Reducing neonatal morbidity by discontinuing oxytocin during the active phase of first stage of labor: a multicenter randomized controlled trial STOPOXY

Feasibility Study to Compare Oxytocin Function Between Body Mass Index Groups at Term Labor Induction

OBJECTIVE

To determine the feasibility of a protocol to examine the association between oxytocin system function and birth outcomes in women with and without obesity before induction of labor.

DESIGN

Prospective descriptive.

SETTING

Academic medical center in the U.S. Midwest.

PARTICIPANTS

Pregnant women scheduled for induction of labor at 40 weeks of gestation or greater (n = 15 normal weight; n = 15 obese).

METHODS

We collected blood samples and abstracted data by chart review. We used percentages to examine adherence to protocol. We used t tests and chi-square tests to describe differences in sample characteristics, oxytocin system function variables, and birth outcomes between the body mass index groups.

RESULTS

The recruitment rate was 85.7%, protocol adherence was 97.1%, and questionnaire completion was 80.0%. Mean plasma oxytocin concentration was higher in the obese group (M = 2774.4 pg/ml, SD = 797.4) than in the normal weight group (M = 2193.5 pg/ml, SD = 469.8). Oxytocin receptor DNA percentage methylation (CpG -934) was higher in the obese group than in the normal weight group.

CONCLUSION

Our protocol was feasible and can serve as a foundation for estimating sample sizes in forthcoming studies investigating the diversity in oxytocin system measurements and childbirth outcomes among pregnant women in different body mass index categories.

Impact of discontinuing oxytocin in active labour on neonatal morbidity: an open-label, multicentre, randomised trial

BACKGROUND

Oxytocin is effective in reducing labour duration but can be associated with fetal and maternal complications that could potentially be reduced by discontinuing the treatment during labour. We aimed to assess the impact of discontinuing oxytocin during active labour on neonatal morbidity.

METHODS

STOPOXY was a multicentre, randomised, open-label, controlled, superiority trial conducted in 21 maternity units in France. Participants who received oxytocin before 4 cm dilation were randomly assigned 1:1 to either discontinuous oxytocin (oxytocin infusion stopped beyond a cervical dilation equal to or greater than 6 cm) or continuous oxytocin (administration of oxytocin continued until delivery). Randomisation was stratified by centre and parity. The primary outcome, neonatal morbidity, was assessed at birth using a composite variable defined by an umbilical arterial pH at birth less than 7·10, a base excess greater than 10 mmol/L, umbilical arterial lactates greater than 7 mmol/L, a 5-min Apgar score less than 7, or admission to the neonatal intensive care unit. Efficacy and safety was assessed in participants who were randomly assigned (excluding those who withdrew consent or were deemed ineligible after randomisation) and had reached a cervical dilation of at least 6 cm. This trial is registered with ClinicalTrials.gov, NCT03991091.

FINDINGS

Of 2459 participants randomly assigned between Jan 13, 2020, and Jan 24, 2022, 2170 were eligible to receive the intervention and were included in the final modified intention-to-treat analysis. The primary outcome occurred for 102 (9·6%) of 1067 participants (95% CI 7·9 to 11·5) in the discontinuous oxytocin group and for 101 (9·2%) of 1103 participants (7·6 to 11·0) in the continuous oxytocin group; absolute difference 0·4% (95% CI -2·1 to 2·9); relative risk 1·0 (95% CI 0·8 to 1·4). There were no clinically significant differences in adverse events between the two groups of the safety population.

INTERPRETATION

Among participants receiving oxytocin in early labour, discontinuing oxytocin when the active phase is reached does not clinically or statistically significantly reduce neonatal morbidity compared with continuous oxytocin.

FUNDING

French Ministry of Health and the Département de la Recherche Clinique et du Développement de l'Assistance Publique-Hôpitaux de Paris.

In-Depth Analysis of Caesarean Section Rate in the Largest Secondary Care-Level Maternity Hospital in Latvia

There is no surgical intervention without risk. A high rate of caesarean sections (CSs) impacts on maternal and newborn mortality and morbidity. For optimisation of the CS rate, regular monitoring is necessary. In 2015, the World Health Organization recommended the Robson classification as a global standard for assessing, monitoring, and comparing CS rates. We analysed all births in 2019 in the Riga Maternity Hospital-a secondary-level monodisciplinary perinatal care hospital in Latvia-according to the Robson classification, seeking to identify which groups make the biggest contribution to the overall CS rate. In total, 5835 women were included. The overall CS rate was 21.5%. In our study, the largest contributors to the overall CS rate were as follows: Group 5 (33.3%); Group 2 (20.8%); and Group 1 (15.6%). The results of our deeper analysis of individual groups (Group 1 and 5) from our study may help to develop targeted interventions for specific subgroups of the obstetric population, effectively reducing both the overall rate of CS and the number of unnecessary CSs performed. The CS rate reduction strategy should be based on decreasing CSs in Group 1 and encouraging VBAC, thus decreasing the number of women undergoing two or more CSs in future.

Continued versus discontinued oxytocin after the active phase of labor: An updated systematic review and meta-analysis

Objective

To systematically assess the effect of discontinued vs continued oxytocin after active stage of labour is established.

Methods

Pubmed, Embase, and the Cochrane Library were systematically searched to 18 April 2021. The risk ratio or mean difference with corresponding 95% confidence interval were computed to investigate the effect of intervention or control on maternal and fetus outcomes. This review was registered in the International Prospective Register of Systematic Reviews: CRD42021249635.

Results

Discontinuing oxytocin when the active labour was established might decrease the risk of cesarean delivery [RR (95% CI): 0.84 (0.72–0.98), P = 0.02]. However, when we restricted our analysis to women who performed cesarean section after the active phase was reached, the difference was no longer significant [RR (95% CI): 0.82 (0.60–1.10), P = 0.19]. The incidence of uterine tachysystole [RR (95% CI): 0.36 (0.27–0.49)], postpartum hemorrhage [RR (95% CI): 0.78 (0.65–0.93)], and non-reassuring fetal heart rate [RR (95% CI): 0.66 (0.58–0.76)] were significantly lower in the oxytocin discontinuation group. We also found a possible decrease in the risk of chorioamnionitis in discontinued oxytocin group [RR (95% CI): 2.77 (1.02–5.08)]. An increased duration of active [MD (95% CI): 2.28 (2.86–41.71)] and second [MD (95% CI): 5.36 (3.18–7.54)] phase of labour was observed in discontinued oxytocin group, while the total delivery time was not significantly different [MD (95% CI): 20.17 (-24.92–65.26)].

Conclusion

After the active labor is reached, discontinuation of oxytocin could be considered a new recommendation for the improved maternal and fetal outcomes without delaying labour.

Impacted fetal head: A retrospective cohort study of emergency caesarean section

OBJECTIVE

To investigate risk factors, management and outcomes of impacted fetal head (IFH) at caesarean section (CS).

STUDY DESIGN

This is a retrospective cohort study of all women with singleton, cephalic pregnancies who had an emergency CS during one-year (2016) at North Bristol NHS Trust, UK (n = 838). The incidence of caesarean section at full dilatation (CSFD) and IFH were calculated using the annual birth rate. To identify risk factors for IFH, maternal, perinatal and intrapartum characteristics were compared according to the presence or absence of IFH, and separately for first- and second-stage CS. Techniques employed to disimpact the fetal head were described. Univariable and multivariable comparisons of maternal and perinatal outcomes were made between cases with and without an IFH. Characteristics and outcomes were compared using modified Poisson regression.

RESULTS

CSFD accounted for 2.1 % of all births. IFH complicated 1.5 % of all births (11.3 % of emergency CS), with 55.8 % occurring prior to full cervical dilatation. Increased rates of IFH at CS were associated with: oxytocin augmentation (RR = 2.47 [1.61-3.80]), full cervical dilatation (RR = 4.24 [2.96-6.07], mid/low station (RR = 4.14 [2.72-6.32]), moulding (RR = 4.39 [2.55-7.54]) and caput (RR = 6.60 [3.09-14.10]). Junior operators documented IFH more than consultants (RR = 9.61 [1.35-68.2]). The strategies recorded for managing IFH included: tocolysis, reverse breech extraction and vaginal push up (33.7 %, 14.7 % and 11.6 % cases respectively) with two or more techniques used in 21.1 % cases. IFH at CS was independently associated with an increased risk of uterine extensions (RR = 3.09 [1.96-4.87]) and a composite adverse perinatal outcome (RR = 1.66 [1.21-2.28]).

CONCLUSIONS

IFH is a common and heterogeneous complication associated with increased complications for both mother and baby, independent of those of CSFD. Obstetricians must remain vigilant to the possibility of IFH at all emergency CS, particularly those at full cervical dilatation or with evidence of obstructed labour. There is an urgent need for a standardised management algorithm and training in evidence-based disimpaction techniques.