about lack of insurance coverage compared to nonusers but nonusers were more concerned about safety, efficacy, need for more data, and long-term neonatal effects. CONCLUSION: Although the use of progesterone to prevent PTB has increased significantly since our last survey, there remain a substantial number of nonusers. Among users, many are using it for indications not yet proven in clinical trials. Current nonusers have higher levels of concerns compared to nonusers in the first survey and their major concern is the need for more data.

Changes in the gestational age distribution among U.S. singleton births: impact on rates of late preterm birth, 1992 to 2002.

There is mounting evidence that infants born late preterm (34-36 weeks) are at greater risk for morbidity than term infants. This article examines the changing epidemiology of gestational length among singleton births in the United States, from 1992 to 2002. Analyzing gestational age by mode of delivery, the distribution of spontaneous births shifted to the left, with 39 weeks becoming the most common length of gestation in 2002, compared with 40 weeks in 1992 (P < 0.001). Deliveries at > or =40 weeks gestation markedly decreased, accompanied by an increase in those at 34 to 39 weeks (P < 0.001). Singleton births with PROM or medical interventions had similar trends. Changes in the distribution of all singleton births differed by race/ethnicity, with non-Hispanic white infants having the largest increase in late preterm births. These observations, in addition to emerging evidence of increased morbidity, suggest the need for investigation of optimal obstetric and neonatal management of these late preterm infants.

Term pregnancy: a period of heterogeneous risk for infant mortality.

OBJECTIVE: To estimate the trend of maternal racial and ethnic differences in mortality for early-term (37 0/7 to 38 6/7 weeks of gestation) compared with full-term births (39 0/7 to 41 6/7 weeks of gestation). METHODS: We analyzed 46,329,018 singleton live births using the National Center for Health Statistics U.S. period-linked birth and infant death data from 1995 to 2006. Infant mortality rates, neonatal mortality rates, and postneonatal mortality rates were calculated according to gestational age, race and ethnicity, and cause of death. RESULTS: Overall, infant mortality rates have decreased for early-term and full-term births between 1995 and 2006. At 37 weeks of gestation, Hispanics had the greatest decline in infant mortality rates (35.4%; 4.8 per 1,000 to 3.1 per 1,000) followed by 22.4% for whites (4.9 per 1,000 to 3.8 per 1,000); blacks had the smallest decline (6.8%; 5.9 per 1,000 to 5.5 per 1,000) as a result of a stagnant neonatal mortality rate. At 37 weeks compared with 40 weeks of gestation, neonatal mortality rates increase. For Hispanics, the relative risk is 2.6 (95% confidence interval [CI] 2.0-3.3); for whites, the relative risk is 2.6 (95% CI 2.2-3.1); and for blacks, the relative risk is 2.9 (95% CI 2.2-3.8). Neonatal mortality rates are still increased at 38 weeks of gestation. At both early- and full-term gestations, neonatal mortality rates for blacks are 40% higher than for whites and postneonatal mortality rates 80% higher, whereas Hispanics have a reduced postneonatal mortality rate when compared with whites. CONCLUSION: Early-term births are associated with higher neonatal, postneonatal, and infant mortality rates compared with full-term births with concerning racial and ethnic disparity in rates and trends.

Cost of hospitalization for preterm and low birth weight infants in the United States.

OBJECTIVE: The objective of this study was to estimate national hospital costs for infant admissions that are associated with preterm birth/low birth weight. METHODS: Infant (<1 year) hospital discharge data, including delivery, transfers, and readmissions, were analyzed by using the 2001 Nationwide Inpatient Sample from the Healthcare Cost and Utilization Project. The Nationwide Inpatient Sample is a 20% sample of US hospitals weighted to approximately >35 million hospital discharges nationwide. Hospital costs, based on weighted cost-to-charge ratios, and lengths of stay were calculated for preterm/low birth weight infants, uncomplicated newborns, and all other infant hospitalizations and assessed by degree of prematurity, major complications, and expected payer. RESULTS: In 2001, 8% (384,200) of all 4.6 million infant stays nationwide included a diagnosis of preterm birth/low birth weight. Costs for these preterm/low birth weight admissions totaled $5.8 billion, representing 47% of the costs for all infant hospitalizations and 27% for all pediatric stays. Preterm/low birth weight infant stays averaged $15,100, with a mean length of stay of 12.9 days versus $600 and 1.9 days for uncomplicated newborns. Costs were highest for extremely preterm infants (<28 weeks' gestation/birth weight <1000 g), averaging $65,600, and for specific respiratory-related complications. However, two thirds of total hospitalization costs for preterm birth/low birth weight were for the substantial number of infants who were not extremely preterm. Of all preterm/low birth weight infant stays, 50% identified private/commercial insurance as the expected payer, and 42% designated Medicaid. CONCLUSIONS: Costs per infant hospitalization were highest for extremely preterm infants, although the larger number of moderately preterm/low birth weight infants contributed more to the overall costs. Preterm/low birth weight infants in the United States account for half of infant hospitalization costs and one quarter of pediatric costs, suggesting that major infant and pediatric cost savings could be realized by preventing preterm birth.