Cervical dilatation patterns of 'low-risk' women with spontaneous labour and normal perinatal outcomes: a systematic review.

BACKGROUND: The call for women-centred approaches to reduce labour interventions, particularly primary caesarean section, has renewed an interest in gaining a better understanding of natural labour progression. OBJECTIVE: To synthesise available data on the cervical dilatation patterns during spontaneous labour of 'low-risk' women with normal perinatal outcomes. SEARCH STRATEGY: PubMed, EMBASE, CINAHL, POPLINE, Global Health Library, and reference lists of eligible studies. SELECTION CRITERIA: Observational studies and other study designs. DATA COLLECTION AND ANALYSIS: Two authors extracted data on: maternal characteristics; labour interventions; the duration of labour centimetre by centimetre; and the duration of labour from dilatation at admission through to 10 cm. We pooled data across studies using weighted medians and employed the Bootstrap-t method to generate the corresponding confidence bounds. MAIN RESULTS: Seven observational studies describing labour patterns for 99 971 women met our inclusion criteria. The median time to advance by 1 cm in nulliparous women was longer than 1 hour until a dilatation of 5 cm was reached, with markedly rapid progress after 6 cm. Similar labour progression patterns were observed in parous women. The 95th percentiles for both parity groups suggest that it was not uncommon for some women to reach 10 cm, despite dilatation rates that were much slower than the 1-cm/hour threshold for most part of their first stage of labours. CONCLUSION: An expectation of a minimum cervical dilatation threshold of 1 cm/hour throughout the first stage of labour is unrealistic for most healthy nulliparous and parous women. Our findings call into question the universal application of clinical standards that are conceptually based on an expectation of linear labour progress in all women. FUNDING: UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Reproductive Health and Research, World Health Organization, and the United States Agency for International Development (USAID). TWEETABLE ABSTRACT: Cervical dilatation threshold of 1 cm/hour throughout labour is unrealistic for most women, regardless of parity.

A global reference for caesarean section rates (C-Model): a multicountry cross-sectional study.

OBJECTIVE: To generate a global reference for caesarean section (CS) rates at health facilities. DESIGN: Cross-sectional study. SETTING: Health facilities from 43 countries. POPULATION/SAMPLE: Thirty eight thousand three hundred and twenty-four women giving birth from 22 countries for model building and 10,045,875 women giving birth from 43 countries for model testing. METHODS: We hypothesised that mathematical models could determine the relationship between clinical-obstetric characteristics and CS. These models generated probabilities of CS that could be compared with the observed CS rates. We devised a three-step approach to generate the global benchmark of CS rates at health facilities: creation of a multi-country reference population, building mathematical models, and testing these models. MAIN OUTCOME MEASURES: Area under the ROC curves, diagnostic odds ratio, expected CS rate, observed CS rate. RESULTS: According to the different versions of the model, areas under the ROC curves suggested a good discriminatory capacity of C-Model, with summary estimates ranging from 0.832 to 0.844. The C-Model was able to generate expected CS rates adjusted for the case-mix of the obstetric population. We have also prepared an e-calculator to facilitate use of C-Model (www.who.int/reproductivehealth/publications/maternal_perinatal_health/c-model/en/). CONCLUSIONS: This article describes the development of a global reference for CS rates. Based on maternal characteristics, this tool was able to generate an individualised expected CS rate for health facilities or groups of health facilities. With C-Model, obstetric teams, health system managers, health facilities, health insurance companies, and governments can produce a customised reference CS rate for assessing use (and overuse) of CS. TWEETABLE ABSTRACT: The C-Model provides a customized benchmark for caesarean section rates in health facilities and systems.

Development of criteria for identifying neonatal near-miss cases: analysis of two WHO multicountry cross-sectional studies.

OBJECTIVE: To develop and test markers of neonatal severe morbidity for the identification of neonatal near-miss cases. DESIGN: This is a database analysis of two World Health Organization cross-sectional studies: the Global Survey on Maternal and Perinatal Health (WHOGS) and the Multicountry Survey on Maternal and Newborn Health (WHOMCS). SETTING: The WHOGS was performed in 373 health facilities in 24 countries (2004-2008). The WHOMCS was conducted in 359 health facilities in 29 countries (2010-2011). POPULATION: Data were collected from hospital records of all women admitted for delivery and their respective neonates. METHODS: Pragmatic markers (birthweight <1750 g, Apgar score at 5 minutes <7, and gestational age <33 weeks) were developed with WHOGS data and validated with WHOMCS data. The diagnostic accuracy of neonatal characteristics and management markers of severity was determined in the WHOMCS. RESULTS: This analysis included 290 610 liveborn neonates from WHOGS and 310 436 liveborn neonates from WHOMCS. The diagnostic accuracy of pragmatic and management markers of severity for identifying early neonatal deaths was very high: sensitivity, 92.8% (95% CI 91.8-93.7%); specificity, 92.7% (95% CI 92.6-92.8%); positive likelihood ratio, 12.7 (95% CI 12.5-12.9); negative likelihood ratio, 0.08 (95% CI 0.07-0.09); diagnostic odds ratio, 163.4 (95% CI 141.6-188.4). A positive association was found between the frequency of neonatal near-miss cases and Human Development Index. CONCLUSION: Newborn infants presenting selected markers of severity and surviving the first neonatal week could be considered as neonatal near-miss cases. This definition and criteria may be seen as a basis for future applications of the near-miss concept in neonatal health. These tools can be used to inform policy makers on how best to apply scarce resources for improving the quality of care and reducing neonatal mortality.

Body composition measures of obese adolescents by the deuterium oxide dilution method and by bioelectrical impedance.

The objectives of the present study were to describe and compare the body composition variables determined by bioelectrical impedance (BIA) and the deuterium dilution method (DDM), to identify possible correlations and agreement between the two methods, and to construct a linear regression model including anthropometric measures. Obese adolescents were evaluated by anthropometric measures, and body composition was assessed by BIA and DDM. Forty obese adolescents were included in the study. Comparison of the mean values for the following variables: fat body mass (FM; kg), fat-free mass (FFM; kg), and total body water (TBW; %) determined by DDM and by BIA revealed significant differences. BIA overestimated FFM and TBW and underestimated FM. When compared with data provided by DDM, the BIA data presented a significant correlation with FFM (r = 0.89; P < 0.001), FM (r = 0.93; P < 0.001) and TBW (r = 0.62; P < 0.001). The Bland-Altman plot showed no agreement for FFM, FM or TBW between data provided by BIA and DDM. The linear regression models proposed in our study with respect to FFM, FM, and TBW were well adjusted. FFM obtained by DDM = 0.842 x FFM obtained by BIA. FM obtained by DDM = 0.855 x FM obtained by BIA + 0.152 x weight (kg). TBW obtained by DDM = 0.813 x TBW obtained by BIA. The body composition results of obese adolescents determined by DDM can be predicted by using the measures provided by BIA through a regression equation.

Body composition measures of obese adolescents by the deuterium oxide dilution method and by bioelectrical impedance

The objectives of the present study were to describe and compare the body composition variables determined by bioelectrical impedance (BIA) and the deuterium dilution method (DDM), to identify possible correlations and agreement between the two methods, and to construct a linear regression model including anthropometric measures. Obese adolescents were evaluated by anthropometric measures, and body composition was assessed by BIA and DDM. Forty obese adolescents were included in the study. Comparison of the mean values for the following variables: fat body mass (FM; kg), fat-free mass (FFM; kg), and total body water (TBW; percent) determined by DDM and by BIA revealed significant differences. BIA overestimated FFM and TBW and underestimated FM. When compared with data provided by DDM, the BIA data presented a significant correlation with FFM (r = 0.89; P < 0.001), FM (r = 0.93; P < 0.001) and TBW (r = 0.62; P < 0.001). The Bland-Altman plot showed no agreement for FFM, FM or TBW between data provided by BIA and DDM. The linear regression models proposed in our study with respect to FFM, FM, and TBW were well adjusted. FFM obtained by DDM = 0.842 x FFM obtained by BIA. FM obtained by DDM = 0.855 x FM obtained by BIA + 0.152 x weight (kg). TBW obtained by DDM = 0.813 x TBW obtained by BIA. The body composition results of obese adolescents determined by DDM can be predicted by using the measures provided by BIA through a regression equation.