ABSTRACT. Background. Existing fetal growth references all suffer from 1 or more major methodologic problems, including errors in reported gestational age, biologically implausible birth weight for gestational age, insufficient sample sizes at low gestational age, singlehospital or other non-population-based samples, and inadequate statistical modeling techniques.Methods. We used the newly developed Canadian national linked file of singleton births and infant deaths for births between 1994 and 1996, for which gestational age is largely based on early ultrasound estimates. Assuming a normal distribution for birth weight at each gestational age, we used the expectation-maximization algorithm to exclude infants with gestational ages that were more consistent with 40-week births than with the observed gestational age. Distributions of birth weight at the corrected gestational ages were then statistically smoothed.Results. The resulting male and female curves provide smooth and biologically plausible means, standard deviations, and percentile cutoffs for defining small-and large-for-gestational-age births. Large-for-gestational age cutoffs (90th percentile) at low gestational ages are considerably lower than those of existing references, whereas small-for-gestational-age cutoffs (10th percentile) postterm are higher.

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Objective: A large trial published in 2000 concluded that planned vaginal delivery of term breech births is associated with high neonatal risks. Because the obstetric practices in that study differed from those in countries where planned vaginal delivery is still common, we conducted an observational prospective study to describe neonatal outcome according to the planned mode of delivery for term breech births in 2 such countries. Study design: Observational prospective study with an intent-to-treat analysis to compare the groups for which cesarean and vaginal deliveries were planned. Associations between the outcome and planned mode of delivery were controlled for confounding by multivariate analysis. The main outcome measure was a variable that combined fetal and neonatal mortality and severe neonatal morbidity. The study population consisted of 8105 pregnant women delivering singleton fetuses in breech presentation at term in 138 French and 36 Belgian maternity units. Results: Cesarean delivery was planned for 5579 women (68.8%) and vaginal delivery for 2526 (31.2%). Of the women with planned vaginal deliveries, 1796 delivered vaginally (71.0%). The rate of the combined neonatal outcome measure was low in the overall population (1.59%; 95% CI [1.33-1.89]) and in the planned vaginal delivery group (1.60%; 95% CI [1.14-2.17]). It did not differ significantly between the planned vaginal and cesarean delivery groups (unadjusted odds ratio = 1.10, 95% CI [0.75-1.61]), even after controlling for confounding variables (adjusted odds ratio = 1.40, 95% CI [0.89-2.23]). Conclusion:In places where planned vaginal delivery is a common practice and when strict criteria are met before and during labor, planned vaginal delivery of singleton fetuses in breech presentation at term remains a safe option that can be offered to women. Keywords: Breech presentation Mode of delivery Neonatal morbidity Observational surveyVaginal deliveries for breech presentations have long been a topic of debate.1 The Term Breech Trial by Hannah et al, published in 2000, confirmed for many physicians that neonatal risks associated with term breech births are much higher among planned vaginal deliveries and implied that cesarean deliveries should be systematically planned for all such women. 2,3Vaginal delivery of breech infants remains standard practice in France. In 1998, the proportion of planned vaginal deliveries among term breech infants here was 51.2%, and 65.1% of this group actually delivered vaginally. 4 In 2000, the French College of Gynecologists and Obstetricians (CNGOF) defined the optimal criteria for deciding to attempt vaginal delivery (Table I). 5,6 Although the internal validity of Hannah's trial is irrefutable, some aspects raise questions about the extrapolation of its results to other settings. The absolute risk of mortality and serious perinatal morbidity for the planned vaginal birth group in countries with low perinatal mortality rates was high (5.7%), as was the difference between the 2 groups (14 times higher in ...

Increased bone turnover has been suggested as a potential risk factor for osteoporotic fractures. We investigated this hypothesis in a prospective cohort study performed on 7598 healthy women more than 75 years of age. One hundred and twenty-six women (mean years 82.5) who sustained a hip fracture during a mean 22-month follow-up were age-matched with three controls who did not fracture. Baseline samples were collected prior to fracture for the measurement of two markers of bone formation and three urinary markers of bone resorption: type I collagen cross-linked N- (NTX) or C-telopeptide (CTX) and free deoxypyridinoline (free D-Pyr). Elderly women had increased bone formation and resorption compared with healthy premenopausal women. Urinary excretion of CTX and free D-Pyr, but not other markers, was higher in patients with hip fracture than in age-matched controls (p = 0.02 and 0.005, respectively). CTX and free D-Pyr excretion above the upper limit of the premenopausal range was associated with an increased hip fracture risk with an odds ratio (95% confidence interval) of 2.2 (1.3-3.6) and 1.9 (1.1-3.2), respectively, while markers of formation were not. Increased bone resorption predicted hip fracture independently of bone mass, i.e., after adjustment for femoral neck bone mineral density (BMD) and independently of mobility status assessed by the gait speed. Women with both a femoral BMD value of 2.5 SD or more below the mean of young adults and either high CTX or high free D-Pyr levels were at greater risk of hip fracture, with an odds ratio of 4.8 and 4.1, respectively, than those with only low BMD or high bone resorption. Elderly women are characterized by increased bone turnover, and some markers of bone resorption predict the subsequent risk of hip fracture independently of hip BMD. Combining the measurement of BMD and bone resorption may be useful to improve the assessment of the risk of hip fracture in elderly women.

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Cesarean delivery is associated with an increased risk of postpartum maternal death. Knowledge of the causes of death associated with this excess risk informs contemporary discussion about cesarean delivery on request and should inform preventive strategies.