Raised nitric oxide levels may cause atonic postpartum hemorrhage in women with anemia during pregnancy

Obstetric blood transfusion in placenta previa patients with prenatal anemia: a retrospective study

BACKGROUND

The appropriate use of obstetric blood transfusion is crucial for patients with placenta previa and prenatal anemia. This retrospective study aims to explore the correlation between prenatal anemia and blood transfusion-related parameters in this population.

METHODS

We retrieved the medical records of consecutive participants who were diagnosed with placenta previa and underwent cesarean section in our hospital. We compared the baseline demographics and clinical characteristics of patients with and without anemia. The correlation between prenatal anemia and obstetric blood transfusion-related parameters was evaluated using multivariate regression analysis.

RESULTS

A total of 749 patients were enrolled, with a mean prenatal hemoglobin level of 10.87 ± 1.37 g/dL. Among them, 54.87% (391/749) were diagnosed with anemia. The rate of obstetric blood transfusion was significantly higher in the anemia group (79.54%) compared to the normal group (44.41%). The median allogeneic red blood cell transfusion volume in the anemia group was 4.00 U (IQR 2.00-6.00), while in the normal group, it was 0.00 U (IQR 0.00-4.00). The prenatal hemoglobin levels had a non-linear relationship with intraoperative allogeneic blood transfusion rate, massive blood transfusion rate, red blood cell transfusion units, and fresh plasma transfusion volume in patients with placenta previa, with a threshold of 12 g/dL.

CONCLUSIONS

Our findings suggest that prenatal anemia is associated with a higher rate of blood transfusion-related parameters in women with placenta previa when the hemoglobin level is < 12 g/dL. These results highlight the importance of promoting prenatal care in placenta previa patients with a high requirement for blood transfusion.

Predicting risk of postpartum hemorrhage associated with vaginal delivery of twins: A retrospective study

Many studies have only focused on the risk factors for postpartum hemorrhage (PPH) in singleton vaginal deliveries and twin cesarean deliveries. We analyzed the factors of influencing PPH occurrence in twin vaginal deliveries and developed a nomogram for clinical application. This retrospective study included 274 pregnant women with twin pregnancies who were hospitalized for delivery from January 2014 to December 2018. The patients opted for vaginal delivery and experienced spontaneous labor. Univariate analysis of PPH risk factors was performed. Multivariate analysis was performed using the least absolute shrinkage and selection operator (LASSO) to obtain relevant factors and build a prediction model, which was presented as a nomogram. The model was internally validated by bootstrap self-sampling method. Model accuracy was evaluated with the concordance index (C-index). There were 36 (13.14%) and 238 (86.9%) patients in the PPH and no PPH groups, respectively. Univariate analysis identified twin chorionicity, hypertensive disorders complicating pregnancy (HDCP), anemia in pregnancy, delivery mode of the second twin, oxytocin use during labor, postpartum curettage, cervical laceration, intrapartum fever, fibrinogen degradation products (FDP), and platelet count (PLT) as significant PPH factors. On multivariate analysis, HDCP, anemia in pregnancy, intrapartum fever, oxytocin use during labor, fetal distress, PLT, direct bilirubin, and FDP were noted as significant PPH factors and were included in the prediction model. A C-index of 0.816 was noted after internal validation, and the calibration curve showed good consistency. We developed a model to predict PPH risk in the vaginal delivery of twin pregnancies and visualized it with a nomogram that can be applied clinically to assess PPH risk and aid PPH prevention.

Hemostatic biomarkers associated with postpartum hemorrhage: a systematic review and meta-analysis

Postpartum hemorrhage (PPH) is a leading cause of maternal morbi-mortality. Although obstetric risk factors are well described, the impact of predelivery hematologic and hemostatic biomarkers remains incompletely understood. In this systematic review, we aimed to summarize the available literature on the association between predelivery hemostatic biomarkers and PPH/severe PPH. Searching MEDLINE, EMBASE, and CENTRAL databases from inception to October 2022, we included observational studies on unselected pregnant women without bleeding disorder reporting on PPH and on predelivery hemostatic biomarkers. Two review authors independently performed title, abstract and full-text screening, upon which quantitative syntheses of studies reporting on the same hemostatic biomarker were conducted, calculating the mean difference (MD) between women with PPH/severe PPH and controls. A search on 18 October 2022 yielded 81 articles fitting our inclusion criteria. The heterogeneity between studies was considerable. With regard to PPH, the estimated average MD in the investigated biomarkers (platelets, fibrinogen, hemoglobin, Ddimer, activated partial thromboplastin time, and prothrombin time) were not statistically significant. Women who developed severe PPH had lower predelivery platelets than controls (MD = -26.0 109/L; 95% confidence interval, -35.8 to -16.1), whereas differences in predelivery fibrinogen concentration (MD = -0.31 g/L; 95% confidence interval, -0.75 to 0.13) and levels of factor XIII or hemoglobin were not statistically significant in women with and without severe PPH. Predelivery platelet counts were, on average, lower in women with severe PPH compared with controls, suggesting the potential usefulness of this biomarker for predicting severe PPH. This trial was registered at the International Prospective Register of Systematic Reviews as CRD42022368075.

Peripartum severe acute maternal morbidity in low-risk women: A population-based study

BACKGROUND

Knowledge of severe acute maternal morbidity (SAMM) and its risk factors is constantly growing, but studies have rarely focused on the specific population of low-risk women.

AIM

To estimate the prevalence and to identify subgroups at risk of peripartum SAMM in low-risk women METHODS: From a population-based cohort-nested case-control study conducted in six French regions, i.e., 182 309 women who gave birth at ≥22 weeks in 119 maternity units, we selected women considered at low risk up to the end of pregnancy before labour according to the NICE guidelines and compared those experiencing peripartum SAMM (during birth and up to 7 days postpartum; n = 489) to a 2% random sample of women without peripartum SAMM from the same units (n = 1800). Risk factors for peripartum SAMM were identified by multivariable logistic regression.

FINDINGS

amongst low-risk women, the estimated rate of SAMM was 0.548/100 deliveries (95%CI 0.501-0.599). Severe obstetric haemorrhage was the main cause (83.6% of SAMM cases). Main risk factors for peripartum SAMM were primiparity (aOR 2.4, 95%CI 1.9-3.0), IVF pregnancy (aOR 1.8, 1.0-3.4), third-trimester anaemia (aOR 1.7, 1.3-2.3), being born out of Europe or Africa (aOR 1.9, 1.2-3.0).

CONCLUSION

amongst women considered at low risk up to the end of pregnancy before labour, peripartum SAMM is rare but still exists. Knowledge of risk factors of SAMM in this population will inform the discussion on peripartum risks and the most appropriate place of birth for each woman.

Prepartum Anemia and Risk of Postpartum Hemorrhage: A Meta-Analysis and Brief Review

Postpartum hemorrhage (PPH) is responsible for 30% to 50% of maternal deaths. There is conflicting evidence if prepartum anemia facilitates PPH. A comprehensive analysis of studies describing their relation is missing. An extensive database search was conducted applying the terms "anemia" OR "hemoglobin" AND "postpartum hemorrhage." We used a random-effects meta-analysis model to estimate an overall odds ratio (OR) for PPH and prepartum anemia, separating studies that were conformant and non-conformant with the World Health Organization (WHO) definitions for anemia. The search yielded 2519 studies, and 46 were appropriate for analysis. The meta-analyses of WHO-conformant (n = 22) and non-conformant (n = 24) studies showed that the risk of PPH was increased when anemia was present. The ORs were 1.45 (CL: 1.23-1.71) for WHO-conformant studies, 2.88 (CL: 1.38-6.02) for studies applying lower thresholds for anemia, and 3.28 (CL: 2.08-5.19) for undefined anemia thresholds. PPH risk appeared to increase with lower anemia thresholds. Prepartum anemia is associated with an increased risk of PPH, an observation that is important regarding improved anemia correction strategies such as iron supplementation.

Iron Deficiency Anaemia and Atonic Postpartum Haemorrhage Following Labour

The purpose of this retrospective cohort study is to determine if iron deficiency anaemia (IDA) is associated with increased atonic postpartum haemorrhage (PPH) following labour. Women with singleton pregnancy carried to 24 or more weeks gestation, who were delivered under our care from 1997 to 2019, constituted the study population. A diagnosis of IDA was based on the finding of haemoglobin <10 g/dL and serum ferritin <15 μg/L in the absence of haemoglobinopathies. Women with elective caesarean section were excluded. Maternal characteristics, use of oxytocin, labour outcome and occurrence of PPH were compared between women with and without a diagnosis of IDA. The 1032 women (0.86%) with IDA exhibited slightly but significantly different maternal characteristics and had significantly higher incidence of total (4.5% versus 3.2%, p = 0.024) and atonic PPH (3.1% versus 2.0%, p = 0.011) despite similar incidences of labour induction, augmentation, and instrumental and intrapartum caesarean delivery. Multivariate analysis with adjustment for the effects of age, body mass index, height, parity, abortion history, labour induction and augmentation, instrumental delivery and infant macrosomia demonstrated that IDA was independently associated with total PPH (adjusted relative risk, aRR: 1.455, 95% confidence ratio, CI: 1.040-2.034) and atonic PPH (aRR: 1.588, 95% CI: 1.067-2.364). Our results indicate that despite the low prevalence in our population, IDA was independently associated with atonic PPH, probably consequent to placental adaptive changes in the presence of IDA. The correction and prevention of IDA could be the most important measure in countering the rising global prevalence of atonic PPH.

Maternal anemia and severe maternal morbidity in a US cohort

BACKGROUND

Maternal anemia is a common pregnancy complication and often leads to a requirement for additional treatments and interventions. Identifying the frequency at which women with antenatally diagnosed anemia experience severe morbidity at the time of admission to the labor and delivery unit will guide future recommendations regarding screening and interventions for anemia during pregnancy.

OBJECTIVE

The objective of this study was to evaluate the association between antenatally diagnosed anemia and severe maternal morbidity as defined by the Centers for Disease Control and Prevention in a large, contemporary, US cohort. Neonatal outcomes were also examined.

STUDY DESIGN

This was a secondary analysis of the Consortium on Safe Labor database from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, which collected data on 228,438 deliveries in 19 United States hospitals from 2002 to 2008. This analysis included women with viable, singleton gestations and excluded stillbirths and gestations with severe congenital anomalies. Women with a diagnosis of antenatal anemia were compared with those without. Identification of diagnoses of antenatal anemia was obtained via electronic medical record abstraction and International Classification of Diseases coding according to each hospital protocol within the Consortium on Safe Labor. The primary maternal outcome consisted of a composite of severe maternal morbidity as defined by the Centers for Disease Control and Prevention and included maternal death, eclampsia, thrombosis, transfusion, hysterectomy, and maternal intensive care unit admission. The primary neonatal outcome was a composite that included a 5-minute Apgar score of <7, hypoxic ischemic encephalopathy, respiratory distress syndrome, necrotizing enterocolitis, seizures, intracranial hemorrhage, periventricular or intraventricular hemorrhage, neonatal sepsis, neonatal intensive care unit admission, and neonatal death. Each outcome within the composites was assessed individually along with other additional secondary outcomes, including a composite of severe maternal morbidity not including transfusion morbidity. All statistical analyses were performed with Stata version 14.2 (StataCorp LLC, College Station, TX) using Student's t test, chi-square test, Fisher's exact test, and Wilcoxon rank-sum (Mann-Whitney U) test, as appropriate. A multivariable logistic regression was performed with potential confounding variables entered into the regression equation if they differed between groups at a significance level of P<.05.

RESULTS

A total of 166,566 women met the inclusion criteria. From the original cohort, 56,734 women could not be included because of an unknown diagnosis of anemia. Of those included, 10,217 (6.1%) were diagnosed with anemia during the pregnancy. Women with anemia were more likely to be younger, non-Hispanic Black, single, multiparous, and have a higher prepregnancy body mass index than those without anemia. The frequency of the primary maternal composite outcome, the neonatal composite outcome, and other secondary outcomes including the severe maternal morbidity composite not including transfusion, maternal death, transfusion during labor and the postpartum period, hysterectomy, postpartum hemorrhage, infectious morbidity, cesarean delivery, and preterm delivery were more common in women with anemia (P<.05). After multivariable logistic regression analysis adjusting for confounders, higher rates of severe maternal morbidity remained persistently associated with anemia (adjusted odds ratio, 2.04; 95% confidence interval, 1.86-2.23) in addition to the association of anemia with the severe maternal morbidity composite not including transfusion, maternal death, thrombosis, transfusion, hysterectomy, intensive care unit admission, postpartum hemorrhage, hypertensive disorders of pregnancy, cesarean delivery, and infectious morbidity. The composite neonatal outcome also remained associated with anemia after adjusting for confounders (adjusted odds ratio, 1.14; 95% confidence interval, 1.06-1.23).

CONCLUSION

Women with antepartum anemia experienced increased rates of severe maternal morbidity and other serious adverse outcomes. Diagnosis and treatment of anemia during the antepartum period may lead to the identification and treatment of women at higher risk for maternal morbidity and mortality.

Prenatal anemia and postpartum hemorrhage risk: A systematic review and meta-analysis

INTRODUCTION

Postpartum hemorrhage (PPH) has remained the leading cause of maternal mortality. While anemia is a leading contributor to maternal morbidity, molecular, cellular and anemia-induced hypoxia, clinical studies of the relationship between prenatal-anemia and PPH have reported conflicting results. Therefore, our objective was to investigate the outcomes of studies on the relationships between prenatal anemia and PPH-related mortality.

MATERIALS AND METHODS

Electronic databases (MEDLINE, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, and the Cochrane Central Register of Controlled Trials) were searched for studies published before August 2019. Keywords included "anemia," "hemoglobin," "postpartum hemorrhage," and "postpartum bleeding." Only studies involving the association between anemia and PPH were included in the meta-analysis. Our primary analysis used random effects models to synthesize odds-ratios (ORs) extracted from the studies. Heterogeneity was formally assessed with the Higgins' I² statistics, and explored using meta-regression and subgroup analysis.

RESULTS

We found 13 eligible studies investigating the relationship between prenatal anemia and PPH. Our findings suggest that severe prenatal anemia increases PPH risk (OR = 3.54; 95% CI: 1.20, 10.4, p-value = 0.020). There was no statistical association with mild (OR = 0.60; 95% CI: 0.31, 1.17, p-value = 0.130), or moderate anemia (OR = 2.09; 95% CI: 0.40, 11.1, p-value = 0.390) and the risk of PPH.

CONCLUSION

Severe prenatal anemia is an important predictive factor of adverse outcomes, warranting intensive management during pregnancy. PROSPERO Registration Number: CRD42020149184; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=149184.

Effect of Delivery by Emergency or Elective Cesarean Section on Nitric Oxide Metabolites and Cortisol Amniotic Concentrations in at Term Normal Newborn Dogs: Preliminary Results

Simple Summary

The high perinatal mortality rates in dogs are partly attributable to stress at parturition, with the production of cortisol (C), and related to the type of delivery, that is elective or emergency cesarean sections (ELCS and EMCS). Nitric oxide metabolites (NOs) are also related to the type of parturition (ELCS or EMCS), because of the different emotional and physical stresses experienced by the bitch in these two scenarios. The study aimed to assess the concentrations of C and NOs in the amniotic fluid of puppies delivered by ELCS or EMCS. In the amniotic fluid of the 32 puppies delivered by ELCS, C, and NOs concentrations were significantly lower than those found in the amniotic fluid of the 22 puppies delivered by EMCS. Lower C concentrations were found at increasing newborn viability assessed by Apgar score. Higher amniotic NOs concentrations were associated to increasing mother’s parity, puppies’ birthweight, and time of labor within the EMCS group. Due to the possible concurrence of several compartments (maternal, maybe placental, and fetal) to the final amniotic fluid composition, the definition of the role played by the three compartments in the higher C and NOs concentrations found in amniotic fluids collected from puppies delivered by EMCS than ELCS needs further clarifications.

Abstract

The neonatal response to stress was reported to be related to the type of delivery, that is elective or emergency cesarean sections (ELCS and EMCS, respectively). Nitric oxide (NO) is also reported to be related to uterine inertia, and high levels of NO metabolites (NOs) are associated with physical and emotional stress. The study aimed to assess the concentrations of cortisol (C) and NOs in the amniotic fluid of puppies delivered by ELCS or EMCS. In total, 32 puppies were delivered by ELCS and 22 by EMCS. ANCOVA showed an effect of the ELCS vs. EMCS on both amniotic NOs (p < 0.001) and C (p < 0.001) concentrations. Lower amniotic C concentrations were found at increasing Apgar score (p < 0.001). Higher amniotic NOs concentrations were associated to increasing mother’s parity (p < 0.001), puppies’ birthweight (p < 0.001), and time of labor within the EMCS group (p < 0.05). A positive correlation between birthweight and amniotic NOs concentrations was also found (p < 0.05) in the EMCS group. Due to the possible concurrence of several compartments (maternal, maybe placental, and fetal) to the final amniotic fluid composition, the definition of the role played by the three compartments in the higher C and NOs concentrations found in amniotic fluids collected from puppies delivered by EMCS than ELCS needs further clarification.

Maternal death and postpartum hemorrhage in sub-Saharan Africa - A pilot study in metropolitan Mozambique

BACKGROUND

Maternal mortality in sub-Saharan Africa is approximately 500 to 1000 per 100 000 births (vs. approximately 5-20 in developed countries). Postpartum hemorrhage (PPH) is deemed responsible for 30% to 50% of the deaths.

OBJECTIVE

To study PPH, risk factors, and mortality in metropolitan Mozambique to inform future studies and intervention strategies.

MATERIALS/METHODS

Retrospective cross-sectional data extraction from all charts available to us (n = 495) recording deliveries between January and June 2018 at Maputo Central Hospital. Data included age, maternal survival, HIV status, parity, delivery mode, complications, vital signs, laboratory values, and maternal/fetal data. PPH was determined by charted diagnosis, interventions for hemorrhaging, placental abruption, transfusion, or blood loss. Autopsy reports from all deceased patients (n = 35) were examined.

RESULTS

Median age was 29 years with 17% HIV prevalence. Risk factors for PPH (frequency, 12%) included parity (adjusted odds ratios (AORs) for 3+ versus nulliparity, 7.20 (95% confidence interval [CI], 2.46-21.10), gestation length (AOR, 0.86; CI, 0.81-0.92 per week), and body temperature (AOR, 1.10; CI, 1.04-1.16 per 0.1°C). Maternal mortality was strongly associated with PPH (AOR, 5.22; 95% CI, 2.26-12.08) and HIV (AOR, 11.66; 95% CI, 4.72-28.78). Laboratory values (n = 241) were available from mothers experiencing complications (approximately 50%). Anemia (prevalence 54%) was a strong predictor of PPH with an inverse relationship between hemoglobin levels on admission (AOR, 0.62; 95% CI, 0.50-0.77 per g/dL higher hemoglobin) and the probability of later suffering from PPH. Mothers who died following PPH had lower median hemoglobin (6.2 g/dL) than mothers who survived (9.2 g/dL). Protocols to estimate peripartum blood loss were not used; antifibrinolytics and/or cryoprecipitate were unavailable.

CONCLUSION

Postpartum hemorrhage is a serious problem even in metropolitan areas of sub-Saharan Africa, and anemia influenced bleeding and death substantially. To address this problem, it is critical to raise awareness and region-specific prevention and intervention protocols.

Systematic review to investigate the safety of induction and augmentation of labour among pregnant women with iron-deficiency anaemia

OBJECTIVE

To conduct a systematic review to investigate the safety of induction and/or augmentation of labour compared with spontaneous-onset normal labour among pregnant women with iron-deficiency anaemia.

DESIGN

Systematic review.

SETTING

Studies from all countries, worldwide.

POPULATION

Pregnant women with iron-deficiency anaemia at labour and delivery.

INTERVENTION

Any intervention related to induction and/or augmentation of labour.

OUTCOME MEASURES

Primary: Postpartum haemorrhage (PPH), heart failure and maternal death. Secondary: Emergency caesarean section, hysterectomy, admission to intensive care unit.

METHOD

We searched 10 databases, including Medline and Embase, from database inception to 1 October 2018. We included all study designs except cross-sectional studies without a comparator group, case reports, case series, ecological studies, and expert opinion. The searches were conducted by a healthcare librarian and two authors independently screened and reviewed the studies. We used the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approachto ascertain risk of bias and conducted a narrative synthesis.

RESULTS

We identified 3217 journal articles, 223 conference papers, 45 dissertations and 218 registered trials. Ten articles were included for full-text review and only one was found to fulfil the eligibility criteria. This was a retrospective cohort study from India, which showed that pregnant women with moderate and severe anaemia could have an increased risk of PPH if they underwent induction and/or augmentation of labour, but the evidence was weak (graded as 'high risk of bias').

CONCLUSION

The best approach is to prevent anaemia, but a large number of women in low-to-middle-income countries present with severe anaemia during labour. In such women, appropriate peripartum management could prevent complications and death. Our review showed that at present we do not know if induction and augmentation of labour is safe in pregnant women with iron-deficiency anaemia and further research is required.

PROSPERO REGISTRATION NUMBER

CRD42015032421.