High and low dose oxytocin in augmentation of labor

Oxytocin: physiology, pharmacology, and clinical application for labor management

Oxytocin is a peptide hormone that plays a key role in regulating the female reproductive system, including during labor and lactation. It is produced primarily in the hypothalamus and secreted by the posterior pituitary gland. Oxytocin can also be administered as a medication to initiate or augment uterine contractions. To study the effectiveness and safety of oxytocin, previous studies have randomized patients to low- and high-dose oxytocin infusion protocols either alone or as part of an active management of labor strategy along with other interventions. These randomized trials demonstrated that active management of labor and high-dose oxytocin regimens can shorten the length of labor and reduce the incidence of clinical chorioamnionitis. The safety of high-dose oxytocin regimens is also supported by no associated differences in fetal heart rate abnormalities, postpartum hemorrhage, low Apgar scores, neonatal intensive care unit admissions, and umbilical artery acidemia. Most studies reported no differences in the cesarean delivery rates with active management of labor or high-dose oxytocin regimens, thereby further validating its safety. Oxytocin does not have a predictable dose response, thus the pharmacologic effects and the amplitude and frequency of uterine contractions are used as physiological parameters for oxytocin infusion titration to achieve adequate contractions at appropriate intervals. Used in error, oxytocin can cause patient harm, highlighting the importance of precise administration using infusion pumps, institutional safety checklists, and trained nursing staff to closely monitor uterine activity and fetal heart rate changes. In this review, we summarize the physiology, pharmacology, infusion regimens, and associated risks of oxytocin.

Exposures during pregnancy and at birth are associated with the risk of offspring eating disorders

BACKGROUND

Eating disorders (ED) are severe psychiatric disorders, commonly debuting early. Aberrances in the intrauterine environment and at birth have been associated with risk of ED. Here, we explore if, and at what effect size, a variety of such exposures associate with offspring ED, that is, anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS).

METHODS

This population-based cohort study, conducted from September 2021 to August 2023, used Finnish national registries of all live births in 1996-2014 (N = 1,097,753). Cox proportional hazards modeling was used to compare ED risk in exposed versus unexposed offspring, adjusting for potential confounders and performing sex-stratified analyses.

RESULTS

A total of 6614 offspring were diagnosed with an ED; 3668 AN, 666 BN, and 4248 EDNOS. Lower risk of offspring AN was seen with young mothers, continued smoking, and instrumental delivery, while higher risk was seen with older mothers, inflammatory disorders, prematurity, small for gestational age, and low Apgar. Offspring risk of BN was higher with continued smoking and prematurity, while lower with postmature birth. Offspring risk of EDNOS was lower with instrumental delivery, higher for older mothers, polycystic ovary syndrome, insulin-treated pregestational diabetes, antibacterial treatment, prematurity, and small for gestational age. Sex-specific associations were found.

CONCLUSIONS

Several prenatal and at birth exposures are associated with offspring ED; however, we cannot exclude confounding by maternal BMI. Nevertheless, several exposures selectively associate with risk of either AN, BN, or EDNOS, and some are sex-specific, emphasizing the importance of subtype- and sex-stratified analyses of ED.

PUBLIC SIGNIFICANCE

We define environmental factors involved in the development of different ED, of importance as preventive measure, but also in order to aid in defining the molecular pathways involved and thus in the longer perspective contribute to the development of pharmacological treatment of ED.

Vaginal Birth at Term - Part 2. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/083, December 2020)

Purpose This guideline aims to summarize the current state of knowledge about vaginal birth at term. The guideline focuses on definitions of the physiological stages of labor as well as differentiating between various pathological developments and conditions. It also assesses the need for intervention and the options to avoid interventions. The second part of this guideline presents recommendations and statements on care during the dilation and expulsion stages as well as during the placental/postnatal stage. Methods The German recommendations largely reproduce the recommendations of the National Institute for Health and Care Excellence (NICE) CG190 guideline "Intrapartum care for healthy women and babies". Other international guidelines were also consulted in individual cases when compiling this guideline. In addition, a systematic search and analysis of the literature was carried out using PICO questions where necessary, and other systematic reviews and individual studies were taken into account. For easier comprehension, the assessment tools of the Scottish Intercollegiate Guidelines Network (SIGN) were used to evaluate the quality of additionally consulted studies. Otherwise, the GRADE system was used for the NICE guideline, and the evidence reports of the IQWiG were used to evaluate the quality of the evidence. Recommendations Recommendations and statements were formulated based on identified evidence and/or a structured consensus.

High dose vs. low dose oxytocin for labor augmentation: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To compare the safety and efficacy between high dose and low dose oxytocin administration for labor augmentation.

METHODS

We searched for the available studies during March 2020 in PubMed, Cochrane Library, Scopus, and ISI Web of science. All randomized clinical trials (RCTs) that assessed safety and efficacy of high dose vs. low dose oxytocin for labor augmentation were considered. The extracted data were entered into RevMan software. Dichotomous and continuous data were pooled as odds ratio (OR) and mean difference (MD) respectively, with the corresponding 95% confidence intervals (CI). Our main outcomes were cesarean delivery rate, spontaneous vaginal delivery rate, uterine hyperstimulation and tachysystole, and labor duration from oxytocin infusion.

RESULTS

Eight RCTs with 3,154 patients were included. High dose oxytocin did not reduce cesarean delivery rate compared to low dose oxytocin (OR=0.76, 95% CI [0.52, 1.10], p=0.15). After solving the reported heterogeneity, high dose oxytocin did not increase the rate of spontaneous vaginal deliveries vs. low dose oxytocin (OR=1.06, 95% CI [0.84, 1.32], p=0.64). Low dose oxytocin was linked to a significant decline in uterine hyperstimulation and tachysystole (p>0.001). A reduction in labor duration was found in high dose oxytocin group over low oxytocin regimen (MD=-1.02 h, 95% CI [-1.77, -0.27], p=0.008).

CONCLUSIONS

We found no advantages for high dose oxytocin over low dose oxytocin in labor augmentation except in reducing labor duration. Low dose oxytocin is safer as it decreases the incidence of uterine hyperstimulation and tachysystole. More trials are needed to confirm our findings.

Labor augmentation strategies: What's the evidence?

Labor augmentation is a commonly used strategy in obstetrics to make labor more efficient or to increase the chance of achieving a vaginal delivery. Intravenous infusion of synthetic oxytocin and early amniotomy are the most widely used methods, but there is considerable variation in how they are used in clinical practice. There remain significant differences in the timing, dosing, and administration of synthetic oxytocin across institutions. The use and timing of amniotomy is similarly controversial. Much of the clinical variation in augmentation practices stem from the significant heterogeneity that exists in the literature, as well as the lack of an optimal strategy that has been subjected to the scientific scrutiny needed to prove its superiority in both efficacy and safety. Further research is needed to allow for better standardized care of women presenting in spontaneous labor.

Effects of Increased Frequency, High Dose, and Pulsatile Oxytocin Regimens on Abnormal Labor Delivery

Background

The current guideline for oxytocin regimens in the abnormal labor of delivery is continuous infusion. The objective of the present study was to compare effects and safety measures of various available regimens of oxytocin in abnormal labor delivery.

Material/Methods

In this clinical experimental study, a total of 900 pregnant women admitted for delivery were randomized into 5 group with 162 each. Pregnant women received oxytocin as continuous administration of 16 mU/min (Group I), 1 mU/min (group II), 4 mU/min (group III), 5 mU/min quarter-hourly (group IV), and through a syringe pump (group V). Measurement of the expense of delivery, the ratio of the instrumental delivery, and the other secondary outcome measures was performed to find the best regimen of oxytocin. The 2-tailed paired t test and Mann-Whitney U test following Dunnett’s multiple comparison tests were used at 95% confidence level.

Results

Pulsatile delivery had least risk of instrumental delivery as compared to continuous infusion (p<0.0001, q=6.663) and normal-frequency low-dose (p<0.0001, q=5.638) of oxytocin. The time required from infusion to delivery was longer for group II (p=0.001, q=2.925), group IV (p<0.0001, q=4.829), and group V (p<0.0001, q=41.456) than for group I. The expense of delivery was: group I < group II < group IV < group III < group V.

Conclusions

High-dose and pulsatile preparation of oxytocin had reduced risks of operative delivery vs. continuous administration.

High-dose versus low-dose oxytocin for augmentation of delayed labour

BACKGROUND

A major cause of failure to achieve spontaneous vaginal birth is delay in labour due to presumed inefficient uterine action. Oxytocin is given to increase contractions and high-dose regimens may potentially increase the number of spontaneous vaginal births, but as oxytocin can cause hyperstimulation of the uterus, there is a possibility of increased adverse events.

OBJECTIVES

To compare starting dose and increment dose of oxytocin for augmentation for women delayed in labour to determine whether augmentation by high-dose regimens of oxytocin improves labour outcomes and to examine the effect on both maternal/neonatal outcomes and women's birth experiences.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2013) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all randomised and quasi-randomised controlled trials for women in delayed labour requiring augmentation by oxytocin comparing high-dose regimens (defined as starting dose and increment of equal to or more than 4 mU per minute) with low-dose regimens (defined as starting dose and an increment of less than 4 mU per minute). Increase interval: between 15 and 40 minutes. The separation of low- and high-dose regimens is based on an arbitrary decision.

DATA COLLECTION AND ANALYSIS

Four review authors undertook assessment of trial eligibility, risk of bias, and data extraction independently.

MAIN RESULTS

We included four studies involving 644 pregnant women. Three studies were randomised controlled trials and one trial was a quasi-randomised study. A higher dose of oxytocin was associated with a significant reduction in length of labour reported from one trial (mean difference (MD) -3.50 hours; 95% confidence interval (CI) -6.38 to -0.62; one trial, 40 women). There was a decrease in the rate of caesarean section (risk ratio (RR) 0.62; 95% CI 0.44 to 0.86 four trials, 644 women) and an increase in the rate of spontaneous vaginal birth in the high-dose group (RR 1.35; 95% CI 1.13 to 1.62, three trials, 444 women), although for both of these outcomes there were inconsistencies between studies in the size of effect. When we carried out sensitivity analysis (temporarily removing a study at high risk of bias) the differences between groups were no longer statistically significantThere were no significant differences between high- and low-dose regimens for instrumental vaginal birth, epidural analgesia, hyperstimulation, postpartum haemorrhage, chorioamnionitis or women's perceptions of experiences. For neonatal outcomes, there was no significant difference between groups for Apgar scores, umbilical cord pH, admission to special care baby unit, or neonatal mortality. The following outcomes were not evaluated in the included studies: perinatal mortality, uterine rupture, abnormal cardiotocography, women's pyrexia, dystocia and neonatal neurological morbidity.

AUTHORS' CONCLUSIONS

Higher-dose regimens of oxytocin (4 mU per minute or more) were associated with a reduction in the length of labour and in caesarean section, and an increase in spontaneous vaginal birth. However, there is insufficient evidence to recommend that high-dose regimens are advised routinely for women with delay in the first stage of labour. Further research should evaluate the effect of high-dose regimens of oxytocin for women delayed in labour and should include maternal and neonatal outcomes as well as the effects on women.

Standardization of HPTLC method for the estimation of oxytocin in edibles

Adulteration in food stuff has been regarded as a major social evil and is a mind-boggling problem in society. In this study, a rapid, reliable and cost effective High Performance thin layer Chromatography (HPTLC) has been established for the estimation of oxytocin (adulterant) in vegetables, fruits and milk samples. Oxytocin is one of the most frequently used adulterant added in vegetables and fruits for increasing the growth rate and also to enhance milk production from lactating animals. The standardization of the method was based on simulation parameters of mobile phase, stationary phase and saturation time. The mobile phase used was MeOH: Ammonia (pH 6.8), optimized stationary phase was silica gel and saturation time of 5 min. The method was validated by testing its linearity, accuracy, precision, repeatability and limits of detection and quantification. Thus, the proposed method is simple, rapid and specific and was successfully employed for quality and quantity monitoring of oxytocin content in edible products.

High dose versus low dose oxytocin for augmentation of delayed labour

BACKGROUND

A major cause of failure to achieve spontaneous vaginal birth is delay in labour caused by presumed inefficient uterine action. High dose may potentially increase the number of spontaneous vaginal births, but as oxytocin can cause hyperstimulation of the uterus, there is a possibility of increased adverse events.

OBJECTIVES

To compare starting dose and increment of amount of oxytocin for augmentation for women delayed in labour to determine whether augmentation by high dose of oxytocin improves labour outcomes and the effect on both maternal/neonatal outcomes and women's birth experiences.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 February 2011) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all randomised and quasi-randomised controlled trials for women in delayed in labour requiring augmentation by oxytocin comparing high starting and increment dose (defined as starting dose and increment of equal to or more than 4 mU per minute) with low dose (defined as starting dose and an increment of less than 4 mU per minute. Increase interval: between 15 and 40 minutes. The separation of low and high doses is based on an arbitrary decision.

DATA COLLECTION AND ANALYSIS

Three review authors undertook assessment of trial eligibility, risk of bias, and data extraction independently.

MAIN RESULTS

We included four studies involving 660 pregnant women. Three studies were randomised controlled trials and one trial was a quasi-randomised study. A higher dose of oxytocin was associated with a significant reduction in length of labour reported from one trial (mean difference (MD) -3.50 hours; 95% confidence interval (CI) -6.38 to -0.62; one trial, 40 women). There was a decrease in rate of caesarean section (risk ratio (RR) 0.53; 95% CI 0.38 to 0.75, four trials, 650 women) and an increase in the rate of spontaneous vaginal birth (RR 1.37; 95% CI 1.15 to 1.64, two trials, 350 women). There were no significant differences for neonatal mortality, hyperstimulation, chorioamnionitis, epidural analgesia; or neonatal outcomes of Apgar scores, umbilical cord pH or admission to special care baby unit. The following outcomes were not evaluated in the included studies: perinatal mortality, women's satisfaction, instrumental vaginal birth, uterine rupture, postpartum haemorrhage, abnormal cardiotocography, women's pyrexia, dystocia and neonatal neurological morbidity.

AUTHORS' CONCLUSIONS

Higher dose of oxytocin starting and increment dose (4 mU per minute or more) was associated with a reduction in the length of labour and in caesarean section, and an increase in spontaneous vaginal birth. However, there is insufficient evidence. The number of studies and the quality of the available evidence is of concern. Additionally, there is insufficient evidence for other maternal and neonatal outcomes, and how women feel about the higher doses of oxytocin. Therefore, no firm recommendation can be made. Further research should evaluate the effect of high dose oxytocin for women delayed in labour and should include these outcomes.

The effect of late pregnancy consumption of date fruit on labour and delivery

We set out to investigate the effect of date fruit (Phoenix dactylifera) consumption on labour parameters and delivery outcomes. Between 1 February 2007 and 31 January 2008 at Jordan University of Science and Technology, a prospective study was carried out on 69 women who consumed six date fruits per day for 4 weeks prior to their estimated date of delivery, compared with 45 women who consumed none. There was no significant difference in gestational age, age and parity between the two groups. The women who consumed date fruit had significantly higher mean cervical dilatation upon admission compared with the non-date fruit consumers (3.52 cm vs 2.02 cm, p < 0.0005), and a significantly higher proportion of intact membranes (83% vs 60%, p = 0.007). Spontaneous labour occurred in 96% of those who consumed dates, compared with 79% women in the non-date fruit consumers (p = 0.024). Use of prostin/oxytocin was significantly lower in women who consumed dates (28%), compared with the non-date fruit consumers (47%) (p = 0.036). The mean latent phase of the first stage of labour was shorter in women who consumed date fruit compared with the non-date fruit consumers (510 min vs 906 min, p = 0.044). It is concluded that the consumption of date fruit in the last 4 weeks before labour significantly reduced the need for induction and augmentation of labour, and produced a more favourable, but non-significant, delivery outcome. The results warrant a randomised controlled trial.

Comparison between amniotomy, oxytocin or both for augmentation of labor in prolonged latent phase: a randomized controlled trial

BACKGROUND

A prolonged latent phase is independently associated with an increased incidence of subsequent labor abnormalities. We aimed to compare between oxytocin augmentation, amniotomy and a combination of both on the duration of labor among women with a prolonged latent phase.

METHODS

Women with a singleton fetus in cephalic presentation who have a prolonged latent phase, were randomly allocated to amniotomy (group 1), oxytocin (group 2) or both (group 3). A group of women who progressed spontaneously without intervention composed the control group (group 4). The primary outcome was the duration of time from initiation of augmentation until delivery.

RESULTS

A total of 213 women were consented and randomized to group 1 (70 women), group 2 (72 women) and group 3 (71 women). Group 4 was composed from additional 70 women. A mean reduction of 120 minutes in labor duration was observed among group 3 compared to group 1 (p = 0.08) and 180 minutes compared to group 2 and 4 (p = 0.001). Women in group 3 had a shorter length of time from augmentation until the beginning of the active phase and a shorter first stage of labor than group 1 (p = 0.03), group 2 (p = 0.001) and group 4 (p = 0.001). Satisfaction was greater among group 3 and 4. Mode of delivery and neonatal outcome were comparable between the groups.

CONCLUSION

Labor augmentation by combined amniotomy and oxytocin among women with a prolonged latent phase at term seems superior compared to either of them alone.

High-dose vs low-dose oxytocin for labor augmentation: a systematic review

The objective of this systematic review was to estimate the efficacy and safety of high-dose vs low-dose oxytocin for labor augmentation on the risk of cesarean section and on indicators of maternal and neonatal morbidity. We searched PubMed, MEDLINE, EMBASE, and the Cochrane Library for randomized clinical trials published until January 2010. Ten randomized clinical trials, including 5423 women, met the inclusion criteria. High-dose oxytocin was associated with a moderate decrease in the risk of cesarean section (relative risk [RR], 0.85; 95% confidence interval [CI], 0.75-0.97), a small increase in spontaneous vaginal delivery (RR, 1.07; 95% CI, 1.02-1.12), and a decrease in labor duration (mean difference: -1.54 hours, 95% CI, -2.44 to -0.64). While hyperstimulation was increased with high-dose oxytocin (RR, 1.91; 95% CI, 1.49-2.45), there was no evidence of an increase in maternal or neonatal morbidity. We conclude that high-dose oxytocin for labor augmentation is associated with a decrease in cesarean section and shortened labor.

Titrated oral misoprostol solution compared with intravenous oxytocin for labor augmentation: a randomized controlled trial

OBJECTIVE

To compare titrated oral misoprostol to intravenous oxytocin for labor augmentation among women at 36 to 42 weeks of gestation with spontaneous onset of active labor.

METHODS

Women meeting the general selection criteria with regular contractions and an effaced cervix dilated between 3 and 9 cm, and who had inadequate uterine contractions (two or fewer contractions every 10 minutes) during the first stage of labor, were randomly assigned to titrated oral misoprostol or intravenous oxytocin. Augmentation-to-vaginal delivery interval and vaginal delivery within 12 or 24 hours were the primary outcomes. The data were analyzed by intention to treat.

RESULTS

Of the 231 women, 118 (51.1%) were randomized to titrated oral misoprostol and 113 (48.9%) to titrated intravenous oxytocin. The median interval from the start of augmentation to vaginal delivery was 5.22 hours (3.77-8.58 hours, 25th-75th percentile) in the misoprostol group, and 5.20 hours (3.23-6.50 hours, 25th-75th percentile) in the intravenous oxytocin group (P=.019). Complete vaginal delivery occurred within 12 hours for 92 women (78.0%) in the misoprostol group and for 97 women (85.8%) in the oxytocin group (P=.121; relative risk 0.91, 95% confidence interval 0.80-1.03). There were no significant differences between the two groups who delivered vaginally within 24 hours. Side effects and neonatal outcomes also did not differ between the two groups.

CONCLUSION

Labor augmentation with titrated oral misoprostol or intravenous oxytocin resulted in similar rates of vaginal delivery within 12 and 24 hours.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00695331.

LEVEL OF EVIDENCE

I.

The effect of early oxytocin augmentation in labor: a meta-analysis

OBJECTIVE

To estimate the effects of early augmentation with oxytocin for slow progress of labor on the delivery method and on indicators of maternal and neonatal morbidity.

DATA SOURCES

We conducted electronic database searches of PubMed, MEDLINE, EMBASE, and the Cochrane Library for articles published through February 2009 using the keywords "oxytocin," "augmentation," "active management of labor," "cesarean section," and "labor." Primary authors were contacted directly if the data sought were unavailable.

METHODS OF STUDY SELECTION

We included randomized controlled trials comparing early oxytocin augmentation with a more conservative approach to care in labor. We included only those studies in which membrane management was similar in the two groups. Early oxytocin augmentation was defined as immediate oxytocin administration when dystocia was identified. Data were extracted by two authors independently and evaluated for potential sources of bias. Relative risk (RR) and 95% confidence interval (CI) were calculated using fixed and random effects models.

TABULATION, INTEGRATION, AND RESULTS

Nine trials with 1,983 women met the inclusion criteria. Early oxytocin was associated with an increase in the probability of spontaneous vaginal delivery (RR 1.09, 95% CI 1.03-1.17). For every 20 patients treated with early oxytocin augmentation, one additional spontaneous vaginal delivery is expected. Although the point estimate for the effect on cesarean delivery (RR 0.87, 95% CI 0.71-1.06) and on operative vaginal delivery (RR 0.84, 95% CI 0.70-1.00) showed modest protective effects, the CIs for both estimates included the null effect. A decrease in antibiotic use (RR 0.45, 95% CI 0.21-0.99) was observed with early intervention. Early oxytocin was associated with an increased risk of hyperstimulation (RR 2.90, 95% CI 1.21-6.94) without evidence of adverse neonatal effects. Women in the early oxytocin group reported higher levels of pain and discomfort in labor.

CONCLUSION

Early oxytocin for augmentation in labor is associated with an increase in spontaneous vaginal delivery.

Improving patient safety and uniformity of care by a standardized regimen for the use of oxytocin

Oxytocin is 1 of the most commonly used drugs in labor and has been associated with adverse maternal and fetal outcomes. In an attempt to improve patient safety, we constructed a standardized protocol for labor induction with oxytocin. We reviewed the numerous publications regarding oxytocin use for either induction or augmentation of labor in order to determine if there was a protocol available that would maximize success of delivery and minimize the adverse maternal and fetal effects of the drug. Using the literature review and the specific pharmacokinetics of oxytocin, we developed a standardized approach for the dilution and administration of oxytocin in order to improve patient safety, develop uniformity of the drug use, maximize its benefits, and minimize its side effects. We suggest that a standardized approach to oxytocin use be adopted that uses an oxytocin dilution of 10 mU/mL, initial dose of 2 mU/min (12 mL/hr), incremental increase of 2 mU (12 mL) every 45 minutes until adequate labor with the maximum dose being 16 mU/min (96 mL/hr).