Abstract: We included no new trials in this update. We included four trials involving more than 13,000 women which were conducted in the UK and Ireland and included women in labour. Three trials were funded by the hospitals where the trials took place and one trial was funded by the Scottish government. No declarations of interest were made in two trials; the remaining two trials did not mention declarations of interest. Overall, the studies were assessed as low risk of bias. Results reported in the 2012 review remain unchanged. Although not statistically significant using a strict P < 0.05 criterion, data were consistent with women allocated to admission CTG having, on average, a higher probability of an increase in incidence of caesarean section than women allocated to intermittent auscultation (risk ratio (RR) 1.20, 95% confidence interval (CI) 1.00 to 1.44, 4 trials, 11,338 women, I² = 0%, moderate quality evidence). There was no clear difference in the average treatment effect across included trials between women allocated to admission CTG and women allocated to intermittent auscultation in instrumental vaginal birth (RR 1.10, 95% CI 0.95 to 1.27, 4 trials, 11,338 women, I² = 38%, low quality evidence) and perinatal mortality rate (RR 1.01, 95% CI 0.30 to 3.47, 4 trials, 11,339 infants, I² = 0%, moderate quality evidence). Women allocated to admission CTG had, on average, higher rates of continuous electronic fetal monitoring during labour (RR 1.30, 95% CI 1.14 to 1.48, 3 trials, 10,753 women, I² = 79%, low quality evidence) and fetal blood sampling (RR 1.28, 95% CI 1.13 to 1.45, 3 trials, 10,757 women, I² = 0%) than women allocated to intermittent auscultation. There were no differences between groups in other secondary outcome measures including incidence and severity of hypoxic ischaemic encephalopathy (incidence only reported) (RR 1.19, 95% CI 0.37 to 3.90; 2367 infants; 1 trial; very low quality evidence) and incidence of seizures in the neonatal period (RR 0.72, 95% CI 0.32 to 1.61; 8056 infants; 1 trial; low quality evidence). There were no data reported for severe neurodevelopmental disability assessed at greater than, or equal to, 12 months of age. Contrary to continued use in some clinical areas, we found no evidence of benefit for the use of the admission CTG for low-risk women on admission in labour. Furthermore, the probability is that admission CTG increases the caesarean section rate by approximately 20%. The data lacked power to detect possible important differences in perinatal mortality. However, it is unlikely that any trial, or meta-analysis, will be adequately powered to detect such differences. The findings of this review support recommendations that the admission CTG not be used for women who are low risk on admission in labour. Women should be informed that admission CTG is likely associated with an increase in the incidence of caesarean section without evidence of benefit. Evidence quality ranged from moderate to very low, with downgrading decisions based on imprecision, inconsistency and a lack of blinding for participants and personnel. All four included trials were conducted in developed Western European countries. One additional study is ongoing. The usefulness of the findings of this review for developing countries will depend on FHR monitoring practices. However, an absence of benefit and likely harm associated with admission CTG will have relevance for countries where questions are being asked about the role of the admission CTG. Future studies evaluating the effects of the admission CTG should consider including women admitted with signs of labour and before a formal diagnosis of labour. This would include a cohort of women currently having admission CTGs and not included in current trials.

Plain-language summary: We compared the admission CTG with intermittent auscultation of the FHR performed on the woman's admission to the labour ward. We searched for evidence to 30 November 2016 but found no new studies for this updated review (previously published in 2012). This review includes four studies and there is one study that is not yet complete. The included studies (carried out in the UK and Ireland) involved more than 13,000 women with low-risk pregnancies. Three trials were funded by the hospitals were the trials took place and one trial was funded by the Scottish government. Women allocated to admission CTG were probably more likely to have a caesarean section than women allocated to intermittent auscultation (moderate quality evidence). There was no difference in the number of instrumental vaginal births (low quality evidence) or in numbers of babies who died during or shortly after labour (moderate quality evidence) between women in the two groups. Admission CTG was associated with an increase in the use of continuous EFM (with an electrode placed on the baby’s scalp) (low quality evidence) and fetal blood sampling (a small blood sample taken from a baby's scalp) during labour. There were no differences in other outcomes measured such as artificial rupture of the membranes, augmentation of labour, use of an epidural, damage to the baby's brain due to lack of oxygen (very low quality evidence), or the baby having fits or seizures just after birth (low quality evidence). No studies reported if the babies developed any severe problems in brain or central nervous system growth and development after one year of age. Although many hospitals carry out CTGs on women when they are admitted to hospital in labour, we found no evidence that this benefits women with low-risk pregnancies. We found that admission CTGs may increase numbers of women having a caesarean section by about 20%. The included studies did not include enough women to show if admission CTGs or intermittent auscultation were better at keeping babies safe. However, studies to show which is better at keeping babies safe would have to be very large. Based on this review, low-risk pregnant women who have an admission CTG could be more likely to have a caesarean section. The benefits to these women of having an admission CTG are not certain. All of the included studies took place in developed Western European countries. The review findings might not be useful to people in very different countries or where different ways of FHR monitoring are used. However, countries that use admission CTGs should start to question why, because there are not clear benefits to using admission CTGs, and they could be causing women harm by making them more likely to have a caesarean section.