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A large brain combined with an upright posture in humans has resulted in a high cephalopelvic proportion and frequently obstructed labor. Fischer and Mitteroecker [B. Fischer, P. Mitteroecker, Proc. Natl. Acad. Sci. U.S.A. 112, 5655–5660 (2015)] proposed that the morphological covariations between the skull and pelvis could have evolved to ameliorate obstructed labor in humans. The availability of quantitative data of such covariation, especially of the fetal skull and maternal pelvis, however, is still scarce. Here, we present direct evidence of morphological covariations between the skull and pelvis using actual mother–fetus dyads during the perinatal period of Macaca mulatta, a species that exhibits cephalopelvic proportions comparable to modern humans. We analyzed the covariation of the three-dimensional morphology of the fetal skull and maternal pelvis using computed tomography-based models. The covariation was mostly observed at the pelvic locations related to the birth canal, and the forms of the birth canal and fetal skull covary in such a way that reduces obstetric difficulties. Therefore, cephalopelvic covariation could have evolved not only in humans, but also in other primate taxa in parallel, or it could have evolved already in the early catarrhines.

The strikingly high incidence of obstructed labor due to the disproportion of fetal size and the mother’s pelvic dimensions has puzzled evolutionary scientists for decades. Here we propose that these high rates are a direct consequence of the distinct characteristics of human obstetric selection. Neonatal size relative to the birth-relevant maternal dimensions is highly variable and positively associated with reproductive success until it reaches a critical value, beyond which natural delivery becomes impossible. As a consequence, the symmetric phenotype distribution cannot match the highly asymmetric, cliff-edged fitness distribution well: The optimal phenotype distribution that maximizes population mean fitness entails a fraction of individuals falling beyond the “fitness edge” (i.e., those with fetopelvic disproportion). Using a simple mathematical model, we show that weak directional selection for a large neonate, a narrow pelvic canal, or both is sufficient to account for the considerable incidence of fetopelvic disproportion. Based on this model, we predict that the regular use of Caesarean sections throughout the last decades has led to an evolutionary increase of fetopelvic disproportion rates by 10 to 20%.

Objective To determine a trend of cesarean section rate (CSR) and main contributing factors in a public sector hospital, representing northern part of Thailand. Methods A retrospective descriptive analysis was conducted by assessing the database of maternal-fetal medicine unit, which had prospectively been collected for 20 years. Trends were evaluated using data for the years 1992–2011. Private sector patients were excluded. Results A total of 50,872 public sector patients were available for analysis. The number of deliveries was gradually decreased from 3,802 in 1992 to 1,748 in 2011. Of them, 7,480 underwent cesarean section, CSR of 14.7 %. However, the CSR was significantly increased from 11.3 % in 1992 to 23.6 % in 2011 ( p value <0.001). The CSRs indicated by cephalopelvic disproportion (CPD) and previous CSs were mainly responsible for a marked increase over the study period. CSR due to CPD was increased from 3.2 % in 1992 to 7.9 % in 2011 ( p value <0.0001). While CSR due to other indications either breech presentation, fetal distress and twin pregnancies were only slightly, but significantly increased in the last decades but they are relatively constant in the recent years. Conclusions In our public sector, CSR has gradually increased. The main reasons of such an increase were likely to be associated with over-diagnosis of CPD and subsequent repeated CS, while other indications played only a minimal role. To achieve the appropriate CSR, audit system for diagnosis of CPD must be instituted.

Objective To clarify the relationship between maternal height and cesarean rate due to cephalopelvic disproportion (CPD) in singleton pregnancies among ethnic groups of relatively short stature. Methods A retrospective cohort study was performed on Thai singleton pregnancies at gestational age of more than 34 weeks. Logistic regression analysis was performed to correlate the maternal height and a risk for CPD. The short stature was defined by a cut-off value at 5th percentile ranking. Odds ratio for CPD was determined. Results Of 11,026 recruited, 9,198 were available for analysis. Considering cut-off value of 145 cm, short stature was significantly associated with higher rate of CPD with odds ratio of 2.4 (95% CI 1.8–3.0). The odds = exp(4.048 − 0.042 × Ht). After control of other variables, the relationship between maternal height and rate of CPD was still high. Conclusion Mothers with short stature were significantly correlated with a higher rate of CPD, even after control of birth weight, parity and type of attendance. Clinical points could be drawn from this study including (1) definition of short statue must be developed for particular geographic or ethnic groups. In Thai population, using 145 cm as a cut-off value, odds of CPD is 2.4; (2) Probability of CPD may be estimated by maternal height as a single variable or multiple variables using logistic regression equations.

Objectives To characterize risk factors and perinatal outcome following cephalopelvic disproportion (CPD). Methods A retrospective population-based study comparing all singleton deliveries of women with and without CPD, between 1988 and 2010, was conducted. A multiple logistic regression model was used to control for confounders. Results Out of 242,520 patients, 0.3% ( n  = 673) were diagnosed with CPD. Using a multivariable analysis, the following obstetric risk factors were significantly associated with CPD: fetal macrosomia (birth weight above 4 kg, OR = 3.3, 95% CI 2.7–4.1, P  < 0.001), infertility treatment (OR = 2.6, 95% CI 1.8–3.8, P  < 0.001), previous caesarean delivery (OR = 2.2, 95% CI 1.9–2.7, P  < 0.001), maternal obesity (OR = 2.1, 95% 1.3–3.4, P  < 0.001), and polyhydramnios (OR = 1.7, 95% CI 1.3–2.3, P  < 0.001). Deliveries complicated by CPD resulted in Caesarean delivery in 99%, and were more likely to have laceration of the cervix (1.2 vs. 0.3%, P  < 0.001), rupture of uterus (0.4 vs. 0.1%, P  < 0.001), intrapartum mortality (0.6 vs. 0.1% in control, P  < 0.001), and low 1-min Apgar scores (<7; 27.2 vs. 6.5%, P  < 0.001). Conclusions In our population, independent risk factors for CPD include fetal macrosomia, infertility treatment, previous caesarean delivery, maternal obesity and polyhydramnion. These pregnancies had higher rates of adverse perinatal outcomes and accordingly high index of suspicion should be pursued when commencing trial of labor of such pregnancies.

Purpose This study aimed to correlate pelvic dimensions and fetal size to the risk for cesarean section caused by protracted labor. Methods This is an observational, retrospective cohort study on pregnant women with an increased risk of labor dystocia. After pelvimetry, pelvic adequacy was clinically tested in a trial of labor. A multivariable regression analysis was made to identify the risk factors for cesarean section. Two subgroups were established according to the size of the estimated fetal head circumference (HC) (arbitrary cutoffs of ≤340 and >340 mm), and the pelvic measurements were compared by the mode of delivery. Receiver operating characteristic (ROC) curves were evaluated. Results Altogether, 274 patients were ultimately included. The mean size of the maternal inlet was 1.0 cm larger in fetal HC >340 mm group compared with ≤340 mm. In the vaginal delivery group, the difference was 1.3 cm. In the multivariable modeling, maternal age (odds ratio [OR] 1.09, 95 % confidence interval [CI] 1.02–1.17), fetal HC (OR 1.05, 95 % CI 1.02–1.09), and maternal inlet circumference (OR 0.95, 95 % CI 0.92–0.97) had significance for the risk of cesarean section. In the ROC analysis, the area under the curve (AUC) value for the pelvic inlet was 0.736 ( p  < 0.001, 95 % CI 0.656–0.816), and in the subgroups with fetal HC ≤340 and >340 mm, AUCs were 0.634 ( p  < 0.11, 95 % CI 0.493–0.775) and 0.836 ( p  < 0.001, 95 % CI 0.751–0921), respectively. Conclusions Labor arrest was associated with the linear relationship between the maternal pelvic dimensions and the fetal size. Therefore, the approach should be changed from standardized pelvimetric threshold values to passenger–passageway ratio analyzed by multivariable modeling to find more accurate methods to predict cephalopelvic disproportion.

Significance Like crystals, glasses are rigid because of the self-caging of their constituent particles. The key difference is that crystal formation is a sharp first-order phase transition at which cages form abruptly and remain stable, whereas glass formation entails the progressive emergence of cages. This loose caging complicates the description of the glass transition. In particular, an important transport mechanism in this regime, hopping, has thus far been difficult to characterize. Here we develop a completely microscopic description of hopping, which allows us to clearly assess its impact on transport anomalies, such as the breakdown of the Stokes–Einstein relation. One of the most actively debated issues in the study of the glass transition is whether a mean-field description is a reasonable starting point for understanding experimental glass formers. Although the mean-field theory of the glass transition—like that of other statistical systems—is exact when the spatial dimension [Formula], the evolution of systems properties with d may not be smooth. Finite-dimensional effects could dramatically change what happens in physical dimensions, [Formula]. For standard phase transitions finite-dimensional effects are typically captured by renormalization group methods, but for glasses the corrections are much more subtle and only partially understood. Here, we investigate hopping between localized cages formed by neighboring particles in a model that allows to cleanly isolate that effect. By bringing together results from replica theory, cavity reconstruction, void percolation, and molecular dynamics, we obtain insights into how hopping induces a breakdown of the Stokes–Einstein relation and modifies the mean-field scenario in experimental systems. Although hopping is found to supersede the dynamical glass transition, it nonetheless leaves a sizable part of the critical regime untouched. By providing a constructive framework for identifying and quantifying the role of hopping, we thus take an important step toward describing dynamic facilitation in the framework of the mean-field theory of glasses.

Reducing failed labor and emergency cesarean section (CS) rates is an important goal. A childbirth simulation tool (PREDIBIRTH software and SIM37 platform) that evaluates a 5-min magnetic resonance imaging (MRI) assessment performed at 37 weeks of gestation was developed to enhance the consulting obstetrician’s ability to predict the optimal delivery mode. We aimed to determine the potential value of this childbirth simulation tool in facilitating the selection of an optimal delivery mode for both mother and infant. A retrospective cohort study was performed on all patients referred by their obstetricians to our level 2 maternity radiology department between December 15, 2015 and November 15, 2016, to undergo MRI pelvimetry at approximately 37 weeks of gestation. The childbirth simulation software was employed to predict the optimal delivery mode based on the assessment of cephalopelvic disproportion. The prediction was compared with the actual outcome for each case. Including childbirth simulations in the decision-making process had the potential to reduce emergency CSs, inappropriately scheduled CSs, and instrumental vaginal deliveries by up to 30.1%, 20.7%, and 20.0%, respectively. Although the use of the simulation tool might not have affected the overall CS rate, consideration of predicted birthing outcomes has the potential to improve the allocation between scheduled CS and trial of labor. The routine use of childbirth simulation software as a clinical support tool when choosing the optimal delivery mode for singleton pregnancies with a cephalic presentation could reduce the number of emergency CSs, insufficiently justified CSs, and instrumental deliveries.

Skin cancer is the most common form of cancer in the United States. The main cause of this cancer is DNA damage induced by the UV component of sunlight. In humans and mice, UV damage is removed by the nucleotide excision repair system. Here, we report that a rate-limiting subunit of excision repair, the xeroderma pigmentosum group A (XPA) protein, and the excision repair rate exhibit daily rhythmicity in mouse skin, with a minimum in the morning and a maximum in the afternoon/evening. In parallel with the rhythmicity of repair rate, we find that mice exposed to UV radiation (UVR) at 4:00 AM display a decreased latency and about a fivefold increased multiplicity of skin cancer (invasive squamous cell carcinoma) than mice exposed to UVR at 4:00 PM. We conclude that time of day of exposure to UVR is a contributing factor to its carcinogenicity in mice, and possibly in humans.

Significance Human respiratory syncytial virus (RSV) is the most important viral agent of serious pediatric respiratory-tract disease. We designed new live attenuated RSV vaccine candidates by codon-pair deoptimization (CPD). Specifically, viral ORFs were recoded to increase the usage of underrepresented codon pairs, leaving amino acid coding unchanged. CPD viruses were temperature-sensitive and grew less efficiently in vitro than wild-type RSV. In addition, the CPD viruses exhibited a range of restriction in mice and African green monkeys that compared favorably with existing attenuated strains presently in clinical studies. This study produced examples of a new type of vaccine candidate for RSV and showed that CPD of a nonsegmented negative-strand RNA virus can rapidly generate vaccine candidates with a range of attenuation.