Cochrane review finds that use of cardiotocograph on admission to the labour ward, rather than intermittent auscultation of the fetal heart rate, may increase risk of caesarean in low-risk women
- Correspondence to Kleanthi Gourounti
Department of Midwifery, Technological Educational Institution, Ag Spyridonos Athens 12210, Greece;
Implications for practice and research
Healthcare professionals should inform women with low obstetric risk factors that intrapartum admission cardiotocography (CTG) increases the likelihood of caesarean section (CS) with no evidence for neonatal benefit.
Future trials with adequate power to detect an impact on perinatal mortality are needed.
The effect of admission CTG on holistic-oriented outcomes (eg, women's labour satisfaction) should be explored.
Admission CTG is a short, usually 20-min, recording of the fetal heart rate immediately after admission to the labour ward that aims to identify a group of women at greater risk of intrapartum fetal hypoxia. It was used by approximately 79% of maternity units in the UK in 2000,1 by all Swedish maternity units in 20082 and by 89% of US hospitals in 2004.3 According to a number of guidelines, admission CTG should be recommended for high-risk pregnant women only.4 ,5 A previous systematic review (SR)5 concluded that admission CTG should not be used routinely in low-risk pregnant women until firm conclusions concerning the effects of the admission CTG on maternal, and specially, on neonatal outcomes, are drawn. Devane et al provide the best current evidence regarding the effects of admission CTG compared with intermittent auscultation on maternal and neonatal outcomes for low-risk pregnant women on admission to the labour ward.
Devane et al conducted a Cochrane Systematic Review identifying four randomised trials with 13 296 participants. Of the four trials, one included women in whom the liquor was known to be clear. There was no reporting on the presence of clear liquor in the other three trials. Due to the evidence of clinical heterogeneity of the studies (presence or not of clear liquor), random-effects meta-analytic techniques were conducted. All studies included low-risk women with the exception of one study, where a relatively small (5%) proportion of women with a previous CS and prior to 37 gestational weeks were included. Devane et al had requested data for the low risk sub-group of this trial, and these data were used in the main analyses of the review.
Compared with women allocated to intermittent auscultation, women allocated to admission CTG were more likely to experience continuous electronic fetal monitoring, fetal blood sampling during labour and caesarean section as mode of birth. There was no statistically significant difference in rates of instrumental vaginal birth, amniotomy, oxytocin for augmentation of labour, epidural, Apgar score <7 at the fifth minute after delivery, hypoxic ischaemic encephalopathy, admission to neonatal intensive care units, neonatal seizures, evidence of neonatal multiple multi-organ compromise 24 h after delivery, and fetal and neonatal deaths.
Although the admission CTG remains in widespread use, this SR concluded that admission CTG should not be routinely offered in low-risk women as it increases the risk of CS and there is no evidence of neonatal benefit. Nevertheless, the authors noted that these findings should be interpreted with caution since the data lacked power, as a sample size of more than 100 000 is required to detect possible important differences in perinatal mortality. However, this SR supports the recommendations of the current guidelines for selective use of CTG monitoring4 ,5 and confirms the findings of a previous SR.6 Limited attention has been paid to the effect of admission CTG on other important outcomes such as women's satisfaction with labour and healthcare professionals. Evidence regarding the cost-effectiveness of admission CTG is also needed to further inform clinical policy and decision making.