Oxytocin administration during spontaneous labor: Guidelines for clinical practice. Chapter 2: Indications of oxytocin according the first and second stages of spontaneous labor

European Guidelines on Perinatal Care - Oxytocin for induction and augmentation of labor[Formula: see text]

OF RECOMMENDATIONS1. Oxytocin for induction or augmentation of labor should not be started when there is a previous scar on the body of the uterus (such as previous classical cesarean section, uterine perforation or myomectomy when uterine cavity is reached) or in any other condition where labor or vaginal delivery are contraindicated. (Moderate quality evidence +++-; Strong recommendation).2. Oxytocin should not be started before at least 1 h has elapsed since amniotomy, 6 h since the use of dinoprostone (30 min if vaginal insert) and 4 h since the use of misoprostol (Low quality evidence ++- -; Moderate recommendation).3. Cardiotocography (CTG) should be performed and a normal pattern without tachysystole should be documented for at least 30 min before oxytocin is used. Continuous CTG, with adequate monitoring of both fetal heart rate and uterine contractions, should be maintained for as long as oxytocin is used, and thereafter until delivery (Low ++- - to moderate +++- quality evidence; Strong recommendation).4. For labor induction, at least 1-h should be allowed after amniotomy before oxytocin infusion is started, to evaluate whether adequate uterine contractility has meanwhile ensued. For augmentation of labor, if the membranes are intact and there are conditions for a safe amniotomy, the latter should be considered before oxytocin is started (Very low quality evidence +- --; Weak recommendation).5. Oxytocin should be administered intravenously using the following regimen: 5 IU oxytocin diluted in 500 mL of 0.9% normal saline (NaCl) (each mL contains 10 mIU of oxytocin), in an infusion pump at increasing rates, as shown in Table 1, until a frequency of 3-4 contractions per 10 min is reached, a non-reassuring CTG pattern ensues, or maximum rates are reached (Low quality evidence ++ - -; Strong recommendation). If the frequency of contractions exceeds 5 in 10 min, the infusion rate should be reduced, even if a normal CTG pattern is present. With a non-reassuring CTG pattern, urgent clinical assessment by an obstetrician is indicated, and strong consideration should be given to reducing or stopping the oxytocin infusion. The minimal effective dose of oxytocin should always be used. (Low ++- - to Moderate +++- - quality evidence; Strong recommendation).[Table: see text]6. Use of oxytocin for induction and augmentation of labor should be regularly audited (Low quality evidence ++--; Strong recommendation).

The Role of Oxytocin in Primary Cesarean Birth Among Low-Risk Women

INTRODUCTION

To examine whether there is a threshold of oxytocin exposure at which the risk for primary cesarean increases among women who are nulliparous with a term, singleton, vertex fetus (NTSV) and how oxytocin interacts with other risk factors to contribute to this outcome.

METHODS

This was a secondary analysis of the Consortium on Safe Labor data set that used a retrospective cohort study design. Women who met the criteria for NTSV who were not admitted for a prelabor cesarean and for whom oxytocin data were available, were included in the sample. Robust logistic regression was used to examine the association of oxytocin exposure with primary cesarean birth, while controlling for demographic and clinical risk factors and clustering by provider.

RESULTS

The sample comprised 17,331 women who were exposed to oxytocin during labor. The women were predominantly white non-Hispanic (59.2%) with an average (SD) gestational age of 39.4 (1.1) weeks and an 18.5% primary cesarean rate. Exposure to greater than 11,400-milliunits (mU) of oxytocin resulted in 1.6 times increased odds of primary cesarean birth compared with less than 11,400 mU (95% CI 1.01-2.6).

DISCUSSION

Exposure to greater than 11,400 mU of oxytocin in labor was associated with an increased odds of primary cesarean birth in NTSV women.

Evaluation of the implementation of a protocol for the restrictive use of oxytocin during spontaneous labor

INTRODUCTION

Use of oxytocin is associated with uterine hyperstimulation and postpartum hemorrhage with a dose-dependent effect. We aimed to evaluate the effect of the implementation of a protocol for the restrictive use of oxytocin during spontaneous labor on obstetric and neonatal outcomes.

MATERIAL AND METHODS

We performed an observational before-and-after study among 2174 women in spontaneous labor with a term singleton cephalic fetus. Obstetric and neonatal outcomes were compared according to the period, before (period A) and after (period B) the implementation of a protocol for the restrictive use of oxytocin.

RESULTS

1235 women were included in period A and 939 in period B. Compared to period A, the use of oxytocin during period B was significantly lower (45.5 vs. 35.1%, p<0.001) in both nulliparous (61.2 vs 54.6%, p=0.04) and multiparous women (34.0 vs. 21.1%, p<0.001). Labor was significantly longer in period B, both in nulliparous (6.7 vs. 7.9 h, p<0.01) and multiparous women (4.1 vs. 4.5 h, p<0.01). A lower frequency of uterine hyperstimulation (6.6 vs. 2.7%, p=0.01) was observed in period B. The odds of instrumental and cesarean delivery were not different between the periods (respectively adjusted odds ratio (AOR), 95% confidence interval (CI), 1.1(0.8-1.4); 1.2(0.8-1.8)) including for nulliparous women (respectively, 1.3(0.9-1.7); 1.3(0.8-1.9)).

DISCUSSION

Reducing the use of oxytocin during spontaneous labor through the implementation of a protocol may reduce the iatrogenic effects without increasing the risk of caesarean section but this implies longer duration of labor.

[Oxytocin administration during spontaneous labour: Guidelines for clinical practice. Guidelines short text]

OBJECTIVES

To define the different stages of spontaneous labour. To determine the indications, modalities of use and the effects of administering synthetic oxytocin. And to describe undesirable maternal and perinatal outcomes associated with the use of synthetic oxytocin.

METHOD

A systematic review was carried out by searching Medline database and websites of obstetrics learned societies until March 2016.

RESULTS

The 1st stage of labor is divided in a latence phase and an active phase, which switch at 5cm of cervical dilatation. Rate of cervical dilatation is considered as abnormal below 1cm per 4hour during the first part of the active phase, and below 1cm per 2hours above 7cm of dilatation. During the latent phase of the first stage of labor, i.e. before 5cm of cervical dilatation, it is recommended that an amniotomy not be performed routinely and not to use oxytocin systematically. It is not recommended to expect the active phase of labor to start the epidural analgesia if patient requires it. If early epidural analgesia was performed, the administration of oxytocin must not be systematic. If dystocia during the active phase, an amniotomy is recommended in first-line treatment. In the absence of an improvement within an hour, oxytocin should be administrated. However, in the case of an extension of the second stage beyond 2hours, it is recommended to administer oxytocin to correct a lack of progress of the presentation. If dynamic dystocia, it is recommended to start initial doses of oxytocin at 2mUI/min, to respect at least 30min intervals between increases in oxytocin doses delivered, and to increase oxytocin doses by 2mUI/min intervals without surpassing a maximum IV flow rate of 20mUI/min. The reported maternal adverse effects concern uterine hyperstimulation, uterine rupture and post-partum haemorrhage, and those of neonatal adverse effects concern foetal heart rate anomalies associated with uterine hyperstimulation, neonatal morbidity and mortality, neonatal jaundice, weak suck/poor breastfeeding latch and autism.

CONCLUSION

The widespread use of oxytocin during spontaneous labour must not be considered as simply another inoffensive prescription without any possible deleterious consequences for mother or foetus. Conditions for administering the oxytocin must therefore respect medical protocols. Indications and patient consent have to be report in the medical file.