Odds Of Postpartum Hemorrhage Research Articles

Oxytocin is not associated with postpartum hemorrhage in labor augmentation in a retrospective cohort study in the United States

Previous studies reported conflicting results on the relationship between oxytocin use for labor augmentation and the risk of postpartum hemorrhage, probably because it is rather challenging to disentangle oxytocin use from labor dystocia. This study aimed to investigate the independent association between oxytocin use for augmentation and the risk of postpartum hemorrhage by using advanced statistical modeling to control for labor patterns and other covariates. We used data from 20,899 term, cephalic, singleton pregnancies of patients with spontaneous onset of labor and no previous cesarean delivery from Intermountain Healthcare in Utah in the Consortium on Safe Labor. Presence of postpartum hemorrhage was identified on the basis of a clinical diagnosis. Propensity scores were calculated using a generalized linear mixed model for oxytocin use for augmentation, and covariate balancing generalized propensity score was applied to obtain propensity scores for the duration and total dosage of oxytocin augmentation. A weighted generalized additive mixed model was used to depict dose-response curves between the duration and total dosage of oxytocin augmentation and the outcomes. The average treatment effects of oxytocin use for augmentation on postpartum hemorrhage and estimated blood loss (mL) were assessed by inverse probability weighting of propensity scores. The odds of both postpartum hemorrhage and estimated blood loss increased modestly when the duration and/or total dosage of oxytocin used for augmentation increased. However, in comparison with women for whom oxytocin was not used, oxytocin augmentation was not clinically or statistically significantly associated with estimated blood loss (6.5 mL; 95% confidence interval, 2.5-10.3) or postpartum hemorrhage (adjusted odds ratio, 1.02; 95% confidence interval, 0.82-1.24) when rigorously controlling for labor pattern and potential confounders. The results remained consistent regardless of inclusion of women with an intrapartum cesarean delivery. The odds of postpartum hemorrhage and estimated blood loss increased modestly with increasing duration and total dosage of oxytocin augmentation. However, in comparison with women for whom oxytocin was not used and after controlling for potential confounders, there was no clinically significant association between oxytocin use for augmentation and estimated blood loss or the risk of postpartum hemorrhage.

Maternal Morbidity Rates Relative to Length of Labor in a Multiethnic Patient Population [ID: 1337798

INTRODUCTION: Prolonged induction of labor is associated with increased morbid maternal outcomes. Induction of labor length varies by institution and labor management. The objective of this study was to determine the risk of morbid outcomes increasing hours of labor induction in a multiethnic tertiary care center. METHODS: We conducted a retrospective cohort study on patients undergoing scheduled induction of labor from June 2020 to May 2021 at a tertiary care center. Nulliparous singleton term pregnancies with intact membranes who had an initial cervical dilation less than 3 were included. Length of labor induction was defined as first intervention to birth. Morbid outcomes included suspected intraamniotic infection (IAI), postpartum hemorrhage (PPH), and cesarean birth. Multivariable logistic regressions were performed relative to the length of labor. RESULTS: Two hundred sixty-seven patients were included in our study, with 18.0% Asian American/Pacific Islander, 6.4% Black/non-Hispanic, 20.2% Hispanic, 32.6% White/non-Hispanic, 17.6% multiracial/other, and 5.2% unknown. The median labor length was 28.5 hours (interquartile range 21.2–38.5). The rates of IAI was 22%, PPH 12%, and cesarean birth 22%. For every hour of labor, there was 1.04 increased odds of IAI, 1.08 odds of cesarean birth, and 1.05 odds of PPH after adjusting for confounders (P<.01). When comparing White versus non-White patients, there were no differences in labor length (28.4 hours versus 28.6 hours, P=.46) and no differences in IAI, PPH, and cesarean. CONCLUSION: For each hour of labor, the risk of IAI, PPH, and cesarean birth increased by 4%, 8%, and 5%, respectively. Characteristics contributing to this association may be multifactorial and suggest labor management should aim for an expedient birth.

This Month in Anesthesiology

This Month in Anesthesiology

694 Impact of neonatal birth weight on adverse perinatal outcomes in cesarean deliveries in nulliparous women

To investigate the association between neonatal birth weight (NBW) and adverse perinatal outcomes in nulliparous cesarean deliveries (CD). This is a retrospective cohort study of singleton, non-anomalous, term CD of nulliparous women 2007-2011 using linked vital statistics and ICD-9 data. Neonatal adverse outcomes examined included brachial plexus injury (BPI), clavicular fracture (CVF), neonatal intensive care unit (NICU) admission, hypoxic-ischemic encephalopathy (HIE), hypoglycemia (HG), and a composite of severe neonatal outcomes (including neonatal seizure, APGAR score ≤3, and neonatal death). Maternal adverse outcomes examined included postpartum hemorrhage (PPH) and maternal blood transfusion (MBT). Chi-square tests were used to compare rates of perinatal adverse outcomes for births in varying neonatal birth weight categories. Multivariable logistic regression was used to control for maternal BMI, diabetes, race/ethnicity, age, education, insurance, parity, and prenatal care. In a cohort of 258,490 CD, we found significantly higher rates of neonatal adverse outcomes, including BPI, CVF, NICU admission, and HG, with rising NBW (Figure 1). Risk of BPI and CVF rose from 0.01% in 3000-3400 neonates to 0.06% and 0.08%, respectively, in neonates ≥4500g (p=0.003). Risk of HG increased from 0.6% in 3000-3400g neonates to 3.7% in neonates ≥4500g (p<0.001). Regarding maternal outcomes, the risk of PPH and MBT rose from 1.8% and 1.1%, respectively, in 3000-3499g neonates, to 4.8% and 2.1%, respectively, in neonates ≥4500g (p<0.001). After controlling for potential confounders, there remains a statistically significant increase in odds of PPH and MBT across all NBW categories when compared with 3000-3499g neonates (Table 1). A statistically significant increase in odds of HG was also noted for 4000-4499g and ≥4500g when compared with 3000-3499g neonates. Higher NBW increases the risk of perinatal complications in the setting of nulliparous CD. Providers should exercise heightened awareness of the effect of NBW on these potential adverse outcomes when managing CD.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Validation of Postpartum Hemorrhage Admission Risk Factor Stratification in a Large Obstetrics Population.

This study aimed to evaluate the performance of the California Maternal Quality Care Collaborative (CMQCC) admission risk criteria for stratifying postpartum hemorrhage risk in a large obstetrics population. Using detailed electronic health record data, we classified 261,964 delivery hospitalizations from Kaiser Permanente Northern California hospitals between 2010 and 2017 into high-, medium-, and low-risk groups based on CMQCC criteria. We used logistic regression to assess associations between CMQCC risk groups and postpartum hemorrhage using two different postpartum hemorrhage definitions, standard postpartum hemorrhage (blood loss ≥1,000 mL) and severe postpartum hemorrhage (based on transfusion, laboratory, and blood loss data). Among the low-risk group, we also evaluated associations between additional present-on-admission factors and severe postpartum hemorrhage. Using the standard definition, postpartum hemorrhage occurred in approximately 5% of hospitalizations (n = 13,479), with a rate of 3.2, 10.5, and 10.2% in the low-, medium-, and high-risk groups. Severe postpartum hemorrhage occurred in 824 hospitalizations (0.3%), with a rate of 0.2, 0.5, and 1.3% in the low-, medium-, and high-risk groups. For either definition, the odds of postpartum hemorrhage were significantly higher in medium- and high-risk groups compared with the low-risk group. Over 40% of postpartum hemorrhages occurred in hospitalizations that were classified as low risk. Among the low-risk group, risk factors including hypertension and diabetes were associated with higher odds of severe postpartum hemorrhage. We found that the CMQCC admission risk assessment criteria stratified women by increasing rates of severe postpartum hemorrhage in our sample, which enables early preparation for many postpartum hemorrhages. However, the CMQCC risk factors missed a substantial proportion of postpartum hemorrhages. Efforts to improve postpartum hemorrhage risk assessment using present-on-admission risk factors should consider inclusion of other nonobstetrical factors.

Anesthetic Management as a Risk Factor for Postpartum Hemorrhage After Cesarean Deliveries

Objective This population-based study aimed to compare the risk of postpartum hemorrhage (PPH) for patients who underwent cesarean section delivery (CS) with general vs spinal/epidural anesthesia. Study Design We identified 67,328 women who had live singleton births by CS by linking the Taiwan National Health Insurance Research Dataset and the national birth certificate registry. Multivariate logistic regression was carried out to explore the relationship between anesthetic management type and PPH. Results Women who received general anesthesia had a higher rate of PPH than women who received epidural anesthesia (5.1% vs 0.4%). The odds of PPH in women who had CS with general anesthesia were 8.15 times higher (95% confidence interval, 6.43–10.33) than for those who had CS with epidural anesthesia, after adjustment was made for the maternal and fetal characteristics. Conclusion The odds that women will experience cesarean PPH with general anesthesia are approximately 8.15 times higher than for women who undergo CS with epidural anesthesia.

Assessment of von Willebrand disease as a risk factor for primary postpartum haemorrhage

It is not clear whether von Willebrand disease (VWD) is associated with an increased risk of postpartum haemorrhage (PPH). We assessed the effect of VWD on PPH in a case-control study. Logistic regression was used to test for differences in the odds of PPH in deliveries to women with and without VWD, before and after adjustment for known risk factors. A total of 62 deliveries in 33 women with VWD were compared with controls matched for age, year of delivery and parity. Primary PPH was observed in 12/62 (19.4%) deliveries in women with VWD and 16/124 (12.9%) controls. The unadjusted odds ratio (OR) for VWD as a risk factor for PPH was 1.62 (95% CI 0.75-3.49, P = 0.22). After adjustment for other risk factors for PPH, the OR for VWD as a risk factor for PPH was 1.31 (95% CI 0.48-3.60, P = 0.60). PPH was observed in 7/24 (29%) deliveries in women known prepregnancy to have VWD. The unadjusted odds for VWD as a risk factor for PPH in this group was significantly greater than the control group (OR 2.78 (95% CI 1.03-7.49) P = 0.043) and remained significant after adjusting for other significant risk factors (OR 3.41 (95% CI 1.07-10.9) P = 0.038). VWD in itself may not be a significant risk factor for PPH, however, women known to have VWD predelivery may represent an at risk sub-group.

P16.16: The association between the length of labour, mode of delivery and neonatal outcomes in women undergoing induction of labour

To determine the association between the length of labour, mode of delivery and neonatal outcomes in women undergoing induction of labour. We performed a prospective study of singleton term pregnancies with intact membranes having induction of labour. The length of the first stage was examined by 12-hourly intervals as predictors of mode of delivery and neonatal morbidity using χ2 and multivariate analysis. 86 women met the inclusion criteria. The mean length of first stage of labour was 8 hrs (range 0.25–36.92). Of these women, 68 (79%) had a length of first stage between 0–12 hrs, 16 (18.6%) between 12–24 hrs and 2 (2.3%) lasting longer than 24 hrs (Table 1). Nulliparity and BMI < 30 were associated with a longer first stage of > 12 hrs (OR 3.50, 95%CI 0.98–12.29 and OR 3.57, 95%CI 0.83–15.05 respectively). Women with longer first stage > 12 hrs had a higher risk of caesarean delivery (OR 3.39, 95%CI 1.15–10.06). Women with a first stage of > 12 hrs also had higher odds of post partum haemorrhage (OR 2.25, 95%CI 0.78–6.47) and 5-min Apgar < 7 (OR 3.94, 95%CI 0.39–39.69). Our study has shown that a longer length of first stage was associated with a higher risk of Caesarean section. This association is represented in both nulliparous and multiparous women however, despite the increased risk of caesarean section, more than half of the women still achieved vaginal delivery.

Anesthetic management as a risk factor for postpartum hemorrhage after cesarean deliveries

This population-based study aimed to compare the risk of postpartum hemorrhage (PPH) for patients who underwent cesarean section delivery (CS) with general vs spinal/epidural anesthesia. We identified 67,328 women who had live singleton births by CS by linking the Taiwan National Health Insurance Research Dataset and the national birth certificate registry. Multivariate logistic regression was carried out to explore the relationship between anesthetic management type and PPH. Women who received general anesthesia had a higher rate of PPH than women who received epidural anesthesia (5.1% vs 0.4%). The odds of PPH in women who had CS with general anesthesia were 8.15 times higher (95% confidence interval, 6.43-10.33) than for those who had CS with epidural anesthesia, after adjustment was made for the maternal and fetal characteristics. The odds that women will experience cesarean PPH with general anesthesia are approximately 8.15 times higher than for women who undergo CS with epidural anesthesia.

The Association Between the Length of First Stage of Labor, Mode of Delivery, and Perinatal Outcomes in Women Undergoing Induction of Labor

Objective To estimate the association between the lengths of the first stage of labor, mode of delivery, and perinatal outcomes in women undergoing labor induction. Study Design Retrospective cohort study of singleton, term pregnancies with labor induction and delivered during the second stage. The length of the first stage was examined by 6-hour intervals as predictors of mode of delivery and perinatal morbidity using χ 2 test and multivariable logistic regression analysis. Results There were 3620 women who met study criteria. Compared with women with a first stage between 0-12 hours, women with longer first stages had a higher risk of cesarean delivery during the second stage, up to an adjusted odds ratio of 7.44 in those with a first stage ≥24 hours (95% confidence interval [CI], 3.43–16.1). Women with a first stage ≥24 hours also had higher odds of postpartum hemorrhage (adjusted odds ratio [aOR], 3.16; 95% CI, 1.73–5.79), chorioamnionitis (aOR, 2.83; 95% CI, 1.19–6.69), and neonatal admission to the intensive care nursery (aOR, 2.03; 95% CI, 1.10–3.74). Conclusion In women who underwent induction of labor, even when a second stage of labor was reached, the risk for cesarean delivery and maternal morbidity remained increased when the length of the first stage was longer than 24 hours. However, in this clinical scenario, the frequency of cesarean delivery remains less than 50%. The decision for surgical intervention thus should not be based on the elapse of time alone.

The effect of induction of labour on perinatal mortality and obstetric outcomes: a population database study

BackgroundInduction of labour (IOL) >41 weeks decreases perinatal mortality without increasing Caesarean rates.1 However, there is lack of data regarding outcomes of IOL prior to 41 weeks, particularly regarding effects...