BackgroundDystocia, difficult labour, is a common but also complex problem during childbirth. It can be attributed to either weak contractions of the uterus, a large infant, reduced capacity of the pelvis or combinations of these. Previous studies have indicated that there is a genetic component in the susceptibility of experiencing dystocia. The purpose of this study was to identify susceptibility genes in dystocia.MethodsA total of 104 women in 47 families were included where at least two sisters had undergone caesarean section at a gestational length of 286 days or more at their first delivery. Study of medical records and a telephone interview was performed to identify subjects with dystocia. Whole-genome scanning using Affymetrix genotyping-arrays and non-parametric linkage (NPL) analysis was made in 39 women exhibiting the phenotype of dystocia from 19 families. In 68 women re-sequencing was performed of candidate genes showing suggestive linkage: oxytocin (OXT) on chromosome 20 and oxytocin-receptor (OXTR) on chromosome 3.ResultsWe found a trend towards linkage with suggestive NPL-score (3.15) on chromosome 12p12. Suggestive linkage peaks were observed on chromosomes 3, 4, 6, 10, 20. Re-sequencing of OXT and OXTR did not reveal any causal variants.ConclusionsDystocia is likely to have a genetic component with variations in multiple genes affecting the patient outcome. We found 6 loci that could be re-evaluated in larger patient cohorts.
Background. Dystocia-prolonged and difficult labor-is a common and worldwide problem during parturition. Epidemiological studies have suggested a familial aggregation. This study aimed to quantify the genetic influence (i.e. the heritability) on dystocia. Methods. A retrospective study of all births in Sweden from 1973 through 1997 was undertaken. Data from the population-based Swedish Birth, Twin and National Family Registers were linked on an individual basis. In total, 2 539 534 births were analyzed. Relationships between sibling and mother-daughter pairs were established. The relative risk for dystocia was calculated. Model-fitting (Mx) was used to estimate the relative contribution of genetic and environmental factors for liability to dystocia. Results. In all, 190 747 women were diagnosed with dystocia. Measures of familial similarity (relative risks and correlation of liability) for dystocia were higher in monozygotic than in dizygotic twins, other sibling pairs and mother-daughter pairs. Correlation of liability was also higher in full-sisters than in half-sisters. Model-fitting suggested that genetic effects accounted for 28% [95% confidence interval (CI) 21-32] of the susceptibility for dystocia. Conclusion. Dystocia is a complex disorder of poor uterine action that is influenced by a significant genetic component as well as environmental factors. The amount of genetic influence makes it interesting to study the gene expression in these patients. Detection of the genes related to dystocia might lead to better pathophysiological understanding of this condition and the possibility of detecting these mothers before parturition.
Dystocia is a complex disorder of poor uterine action that is influenced by a significant genetic component as well as environmental factors. The amount of genetic influence makes it interesting to study the gene expression in these patients. Detection of the genes related to dystocia might lead to better pathophysiological understanding of this condition and the possibility of detecting these mothers before parturition.
Dystocia is a disorder characterized by prolonged or dysfunctional labour. Delivery that starts late or not at all, leads to an increased risk for Caesarean section, infant morbidity and mortality. Familial aggregations of dystocia suggest a polygenic background. We have studied three candidate genes for dystocia, i.e. the genes for testosterone 5-alpha reductase type 1, prostaglandin F2alpha receptor and endothelin 1 and performed mutational screening in 23 women with dystocia, of which 12 have affected relatives. No mutations were found, making it unlikely that any of these genes represent a major cause of dystocia in man.
Introduction A revised intrapartum cardiotocography (CTG) classification was introduced in Sweden in 2017. The aims of the revision were to adapt to the international guideline published in 2015 and to adjust the classification of CTG patterns to current evidence regarding intrapartum fetal physiology. This study aimed to investigate adverse neonatal outcomes before and after implementation of the revised CTG classification. Material and Methods A before‐and‐after design was used. Cohort I (n = 160 210) included births from June 1, 2014 through May 31, 2016 using the former CTG classification, and cohort II (n = 166 558) included births from June 1, 2018 through May 31, 2020 with the revised classification. Data were collected from the Swedish Pregnancy and Neonatal Registers. The primary outcome was moderate to severe neonatal hypoxic ischemic encephalopathy (HIE 2–3). Secondary outcomes were birth acidemia (umbilical artery pH <7.05 and base excess < −12 mmol/L or pH <7.00), A‐criteria for neonatal hypothermia treatment, 5‐min Apgar scores <4 and <7, neonatal seizures, meconium aspiration, neonatal mortality and delivery mode. Logistic regression was used (period II vs period I), and results are presented as adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs). Results There were no statistically significant differences in HIE 2–3 (aOR 1.27; 95% CI 0.97–1.66), proportion of neonates meeting A‐criteria for hypothermia treatment (aOR 0.96; 95% CI 0.89–1.04) or neonatal mortality (aOR 0.68; 95% CI 0.39–1.18) between the cohorts. Birth acidemia (aOR 1.36; 95% CI 1.25–1.48), 5‐min Apgar scores <7 (aOR 1.27; 95% CI 1.18–1.36) and <4 (aOR 1.40; 95% CI 1.17–1.66) occurred more often in cohort II. The absolute risk difference for HIE 2–3 was 0.02% (95% CI 0.00–0.04). Operative delivery (vacuum or cesarean) rates were lower in cohort II (aOR 0.82; 95% CI 0.80–0.85 and aOR 0.94; 95% CI 0.91–0.97, respectively). Conclusions Although not statistically significant, a small increase in the incidence of HIE 2–3 after implementation of the revised CTG classification cannot be excluded. Operative deliveries were fewer but incidences of acidemia and low Apgar scores were higher in the latter cohort. This warrants further in‐depth analyses before a full re‐evaluation of the revised classification can be made.
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