Duration of the active first stage of labour and severe perineal lacerations and maternal postpartum complications: a population-based cohort study.

OBJECTIVE: The impact of first stage labour duration on maternal outcomes is sparsely investigated. We aimed to study the association between a longer active first stage and maternal complications in the early postpartum period. DESIGN: A population-based cohort study. SETTING: Regions of Stockholm and Gotland, Sweden, 2008-2020. POPULATION: A cohort of 159 459 term, singleton, vertex pregnancies, stratified by parity groups. METHODS: The exposure was active first stage duration, categorised in percentiles. Poisson regression analysis was performed to estimate the adjusted relative risk (aRR) and the 95% confidence interval (95% CI). To investigate the effect of second stage duration on the outcome, mediation analysis was performed. MAIN OUTCOME MEASURES: Severe perineal lacerations (third or fourth degree), postpartum infection, urinary retention and haematoma in the birth canal or ruptured sutures. RESULTS: The risks of severe perineal laceration, postpartum infection and urinary retention increased with a longer active first stage, both overall and stratified by parity group. The aRR increased with a longer active first stage, using duration of <50th percentile as the reference. In the ≥90th percentile category, the aRR for postpartum infection was 1.64 (95% CI 1.46-1.84) in primiparous women, 2.43 (95% CI 1.98-2.98) in parous women with no previous caesarean delivery (CD) and 2.33 (95% CI 1.65-3.28) in parous women with a previous CD. The proportion mediated by second stage duration was 33.4% to 36.9% for the different outcomes in primiparous women. The risk of haematoma or ruptured sutures did not increased with a longer active first stage. CONCLUSIONS: Increasing active first stage duration is associated with maternal complications in the early postpartum period.

First stage of labour duration and associated risk of adverse neonatal outcomes.

Prior evidence evaluating the benefits and harms of expectant labour duration during active first stage is inconclusive regarding potential consequences for the neonate. Population-based cohort study in Stockholm-Gotland region, Sweden, including 46,040 women (Robson 1), between October 1st, 2008 and June 15th, 2020. Modified Poisson regression was used for the association between active first stage of labour duration and adverse neonatal outcomes. 94.2% experienced a delivery with normal neonatal outcomes. Absolute risk for severe outcomes increased from 1.9 to 3.0%, moderate outcomes increased from 2.8 to 6.2% (> 10.1 h). Compared to the reference, (< 5.1 h; median), the adjusted relative risk (aRR) of severe neonatal outcome significantly increased beyond 10.1 h (> 90th percentile) (aRR 1.53, 95% CI 1.26, 1.87), for moderate neonatal outcome the aRR began to slowly increase beyond 5.1 h (≥ 50 percentile; aRR 1.40, 95% CI 1.24, 1.58). Mediation analysis indicate that most of the association was due to a longer active first stage of labour, 13% (severe neonatal outcomes) and 20% (moderate neonatal outcomes) of the risk was mediated (indirect effect) by longer second stage of labour duration. We report an association between increasing active first stage duration and increased risk of adverse neonatal outcomes. We did not observe a clear labour duration risk threshold.

Validating a predictive model for caesarean section in low-risk nulliparous pregnancies.

PROBLEM: Caesarean birth (CS) rates are steadily increasing. BACKGROUND: In 2017 Janssen et al. developed a model which could predict CB in nulliparous healthy woman with 71 % accuracy based on factors measurable on admission to the hospital. AIM: To validate the predictive model for risk of caesarean birth among low-risk, nulliparous women in a new setting. METHODS: A retrospective chart study in Abbotsford Regional Hospital (British Columbia, Canada) of healthy nulliparous women in spontaneous labour, at term, with a singleton fetus in cephalic position. Sociodemographic, pregnancy and labour-related characteristics were collected and independent predictors of CS were determined using multivariate logistic regression. The Janssen model was tested in the Abbotsford sample and additionally novel predictors were tested in an effort to improve the model. The area under the ROC curve (C-statistic) was computed and model calibration, sensitivity and specificity evaluated for the final model. FINDINGS AND DISCUSSION: Of 348 women, 106 (30.5 %) had a CB. Applying the Janssen predictive model to the Abbotsford data resulted in a C-statistic of 0.77. No new predictors were added to the model. The mean predicted risk score for CS in the cohort was 0.30 ± 0.20. A risk score cut-off of 0.32 was determined resulting in a sensitivity and specificity of 69 %. The model had acceptable calibration. CONCLUSION: A model with variables easily accessible at admission can predict caesarean birth in nulliparous women. The results from this study can guide provision of more intensive care during labour to women at higher risk, with the overall goal of reducing CB rates.

Increased incidence of shoulder dystocia but a declining incidence of obstetric brachial plexus palsy in vaginally delivered infants.

INTRODUCTION: Obstetric brachial plexus palsy (OBPP) is a serious form of neonatal morbidity. The primary aim of this population-based registry study was to examine temporal trends, 1997-2019, of OBPP in infants delivered vaginally in a cephalic presentation. The secondary aim was to examine temporal changes in the incidence of associated risk factors. MATERIAL AND METHODS: This was a population-based registry study including singleton, cephalic, vaginally delivered infants, 1997-2019, in Sweden. To compare changes in the incidence rates of OBPP and associated risk factors over time, univariate logistic regression was used and odds ratios (OR) with 95% confidence intervals (CI) were calculated. RESULTS: The incidence of OBPP in infants delivered vaginally in a cephalic presentation decreased from 3.1 per 1000 births in 1997 to 1.0 per 1000 births in 2019 (OR 0.31, 95% CI 0.24-0.40). Conversely, the incidence of shoulder dystocia increased from 2.0 per 1000 in 1997 to 3.3 per 1000 in 2019 (OR 1.64, 95% CI 1.34-2.01). Over time, the proportion of women with body mass index of 30 kg/m2 or greater increased (14.5% in 2019 compared with 8.0% in year 1997, OR 1.96, 95% CI 1.89-2.03), more women had induction of labor (20.5% in 2019 compared with 8.6% in 1997, OR 2.74, 95% CI 2.66-2.83) and epidural analgesia (41.2% in 2019 compared with 29.0% in 1997, OR 1.72, 95% CI 1.68-1.75). In contrast, there was a decrease in the rate of operative vaginal delivery (6.0% in 2019, compared with 8.1% in 1997, OR 0.72, 95% CI 0.69, 0.75) and in the proportion of infants with a birthweight greater than 4500 g (2.7% in 2019 compared with 3.8% in 1997, OR 0.70, 95% CI 0.66-0.74). The decline in the incidence of these two risk factors explained only a small fraction of the overall decrease in OBPP between 1997-2002 and 2015-219. CONCLUSIONS: The incidence of OBPP in vaginally delivered infants in a cephalic presentation at birth decreased during the period 1997-2019 despite an increase in important risk factors including shoulder dystocia.

Crude and adjusted comparisons of cesarean delivery rates using the Robson classification: A population-based cohort study in Canada and Sweden, 2004 to 2016.

BACKGROUND: The Robson classification has become a global standard for comparing and monitoring cesarean delivery (CD) rates across populations and over time; however, this classification does not account for differences in important maternal, fetal, and obstetric practice factors known to impact CD rates. The objectives of our study were to identify subgroups of women contributing to differences in the CD rate in Sweden and British Columbia (BC), Canada using the Robson classification and to estimate the contribution of maternal, fetal/infant, and obstetric practice factors to differences in CD rates between countries and over time. METHODS AND FINDINGS: We conducted a population-based cohort study of deliveries in Sweden (January 1, 2004 to December 31, 2016; n = 1,392,779) and BC (March 1, 2004 to April 31, 2017; n = 559,205). Deliveries were stratified into Robson categories and the CD rate, relative size of each group and its contribution to the overall CD rate were compared between the Swedish and the Canadian cohorts. Poisson and log-binomial regression were used to assess the contribution of maternal, fetal, and obstetric practice factors to spatiotemporal differences in Robson group-specific CD rates between Sweden and BC. Nulliparous women comprised 44.8% of the study population, while women of advanced maternal age (≥35 years) and women with overweight/obesity (≥25 kg/m2) constituted 23.5% and 32.4% of the study population, respectively. The CD rate in Sweden was stable at approximately 17.0% from 2004 to 2016 (p for trend = 0.10), while the CD rate increased in BC from 29.4% to 33.9% (p for trend < 0.001). Differences in CD rates between Sweden and BC varied by Robson group, for example, in Group 1 (nullipara with a term, single, cephalic fetus with spontaneous labor), the CD rate was 8.1% in Sweden and 20.4% in BC (rate ratio [RR] for BC versus Sweden = 2.52, 95% confidence interval [CI] 2.49 to 2.56, p < 0.001) and in Group 2 (nullipara, single, cephalic fetus, term gestation with induction of labor or prelabor CD), the rate of CD was 37.3% in Sweden and 45.9% in BC (RR = 1.23, 95% CI 1.22 to 1.25, p < 0.001). The effect of adjustment for maternal characteristics (e.g., age, body mass index), maternal comorbidity (e.g., preeclampsia), fetal characteristics (e.g., head position), and obstetric practice factors (e.g., epidural) ranged from no effect (e.g., among breech deliveries; Groups 6 and 7) to explaining up to 5.2% of the absolute difference in the CD rate (Group 2: adjusted CD rate in BC 40.7%, adjusted RR = 1.09, 95% CI 1.08 to 1.12, p < 0.001). Adjustment also explained a substantial fraction of the temporal change in CD rates among some Robson groups in BC. Limitations of the study include a lack of information on intrapartum details, such as labor duration as well as maternal and perinatal outcomes associated with the observed differences in CD rates. CONCLUSIONS: In this study, we found that several factors not included in the Robson classification explain a significant proportion of the spatiotemporal difference in CD rates in some Robson groups. These findings suggest that incorporating these factors into explanatory models using the Robson classification may be useful for ensuring that public health initiatives regarding CD rates are evidence informed.

Accuracy of postpartum hemorrhage coding in the Swedish Pregnancy Register.

INTRODUCTION: Postpartum hemorrhage (PPH) is recognized as a leading cause of obstetric morbidity and mortality. Population-wide studies have used International Classification of Diseases (ICD) diagnostic codes to track and report the prevalence of PPH. Although the 10th revision (ICD-10) was introduced in Sweden in 1997, the accuracy of ICD-10 codes for PPH is not known. Thus, the aim was to determine the accuracy of diagnostic coding for PPH in the Swedish Pregnancy Register. MATERIAL AND METHODS: We performed a retrospective cohort study of 609 807 deliveries in Sweden between 2014 and 2019. Information on ICD-10 codes for PPH and estimated blood loss were extracted from the Swedish Pregnancy Register. Using an estimated blood loss >1000 mL as the reference standard, we evaluated the diagnostic accuracy of ICD-10 codes for PPH by estimating sensitivity, specificity, positive predictive value and negative predictive value with exact binomial 95% confidence intervals (CIs). In our secondary analysis, we assessed the ICD-10 coding accuracy for severe PPH, defined as an estimated blood loss >1000 mL and transfusion of at least 1 unit of red blood cells registered in the Scandinavian Donations and Transfusion database. RESULTS: Of the 609 807 deliveries, 43 312 (7.1%) had an ICD-10 code for PPH and 45 071 (7.4%) had an estimated blood loss >1000 mL. The ICD codes had a sensitivity of 88.5% (95% CI 88.2-88.7), specificity of 99.4% (95% CI 99.4-99.4), positive predictive value of 92.0% (95% CI 91.8-92.3) and negative predictive value of 99.1% (95% CI 99.1-99.1). In our secondary analysis, on deliveries with severe PPH, the sensitivity for an ICD code was 91.3% (95% CI 90.7-91.9), whereas specificity was 83.5% (95% CI 82.3-84.6). CONCLUSIONS: Our findings indicate that ICD-10 codes for PPH in Sweden have moderately high sensitivity and excellent specificity. These results suggest that PPH diagnostic codes in medical records and linked pregnancy and birth registers can be used for research, quality improvement and reporting PPH prevalence in Sweden.

Fetal overgrowth in women with type 1 and type 2 diabetes mellitus.

OBJECTIVES: Despite improved glycemic control, the rate of large-for-gestational-age (LGA) infants remains high in pregnancies complicated by diabetes mellitus type 1 (T1DM) and type 2 (T2DM). Poor glycemic control, obesity, and excessive gestational weight gain are the main risk factors. The aim of this study was to determine the relative contribution of these risk factors for LGA in women with T1DM and T2DM, after controlling for important confounders such as age, smoking, and parity. METHODS: In this retrospective chart review study, we analyzed the medical files of pregnant women with T1DM and T2DM who attended the antenatal care program at Skåne University Hospital during the years 2006 to 2016. HbA1c was used as a measure of glycemic control. Maternal weight in early pregnancy and at term was registered. LGA was defined as birth weight > 2 standard deviations of the mean. Univariable and multivariable logistic regression analysis was used to calculate odds ratios (OR's) and 95% confidence intervals (CIs) for LGA. RESULTS: Over the 11-year period, we identified 308 singleton pregnancies in 221 women with T1DM and in 87 women with T2DM. The rate of LGA was 50% in women with T1DM and 23% in women with T2DM. The multivariable regression model identified gestational weight gain and second-trimester HbA1c as risk factors for LGA in T1DM pregnancies (OR = 1.107, 95% CI: 1.044-1.17, and OR = 1.047, 95% CI: 1.015-1.080, respectively) and gestational weight gain as a risk factor in T2DM pregnancies (OR = 1.175, 95% CI: 1.048-1.318), independent of body mass index. CONCLUSIONS: Gestational weight gain was associated with LGA in women with T1DM and T2DM, independent of maternal body mass index. The findings suggest that monitoring and regulation of gestational weight gain is important in the clinical care of these women, to minimize the risk of fetal overgrowth.