Maternal outcomes of planned mode of delivery for term breech in nulliparous women.

OBJECTIVE: To estimate short- and long-term maternal complications in relation to planned mode of term breech delivery in first pregnancy. DESIGN: Register-based cohort study. SETTING: Denmark. POPULATION: Nulliparous women with singleton breech delivery at term between 1991 and 2018 (n = 30,778). METHODS: We used data from the Danish national health registries to identify nulliparous women with singleton breech presentation at term and their subsequent pregnancies. We performed logistic regression to compare the risks of maternal complications by planned mode of delivery. All data were proceeded and statistical analyses were performed in SAS 9.4 (SAS Institute Inc. Cary, NC, USA). MAIN OUTCOME MEASURES: Postpartum hemorrhage, operative complications, puerperal infections in first pregnancy and uterine rupture, placenta previa, post-partum hemorrhage, hysterectomy and stillbirth in the subsequent two pregnancies. RESULTS: We identified 19,187 with planned cesarean and 9,681 with planned vaginal breech delivery of which 2,970 (30.7%) delivered vaginally. Planned cesarean significantly reduced the risk of postoperative infections (2.4% vs 3.9% adjusted odds ratio (aOR): 0.54 95% confidence interval (CI) 0.44-0.66) and surgical organ lesions (0.06% vs 0.1%; (aOR): 0.29 95% CI 0.11-0.76) compared to planned vaginal breech delivery. Planned cesarean delivery in the first pregnancy was associated with a significantly higher risk of uterine rupture in the subsequent pregnancies but not with risk of postpartum hemorrhage, placenta previa, hysterectomy, or stillbirth. CONCLUSION: Compared to planned vaginal breech delivery at term, nulliparous women with planned cesarean breech delivery have a significantly reduced risk of postoperative complications but a higher risk of uterine rupture in their subsequent pregnancies.

Incidence of shoulder dystocia and risk factors for recurrence in the subsequent pregnancy-A historical register-based cohort study.

INTRODUCTION: Shoulder dystocia is a rare obstetric complication, and the risk of recurrence is important for planning future deliveries. MATERIAL AND METHODS: The objectives of our study were to estimate the incidence and risk factors for recurrence of shoulder dystocia and to identify women at high risk of recurrence in a subsequent vaginal delivery. The study design was a nationwide register-based study including data from the Danish Medical Birth Registry and National Patient Register in the period 2007-2017. Nulliparous women with a singleton fetus in cephalic presentation were included for analysis of risk factors in index and subsequent delivery. RESULTS: During the study period, 6002 cases of shoulder dystocia were reported with an overall incidence among women with vaginal delivery of 1.2%. Among 222 225 nulliparous women with vaginal births, shoulder dystocia complicated 2209 (1.0%) deliveries. A subsequent birth was registered in 1106 (50.1%) of the women with shoulder dystocia in index delivery of which 837 (77.8%) delivered vaginally. Recurrence of shoulder dystocia was reported in 60 (7.2%) with a six-fold increased risk compared with women without a prior history of shoulder dystocia (risk ratio [RR] 5.70, 95% confidence interval [CI]: 4.41 to 7.38; adjusted RR 3.06, 95% CI: 2.03 to 4.68). Low maternal height was a significant risk factor for recurrence of shoulder dystocia. In the subsequent delivery, significant risk factors for recurrence were birthweight >4000 g, positive fetal weight difference exceeding 250 g from index to subsequent delivery, stimulation with oxytocin and operative vaginal delivery. In the subsequent pregnancy following shoulder dystocia, women who underwent a planned cesarean (n = 176) were characterized by more advanced age and a higher prevalence of diabetes in the subsequent pregnancy. Furthermore, they had more often experienced operative vaginal delivery, severe perineal lacerations, and severe neonatal complications at the index delivery. CONCLUSIONS: The incidence of shoulder dystocia among nulliparous women with vaginal delivery was 1.0% with a 7.2% risk of recurrence in a population where about 50% had a subsequent birth and of these 78% had subsequent vaginal delivery. Important risk factors for recurrence were low maternal height, increase of birthweight ≥250 g from index to subsequent delivery and operative vaginal delivery.

Age-dependent influenza infection patterns and subtype circulation in Denmark, in seasons 2015/16 to 2021/22.

BackgroundInfluenza was almost absent for 2 years following the implementation of strict public health measures to prevent the spread of SARS-CoV-2. The consequence of this on infections in different age groups is not yet known.AimTo describe the age groups infected with the influenza virus in 2021/22, the first post-pandemic influenza season in Denmark, compared with the previous six seasons, and subtypes circulating therein.MethodsInfection and hospitalisation incidences per season and age group were estimated from data in Danish registries. Influenza virus subtypes and lineages were available from samples sent to the National Influenza Centre at Statens Serum Institut.ResultsTest incidence followed a similar pattern in all seasons, being highest in 0-1-year-olds and individuals over 75 years, and lowest in 7-14-year-olds and young people 15 years to late twenties. When the influenza A virus subtypes A(H3N2) and A(H1N1)pdm09 co-circulated in seasons 2015/16 and 2017/18 to 2019/20, the proportion of A(H1N1)pdm09 was higher in 0-1-year-olds and lower in the over 85-year-olds compared with the overall proportion of A(H1N1)pdm09 in these seasons. The proportion of A(H3N2) was higher in the over 85 years age group compared with the overall proportion of A(H3N2). The 2016/17 and 2021/22 seasons were dominated by A(H3N2) but differed in age-specific trends, with the over 85 years age group initiating the 2016/17 season, while the 2021/22 season was initiated by the 15-25-year-olds, followed by 7-14-year-olds.ConclusionThe 2021/22 influenza season had a different age distribution compared with pre-COVID-19 pandemic seasons.

Winter, spring, summer or fall: temporal patterns in placenta-mediated pregnancy complications-an exploratory analysis.

PURPOSE: Placenta-mediated pregnancy complications, like growth restriction and hypertensive disorders, are leading causes of maternal, fetal and neonatal morbidity and mortality in high-income countries. The purpose was to investigate if there is a seasonal variation in placenta-mediated pregnancy complications (small for gestational age, intrauterine growth restriction, preeclampsia, preterm birth and intrauterine fetal death). METHODS: This is a Danish cohort study including all singleton deliveries at gestational week 22 up to and including week 41 conceived from December 2006 to November 2016 (N = 555,459). We used statistical process control charts to visualize data and to test for patterns of non-random variation in data over time for pregnancies with risk factors (BMI, diabetes, in vitro fertilization, maternal age > 40 years, primipara, previous caesarean and smoking) and each of the following outcome: fetal growth restriction, hypertensive disorders, preterm birth and intrauterine fetal death. The study was approved by the Danish Data Protection agency; REG-039-2019. RESULTS: We found a seasonal pattern in hypertensive disorders during pregnancy with dips in pregnancies conceived in the fall season and highest risk by conception in the spring and summer season. We found no apparent seasonality in cases of preterm delivery, small for gestational age and intrauterine mortality. Individual risk factors (e.g. smoking and obesity) for placenta-mediated complicated over time were in consistency with the general trends. CONCLUSIONS: We found a significant seasonal variation in the risk of hypertensive disorders of pregnancy with highest risk by conception in the spring and summer season. This study found no seasonal variation in other placenta-mediated complications.

Placental weight percentile curves in a Danish population.

INTRODUCTION: The role of the placenta is to transport oxygen and nutrients to the fetus, and a well-functioning placenta is vital to fetal health. Our aim was to develop placental weight percentile curves adjusted by gestational age, and stratified by major maternal comorbidities. MATERIAL AND METHODS: The study was a population study in a Danish cohort. Data was drawn from The Medical Birth Register and the National Patient Register. We included singleton births with a gestational age of 22 + 0 to 42 + 6 weeks. We excluded multiple pregnancies, stillbirths and retained placentas. A total of 611 418 placentas were included. Percentile line graphs were created in groups of all placentas, hypertensive disorders and diabetic disorders. RESULTS: Tables and figures are presented for placental weight percentile curves according to gestational age for all placentas, hypertensive disorders and diabetic disorders, respectively. Placental weight was generally higher in the diabetic placentas, and lower in the hypertensive placentas. CONCLUSIONS: These percentile curves may serve as a reference for other populations, and may be useful for other studies investigating the role of the placenta in relation to pregnancy outcomes, and health in later life.

Risk of congenital malformations in live-born singletons conceived after intracytoplasmic sperm injection: a Nordic study from the CoNARTaS group.

OBJECTIVE: To investigate whether the risk of major congenital malformations is higher in live-born singletons conceived with intracytoplasmic sperm injection (ICSI) compared with in vitro fertilization (IVF)? DESIGN: Nordic register-based cohort study. SETTING: Cross-linked data from Medical Birth Registers and National ART and Patient Registers in Denmark, Norway and Sweden. Data were included from the year the first child conceived using ICSI was born: Sweden, 1992; Denmark, 1994; and Norway, 1996. Data were included until 2014 for Denmark and 2015 for Norway and Sweden. PATIENT(S): All live-born singletons conceived using fresh ICSI (n = 32,484); fresh IVF (n = 47,178); without medical assistance (n = 4,804,844); and cryo-ICSI (n = 7,200) during the study period. INTERVENTION(S): Different in vitro conception methods, and cryopreservation of embryos. MAIN OUTCOME MEASURE(S): Risk of major congenital malformations on the basis of International Classification of Diseases codes. The European Concerted Action on Congenital Anomalies and Twins was used to differentiate between major and minor malformations. RESULT(S): Among singletons conceived using fresh ICSI, 6.0% had a major malformation, compared with 5.3% of children conceived using fresh IVF; 4.2% of children conceived without medical assistance; and 4.9% of children conceived using cryo-ICSI; adjusted odds ratio (AOR) 1.07 (95% confidence interval [CI] 1.01-1.14) in ICSI vs. IVF; and AOR 1.28 (95% CI, 1.23-1.35) in ICSI vs. no medical assistance; and AOR 1.11 (95% CI, 0.99-1.26) in ICSI fresh vs. cryo-ICSI. When malformations were grouped by different organ systems, children conceived using ICSI had a higher risk of respiratory and chromosomal malformations compared with children conceived using IVF, but there were very few cases in each group. When categorizing children conceived using ICSI according to treatment indication (male factor infertility only vs. other indications), we found a higher risk of hypospadias when ICSI was performed because of male factor infertility only (AOR 1.85 [95% CI 1.03-332]). The indications for ICSI changed over time, as male factor infertility did not remain the primary indication for ICSI throughout the study period. CONCLUSION(S): In this large cohort study, we found the risk of major malformations in live-born singletons to be slightly higher after fresh ICSI compared with fresh IVF. These findings should be considered when choosing the assisted reproductive technology method for couples without male factor infertility.

Incidence of postpartum hemorrhage and risk factors for recurrence in the subsequent pregnancy.

PURPOSE: To assess incidence and risk factors for postpartum hemorrhage (PPH) and identify women at high risk of recurrence in the subsequent pregnancy. METHODS: This register-based study includes data on women from the Capital Region of Denmark with two consecutive deliveries recorded in the Copenhagen Obstetric Database from 2007 to 2020. PPH, defined as a blood loss of 1000 mL or more within 24 h after delivery, was the primary outcome measure. We calculated incidence and recurrence rate of PPH and assessed possible risk factors at index and subsequent deliveries. RESULTS: We included 44,800 women with 95,673 deliveries. The overall incidence of PPH was 6.3%. Women with previous PPH had a 3.5-fold increased risk of PPH in a subsequent delivery compared to unaffected women (19.1 vs. 5.4%; OR 4.1; 95% CI 3.7-4.5). Major risk factors for recurrence were PPH in combination with blood transfusion or manual removal of placenta at the index delivery. Labor induction in subsequent pregnancy increased the risk of recurrent PPH compared to spontaneous onset (OR 1.5; 95% CI 1.2-1.9), while planned caesarean section reduced the risk, compared to planned vaginal delivery (OR 0.6; 95% CI 0.4-0.7). CONCLUSION: Previous PPH increases the risk of PPH in subsequent pregnancy 3.5-fold. The risk of recurrent PPH increases with labor induction and decreases with planned caesarean section in the subsequent pregnancy. To prevent recurrent PPH, personalized counseling based on risk factors, relevant labor history and maternal preferences is suggested.

Outcome of subsequent pregnancies in women with complete uterine rupture: A population-based case-control study.

INTRODUCTION: In the attempt of a trial of labor after a cesarean section approximately one in 200 women experience a complete uterine rupture. As a complete uterine rupture is associated with an adverse perinatal outcome, data regarding subsequent pregnancies are needed to provide proper care and guidance to women with a complete uterine rupture when informing them of future possibilities. The objective of this study was to investigate the fetal and maternal outcomes in subsequent pregnancies after a complete uterine rupture. MATERIAL AND METHODS: Retrospective population-based case-control study. Denmark 1997-2017. A total of 175 women with complete uterine rupture during an attempted trial of labor after cesarean (TOLAC) at term (cases) and a corresponding group of 272 women with no uterine rupture during an attempted TOLAC at term (controls) were labeled as index deliveries. Index deliveries were included from January 1, 1997 to December 31, 2008. From the date of the index delivery to December 31, 2017 the information on subsequent pregnancies and deliveries, and on referral to hospital with any obstetric or gynecological diagnosis were retrieved from the Danish Medical Birth Registry and National Patient Registry. Main outcome measures were miscarriage, perinatal death, neonatal morbidity, preterm birth, and recurrence of uterine rupture. Outcome measures were compared between cases and controls. RESULTS: After the index deliveries; there were 109 pregnancies and 70 deliveries after gestational age 22+0  weeks in the population of cases. In the population of controls, there were 183 pregnancies and 126 deliveries after 22+0  weeks. Cases had a significantly higher risk of miscarriage (odds ratio [OR] 3.99; 95% confidence interval [CI] 1.36-13.17). The incidence of uterine rupture was 8.6% among cases and 0.8% among controls (OR 11.7; 95% CI 1.36-543.1). Among cases, 98.6% had live-born infants, and none of these had severe neonatal morbidity. No significant association was found between previous complete uterine rupture and preterm delivery, placenta previa, hysterectomy in relation to subsequent births, diagnosis such as meno/metrorrhagia, dysmenorrhea, or procedures such as hysteroscopy or hysterectomy. CONCLUSIONS: In pregnancies following complete uterine rupture continuing after 22+0  weeks, maternal and fetal outcomes are good when managed promptly with cesarean delivery.

Gender incongruence in Denmark, a quantitative assessment.

INTRODUCTION: The number of persons with gender incongruence referred to health care is increasing, but national data on the incidence of gender incongruence are lacking. The aim of this study was to quantify the development in number of individuals with gender incongruence over time and to estimate the national incidence in Denmark. MATERIAL AND METHODS: Historical descriptive cohort study. Individuals older than 18 years with legal sex-change in their person registration number were achieved from Statistics Denmark, and the National Health Register provided data on contact diagnoses related to gender-identity conditions. By combining these two data sources, we made estimates on incidence and incidence rates for individuals with gender incongruence in Denmark through a 41-year period 1980-2020. RESULTS: Through 1980-2020, the annual number of legal sex-changes increased in individuals assigned female at birth from 5 to approximately 170 and among individuals assigned male at birth from 10 to approximately 150. The cumulative number of legal sex-changes at the end of 2019 was 1275 assigned female at birth and 1422 assigned male at birth and 66% of the legal sex-changes were in individuals below 30 years. Correspondingly, the annual number of contacts with the healthcare system due for gender-identity-related conditions increased from 30 during 1990-1999 to around 500 in 2017 (both genders combined), with a 10-fold increase from 2010 to 2017. CONCLUSIONS: The number of legal sex-changes and healthcare contacts due to gender-identity-related diagnoses increased substantially over the last 40 years with a more than 10-fold increase during the last decade. This calls for research on possible explanations for this increase, for research on the short-term and long-term health consequences of hormonal and surgical treatment regimens and for ensuring adequate healthcare facilities.

SARS-CoV-2 infection dynamics in Denmark, February through October 2020: Nature of the past epidemic and how it may develop in the future.

BACKGROUND: Initially, the relative sizes of the asymptomatic and the symptomatic infected populations were not known for the COVID-19 pandemic and neither was the actual fatality rate. Therefore it was not clear either how the pandemic would impact the healthcare system. As a result it was initially predicted that the COVID-19 epidemic in Denmark would overwhelm the healthcare system and thus both the diagnosis and treatment of other hospital patients were compromised for an extended period. AIM: To develop a mathematical model, which includes both asymptomatic and symptomatic infected persons, for early estimation of the epidemic's course, its Infection Fatality Rate and the healthcare system load in Denmark, both retrospectively and prospectively. METHODS: The SEIRS (Susceptible-Exposed-Infected-Recovered-Susceptible) model including deaths outside hospitals and separate assessments of symptomatic and asymptomatic cases (based on seroprevalence) with different immunological memories. Optimal model parameters are in part identified by Monte Carlo based Least Square Error methods while micro-outbreaks are modeled by noise and explored in Monte Carlo simulations. Estimates for infected population sizes are obtained by using a quasi steady state method. RESULTS: The calculations and simulations made by the model were shown to fit with the observed development of the COVID-19 epidemic in Denmark. The antibody prevalence in the general population in May 2020 was 1.37%, which yields a relative frequency of symptomatic and asymptomatic cases of 1 to 5.2. Due to the large asymptomatic population, the Infection Mortality Rate was only 0.4%. However, with no non-pharmacological restrictions the COVID-19 death toll was calculated to have more than doubled the national average yearly deaths within a year. The transmission rate ℜ0 was 5.4 in the initial free epidemic period, 0.4 in the lock-down period and 0.8-1.0 in the successive re-opening periods through August 2020. The large asymptomatic population made the termination of the epidemic difficult and micro-outbreaks occurred when the country re-opened. The estimated infected population size July 15 to August 15 was 2,100 and 12,200 for October 1-20, 2020. CONCLUSIONS: The results of the model show, that COVID-19 has a low Infection Fatality Rate because the majority of infected persons are either asymptomatic or with few symptoms. A minority of the infected persons, therefore, requires hospitalization. That means that for a given infection pressure of both symptomatic and asymptomatic infected there will be a lower pressure on the capacity of the health care system than previously predicted. Further the epidemic will be difficult to terminate since about 84% of the infected individuals are asymptomatic but still contagious. The model may be useful if a major infection wave occurs in the autumn-winter season as it could make robust estimates both for the scale of an ongoing expanding epidemic and for the expected load on the healthcare system. The simulation may also be useful to evaluate different testing strategies based on estimated infected population sizes. The model can be adjusted and scaled to other regions and countries, which is illustrated with Spain and USA.

Annual incidence of severe ovarian hyperstimulation syndrome.

INTRODUCTION: Ovarian hyperstimulation syndrome (OHSS) is one of the major complications of assisted reproductive technology treatment. We assumed that it had declined in recent years owing to the options of new preventive strategies. The aim of the present study was to investigate the annual incidence of OHSS in Denmark in the course of a 17-year period. METHODS: This was a national register-based historical cohort study including all women with an OHSS diagnosis admitted to Danish hospitals between 2001 and 2017. Data included information on all OHSS diagnoses, duration of hospital stay, early pregnancy complications and other complications like thromboembolism and ovarian torsion. The annual number of initiated stimulated in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) cycles was based on the annual reporting by the Danish Fertility Society. RESULTS: From 2001 to 2017, a total of 2,261 (1.2%) women with an OHSS admission were identified among 186,168 stimulated IVF/ICSI cycles. The annual incidence of OHSS varied from 0.9% to 1.2-1.4% with no overall change over time (p = 0.24. Early OHSS (defined as OHSS without a pregnancy in the cycle) was seen in 48.5% of the events, late OHSS (defined as OHSS with a pregnancy in the cycle) in 51.2% of cycles. Among all women with OHSS, 75% were hospitalised for more than 24 hours, with mean 4.3 and 6.2 days in hospital for early and late OHSS, respectively. CONCLUSIONS: The annual incidence of severe OHSS leading to a hospital admission remained stable for 17 years, which suggests that OHSS preventive actions like use of antagonist cycles, agonist triggering and freeze all should be better implemented in Denmark. FUNDING: none. TRIAL REGISTRATION: not relevant.

Pregnancy loss is associated with type 2 diabetes: a nationwide case-control study.

AIMS/HYPOTHESIS: Type 2 diabetes is killing more people than ever, and early-life predictors remain critical for the development of effective preventive strategies. Pregnancy loss is a common event associated with later atherosclerotic disease and ischaemic heart failure and might constitute a predictor for type 2 diabetes. The objective of this study was to investigate whether pregnancy loss is associated with later development of type 2 diabetes. METHODS: Using a Danish nationwide cohort, we identified all women born from 1957 through to 1997 and who had a diagnosis of type 2 diabetes during the period 1977 to 2017. The women were matched 1:10 on year of birth and educational level to women without diabetes in the general Danish population. Conditional logistic regression models provided odds ratios for type 2 diabetes with different numbers of pregnancy losses. RESULTS: We identified 24,774 women with type 2 diabetes and selected 247,740 controls without diabetes. Women who had ever been pregnant (ever-pregnant women) with 1, 2 and ≥ 3 pregnancy losses had ORs of type 2 diabetes of 1.18 (95% CI 1.13, 1.23), 1.38 (95% CI 1.27, 1.49) and 1.71 (95% CI 1.53, 1.92) compared with ever-pregnant women with no pregnancy losses, respectively. Women who never achieved a pregnancy had an OR of type 2 diabetes of 1.56 (95% CI 1.51, 1.61) compared with ever-pregnant women with any number of losses. Similar results were found after adjustment for obesity and gestational diabetes. CONCLUSIONS/INTERPRETATION: We found a significant and consistent association between pregnancy loss and later type 2 diabetes that increased with increasing number of losses. Thus, pregnancy loss and recurrent pregnancy loss are significant risk factors for later type 2 diabetes. Future studies should explore whether this association is due to common background factors or whether prediabetic metabolic conditions are responsible for this association. Graphical abstract.

Pregnancy loss: A 40-year nationwide assessment.

INTRODUCTION: Pregnancy loss is frequent. We aimed to assess the frequency and trends in pregnancy losses according to female age and mode of conception over a 40-year follow-up period. MATERIAL AND METHODS: In a national historical prospective cohort study, we followed all Danish women 10-49 years over the 40-year study period 1978-2017. Data on pregnancies and their outcomes were obtained from the National Health Registry, the Medical Birth Registry and the National Fertility Registry. Incidence rates per 100 pregnancies and per 1,000 women-years as well as lifetime risks per 100 women were calculated. Women included in the lifetime analysis were followed from age 12 to age 49. Pregnancy loss included spontaneous abortion, missed abortion and anembryonic pregnancy. RESULTS: In 3 519 455 recorded pregnancies, 337 008, or 9.6%, were diagnosed with a pregnancy loss. The proportion increased from 7.5% in 1978-1979, peaked at 10.7% in 2000 and thereafter decreased to 9.1% in 2015-2017. Pregnancy loss rate in women 10-14 years was 3.9%, increasing gradually with age to 26.9% in pregnant women 45-49 years, a 6.9-fold increase. Loss rates were slightly lower in naturally conceived pregnancies than in assisted pregnancies except for women above 45 years, where the risk of loss was higher in the spontaneously conceived group. Lifetime risk of specific numbers of losses were: 0: 76.9%, 1: 17.9%, 2: 3.9%, 3: 0.87%, and 4+: 0.35%. CONCLUSIONS: The proportion of women experiencing pregnancy loss has changed little throughout four decades and is still primarily influenced by female age. More than 75% of pregnant women are never recorded with a pregnancy loss, and <1.5% will experience three or more losses.

Is cesarean section a cause of affective disorders?-A national cohort study using sibling designs.

BACKGROUND: The gut microbiota of children delivered by cesarean section differs from that of children delivered vaginally. In light of the gut-brain axis hypothesis, cesarean section may influence risk of affective disorders. METHODS: Population based prospective cohort study included Danish children born 1982 through 2001, with follow-up until 2015. The effect of delivery mode on the risk of affective disorders was assessed using a standard Cox model and two types of Cox sibling models. Diagnostic codes or prescriptions for antidepressants and lithium were used to define cases of affective disorders. RESULTS: 1,009,444 children were followed for 8,880,794 person-years from the age of 13 years, with relevant covariates available from birth. There are strong calendar time trends in the occurrence of affective disorders with an increasingly younger age at first diagnosis and with a hotspot between the years 2007-2012. Fully adjusted standard Cox models showed an increased risk of affective disorders for both pre-labor (hazard ratio [HR], 1.11; 95% confidence interval [CI], 1.08-1.15) and intrapartum (HR, 1.07; 95% CI, 1.05-1.10) cesarean section, compared to vaginal delivery. This effect disappeared in the between-within sibling model for pre-labor (HR, 1.00; 95% CI, 0.94-1.07) but not intrapartum (HR, 1.05; 95% CI, 1.00-1.12) cesarean section. LIMITATIONS: Interpretation of results from sibling models may not be relevant to children without siblings. CONCLUSIONS: These results do not support the hypothesis that a delivery-mode dependent change in gut microbiota is a cause of subsequent affective disorders, despite an apparent association with delivery mode.

Maternal age and risk of cesarean section in women with induced labor at term-A Nordic register-based study.

INTRODUCTION: Over the last decades, induction of labor has increased in many countries along with increasing maternal age. We assessed the effects of maternal age and labor induction on cesarean section at term among nulliparous and multiparous women without previous cesarean section. MATERIAL AND METHODS: We performed a retrospective national registry-based study from Denmark, Finland, Iceland, Norway, and Sweden including 3 398 586 deliveries between 2000 and 2011. We investigated the impact of age on cesarean section among 196 220 nulliparous and 188 158 multiparous women whose labor was induced, had single cephalic presentation at term, and no previous cesarean section. Confounders comprised country, time-period, and gestational age. RESULTS: In nulliparous women with induced labor the rate of cesarean section increased from 14.0% in women less than 20 years of age to 39.9% in women 40 years and older. Compared with women aged 25-29 years, the corresponding relative risks were 0.60 (95% confidence interval [95% CI] 0.57 to 0.64) and 1.72 (95% CI 1.66 to 1.79). In multiparous induced women the risk of cesarean section was 3.9% in women less than 20 years rising to 9.1% in women 40 years and older. Compared with women aged 25-29 years, the relative risks were 0.86 (95% CI 0.54 to 1.37) and 1.98 (95% CI 1.84 to 2.12), respectively. There were minimal confounding effects of country, time-period, and gestational age on risk for cesarean section. CONCLUSIONS: Advanced maternal age is associated with increased risk of cesarean section in women undergoing labor induction with a single cephalic presentation at term without a previous cesarean section. The absolute risk of cesarean section is 3-5 times higher across 5-year age groups in nulliparous relative to multiparous women having induced labor.

Reduced Complications Following Implementation of Laparoscopic Hysterectomy: A Danish Population-based Cohort Study of Minimally Invasive Benign Gynecologic Surgery between 2004 and 2018.

STUDY OBJECTIVE: To monitor and report nationwide changes in the rates of and complications after different methods for benign hysterectomy, operative hysteroscopy, myomectomy, and embolization in Denmark. To report the national mortality after benign hysterectomy DESIGN: National prospective, observational cohort study. SETTING: The Danish Hysterectomy and Hysteroscopy Database. PATIENTS: Women undergoing surgery for benign gynecologic diseases: 64 818 hysterectomies, 84 175 hysteroscopies, 4016 myomectomies, and 1209 embolizations in Denmark between 2004 and 2018. INTERVENTIONS: National meetings with representatives from all departments, annual working reports of institutional complication rates, workshops, and national guideline initiative to improve minimally invasive surgical methods. MEASUREMENTS AND MAIN RESULTS: Rates of the different methods and complications after each method with follow-up to 5 years as recorded by the database directly in the National Patient Registry. Nationwide, a decline in the use of hysterectomy, myomectomy, embolizations, and endometrial ablation. The total short-term complications were 9.8%, 7.5%, 8.9%, and 2.7% respectively, however, with a persistent risk of approximately 20% for recurrent operations within 5 years after endometrial ablation. Initially, we urged for increased use of vaginal hysterectomy, but only reached 36%. From 2010, we urged for reducing abdominal hysterectomies by implementing laparoscopic hysterectomy and reached 72% laparoscopic and robotic procedures. Since 2015, we used coring or contained morcellation for removal of large uterus at laparoscopic hysterectomy. The major and minor complication rates (modified Clavien-Dindo classification) were reduced significantly from 8.1% to 4.1% and 9.9% to 5.7% respectively. Mortality after benign hysterectomy was 0.27‰. The odds ratio for major complications after abdominal hysterectomy was 1.66 (1.52-1.81) compared to minimally invasive hysterectomy independent of the length of stay, high-volume departments, indications, comorbidity, age, and calendar year. CONCLUSION: Fifteen years with a national database has resulted in a marked quality improvement. Denmark has 85% minimally invasive hysterectomies and has reduced the number of major complications by 50%.

An Overview of Open-Ended Evolution: Editorial Introduction to the Open-Ended Evolution II Special Issue.

Nature's spectacular inventiveness, reflected in the enormous diversity of form and function displayed by the biosphere, is a feature of life that distinguishes living most strongly from nonliving. It is, therefore, not surprising that this aspect of life should become a central focus of artificial life. We have known since Darwin that the diversity is produced dynamically, through the process of evolution; this has led life's creative productivity to be called Open-Ended Evolution (OEE) in the field. This article introduces the second of two special issues on current research in OEE and provides an overview of the contents of both special issues. Most of the work was presented at a workshop on open-ended evolution that was held as a part of the 2018 Conference on Artificial Life in Tokyo, and much of it had antecedents in two previous workshops on open-ended evolution at artificial life conferences in Cancun and York. We present a simplified categorization of OEE and summarize progress in the field as represented by the articles in this special issue.

Open-Ended Evolution and Open-Endedness: Editorial Introduction to the Open-Ended Evolution I Special Issue.

Nature's spectacular inventiveness, reflected in the enormous diversity of form and function displayed by the biosphere, is a feature of life that distinguishes living most strongly from nonliving. It is, therefore, not surprising that this aspect of life should become a central focus of artificial life. We have known since Darwin that the diversity is produced dynamically, through the process of evolution; this has led life's creative productivity to be called Open-Ended Evolution (OEE) in the field. This article introduces the first of two special issues on current research on OEE and on the more general concept of open-endedness. Most of the papers presented in these special issues are elaborations of work presented at the Third Workshop on Open-Ended Evolution, held in Tokyo as part of the 2018 Conference on Artificial Life.

Two Modes of Evolution: Optimization and Expansion.

We document and discuss two different modes of evolution across multiple systems, optimization and expansion. The former suffices in systems whose size and interactions do not change substantially over time, while the latter is a key property of open-ended evolution, where new players and interaction types enter the game. We first investigate systems from physics, biology, and engineering and argue that their evolutionary optimization dynamics is the cumulative effect of multiple independent events, or quakes, which are uniformly distributed on a logarithmic time scale and produce a decelerating fitness improvement when using the appropriate independent variable. The appropriate independent variable can be physical time for a disordered magnetic system, the number of generations for a bacterial system, or the number of produced units for a particular technological product. We then derive and discuss a simple microscopic theory that explains the nature of the involved optimization processes, and provide simulation results as illustration. Finally, we explore the evolution of human culture and technology, using empirical economic data as a proxy for human fitness. Assuming the overall dynamics is a combined optimization and expansion process, the two processes can be separated and quantified by superimposing the mathematical form of an optimization process on the empirical data and thereby transforming the independent variable. This variable turns out to increase faster than any exponential function of time, a property likely due to strong historical changes in the web of human interactions and to the associated increase in the amount of available knowledge. A microscopic theory for this time dependence remains, however, a challenging open problem.