BACKGROUND: The majority of newborns are exclusively breastfed during the birth hospitalization, and weight loss is nearly universal for these neonates. The amount of weight lost varies substantially among newborns with higher amounts of weight loss increasing risk for morbidity. No hour-by-hour newborn weight loss nomogram exists to assist in early identification of those on a trajectory for adverse outcomes.METHODS: For 161 471 term, singleton neonates born at $36 weeks' gestation at Northern California Kaiser Permanente hospitals in 2009-2013, data were extracted from the birth hospitalization regarding delivery mode, race/ethnicity, feeding type, and weights from electronic records. Quantile regression was used to create nomograms stratified by delivery mode that estimated percentiles of weight loss as a function of time among exclusively breastfed neonates. Weights measured subsequent to any nonbreastmilk feeding were excluded.RESULTS: Among this sample, 108 907 newborns had weights recorded while exclusively breastfeeding with 83 433 delivered vaginally and 25 474 delivered by cesarean. Differential weight loss by delivery mode was evident 6 hours after delivery and persisted over time. Almost 5% of vaginally delivered newborns and .10% of those delivered by cesarean had lost $10% of their birth weight 48 hours after delivery. By 72 hours, .25% of newborns delivered by cesarean had lost $10% of their birth weight.CONCLUSIONS: These newborn weight loss nomograms demonstrate percentiles for weight loss by delivery mode for those who are exclusively breastfed. The nomograms can be used for early identification of neonates on a trajectory for greater weight loss and related morbidities. WHAT'S KNOWN ON THIS SUBJECT:Exclusively breastfed newborns lose weight daily in the first few days after birth. The amount of weight lost varies substantially between newborns, with higher amounts of weight loss increasing risk for morbidity. WHAT THIS STUDY ADDS:This study presents nomograms demonstrating percentiles for weight loss by delivery mode for those who are exclusively breastfed. The nomograms have potential to be used for early identification of neonates on a trajectory for greater weight loss and related morbidities.

Background Postpartum anemia is associated with maternal and perinatal morbidity. Population-level data may inform guideline development for postpartum anemia screening. Our objectives were to evaluate the associations between potential predictors (predelivery anemia and postpartum hemorrhage (PPH)) with severe postpartum anemia after cesarean section. Study Design and Methods Data were collected from 70,939 hospitalizations for cesarean section performed at Kaiser Permanente Northern California facilities between 2005 and 2013. Severe postpartum anemia was defined as a hemoglobin < 8 g/dl before hospital discharge. Using multivariable logistic regression, we assessed the associations between predelivery anemia and PPH with severe postpartum anemia. Distributions of these characteristics among women with severe postpartum anemia were evaluated. Results The overall rate of severe postpartum anemia was 7.3%; 95% confidence interval (CI) = 7.1 – 7.4. Severe postpartum anemia was strongly associated with a predelivery hemoglobin between 10 and 10.9 g/dl (adjusted odds ratio (aOR) 5.4; 95% CI = 4.89– 5.91), predelivery hemoglobin <10 g/dl (aOR 30.6; 95% CI = 27.21– 34.6, and PPH (aOR 8.45; 95% CI = 7.8–9.16). The proportions of women with severe postpartum anemia were highest for those experiencing PPH but no predelivery anemia (12.2%; 95% CI = 11.0 – 13.6), and those who did not incur PPH nor predelivery anemia (10.7%; 95% CI = 9.6 – 12.0). Conclusions Our findings suggest that PPH and predelivery anemia are strong independent risk factors for severe postpartum anemia. Optimization of patients’ hemoglobin prior to delivery may reduce the incidence of severe anemia after cesarean section.

BackgroundRespiratory syncytial virus (RSV) infection in infancy is associated with subsequent recurrent wheezing.MethodsA retrospective cohort study examined children born at ≥32 weeks gestation between 1996–2004. All children were enrolled in an integrated health care delivery system in Northern California and were followed through the fifth year of life. The primary endpoint was recurrent wheezing in the fifth year of life and its association with laboratory-confirmed, medically-attended RSV infection during the first year, prematurity, and supplemental oxygen during birth hospitalization. Other outcomes measured were recurrent wheezing quantified through outpatient visits, inpatient hospital stays, and asthma prescriptions.ResultsThe study sample included 72,602 children. The rate of recurrent wheezing in the second year was 5.6% and fell to 4.7% by the fifth year. Recurrent wheezing rates varied by risk status: the rate was 12.5% among infants with RSV hospitalization, 8% among infants 32–33 weeks gestation, and 18% in infants with bronchopulmonary dysplasia. In multivariate analyses, increasing severity of respiratory syncytial virus infection was significantly associated with recurrent wheezing in year 5; compared with children without RSV infection in infancy, children who only had an outpatient RSV encounter had an adjusted odds ratio of 1.38 (95% CI,1.03–1.85), while children with a prolonged RSV hospitalization had an adjusted odds ratio of 2.59 (95% CI, 1.49–4.50).ConclusionsLaboratory-confirmed, medically attended RSV infection, prematurity, and neonatal exposure to supplemental oxygen have independent associations with development of recurrent wheezing in the fifth year of life.

It is not uncommon for newborns to be below birth weight 10 to 14 days after delivery. A larger percentage of newborns delivered by cesarean had yet to regain birth weight at every time point through 1 month.

The continuing rise in the prevalence of autism spectrum disorders has led to heightened interest in the role of nongenetic factors, including exogenous exposures, but little research has been conducted. To explore a possible role in autism etiology, we used data available from our prior studies to examine potential occupational exposures, as these may occur at higher levels than environmental exposures. Parental occupation was obtained from birth certificates for 284 children with autism and 659 controls, born in 1994 in the San Francisco Bay Area. Self-reported occupation and industry were coded into eight exposure/chemical groups based on potential neurotoxicity or reprotoxicity by a board-certified physician in occupational medicine and an industrial hygienist blinded to case-control status. Mothers of autistic children were twice as likely to work in occupations considered exposed (14.4%) as mothers of controls (7.2%) (adjusted odds ratio [AOR] 2.3 [95% confidence interval {CI} 1.3-4.2]). The exposure categories of the greatest frequency among case mothers were exhaust and combustion products (AOR = 12.0 [95% CI 1.4-104.6]) and disinfectants (AOR = 4.0 [95% CI 1.4-12.0]). Paternal occupational exposure was not associated with autism, potentially consistent with a direct in-utero exposure effect. There are several limitations of this hypothesis-generating study, including lack of detail on workplace and job duties, leading to possible misclassification and low proportion exposed. However, this misclassification would not be biased by case-control status and is unlikely to explain the associations we did find, suggesting that further research on exogenous exposures may yield useful etiologic clues.