High-dose versus low-dose of oxytocin for labour augmentation: a randomised controlled trial.

PROBLEM: Delayed labour progress is common in nulliparous women, often leading to caesarean section despite augmentation of labour with synthetic oxytocin. BACKGROUND: High- or low-dose oxytocin can be used for augmentation of delayed labour, but evidence for promoting high-dose is weak. Aim To ascertain the effect on caesarean section rate of high-dose versus low-dose oxytocin for augmentation of delayed labour in nulliparous women. Methods Multicentre parallel double-blind randomised controlled trial (ClinicalTrials.gov: NCT01587625) in six labour wards in Sweden. Healthy nulliparous women at term with singleton cephalic fetal presentation, spontaneous labour onset, confirmed delay in labour and ruptured membranes (n=1351) were randomised to labour augmentation with either high-dose (6.6 mU/minute) or low-dose (3.3 mU/minute) oxytocin infusion. FINDINGS: 1295 women were included in intention-to-treat analysis (high-dose n=647; low-dose n=648). Caesarean section rates did not differ between groups (12.4% and 12.3%, 95% Confidence Interval -3.7 to 3.8). Women with high-dose oxytocin had: shorter labours (-23.4min); more uterine tachysystole (43.2% versus 33.5%); similar rates of instrumental vaginal births, with more due to fetal distress (43.8% versus 22.7%) and fewer due to failure to progress (39.6% versus 58.8%). There were no differences in neonatal outcomes. DISCUSSION: Our study could not confirm results of two systematic reviews indicating, with weak evidence, that use of high-dose oxytocin was associated with lower frequency of caesarean section. CONCLUSION: We found no advantages for routine use of high-dose oxytocin in the management of delay in labour. Low-dose oxytocin regimen is recommended to avoid unnecessary events of tachysystole and fetal distress.

Transvaginal sonographic evaluation of cervical length in the second trimester of asymptomatic singleton pregnancies, and the risk of preterm delivery.

OBJECTIVE: To evaluate cervical length in asymptomatic women with singleton pregnancies in the second trimester by means of transvaginal ultrasonography, and to examine the relation between cervical length and spontaneous preterm delivery. DESIGN: Observational, prospective study. SETTING: A university hospital and a county hospital in Western Sweden. POPULATION: A total of 2122 asymptomatic women with live singleton pregnancies without fetal anomalies. METHODS: Cervical length was measured at between 16 and 23 weeks of gestation by means of transvaginal ultrasonography. Data were analysed using logistic regression analysis. MAIN OUTCOME MEASURES: Cervical length in relation to spontaneous preterm delivery <34 weeks (primary outcome) and <37 weeks of gestation (secondary outcome). RESULTS: Eleven women had a cervical length of ≤25 mm (0.5%) and 73 women had a cervical length of ≤30 mm (3.4%). Spontaneous preterm delivery at <34 weeks occurred in 22/2061 women (1.1%) and at <37 weeks in 87/2061 women (4.2%). There was a significant association between cervical length and spontaneous preterm delivery at <34 weeks (odds ratio 1.78; 95% confidence interval 1.19-2.65 for a decrease of cervical length by 5 mm) but no significant association at <37 weeks. CONCLUSIONS: The rate of short cervical length of ≤25 mm was lower than expected. The study confirmed the increased risk of spontaneous preterm delivery in women with a short cervix, although the analysis was based on only a few cases. In Sweden, a larger study is needed to evaluate the prevalence of short cervical length and the possible association with preterm delivery before universal screening can be recommended.

Nitroglycerin for management of retained placenta: a multicenter study.

The primary aim was to determine if sequential administration of oxytocin and nitroglycerin is effective for management of retained placenta when performed by obstetricians with no experience of the method. Secondary aims were to examine possible adverse effects of nitroglycerin. One hundred and five women with retained placenta were randomly selected to receive either 1 mg nitroglycerin or placebo tablets sublingually if intravenous oxytocin had failed to expel the placenta. At two of the hospitals some of the midwives were familiar with the use of nitroglycerin. The other midwives and all the participating obstetricians had no clinical experience of the method. In the treatment group, detachment of placenta following nitroglycerin occurred in 37.3% of the women compared to 20.4% in the placebo group (P = 0.056). In the two hospitals with some experience of the method, placenta was removed in 9 of 19 (47.4%) women in the nitroglycerin group compared to 3 of 17 (15.0%) women in the placebo group. No adverse effects of clinical importance were registered. Although the difference between the two groups did not reach statistical significance, the higher success rate in the two hospitals with some experience could indicate that clinical experience is of importance in order to achieve placental detachment.

Use and abuse of oxytocin for augmentation of labor.

OBJECTIVE: To investigate the use of oxytocin for augmentation of labor and its relation to labor progress and delivery outcome. DESIGN AND SETTING: A retrospective observational study undertaken in a Swedish hospital during 2000-2001. SAMPLE: Singleton pregnancies at > or = 37 weeks of gestation with cephalic presentation and spontaneous onset of labor. METHODS: Data were collected from 1,263 clinical records. The partogram was used to diagnose labor dystocia (LD). MAIN OUTCOME MEASURES: Prevalence of oxytocin administration, LD and operative delivery. RESULTS: Oxytocin was administered to 55% of the women (75% of primiparas and 38.1% of multiparas); a majority did not meet LD criteria. LD frequency was 19.8% (32.7% in primiparas and 7.4% in multiparas). Oxytocin was started both 'too early' and 'too late' in relation to the diagnosis of LD. Cesarean section (CS) was performed on 17.1% of primiparous and 2.4% of multiparous oxytocin recipients with LD, compared to 2.3 and 1.5%, respectively, of oxytocin recipients without diagnosed LD. CONCLUSIONS: Oxytocin augmentation was undertaken in an unstructured manner; some women were inadequately treated and others were treated unnecessarily. Oxytocin recipients with LD underwent operative delivery to a higher extent than oxytocin recipients without LD, suggesting that the main reason for CS was the underlying problem of LD rather than the oxytocin augmentation itself.