Trends in Term Intrapartum Stillbirth in Norway.

Importance: Fetal death during labor at term is a complication that is rarely studied in high-income countries. There is a need for large population-based studies to examine the rate of term intrapartum stillbirth in high-income countries and the factors associated with its occurrence. Objective: To evaluate trends in term intrapartum stillbirth over time and to investigate the association between the trends and term intrapartum stillbirth risk factors from 1999 to 2018 in Norway. Design, Setting, and Participants: This cohort study used data from the Medical Birth Registry of Norway from 1999 to 2018 to examine rates of term intrapartum stillbirth and risk factors associated with this event. A population of 1 021 268 term singleton pregnancies without congenital anomalies or antepartum stillbirths was included in analyses, which were performed from September 2022 to February 2023. Exposure: The main exposure variable was time, which was divided into four 5-year periods: 1999 to 2003, 2004 to 2008, 2009 to 2013, and 2014 to 2018. Main Outcomes and Measures: The primary study outcome was term intrapartum stillbirth. Risk ratios were calculated, and multivariable logistic regression analyses were conducted to identify factors associated with secular trends of term intrapartum stillbirth. Results: The study population consisted of 1 021 268 term singleton births (maternal mean [SD] age, 29.72 [5.01] years; mean [SD] gestational age, 39.69 [1.27] weeks). During the study period, there were 95 term intrapartum stillbirths (0.09 per 1000 births). Maternal age, the proportion of individuals born in a country other than Norway, and the prevalence of gestational diabetes, labor induction, operative vaginal delivery, and previous cesarean delivery increased over the course of the study period. Conversely, the prevalence of infants large for gestational age, hypertensive disorder in pregnancy, and spontaneous vaginal delivery and the proportion of individuals who smoked decreased. The term intrapartum stillbirth rate decreased by 87% (95% CI, 68%-95%) from 0.15 per 1000 births in 1999 to 2008 to 0.02 per 1000 births in 2014 to 2018. Three in 4 term intrapartum stillbirths (70 of 95) occurred during intrapartum operative deliveries. The increased prevalence of older maternal age and obstetric risk factors were not associated with the variation in intrapartum stillbirth rates among the time periods. The prevalence of term intrapartum stillbirth was higher for individuals who gave birth in maternity units with fewer than 3000 annual births (adjusted odds ratio, 1.67; 95% CI, 1.07-2.61) than for those who gave birth in units with 3000 or more annual births. Conclusions and Relevance: Findings of this study suggest that, despite increases in maternal and obstetric risk factors, term intrapartum stillbirth rates substantially decreased during the study period. Reasons for this decrease may be due to improvements in intrapartum care.

Neonatal outcomes associated with time from a high fetal blood lactate concentration to operative delivery.

INTRODUCTION: Adjunctive technologies to cardiotocography intend to increase the specificity of the diagnosis of fetal hypoxia. If correctly diagnosed, time to delivery could affect neonatal outcome. In the present study, we aimed to investigate the effect of time from when fetal distress is indicated by a high fetal blood sample (FBS) lactate concentration to operative delivery on the risk of adverse neonatal outcomes. MATERIAL AND METHODS: We conducted a prospective observational study. Deliveries with a singleton fetus in cephalic presentation at 36+0 weeks of gestation or later were included. Adverse neonatal outcomes, related to decision-to-delivery interval (DDI), were investigated in operative deliveries indicated by an FBS lactate concentration of at least 4.8 mmol/L. We applied logistic regression to estimate crude and adjusted odds ratios (aOR) of various adverse neonatal outcomes, with associated 95% confidence intervals (CI), for a DDI exceeding 20 minutes, compared with a DDI of 20 minutes or less. CLINICALTRIALS: gov Identifier: NCT04779294. RESULTS: The main analysis included 228 women with an operative delivery indicated by an FBS lactate concentration of 4.8 mmol/L or greater. The risk of all adverse neonatal outcomes was significantly increased for both DDI groups compared with the reference group (deliveries with an FBS lactate below 4.2 mmol/L within 60 minutes before delivery). In operative deliveries indicated by an FBS lactate concentration of 4.8 mmol/L or more, there was a significantly increased risk of a 5-minute Apgar score less than 7 if the DDI exceeded 20 minutes, compared with a DDI of 20 minutes or less (aOR 8.1, 95% CI 1.1-60.9). We found no statistically significant effect on other short-term outcomes for deliveries with DDI longer than 20 minutes, compared with those with DDI of 20 minutes or less (pH ≤7.10: aOR 2.0, 95% CI 0.5-8.4; transfer to the neonatal intensive care unit: aOR 1.1, 95% CI 0.4-3.5). CONCLUSIONS: After a high FBS lactate measurement, the increased risk of adverse neonatal outcome is further augmented if the DDI exceeds 20 minutes. These findings give support to current Norwegian guidelines for intervention in cases of fetal distress.

Time trends in caesarean section rates and associations with perinatal and neonatal health: a population-based cohort study of 1 153 789 births in Norway.

OBJECTIVES: To study caesarean section (CS) rates and associations with perinatal and neonatal health in Norway during 1999-2018. DESIGN: Population-based cohort study. SETTING: Medical Birth Registry of Norway. PARTICIPANTS: 1 153 789 births and 1 174 066 newborns. METHODS: CS, intrapartum, perinatal and neonatal mortality rates expressed as percentages (%) or per mille (‰) with 95% CIs. PRIMARY AND SECONDARY OUTCOME MEASURES: CS rates in the Robson Ten-Group Classification System; intrapartum, perinatal and neonatal mortality rates. RESULTS: The overall CS rate increased from 12.9% in 1999 to 16.7% in 2008 (p<0.001), and then reduced to 15.8% in 2018 (p<0.001). The largest reductions were observed in Robson groups 2 and 4. In Robson group 2, the planned CS rate decreased from 9.6% in 2007-2008 to 4.6% in 2017-2018, the intrapartum CS rate decreased from 26.6% in 2007-2008 to 22.3% in 2017-2018. In Robson group 4, the planned CS rate decreased from 16.1% in 2007-2008 to 7.6% in 2017-2018, and the intrapartum CS rate decreased from 7.8% in 2007-2008 to 5.2% in 2017-2018.The intrapartum fetal mortality rate decreased from 0.51 per 1000 (‰) in 1999-2000 to 0.14‰ in 2017-2018. Neonatal mortality decreased from 2.52‰ to 1.58‰. CONCLUSIONS: CS rates in Norway increased between 1999 and 2008, followed by a significant reduction between 2008 and 2018. At the same time, fetal and neonatal mortality rates decreased. Norwegian obstetricians and midwives have contributed to maintaining a low CS rate under 17%. These findings indicate that restricting the use of CS is a safe option for perinatal health.

European guidelines on perinatal care- Peripartum care Episiotomy.

OF RECOMMENDATIONS1. Episiotomy should be performed by indication only, and not routinely (Moderate quality evidence +++-; Strong recommendation). Accepted indications for episiotomy are to shorten the second stage of labor when there is suspected fetal hypoxia (Low quality evidence ++-; Weak recommendation); to prevent obstetric anal sphincter injury in vaginal operative deliveries, or when obstetric sphincter injury occurred in previous deliveries (Moderate quality evidence +++-; Strong recommendation)2. Mediolateral or lateral episiotomy technique should be used (Moderate quality evidence +++-; Strong recommendation). Labor ward staff should be offered regular training in correct episiotomy techniques (Moderate quality evidence +++-; Strong recommendation).3. Pain relief needs to be considered before episiotomy is performed, and epidural analgesia may be insufficient. The perineal skin needs to be tested for pain before an episiotomy is performed, even when an epidural is in place. Local anesthetics or pudendal block need to be considered as isolated or additional pain relief methods (Low quality evidence ++-; Strong recommendation).4. After childbirth the perineum should be carefully inspected, and the anal sphincter palpated to identify possible injury (Moderate quality evidence +++-; Strong recommendation). Primary suturing immediately after childbirth should be offered and a continuous suturing technique should be used when repairing an uncomplicated episiotomy (High quality evidence ++++; Strong recommendation).

Fetal electrocardiography ST-segment analysis for intrapartum monitoring: a critical appraisal of conflicting evidence and a way forward.

BACKGROUND: In the past century, some areas of obstetric including intrapartum care have been slow to benefit from the dramatic advances in technology and medical care. Although fetal heart rate monitoring (cardiotocography) became available a half century ago, its interpretation often differs between institutions and countries, its diagnostic accuracy needs improvement, and a technology to help reduce the unnecessary obstetric interventions that have accompanied the cardiotocography is urgently needed. STUDY DESIGN: During the second half of the 20th century, key findings in animal experiments captured the close relationship between myocardial glycogenolysis, myocardial workload, and ST changes, thus demonstrating that ST waveform analysis of the fetal electrocardiogram can provide information on oxygenation of the fetal myocardium and establishing the physiological basis for the use of electrocardiogram in intrapartum fetal surveillance. RESULTS: Six randomized controlled trials, 10 meta-analyses, and more than 20 observational studies have evaluated the technology developed based on this principle. Nonetheless, despite this intensive assessment, differences in study protocols, inclusion criteria, enrollment rates, clinical guidelines, use of fetal blood sampling, and definitions of key outcome parameters, as well as inconsistencies in randomized controlled trial data handling and statistical methodology, have made this voluminous evidence difficult to interpret. Enormous resources spent on randomized controlled trials have failed to guarantee the generalizability of their results to other settings or their ability to reflect everyday clinical practice. CONCLUSION: The latest meta-analysis used revised data from primary randomized controlled trials and data from the largest randomized controlled trials from the United States to demonstrate a significant reduction of metabolic acidosis rates by 36% (odds ratio, 0.64; 95% confidence interval, 0.46-0.88) and operative vaginal delivery rates by 8% (relative risk, 0.92; 95% confidence interval, 0.86-0.99), compared with cardiotocography alone.

Maternal deaths from hypertensive disorders: lessons learnt.

INTRODUCTION: Hypertensive disorders of pregnancy have been the most frequent cause of maternal death in Norway since 1996 and are strongly associated with substandard care. In the UK, the number of maternal deaths due to hypertensive disorders has decreased drastically due to the implementation of updated guidelines, indicating a potential for reducing the number of deaths in other countries as well. Through audits of maternal deaths, we aim to prevent future deaths from hypertensive disorders in pregnancy by identifying suboptimal factors in treatment. MATERIAL AND METHODS: Maternal deaths in Norway from 1996 to 2014 were identified through linked registries. The Norwegian Maternal Mortality Audit Group performed all case assessments included in this study, classified the cause of death, evaluated the treatment, and identified suboptimal factors to care in each case. Emphasis was placed on antihypertensive treatment, timing of delivery, stabilization before delivery, and quality of care. Learning points were prepared to improve the treatment of hypertensive disorders of pregnancy. RESULTS: We identified 74 maternal deaths. The maternal mortality rate was 6.5 deaths per 100 000 live births. The most common cause of death was hypertensive disorders (n = 16 deaths). In 14 of these deaths (87%), the audit group concluded that improvements to care could have made a difference to the outcome. CONCLUSIONS: In 1996-2014, hypertensive disorders were the most common cause of maternal death in Norway. Our study indicates that such deaths can be prevented by improvements in antihypertensive treatment and the timing of delivery.

Pathophysiology of foetal oxygenation and cell damage during labour.

A foetus exposed to oxygenation compromise is capable of several adaptive responses, which can be categorised into those affecting metabolism and those affecting oxygen transport. However, both the extent and duration of the impairment in oxygenation will have a bearing on these adaptive responses. Although intrapartum events may account for no more than one-third of cases with an adverse neurological outcome, they are important because they can be influenced successfully. This review describes the mechanisms underlying foetal hypoxia during labour, acid-base balance and gas exchange, and the current scientific understanding of the role of intrauterine asphyxia in the pathophysiology of neonatal encephalopathy and cerebral palsy. Although the mechanisms involved include similar initiating events, principally ischaemia and excitotoxicity, and similar final common pathways to cell death, there are certain unique maturational factors that influence the type and pattern of cellular injury.

A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part II: the meta-analyses.

We appraised the methodology, execution and quality of the five published meta-analyses that are based on the five randomized controlled trials which compared cardiotocography (CTG)+ST analysis to cardiotocography. The meta-analyses contained errors, either created de novo in handling of original data or from a failure to recognize essential differences among the randomized controlled trials, particularly in their inclusion criteria and outcome parameters. No meta-analysis contained complete and relevant data from all five randomized controlled trials. We believe that one randomized controlled trial excluded in two of the meta-analyses should have been included, whereas one randomized controlled trial that was included in all meta-analyses, should have been excluded. After correction of the uncovered errors and exclusion of the randomized controlled trial that we deemed inappropriate, our new meta-analysis showed that CTG+ST monitoring significantly reduces the fetal scalp blood sampling usage (risk ratio 0.64; 95% confidence interval 0.47-0.88), total operative delivery rate (0.93; 0.88-0.99) and metabolic acidosis rate (0.61; 0.41-0.91).

A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part I: the randomized controlled trials.

We reappraised the five randomized controlled trials that compared cardiotocography plus ECG ST interval analysis (CTG+ST) vs. cardiotocography. The numbers enrolled ranged from 5681 (Dutch randomized controlled trial) to 799 (French randomized controlled trial). The Swedish randomized controlled trial (n = 5049) was the only trial adequately powered to show a difference in metabolic acidosis, and the Plymouth randomized controlled trial (n = 2434) was only powered to show a difference in operative delivery for fetal distress. There were considerable differences in study design: the French randomized controlled trial used different inclusion criteria, and the Finnish randomized controlled trial (n = 1483) used a different metabolic acidosis definition. In the CTG+ST study arms, the larger Plymouth, Swedish and Dutch trials showed lower operative delivery and metabolic acidosis rates, whereas the smaller Finnish and French trials showed minor differences in operative delivery and higher metabolic acidosis rates. We conclude that the differences in outcomes are likely due to the considerable differences in study design and size. This will enhance heterogeneity effects in any subsequent meta-analysis.

Association between umbilical cord artery pCO2 and the Apgar score; elevated levels of pCO2 may be beneficial for neonatal vitality after moderate acidemia.

OBJECTIVE: To determine the association between 5-min Apgar score and umbilical cord artery carbon dioxide tension (pCO2). DESIGN: Observational study. SETTING: European hospital labor wards. POPULATION: Data from 36,432 newborns ≥36 gestational weeks were obtained from three sources: two trials of monitoring with fetal electrocardiogram (the Swedish randomized controlled trial and the European Union Fetal ECG trial) and Mölndal Hospital data. After validation of the acid-base values, 25,806 5-min Apgar scores were available for analysis. METHODS: Validation of the umbilical cord acid-base values was performed to obtain reliable data. 5-min Apgar score was regressed against cord artery pCO2 in a polynomial multilevel model. MAIN OUTCOME MEASURES: Five-min Apgar score, umbilical cord pCO2, pH, and base deficit. RESULTS: Overall, a higher cord artery pCO2 was found to be associated with lower 5-min Apgar scores. However, among newborns with moderate acidemia, lower umbilical cord artery pCO2 (≤median pCO2 for the specific cord artery pH) was associated with lower 5-min Apgar scores, with a relative risk of 2.0 (95% confidence interval: 1.4-2.8) for 5-min Apgar scores 0-6. CONCLUSIONS: Metabolic acidosis affects the newborn's vitality more than respiratory acidosis. In addition, elevated levels of pCO2 may be beneficial for fetuses with moderate acidemia, and thus cord artery pCO2 is a factor that should be considered when assessing the compromised newborn.

What is the gold standard for intrapartum fetal monitoring?

The health authorities of Stockholm county recently published a Health Technology Assessment report: "Fetal monitoring with computerized STAN analysis during labor - a systematic review" with the aim to ensure that high quality research information on costs, effectiveness and broader impact of health technologies is analysed and presented in the most efficient way for those who use, manage and work in this field. The report claims to analyse available research in relation to ST interval analysis of fetal electrocardiogram (STAN) and concludes that scientific evidence for advantages of the STAN technology for maternal and fetal outcome was insufficient and that clinical use cannot be recommended and should be restricted to research protocols. The Norwegian reference group for fetal surveillance points out that the report suffers from two insufficiencies: selection bias by not providing a complete collection of the evidence for the clinical performance of the STAN technology and, secondly, that it does not provide evidence-based alternative methods.

How does the duration of active pushing in labor affect neonatal outcomes?

AIM: To assess the effect of time of active pushing (TAP) on neonatal outcome. MATERIALS AND METHODS: The study population (n=36,432) was taken from a Swedish randomized control trial on intrapartum monitoring, a European Union fetal electrocardiogram trial, and from Mölndal Hospital. After validation of acid-base samples and TAP, 22,812 cases were accepted for analysis. RESULTS: The median active TAP was 36 min for P0 and 13 min for P≥1 (P<0.001). After adjustments for parity, epidural, labor induction, birth weight, and gender, pushing for 15-29 min (n=6589) relative to pushing for <15 min (n=7264) increased the OR of a cord artery pH of <7.00 to 3.20 (95% CI 1.7-6.0), and that of a base deficit in extracellular fluid of >12 mmol/L to 3.5 (95% CI 1.3-9.0). The group with a cord artery pH of <7.00 had a longer TAP than the group with pH≥7.00: median (5th-95th percentile), 38 (9-107) min vs. 23 (5-87) min, P<0.001. The probability of a spontaneous vaginal delivery decreased significantly with every subsequent increase of 30 min in TAP (P<0.05). CONCLUSION: The risks of severe acidemia, metabolic acidosis, and deteriorated neonatal outcome gradually increased with the length of TAP (>15 min), while the probability of a spontaneous vaginal delivery decreased with the duration of pushing. We suggest active physiological evaluation of the labor progress together with continuous electronic fetal monitoring during pushing irrespective of guideline thresholds.

Intrapartum cardiotocography (CTG) and ST-analysis of labor in diabetic patients.

AIM: To determine the prevalence and types of intrapartum cardiotocography (CTG) patterns and investigate their relationship to moderate acidemia in term fetuses of diabetic mothers. Also, to assess if the combination of fetal electrocardiogram (FECG) and those CTG patterns strengthens the association with moderate acidemia. MATERIAL AND METHODS: The material for this study is obtained from the Swedish randomized control trial and the European Union ST-analysis trial. We developed an analytical model for CTG patterns based on the progress in CTG changes, in a longitudinal periodic manner. The model was then combined with information regarding changes in ST interval that indicate threatening asphyxia, and the findings were analyzed to determine correlation with the presence of moderate acidemia at birth. RESULTS: This study involved data of 413 diabetic mothers. A preterminal CTG was more common in the diabetes mellitus (DM) group (6/70, 8.6%) than in the gestational diabetes (GD) group (3/307, 1.0%; P=0.003). For diabetic mothers (i.e., DM+GD) with a normal CTG at the start of monitoring, the presence of FECG data indicating asphyxia significantly increased the likelihood of an umbilical artery pH<7.15 at birth [odds ratio (OR)=3.65, 95% confidence interval (CI)=1.33-10.05]. Among labors where the CTG was non-reassuring at the start of monitoring, no significant association was found between pH<7.15 and indication to intervene according to FECG information (OR=1.51, 95% CI=0.33-7.0). CONCLUSIONS: A preterminal CTG is more common in the fetuses of DM than GD mothers during labor. When CTG was normal at the start of recording, the addition of FECG information gave a significant add on information to predict moderate acidemia.

Intrapartum fetal ECG and diabetes.

AIM: The objective of this study was to determine the prevalence and types of ST-segment changes of the fetal electrocardiogram (FECG) during labour in term fetuses born to mothers with diabetes mellitus (DM) or gestational diabetes. METHODS: This was a retrospective case-control study involving populations from two multi centre trials: the Swedish Randomized Control Trial and the European Union ST-analysis (EU-STAN) trial. ST-segment changes were assessed in 104/309 cases and 207/468 controls from the Swedish and EU-STAN trials, respectively. RESULTS: ST depression was present on the FECG in 22.1% of fetuses of mothers with DM compared to 12% of controls OR = 2.6, 95% CI = 1.4-4.7, p = 0.002 after adjusting for trial, birth weight, and nulliparity. ST elevation was present in 47.1% of DM patients and 41.2% of controls (OR = 1.4, 95% CI = 0.9-2.3, p = 0.18). CONCLUSION: ST depression on the FECG was significantly more prevalent in the fetuses of mothers with DM, probably not indicating hypoxia but an altered ability of the myocardium to respond to the stress of labour. Further studies into the mechanism of fetal compromise during diabetic labour, are required.