Clinicians' guide to the use of oxytocin for labor induction and augmentation

Evaluating the efficacy of oxytocin for pain management: An updated systematic review and meta-analysis of randomized clinical trials and observational studies

Background

There is a need for novel analgesics with favorable risk to benefit profiles. Oxytocin has recently gained attention for its potential analgesic properties.

Aim

The aim of this study was to perform an updated systematic review and meta-analysis evaluating the effect of oxytocin for pain management.

Method

Ovid MEDLINE, Embase, PsycINFO, CINAHL, and Clinicaltrials.gov were searched for articles reporting on associations between oxytocin and chronic pain management from January 2012 to February 2022. Studies published before 2012 that were identified in our previous systematic review were also eligible. Risk of bias of included studies was assessed. Synthesis of results was performed using meta-analysis and narrative synthesis.

Results

Searches returned 2087 unique citations. In total, 14 articles were included that reported on 1504 people living with pain. Results from meta-analysis and narrative review were mixed. Meta-analysis of three studies indicated that exogenous oxytocin administration did not result in a significant reduction in pain intensity relative to placebo (N = 3; n = 95; g = 0.31; 95% confidence interval [CI] -0.10, 0.73). Narrative review provided encouraging evidence that exogenous oxytocin administration reduced pain sensitivity among individuals with back pain, abdominal pain, and migraines. Results suggested that individual difference factors (e.g., sex and chronic pain condition) may influence oxytocin-induced nociception, but the heterogeneity and limited number of studies identified precluded further investigation.

Discussion

There is equipoise for the benefit of oxytocin for pain management. Future studies are imperative and should undertake more precise exploration of potential confounds and mechanisms of analgesic action to clarify inconsistency in the literature.

Maternal and newborn plasma oxytocin levels in response to maternal synthetic oxytocin administration during labour, birth and postpartum - a systematic review with implications for the function of the oxytocinergic system

BACKGROUND

The reproductive hormone oxytocin facilitates labour, birth and postpartum adaptations for women and newborns. Synthetic oxytocin is commonly given to induce or augment labour and to decrease postpartum bleeding.

AIM

To systematically review studies measuring plasma oxytocin levels in women and newborns following maternal administration of synthetic oxytocin during labour, birth and/or postpartum and to consider possible impacts on endogenous oxytocin and related systems.

METHODS

Systematic searches of PubMed, CINAHL, PsycInfo and Scopus databases followed PRISMA guidelines, including all peer-reviewed studies in languages understood by the authors. Thirty-five publications met inclusion criteria, including 1373 women and 148 newborns. Studies varied substantially in design and methodology, so classical meta-analysis was not possible. Therefore, results were categorized, analysed and summarised in text and tables.

RESULTS

Infusions of synthetic oxytocin increased maternal plasma oxytocin levels dose-dependently; doubling the infusion rate approximately doubled oxytocin levels. Infusions below 10 milliunits per minute (mU/min) did not raise maternal oxytocin above the range observed in physiological labour. At high intrapartum infusion rates (up to 32 mU/min) maternal plasma oxytocin reached 2-3 times physiological levels. Postpartum synthetic oxytocin regimens used comparatively higher doses with shorter duration compared to labour, giving greater but transient maternal oxytocin elevations. Total postpartum dose was comparable to total intrapartum dose following vaginal birth, but post-caesarean dosages were higher. Newborn oxytocin levels were higher in the umbilical artery vs. umbilical vein, and both were higher than maternal plasma levels, implying substantial fetal oxytocin production in labour. Newborn oxytocin levels were not further elevated following maternal intrapartum synthetic oxytocin, suggesting that synthetic oxytocin at clinical doses does not cross from mother to fetus.

CONCLUSIONS

Synthetic oxytocin infusion during labour increased maternal plasma oxytocin levels 2-3-fold at the highest doses and was not associated with neonatal plasma oxytocin elevations. Therefore, direct effects from synthetic oxytocin transfer to maternal brain or fetus are unlikely. However, infusions of synthetic oxytocin in labour change uterine contraction patterns. This may influence uterine blood flow and maternal autonomic nervous system activity, potentially harming the fetus and increasing maternal pain and stress.

Perinatal maternal characteristics predict a high risk of neonatal asphyxia: A multi-center retrospective cohort study in China

Objective

This study aimed to identify various perinatal maternal characteristics that contributed to neonatal asphyxia (NA) in term and late-preterm newborns based on the data obtained from a Chinese birth registry cohort and to establish an effective model for predicting a high risk of asphyxia.

Method

We retrospectively reviewed and analyzed the birth database from July 1, 2016, to June 30, 2017, in the main economically developed regions of China. Asphyxia was defined as an Apgar score <7 at 5 min post-delivery with umbilical cord arterial blood pH < 7.2 in the infant born after 34weeks. We compared the perinatal maternal characteristics of the newborns who developed asphyxia (NA group, n = 1,152) and those who did not (no NA group, n = 86,393). Candidate predictors of NA were analyzed using multivariable logistic regression. Subsequently, a prediction model was developed and validated by an independent test group.

Result

Of the maternal characteristics, duration of PROM ≥ 48 h, a gestational week at birth <37, prolonged duration of labor, hypertensive disorder, nuchal cord, and birth weight <2,500 or ≥4,000 g, abnormal fetal heart rate, meconium-stained amniotic fluid, and placenta previa were included in the predicting model, which presented a good performance in external validation (c-statistic of 0.731).

Conclusion

Our model relied heavily on clinical predictors that may be determined before or during birth, and pregnant women at high risk of NA might be recognized earlier in pregnancy and childbirth using this methodology, allowing them to avoid being neglected and delayed. Future studies should be conducted to assess its usefulness.

Induction of parturition in horses - from physiological pathways to clinical applications

Based on the marked variability in physiological equine gestation length, induction of foaling in mares often results in the birth of dysmature foals. Precise prediction of preparedness of the mare for foaling is thus essential. Treatment with glucocorticoids mimics the fetal signal that initiates birth. Repeated daily dexamethasone treatment in late gestation results in birth of mature foals but the time from initiation of treatment to foaling is highly variable and complications such as dystocia have been reported. Contrary to most expectations, treatment of prepartum mares with progestogens does not delay but advances the onset of foaling. Prostaglandin F_2α (PGF_2α) and its analogues are effective to induce foaling but even in mares ready for parturition, foal health remains to some extent unpredictable. This may be caused by a relatively long interval between PGF_2α treatment and birth, exposing the fetus for several hours to uterine contractions. Oxytocin reliably induces foaling towards the end of pregnancy, but when given at high doses is effective also in the pre-viable period of gestation, resulting in birth of premature foals. Recent research has focused on reducing the amount of oxytocin with the aim to induce foaling only in mares prepared for foaling. Mares selected on clinical criteria receive 1 dose of 2.5 to 3.5 IU of oxytocin. Mares not responding to oxytocin are judged not yet ready for foaling and treatment is repeated the earliest after 24 h. This protocol at present is the most reliable and safest way to induce parturition in mares.

Review of Evidence-Based Methods for Successful Labor Induction

Induction of labor is increasingly a common component of the intrapartum care. Knowledge of the current evidence on methods of labor induction is an essential component of shared decision-making to determine which induction method meets an individual's health needs and personal preferences. This article provides a review of the current research evidence on labor induction methods, including cervical ripening techniques, and contraction stimulation techniques. Current evidence about expected duration of labor following induction, use of the Bishop score to guide induction, and guidance on the use of combination methods for labor induction are reviewed.

Intrapartum synthetic oxytocin, behavioral and emotional problems in children, and the role of postnatal depressive symptoms, postnatal anxiety and mother-to-infant bonding: A Dutch prospective cohort study

OBJECTIVE

To examine the association between intrapartum synthetic oxytocin and child behavioral and emotional problems and to assess if maternal depressive or anxious symptoms or mother-to-infant bonding play a mediating role in this association.

DESIGN

Prospective cohort study.

SETTING

Population-based Pregnancy Anxiety and Depression Study.

PARTICIPANTS

Pregnant women in their first trimester of pregnancy visiting a total of 109 primary and nine secondary obstetric care centers in the Netherlands between 2010 and 2014 were invited to participate. Follow-up measures used for the present study were collected from May 2010 to January 2019. Women with multiple gestations and with a preterm birth were excluded.

MEASUREMENTS

Intrapartum synthetic oxytocin exposure status was based on medical birth records and was defined as its administration (Yes/No), either for labour induction or augmentation. Child behavioral and emotional problems were measured with the Child Behavior Checklist at up to 60 months postpartum. Maternal depressive symptoms, anxiety and mother-to infant bonding were measured with the Edinburgh Postnatal Depression Scale, State Trait Anxiety Inventory and the Mother-to-Infant Bonding Scale from 6 months postpartum. We used multivariable linear regression models to estimate standardized beta coefficients and unique variance explained.

FINDINGS

1,528 women responded. In total 607 women received intrapartum synthetic oxytocin. Intrapartum synthetic oxytocin administration was not associated with child behavioral and emotional problems, mother-to-infant bonding nor with postnatal anxiety. Intrapartum synthetic oxytocin was however significantly but weakly associated with more postnatal depressive symptoms (β=0.17, 95%CI of 0.03 to 0.30) explaining 0.6% of unique variance. Maternal postnatal depressive symptoms, postnatal anxiety symptoms and suboptimal mother-to-infant bonding were positively associated with child behavioral and emotional problems.

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

We found no evidence that intrapartum synthetic oxytocin is associated with child behavioral and emotional problems, mother-to-infant bonding, or with postnatal anxiety symptoms. Because there was no association between intrapartum synthetic oxytocin and behavioral and emotional problems in children no mediation analysis was carried out. However, intrapartum synthetic oxytocin was positively but weakly associated with postnatal depressive symptoms. The clinical relevance of this finding is negligible in the general population, but unknown in a population with a high risk of depression.

Oxytocin-Induced Acute Pulmonary Edema: A Case Report and Literature Review

The use of intravenous (IV) oxytocin has been commonly associated with the development of nausea, vomiting, headache, flushing, and hypotension. To date, only a few previously published studies have linked the administration of IV oxytocin, in high doses exceeding 15 mU/min, with the development of acute pulmonary edema. In this article, we aim to report the rare occurrence of acute pulmonary edema following administration of IV oxytocin at a small dose of 2 mU/min, in a 20-year-old pregnant female, to allow its recognition and prompt treatment by the clinician caring for the patient.

Oxytocin Administration in Low-Risk Women, a Retrospective Analysis of Birth and Neonatal Outcomes

Background: In recent years, higher than the recommended rate of oxytocin use has been observed among low-risk women. This study examines the relationship between oxytocin administration and birth outcomes in women and neonates. Methods: A retrospective analysis of birth and neonatal outcomes for women who received oxytocin versus those who did not. The sample included 322 women with a low-risk pregnancy. Results: Oxytocin administration was associated with cesarean section (aOR 4.81, 95% CI: 1.80–12.81), instrumental birth (aOR 3.34, 95% CI: 1.45–7.67), episiotomy (aOR 3.79, 95% CI: 2.20–6.52) and length of the second stage (aOR 00:18, 95% CI: 00:04–00:31). In neonatal outcomes, oxytocin in labor was associated with umbilical artery pH ≤ 7.20 (OR 3.29, 95% CI: 1.33–8.14). Admission to neonatal intensive care unit (OR 0.56, 95% CI: 0.22–1.42), neonatal resuscitation (OR 1.04, 95% CI: 0.22–1.42), and Apgar score <7 (OR 0.48, 95% CI: 0.17–1.33) were not associated with oxytocin administration during labor. Conclusions: Oxytocin administration during labor for low-risk women may lead to worse birth outcomes with an increased risk of instrumental birth and cesarean, episiotomy and the use of epidural analgesia for pain relief. Neonatal results may be also worse with an increased proportion of neonates displaying an umbilical arterial pH ≤ 7.20.

Synthesis of Non-canonical Amino Acids and Peptide Containing Them for Establishment of the Template for Drug Discovery

Non-canonical amino acid derivatives are an attractive scaffold for novel drug candidates. Among the methods used to prepare this motif, the asymmetric Mannich-type reaction of α-imino carboxylic acid derivatives is a preeminent strategy because a wide variety of non-canonical amino acids can be accessed by changing only the nucleophile. Preparing the common substrate is difficult, however, which makes this method problematic. We developed a convenient method for synthesizing common substrates using MnO₂-mediated oxidation of stable precursors. Peptides bearing non-canonical amino acids are another attractive synthetic target. We propose a new approach for synthesizing non-canonical amino acid-containing peptides by directly applying various organic reactions to peptidic substrates. Using hydrophobic anchor-supported peptides, we directly applied ring-closing metathesis and asymmetric Friedel-Crafts reactions to peptidic substrates. We also developed a novel recyclable organocatalyst according to the nature of the hydrophobic anchor tagged compound.

Spontaneous vaginal birth following induction with intravenous oxytocin: Three oxytocic regimes to minimise blood loss post birth

BACKGROUND

No evidence was identified in relation to the downward titration/cessation of intravenous oxytocin post spontaneous vaginal birth, in the absence of postpartum haemorrhage (PPH); suggesting clinicians' management is based on personal preference in the absence of evidence.

AIM

To determine the proportion of induced women with a spontaneous vaginal birth and PPH, when intravenous oxytocin was utilised intrapartum and ceased 15, 30 or 60minutes post birth.

METHODS

This three armed pilot randomised controlled trial, was undertaken on the Birth Suite of an Australian tertiary obstetric hospital. Incidence of PPH was assessed using univariable and adjusted logistic regression, which compared the effect of titrating intravenous oxytocin post birth on the likelihood of PPH, relative to the 15minute titration group.

FINDINGS

Postpartum haemorrhage occurred in 26% (30 of 115), 20% (23 of 116), and 22% (30 of 134) of women randomised to a 15, 30 and 60minute titration time post birth, with no statistically significant differences between groups.

CONCLUSION

There was no difference in the incidence of PPH between the three groups. Therefore, we question the benefit of delaying cessation of intravenous oxytocin for 60minutes post birth. Further investigation in this cohort is recommended, to compare the incidence of PPH when intravenous oxytocin is ceased either immediately, or 30minutes post birth. This research is warranted, as an evidence-based framework is lacking, to guide midwives globally in relation to their management of intravenous oxytocin post an induced spontaneous vaginal birth, in the absence of PPH.

An association of intrapartum synthetic oxytocin dosing and the odds of developing autism

A case-control study was performed to determine whether an association exists between exposure to synthetic oxytocin and a subsequent autism spectrum disorder diagnosis; 171 children under age 18 meeting Diagnostic and Statistical Manual of Mental Disorders (5th ed.) autism spectrum disorder criteria were compared to 171 children without autism spectrum disorder diagnosis matched by gender, birth year, gestational age, and maternal age at birth. A conditional logistic regression model was used to examine the association of clinical variables and autism spectrum disorder. Significantly elevated odds ratios for autism spectrum disorder were associated with first-time Cesarean section (odds ratio = 2.56), but not a repeat Cesarean section. Odds ratios were also significantly elevated for subjects whose mother’s body mass index was 35 or higher at birth (odds ratio = 2.34) and subjects in which the reason for delivery was categorized as “fetal indication” (odds ratio = 2.00). When controlling for these and other variables, the odds of developing autism spectrum disorder were significantly elevated in males with long duration of exposure (odds ratio = 3.48) and high cumulative dose of synthetic oxytocin (odds ratio = 2.79). No significant associations of synthetic oxytocin dosing and autism spectrum disorder were noted in female subjects. The association of elevated autism spectrum disorder odds found with high duration and high cumulative dose synthetic oxytocin in male subjects suggests the need for further investigation to fully elucidate any cause and effect relationship.

Intrapartum interventions that affect maternal and neonatal outcomes for vaginal birth after cesarean section

Objective

To investigate maternal and neonatal outcomes after different intrapartum interventions for vaginal birth after cesarean section (VBAC) in mainland China.

Methods

A retrospective study was performed on 143 VBAC cases from Beijing Obstetrics and Gynecology Hospital between January 2015 and November 2016. These cases were divided into two groups on the basis of different intrapartum interventions. Maternal and neonatal outcomes were compared.

Results

The durations of the first stage and total labor after oxytocin were significantly longer than those before oxytocin use. The proportion of operative vaginal delivery with oxytocin was significantly higher than that without oxytocin (43.9% vs. 11.8%). The times of the first stage, second stage, and total labor with analgesia were significantly longer than those without analgesia (548.4±198.1 vs. 341.8±233.0 minutes, 52.0±38.9 vs. 36.0± 29.1 minutes, and 606.3±212.1 vs. 387.3±233.0 minutes, respectively). Postpartum hemorrhage and operative vaginal delivery occurred significantly more frequently in women with epidural analgesia than in those without epidural analgesia (29.7% vs. 12.3 and 35.1% vs. 16.0%, respectively).

Conclusions

Induction can increase the rate of operative vaginal delivery in VBAC. Oxytocin and epidural analgesia may increase the risk of operative vaginal delivery, and may be associated with a prolonged duration of labor.

Inter-institutional variations in oxytocin augmentation during labour in German university hospitals: a national survey

BACKGROUND

There are several international guidelines on oxytocin regimens for induction and augmentation of labour, but no agreement on a standardised regimen in Germany. This study collated and reviewed the oxytocin regimens used for labour augmentation in university hospitals, with the long-term aim of contributing to the development of a national clinical guideline.

METHODS

Germany has 34 university hospital compounds, representing 39 maternity units. In this observational study we asked units to provide standard operational procedures on oxytocin augmentation during labour or provide the details in a structured survey. Data were collected on the dosage of oxytocin, type and volume of solutions used, indications and contraindications for use and discontinuation, case-specific administration, and on who developed the procedures. Findings were analysed descriptively.

RESULTS

A total of 35 (90%) units participated in this study. Standard operating procedures were available in 24 units (69%), seven units (20%) did not have procedures and information was missing from four units (11%). Midwives participated in the development of standard operating procedures in 15 units (43%). Infusions were most commonly prepared using six units of oxytocin in 500 ml 0.9% normal saline solution (12 mU/ml). The infusions were started at 120 mU/hour and increased by 120 mU/hour at 20-min intervals up to a maximum dosage of 1200 mU/hour. The most common indication for use was delayed progress in labour. Infusions were stopped when uterine contractions became hypertonic and/or the fetal heart rate showed signs of distress. Most of the practices described aligned with international guidance. All units used reduced oxytocin dosages for women with a history of previous caesareans section, as recommended in the international guidelines, and restrictive use was advised in multiparous women. The main difference between units related to combined use of amniotomy and oxytocin, recommended by three guidelines but used in only four maternity units (11%).

CONCLUSIONS

While there was considerable variation in the oxytocin augmentation procedures, most but not all practices used in these 35 German maternity units were comparable. Establishing a national guideline on the criteria for and administration of oxytocin for augmentation of labour would eliminate the observed differences and minimise risk of administration and medication error.

Implementation of an Oxytocin Checklist to Improve Clinical Outcomes

BACKGROUND

Oxytocin is one of the most common drugs administered in obstetrics. Since its designation as a high-alert medication by the Institute for Safe Medication Practices in 2007, there has been much attention to oxytocin administration during labor. Oxytocin is generally safe when administered correctly, but adverse perinatal outcomes can occur during uterine tachysystole.

PURPOSE

The purpose of this project was to evaluate and compare results of maternal and fetal outcomes of induction of labor for women at term prior to and after implementation of a newly developed oxytocin checklist.

PROJECT DESIGN AND METHODS

To evaluate the practice change associated with the implementation of the new oxytocin checklist, 200 cases based on retrospective medical record reviews were compared with 200 cases after implementation.

RESULTS

Use of the checklist was associated with several significant clinical outcomes, including decreases in tachysystole, decreases in cesarean births for concern about fetal status based on electronic fetal monitoring data, decreases in length of first stage labor, and decreases in maximum dose of oxytocin.

CLINICAL IMPLICATIONS

Results are similar to previous research. Early physician buy-in, clinical team education, and ongoing evaluation enhanced facilitation of the oxytocin checklist. Clinical outcomes were favorable.

Oxytocin administration: the transition to a safer model of care

The use of oxytocin, a high-alert medication, has increased dramatically in recent years as induction rates have risen. Methods for administration of oxytocin and subsequent outcomes have long been a source of debate. Furthermore, one of the leading causes of obstetrical liability claims involves the administration of oxytocin leading to tachysystole. This article describes how a collaborative of Perinatal Clinical Nurse Specialists and Obstetric Nurse Educators for a 9-hospital healthcare system throughout Colorado undertook a system-wide process-improvement project to increase safety for pregnant women receiving oxytocin. The goal of this initiative was to decrease risk exposure by successfully implementing a standardized evidence-based protocol and processes across the healthcare system. There has been implementation of standardized oxytocin mixtures, low-dose administration guidelines, and safety checklists to assure fetal and maternal well-being before initiation of oxytocin and increases in oxytocin dosages. The associated outcomes after this initiative have been shorter lengths of labor, decreased incidence of tachysystole, and decreased incidence of primary cesarean birth.