The predicted clinical workload associated with early post-term surveillance and inductions of labour in south Asian women in a non-tertiary hospital setting.

BACKGROUND: Stillbirth increases steeply after 42 weeks gestation; hence, induction of labour (IOL) is recommended after 41 weeks. Recent Victorian data demonstrate that term stillbirth risk rises at an earlier gestation in south Asian mothers (SAM). AIMS: To determine the impact on a non-tertiary hospital in Melbourne, Australia, if post-dates IOL were recommended one week earlier at 40 + 3 for SAM; and to calculate the proportion of infants with birthweight < 3rd centile that were undelivered by 40 weeks in SAM and non-SAM, as these cases may represent undetected fetal growth restriction. MATERIALS AND METHODS: Singleton births ≥ 37 weeks during 2017-18 were extracted from the hospital Birthing Outcomes System. Obstetric and neonatal outcomes for pregnancies that birthed after spontaneous onset of labour or IOL were analysed according to gestation and country of birth. RESULTS: There were 5408 births included, and 24.9% were born to SAM (n = 1345). SAM women had a higher rate of IOL ≥ 37 weeks compared with non-SAM women (42.5% vs 35.0%, P < 0.001). If all SAM accepted an offer of IOL at 40 + 3, there would be an additional 80 term inductions over two years. There was no significant difference in babies < 3rd centile undelivered by 40 weeks in SAM compared with non-SAM (29.6% vs 37.7%, P = 0.42). CONCLUSIONS: Earlier IOL for post-term SAM would only modestly increase the demand on birthing services, due to pre-existing high rates of IOL. Our current practices appear to capture the majority at highest risk of stillbirth in our SAM population.

Ultra high-dimensional semiparametric longitudinal data analysis.

As ultra high-dimensional longitudinal data are becoming ever more apparent in fields such as public health and bioinformatics, developing flexible methods with a sparse model is of high interest. In this setting, the dimension of the covariates can potentially grow exponentially as exp(n1/2) with respect to the number of clusters n. We consider a flexible semiparametric approach, namely, partially linear single-index models, for ultra high-dimensional longitudinal data. Most importantly, we allow not only the partially linear covariates but also the single-index covariates within the unknown flexible function estimated nonparametrically to be ultra high dimensional. Using penalized generalized estimating equations, this approach can capture correlation within subjects, can perform simultaneous variable selection and estimation with a smoothly clipped absolute deviation penalty, and can capture nonlinearity and potentially some interactions among predictors. We establish asymptotic theory for the estimators including the oracle property in ultra high dimension for both the partially linear and nonparametric components, and we present an efficient algorithm to handle the computational challenges. We show the effectiveness of our method and algorithm via a simulation study and a yeast cell cycle gene expression data.

Machine Learning Classification of Verified Head Impact Exposure Strengthens Associations with Brain Changes.

Cumulative exposure to head impacts during contact sports can elicit potentially deleterious brain white matter alterations in young athletes. Head impact exposure is commonly quantified using wearable sensors; however, these sensors tend to overestimate the number of true head impacts that occur and may obfuscate potential relationships with longitudinal brain changes. The purpose of this study was to examine whether data-driven filtering of head impact exposure using machine learning classification could produce more accurate quantification of exposure and whether this would reveal more pronounced relationships with longitudinal brain changes. Season-long head impact exposure was recorded for 22 female high school soccer athletes and filtered using three methods-threshold-based, heuristic filtering, and machine learning (ML) classification. The accuracy of each method was determined using simultaneous video recording of a subset of the sensor-recorded impacts, which was used to confirm which sensor-recorded impacts corresponded with true head impacts and the ability of each method to detect the true impacts. Each filtered dataset was then associated with the athletes' pre- and post-season MRI brain scans to reveal longitudinal white matter changes. The threshold-based, heuristic, and ML approaches achieved 22.0% accuracy, 44.6%, and 83.5% accuracy, respectively. ML classification also revealed significant longitudinal brain white matter changes, with negative relationships observed between head impact exposure and reductions in mean and axial diffusivity and a positive relationship observed between exposure and fractional anisotropy (all p < 0.05).

Accuracy of clinical suspicion of growth restriction at term despite a normal growth ultrasound: A retrospective cohort study.

BACKGROUND: Small for gestational age (SGA) is a major determinant of poor perinatal outcome. Detecting SGA at term using ultrasound is challenging and we often plan birth based on clinical assessment. AIMS: To determine the incidence of SGA infants with birthweight <10th centile among women undergoing planned birth at term for suspected SGA despite a normal estimated fetal weight (EFW) on ultrasound at 35-37 weeks. MATERIALS AND METHODS: We performed a retrospective study including all women with a fetal growth ultrasound at ≥35 weeks reporting an EFW ≥ 10th centile (appropriate for gestational age, AGA) who subsequently had an induction of labour or caesarean birth at ≥37 weeks due to ongoing clinical suspicion of SGA between 2012-2014. The primary outcome was the incidence of SGA newborns using customised centiles. RESULTS: There were 532 women who had a planned birth for clinical suspicion of SGA during the study period. Of these, 205 (38.5%) had an AGA fetus on ultrasound ≥35 weeks but were subsequently delivered because of a persisting clinical suspicion of SGA on abdominal assessment. Sixty-eight percent (n = 139/205) delivered an SGA infant. Furthermore, almost half of these SGA infants (47.5%) had a birthweight <3rd centile. Neonatal outcomes were worse for the SGA infants, with 15.1% (n = 21/205) requiring special care nursery compared to 1.5% (n = 1/205) of those AGA at birth. CONCLUSIONS: A reassuring ultrasound with EFW ≥10th centile in the late third trimester should not override clinical concerns of impaired fetal growth at term.

Identification of the optimal growth charts for use in a preterm population: An Australian state-wide retrospective cohort study.

BACKGROUND: Preterm infants are a group at high risk of having experienced placental insufficiency. It is unclear which growth charts perform best in identifying infants at increased risk of stillbirth and other adverse perinatal outcomes. We compared 2 birthweight charts (population centiles and INTERGROWTH-21st birthweight centiles) and 3 fetal growth charts (INTERGROWTH-21st fetal growth charts, World Health Organization fetal growth charts, and Gestation Related Optimal Weight [GROW] customised growth charts) to identify which chart performed best in identifying infants at increased risk of adverse perinatal outcome in a preterm population. METHODS AND FINDINGS: We conducted a retrospective cohort study of all preterm infants born at 24.0 to 36.9 weeks gestation in Victoria, Australia, from 2005 to 2015 (28,968 records available for analysis). All above growth charts were applied to the population. Proportions classified as <5th centile and <10th centile by each chart were compared, as were proportions of stillborn infants considered small for gestational age (SGA, <10th centile) by each chart. We then compared the relative performance of non-overlapping SGA cohorts by each chart to our low-risk reference population (infants born appropriate size for gestational age [>10th and <90th centile] by all intrauterine charts [AGAall]) for the following perinatal outcomes: stillbirth, perinatal mortality (stillbirth or neonatal death), Apgar <4 or <7 at 5 minutes, neonatal intensive care unit admissions, suspicion of poor fetal growth leading to expedited delivery, and cesarean section. All intrauterine charts classified a greater proportion of infants as <5th or <10th centile than birthweight charts. The magnitude of the difference between birthweight and fetal charts was greater at more preterm gestations. Of the fetal charts, GROW customised charts classified the greatest number of infants as SGA (22.3%) and the greatest number of stillborn infants as SGA (57%). INTERGROWTH classified almost no additional infants as SGA that were not already considered SGA on GROW or WHO charts; however, those infants classified as SGA by INTERGROWTH had the greatest risk of both stillbirth and total perinatal mortality. GROW customised charts classified a larger proportion of infants as SGA, and these infants were still at increased risk of mortality and adverse perinatal outcomes compared to the AGAall population. Consistent with similar studies in this field, our study was limited in comparing growth charts by the degree of overlap, with many infants classified as SGA by multiple charts. We attempted to overcome this by examining and comparing sub-populations classified as SGA by only 1 growth chart. CONCLUSIONS: In this study, fetal charts classified greater proportions of preterm and stillborn infants as SGA, which more accurately reflected true fetal growth restriction. Of the intrauterine charts, INTERGROWTH classified the smallest number of preterm infants as SGA, although it identified a particularly high-risk cohort, and GROW customised charts classified the greatest number at increased risk of perinatal mortality.

An Online Calculator to Estimate the Impact of Changes in Breastfeeding Rates on Population Health and Costs.

OBJECTIVE: We sought to determine the impact of changes in breastfeeding rates on population health. MATERIALS AND METHODS: We used a Monte Carlo simulation model to estimate the population-level changes in disease burden associated with marginal changes in rates of any breastfeeding at each month from birth to 12 months of life, and in rates of exclusive breastfeeding from birth to 6 months of life. We used these marginal estimates to construct an interactive online calculator (available at www.usbreastfeeding.org/saving-calc ). The Institutional Review Board of the Cambridge Health Alliance exempted the study. RESULTS: Using our interactive online calculator, we found that a 5% point increase in breastfeeding rates was associated with statistically significant differences in child infectious morbidity for the U.S. population, including otitis media (101,952 cases, 95% confidence interval [CI] 77,929-131,894 cases) and gastrointestinal infection (236,073 cases, 95% CI 190,643-290,278 cases). Associated medical cost differences were $31,784,763 (95% CI $24,295,235-$41,119,548) for otitis media and $12,588,848 ($10,166,203-$15,479,352) for gastrointestinal infection. The state-level impact of attaining Healthy People 2020 goals varied by population size and current breastfeeding rates. CONCLUSION: Modest increases in breastfeeding rates substantially impact healthcare costs in the first year of life.

Suboptimal breastfeeding in the United States: Maternal and pediatric health outcomes and costs.

The aim of this study was to quantify the excess cases of pediatric and maternal disease, death, and costs attributable to suboptimal breastfeeding rates in the United States. Using the current literature on the associations between breastfeeding and health outcomes for nine pediatric and five maternal diseases, we created Monte Carlo simulations modeling a hypothetical cohort of U.S. women followed from age 15 to age 70 years and their children from birth to age 20 years. We examined disease outcomes using (a) 2012 breastfeeding rates and (b) assuming that 90% of infants were breastfed according to medical recommendations. We measured annual excess cases, deaths, and associated costs, in 2014 dollars, using a 2% discount rate. Annual excess deaths attributable to suboptimal breastfeeding total 3,340 (95% confidence interval [1,886 to 4,785]), 78% of which are maternal due to myocardial infarction (n = 986), breast cancer (n = 838), and diabetes (n = 473). Excess pediatric deaths total 721, mostly due to Sudden Infant Death Syndrome (n = 492) and necrotizing enterocolitis (n = 190). Medical costs total $3.0 billion, 79% of which are maternal. Costs of premature death total $14.2 billion. The number of women needed to breastfeed as medically recommended to prevent an infant gastrointestinal infection is 0.8; acute otitis media, 3; hospitalization for lower respiratory tract infection, 95; maternal hypertension, 55; diabetes, 162; and myocardial infarction, 235. For every 597 women who optimally breastfeed, one maternal or child death is prevented. Policies to increase optimal breastfeeding could result in substantial public health gains. Breastfeeding has a larger impact on women's health than previously appreciated.

Disparities in Breastfeeding: Impact on Maternal and Child Health Outcomes and Costs.

OBJECTIVE: To estimate the disease burden and associated costs attributable to suboptimal breastfeeding rates among non-Hispanic blacks (NHBs), Hispanics, and non-Hispanic whites (NHWs). STUDY DESIGN: Using current literature on associations between breastfeeding and health outcomes for 8 pediatric and 5 maternal diseases, we used Monte Carlo simulations to evaluate 2 hypothetical cohorts of US women followed from age 15 to 70 years and their infants followed from birth to age 20 years. Accounting for differences in parity, maternal age, and birth weights by race/ethnicity, we examined disease outcomes and costs using 2012 breastfeeding rates by race/ethnicity and outcomes that would be expected if 90% of infants were breastfed according to recommendations for exclusive and continued breastfeeding duration. RESULTS: Suboptimal breastfeeding is associated with a greater burden of disease among NHB and Hispanic populations. Compared with a NHW population, a NHB population had 1.7 times the number of excess cases of acute otitis media attributable to suboptimal breastfeeding (95% CI 1.7-1.7), 3.3 times the number of excess cases of necrotizing enterocolitis (95% CI 2.9-3.7), and 2.2 times the number of excess child deaths (95% CI 1.6-2.8). Compared with a NHW population, a Hispanic population had 1.4 times the number of excess cases of gastrointestinal infection (95% CI 1.4-1.4) and 1.5 times the number of excess child deaths (95% CI 1.2-1.9). CONCLUSIONS: Racial/ethnic disparities in breastfeeding have important social, economic, and health implications, assuming a causal relationship between breastfeeding and health outcomes.

Impact of Optimized Breastfeeding on the Costs of Necrotizing Enterocolitis in Extremely Low Birthweight Infants.

OBJECTIVE: To estimate risk of necrotizing enterocolitis (NEC) for extremely low birth weight (ELBW) infants as a function of preterm formula (PF) and maternal milk intake and calculate the impact of suboptimal feeding on the incidence and costs of NEC. STUDY DESIGN: We used aORs derived from the Glutamine Trial to perform Monte Carlo simulation of a cohort of ELBW infants under current suboptimal feeding practices, compared with a theoretical cohort in which 90% of infants received at least 98% human milk. RESULTS: NEC incidence among infants receiving ≥98% human milk was 1.3%; 11.1% among infants fed only PF; and 8.2% among infants fed a mixed diet (P = .002). In adjusted models, compared with infants fed predominantly human milk, we found an increased risk of NEC associated with exclusive PF (aOR = 12.1, 95% CI 1.5, 94.2), or a mixed diet (aOR 8.7, 95% CI 1.2-65.2). In Monte Carlo simulation, current feeding of ELBW infants was associated with 928 excess NEC cases and 121 excess deaths annually, compared with a model in which 90% of infants received ≥98% human milk. These models estimated an annual cost of suboptimal feeding of ELBW infants of $27.1 million (CI $24 million, $30.4 million) in direct medical costs, $563 655 (CI $476 191, $599 069) in indirect nonmedical costs, and $1.5 billion (CI $1.3 billion, $1.6 billion) in cost attributable to premature death. CONCLUSIONS: Among ELBW infants, not being fed predominantly human milk is associated with an increased risk of NEC. Efforts to support milk production by mothers of ELBW infants may prevent infant deaths and reduce costs.