Intravenous Calcium to Decrease Blood Loss During Intrapartum Cesarean Delivery: A Randomized Controlled Trial

OBJECTIVE

To evaluate whether prophylactic administration of 1 g of intravenous calcium chloride after cord clamping reduces blood loss from uterine atony during intrapartum cesarean delivery.

METHODS

This single-center, block-randomized, placebo-controlled, double-blind superiority trial compared the effects of 1 g intravenous calcium chloride with those of saline placebo control on blood loss at cesarean delivery. Parturients at 34 or more weeks of gestation requiring intrapartum cesarean delivery after oxytocin exposure in labor were enrolled. Calcium or saline placebo was infused over 10 minutes beginning 1 minute after umbilical cord clamping in addition to standard care with oxytocin. The primary outcome was quantitative blood loss, analyzed by inverse Gaussian regression. Planned subgroup analysis excluded nonatonic bleeding, such as hysterotomy extension, arterial bleeding, and occult placenta accreta. We planned to enroll 120 patients to show a 200-mL reduction in quantitative blood loss in planned subgroup analysis, assuming up to 40% incidence of nonatonic bleeding (80% power, α<0.05).

RESULTS

From April 2022 through March 2023, 828 laboring parturients provided consent and 120 participants were enrolled. Median blood loss was 840 mL in patients allocated to calcium chloride (n=60) and 1,051 mL in patients allocated to placebo (n=60), which was not statistically different (mean reduction 211 mL, 95% CI -33 to 410). In the planned subgroup analysis (n=39 calcium and n=40 placebo), excluding cases of surgeon-documented nonatonic bleeding, calcium reduced quantitative blood loss by 356 mL (95% CI 159-515). Rates of reported side effects were similar between the two groups (38% calcium vs 42% placebo).

CONCLUSION

Prophylactic intravenous calcium chloride administered during intrapartum cesarean delivery after umbilical cord clamping did not significantly reduce blood loss in the primary analysis. However, in the planned subgroup analysis, calcium infusion significantly reduced blood loss by approximately 350 mL. These data suggest that this inexpensive and shelf-stable medication warrants future study as a novel treatment strategy to decrease postpartum hemorrhage, the leading global cause of maternal morbidity and mortality.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov , NCT05027048.

The Association between Placenta Accreta Spectrum Severity and Incidence of Small for Gestational Age Neonates

OBJECTIVE

The aim of the study is to evaluate whether pathologic severity of placenta accreta spectrum (PAS) is correlated with the incidence of small for gestational age (SGA) and neonatal birthweight.

STUDY DESIGN

This was a multicenter cohort study of viable, non-anomalous, singleton gestations delivered with histology-proven PAS. Data including maternal history, neonatal birthweight, and placental pathology were collected and deidentified. Pathology was defined as accreta, increta, or percreta. The primary outcome was rate of SGA defined by birth weight less than the 10th percentile. The secondary outcomes included incidence of large for gestational age (LGA) babies as defined by birth weight greater than the 90th percentile as well as incidence of SGA and LGA in preterm and term gestations. Statistical analysis was performed using Chi-square, Kruskal-Wallis, and log-binomial regression. Increta and percreta patients were each compared with accreta patients.

RESULTS

Among the cohort of 1,008 women from seven United States centers, 865 subjects were included in the analysis. The relative risk (RR) of SGA for increta and percreta did not differ from accreta after adjusting for confounders (adjusted RR = 0.63, 95% confidence interval [CI]: 0.36-1.10 for increta and aRR = 0.72, 95% CI: 0.45-1.16 for percreta). The results were stratified by placenta previa status, which did not affect results. There was no difference in incidence of LGA (p = 1.0) by PAS pathologic severity. The incidence of SGA for all PAS patients was 9.2% for those delivered preterm and 18.7% for those delivered at term (p = 0.004). The incidence of LGA for all PAS patients was 12.6% for those delivered preterm and 13.2% for those delivered at term (p = 0.8203).

CONCLUSION

There was no difference in incidence of SGA or LGA when comparing accreta to increta or percreta patients regardless of previa status. Although we cannot suggest causation, our results suggest that PAS, regardless of pathologic severity, is not associated with pathologic fetal growth in the preterm period.

KEY POINTS

· PAS severity is not associated with SGA in the preterm period.. · PAS severity is not associated with LGA.. · Placenta previa does not affect the incidence of SGA in women with PAS..

How do I manage severe postpartum hemorrhage?

In the United States, postpartum hemorrhage (PPH) accounts for 4.6% of all maternal deaths and is responsible for major peripartum medical and surgical morbidity. Therefore, a national health priority is to ensure that women who experience severe PPH receive timely, appropriate, and effective treatment. In this article, we describe our system-wide approach for the planning and delivery of women with suspected placenta accreta spectrum disorder, a condition associated with life-threatening blood loss at the time of delivery. We also highlight current evidence related to transfusion decision making and hemostatic monitoring during active postpartum bleeding. Specifically, we describe how we activate and use the massive transfusion protocol to obtain sufficient volumes and types of blood products. We also describe how we use viscoelastic monitoring (thromboelastography) and standard laboratory tests to assess the maternal coagulation profile. Finally, we review the findings of recent studies examining the potential efficacy of tranexamic acid and fibrinogen concentrate as adjuncts for PPH prevention and treatment. We describe how we have incorporated these drugs into PPH treatment protocols at our institution.

Health resource utilization of labor induction versus expectant management

BACKGROUND

Although induction of labor of low-risk nulliparous women at 39 weeks reduces the risk of cesarean delivery compared with expectant management, concern regarding more frequent use of labor induction remains, given that this intervention historically has been thought to incur greater resource utilization.

OBJECTIVE

The objective of the study was to determine whether planned elective labor induction at 39 weeks among low-risk nulliparous women, compared with expectant management, was associated with differences in health care resource utilization from the time of randomization through 8 weeks postpartum.

STUDY DESIGN

This is a planned secondary analysis of a multicenter randomized trial in which low-risk nulliparous women were assigned to induction of labor at 39 weeks or expectant management. We assessed resource utilization after randomization in 3 time periods: antepartum, delivery admission, and discharge through 8 weeks postpartum.

RESULTS

Of 6096 women with data available, those in the induction of labor group (n = 3059) were significantly less likely in the antepartum period after randomization to have at least 1 ambulatory visit for routine prenatal care (32.4% vs 68.4%), unanticipated care (0.5% vs 2.6%), or urgent care (16.2% vs 44.3%), or at least 1 antepartum hospitalization (0.8% vs 2.2%, P < .001 for all). They also had fewer tests (eg, sonograms, blood tests) and treatments (eg, antibiotics, intravenous hydration) prior to delivery. During the delivery admission, women in the induction of labor group spent a longer time in labor and delivery (median, 0.83 vs 0.57 days), but both women (P = .002) and their neonates (P < .001) had shorter postpartum stays. Women and neonates in both groups had similar frequencies of postpartum urgent care and hospital readmissions (P > .05 for all).

CONCLUSION

Women randomized to induction of labor had longer durations in labor and delivery but significantly fewer antepartum visits, tests, and treatments and shorter maternal and neonatal hospital durations after delivery. These results demonstrate that the health outcome advantages associated with induction of labor are gained without incurring uniformly greater health care resource use.

Cognitive Behavioral Therapy for Prenatal Insomnia: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effectiveness of cognitive behavioral therapy for insomnia during pregnancy.

METHODS

Randomized, unmasked, 3-site controlled trial. Participants were randomly allocated to cognitive behavioral therapy for insomnia (a first-line, empirically supported psychosocial intervention that addresses sleep-related behaviors and cognitions) or a control intervention consisting of imagery exercises that paired patient-identified distressing nighttime experiences with patient-identified neutral images. Participants were eligible if they met diagnostic criteria for insomnia disorder and were between 18 and 32 weeks of gestation. Patients were ineligible if they met diagnostic criteria for major psychiatric disorders, including depression, or were receiving nonstudy treatments that could affect sleep (or both). The primary outcome was the Insomnia Severity Index score, a validated brief questionnaire, with scores between 14 and 21 representing clinically meaningful insomnia of moderate severity, scores higher than 21 representing severe insomnia, and scores less than 8 representing no insomnia. Secondary outcomes included remission of insomnia (Insomnia Severity Index score less than 8), objectively measured and self-reported time awake (ie, total wake time), and the Edinburgh Postnatal Depression Scale score. All outcomes were measured weekly. Analysis included 48 participants who did not complete treatment. We estimated that 184 women would be required to have 80% power, with a two-tailed test, to detect a moderate Cohen's d effect size (.5) with α=.05.

RESULTS

Between May 2013 and April 2017, 194 pregnant women were randomized and 149 completed treatment; 179 with available baseline data (92%) were ultimately analyzed, 89 in the cognitive therapy group and 90 in the control group. Women assigned to cognitive behavioral therapy for insomnia experienced significantly greater reductions in insomnia severity (scores decreased from 15.4±4.3 to 8.0±5.2 in the cognitive behavioral therapy group vs from 15.9±4.4 to 11.2±4.9 in the control therapy group [P<.001, d=0.5]). Remission of insomnia (to an Insomnia Severity Index score less than 8) disorder was attained by 64% of women in the cognitive behavioral therapy for insomnia group vs 52% in the control group. Women receiving cognitive behavioral therapy for insomnia experienced faster remission of insomnia disorder, with a median of 31 days vs 48 days in the control therapy (P<.001). Cognitive behavioral therapy for insomnia led to significantly greater reduction in self-reported but not objective total wake time and a small but significantly greater decline in Edinburgh Postnatal Depression Scale scores vs the control group.

CONCLUSION

Cognitive behavioral therapy for insomnia is an effective nonpharmacologic treatment for insomnia during pregnancy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01846585.

The transient receptor potential vanilloid 4 channel modulates uterine tone during pregnancy

The importance of gaining insight into the mechanisms underlying uterine quiescence and contractility is highlighted by the absence of an effective strategy to prevent or treat preterm labor, the greatest cause of perinatal mortality and morbidity worldwide. Although current evidence suggests that in myometrial smooth muscle cells (mSMCs) calcium homeostasis is modulated near term to promote uterine contractility, the efficacy of blocking voltage-operated calcium channels is limited by dose-related cardiovascular side effects. Thus, we considered whether uterine contractility might be modulated by calcium entry via transient receptor potential vanilloid 4 (TRPV4) channels. In mSMC, TRPV4 gene and protein expression increased with gestation, and TRPV4-mediated Ca(2+) entry and contractility were increased in mSMC from pregnant compared to nonpregnant rats. Cell membrane TRPV4 expression was specifically increased, whereas the expression of β-arrestin-1 and β-arrestin-2, molecules that can sequester TRPV4 in the cytoplasm, decreased. Physical interaction of β-arrestin-2 and TRPV4 was apparent in nonpregnant, but absent in pregnant, mouse uterus. Moreover, direct pharmacologic activation of TRPV4 increased uterine contraction, but oxytocin-induced myometrial contraction was blocked by pharmacologic inhibition of TRPV4 and decreased in mice with global deletion of TRPV4. Finally, TRPV4 channel blockade prolonged pregnancy in two distinct in vivo murine models of preterm labor, whereas the absence of either β-arrestin-1 or β-arrestin-2 increased susceptibility to preterm labor. These data suggest that TRPV4 channel activity modulates uterine contractility and might represent a therapeutic target to address preterm labor.

Feasibility of neonatal pulse wave velocity and association with maternal hemoglobin A1c

BACKGROUND

Use of non-invasive peripheral arterial tonometry to assess arterial stiffness has not been studied in neonates. Perinatal factors impact childhood vascular health, but the effect in neonates remains to be examined.

OBJECTIVES

To examine the feasibility of pulse wave velocity (PWV) among healthy term neonates, and to evaluate the effects of perinatal factors on neonatal PWV.

METHODS

Pregnant women with singleton gestation presenting for routine care were enrolled. Postnatally, PWV measurements of their neonates were obtained using an arterial tonometer. A variability index was calculated for each PWV measurement. Intra- and inter-observer reproducibility were illustrated with Bland-Altman plots. Medical records were reviewed. Relationships between neonatal PWV and perinatal factors were examined.

RESULTS

PWV measurements were attempted in 76 neonates and successfully obtained in 67 (88%). Using PWV measurements with a variability index ≤ 0.25 (48 neonates), the intra-class coefficient was 0.69. The mean differences (limits of agreement) for intra- and inter-rater reproducibility were 0.02 (-3.64 to 3.60) and 0.34 (-2.23 to 2.39), respectively. Median neonatal PWV was 2.80 m/s (range 0.60-8.40). Neonates of mothers with HgbA1c ≥6% had significantly higher PWV than neonates of mothers with HgbA1c <6% (4.12 m/s, 95% CI 3.22-5.02, vs. 2.78 m/s, 95% CI 2.28-3.28, p = 0.02).

CONCLUSIONS

Neonatal PWV using peripheral arterial tonometry is feasible and reproducible when using measurements with a variability index ≤ 0.25. Neonates of mothers with increased HgbA1c had higher PWV, suggesting an effect of maternal hyperglycemia on neonatal vasculature. The long-term implications of this finding warrant further investigation.

Anticoagulant prescribing practices and anesthetic interventions among anticoagulated pregnant patients: a retrospective study

BACKGROUND

The peripartum management of anticoagulated patients poses important challenges for obstetric anesthesiologists, especially when deciding to perform neuraxial block. However, there is limited evidence evaluating anticoagulant prescribing practices and neuraxial block utilization in this setting. Our objective was to examine peripartum anticoagulant prescribing and anesthetic practices in a cohort of anticoagulated patients receiving subcutaneous enoxaparin, and subcutaneous or intravenous unfractionated heparin.

METHODS

We performed a retrospective study of anticoagulant prescribing patterns and anesthetic interventions among patients receiving enoxaparin and/or unfractionated heparin who delivered at a USA obstetric center over a seven-year period.

RESULTS

We identified 101 patients who received enoxaparin and/or unfractionated heparin before delivery. Thirty-nine (38.6%) patients received enoxaparin only, 41 (40.6%) patients received enoxaparin bridged to subcutaneous unfractionated heparin, 11 (10.9%) patients received enoxaparin and were converted to intravenous unfractionated heparin and 10 (9.9%) patients received only subcutaneous unfractionated heparin. The overall rate of neuraxial block utilization was 80.2%. The median [IQR] time-period between the last dose of enoxaparin and neuraxial block was significantly shorter for patients who received only enoxaparin vs. enoxaparin with subcutaneous unfractionated heparin (54h [12-192h] (n=26) vs. 216h [39-504h] (n=23), P=0.04). Among patients who received only subcutaneous unfractionated heparin, the time period between unfractionated heparin and neuraxial block was 24h [19-51h].

CONCLUSION

In this study, the neuraxial block rate was high among patients receiving enoxaparin and/or subcutaneous unfractionated heparin with patients undergoing relatively long periods off anticoagulation. Careful multidisciplinary planning is recommended for the peripartum management of anticoagulated pregnant patients.

Randomized comparison of intravenous nitroglycerin and subcutaneous terbutaline for external cephalic version under tocolysis

OBJECTIVE

The purpose of this study was to compare the efficacy and safety of intravenous nitroglycerin with that of subcutaneous terbutaline as a tocolytic agent for external cephalic version at term.

STUDY DESIGN

We performed a prospective randomized trial. Patients between 37 and 42 weeks of gestation were assigned randomly to receive either 200 microg of intravenous nitroglycerin therapy or 0.25 mg of subcutaneous terbutaline therapy for tocolysis during external cephalic version. The rate of successful external cephalic version and side effects were compared between groups.

RESULTS

Of 59 randomly assigned patients, 30 patients received intravenous nitroglycerin, and 29 patients received subcutaneous terbutaline. The overall success rate of external cephalic version in the study was 39%. The rate of successful external cephalic version was significantly higher in the terbutaline group (55% vs 23%; P = .01). The incidence of palpitations was significantly higher in patients who received terbutaline therapy (17.2% vs 0%; P = .02), as was the mean maternal heart rate at multiple time periods.

CONCLUSION

Compared with intravenous nitroglycerin, subcutaneous terbutaline was associated with a significantly higher rate of successful external cephalic version at term.

Neonatal chest wall rigidity following the use of remifentanil for cesarean delivery in a patient with autoimmune hepatitis and thrombocytopenia

Remifentanil is a useful adjunct in general anesthesia for high-risk obstetric patients. It provides effective blunting of the rapid hemodynamic changes that may be associated with airway manipulation and surgical stimulation. There have been no previous reports of opioid-related rigidity in the neonate delivered by a parturient receiving intraoperative remifentanil. We present a case of short-lived neonatal rigidity and respiratory depression following remifentanil administration during cesarean section to a parturient with autoimmune hepatitis complicated by cirrhosis, esophageal varices and thrombocytopenia.