Table 1. Characteristics of included studies.

Author, year, country	Aim of study	Design and study population	Information of interest
Studies describing devices and modes of performing intermittent auscultation (IA)
Smith et al, 2019, Ireland [38]	Compare the effect on caesarean section rates of admission CTG vs. IA	RCT 3034 low-risk women in labour (1513 IA, 1521 admission CTG)	Descriptions of IA practices (device, frequency, timing, duration)
Kamala et al, 2018, Tanzania [37]	Compare continuous fetal heart rate monitoring using the Moyo strap-on monitor with IA using a Pinard for the detection of FHR abnormalities	Pre- and post-intervention study. 1640 low-risk women monitored with a Pinard and 2442 with a Moyo device	Descriptions of IA practice (device, frequency, timing, abnormal FHR)
Maude et al, 2014, NZ [9]	Describe the implementation of the Intelligent Structured Intermittent Auscultation (ISIA) framework in one maternity unit	Mixed method pre- and post-intervention study. Audit of 511 medical records before intervention and 422 after intervention	Descriptions of IA practices (device, frequency, timing, duration, definitions of normal and abnormal FHR, assessments of uterine contractions, fetal movements and maternal pulse). Presentation and evaluation of a decision-making framework for fetal heart monitoring in low-risk women
Rathore et al, 2011, India [19]	Evaluate fetal scalp stimulation test as an adjunct to IA in diagnosis of intrapartum fetal acidosis	Prospective observational cohort 750 women in labour, with fetal heart abnormalities and/or thick meconium stained amniotic fluid	Descriptions of IA practices (device, frequency, timing, duration)
Maude et al, 2009, NZ [17]	Explore the fetal heart rate monitoring practices of midwives and doctors and determine compliance with a NZ evidence-based guideline for fetal heart monitoring	Retrospective audit of 193 randomly selected medical records undertaken over six months in 2006	Descriptions of IA practices (device, frequency, timing, duration, definitions of normal and abnormal FHR, assessments of uterine contractions, fetal movements and maternal pulse, documentation practices for IA).
Soltani, 2009, Iran [20]	Present and evaluate a new electronic device for IA	Presentation of a new device for IA, with evaluations from 28 medical trainees	Description of a device for IA, a Personal Digital Assistant, an electronic stethoscope attached to a hand-held computer.
Madaan & Trivedi, 2006, India [21]	Compare the effect of EFM and IA for intrapartum fetal monitoring	RCT 100 women included (50 EFM, 50 IA), with post caesarean pregnancies and no contraindications for a vaginal delivery	Descriptions of IA practices (frequency, timing, duration, definition of abnormal FHR)
Impey et al, 2003, Ireland [22]	Compare the effect on neonatal outcome of admission CTG vs. IA	RCT 8580 low-risk women included (4320 admission CTG, 4308 IA)	Descriptions of IA practices (frequency, timing, duration)
Mires et al, 2001, UK [23]	Compare the effect on neonatal outcome of admission CTG vs. IA and levels of obstetric interventions in a low-risk obstetric population	RCT 3751 low-risk women included (1866 admission CTG, 1885 IA)	Descriptions of IA practices (device, duration)
Gilles et al, 1997, Australia [25]	Survey the use of IA throughout maternity units in Western Australia, compare protocols and suggest a protocol for use in women with low-risk labours	Survey to all hospitals in Western Australia	Descriptions of IA practices (frequency, definition abnormal FHR). A new protocol for IA based on review of practices and research literature
Vintzileos et al, 1993, Greece [27]	Compare the effect on neonatal outcome of EFM vs. IA	RCT 1428 women with singleton living fetus and gestational age ≥26 weeks included (746 EFM, 682 IA).	Description of IA practices (device, frequency, timing, duration, definition of abnormal FHR, assessments of uterine contractions)
Luthy et al, 1987, Canada and USA [28]	Compare the effect on neonatal outcome of EFM vs. IA	RCT 246 women with preterm singleton pregnancies with fetal weights 700–1750 g included (122 EFM. 124 IA)	Description of IA practices (device, frequency, timing, duration,definition of normal FHR, definition of abnormal FHR, assessments of uterine contractions)
Neldam et al, 1986, Denmark [29]	Compare the effect on maternal and neonatal outcome of EFM vs. IA	RCT 969 low- and high-risk women included (482 EFM, 487 IA)	Description of IA practices (device, frequency, timing, duration, definition of normal baseline, definition of abnormal FHR)
MacDonald et al, 1985, Ireland [4]	Compare the effect on maternal and neonatal outcome of EFM vs. IA	RCT 12964 women with a live fetus and gestational age ≥ 28 weeks were included (6474 EFM, 6490 IA)	Description of IA practices (devise, frequency, duration, definition of abnormal FHR)
Appelgate et al, 1979, USA [31] and Haverkamp et al, 1976, USA [33]	Compare the effect on maternal and neonatal outcome of EFM vs. IA	RCT 483 high-risk women included (242 EFM, 241 IA)	Description of IA practices (frequency, timing, duration, definition of normal baseline, definition of abnormal FHR)
Haverkamp et al, 1979, USA [32]	Compare the effect on maternal and neonatal outcome of EFM alone or EFM with option to FBS or IA	RCT 669 high-risk women included (220 EFM alone, 223 EFM with option to FBS, 226 IA)	Description of IA practices (frequency, timing, duration, definition abnormal FHR)
Kelso et al, 1978, UK [34]	Compare the effect on maternal and neonatal outcome of EFM vs. IA	RCT 504 low-risk women included (253 EFM, 251 IA)	Description of IA practices (device, frequency, timing, duration, definition normal baseline)
Studies describing devices and modes of performing, and assessing the effect of different modes of IA
Kamala et al, 2018, Tanzania [15]	Compare the effect on maternal and neonatal outcome of IA with Doppler device vs. IA with Pinard	RCT 2844 women with cephalic presentation, gestational age ≥ 37 weeks and normal FHR at admission included (1421 Doppler, 1423 Pinard)	Description of IA practices (device, frequency, timing, definition of abnormal baseline). Effects of Doppler device vs. Pinard (detection of abnormal FHR, caesarean section, Apgar score < 7 at 5 min, bag mask ventilation attempted, admission to neonatal unit, fresh stillbirth, perinatal death, composite outcome)
Mdoe et al, 2018, Tanzania [16]	Compare the effect on maternal and neonatal outcome of IA with Doppler device vs. IA with Pinard	RCT 2684 women with cephalic presentation, gestational age ≥ 36 weeks and normal FHR at admission included (1309 Doppler device, 1375 Pinard)	Description of IA practices (device, definition of normal and abnormal baseline. Effects of Doppler device vs. Pinard (detection of abnormal FHR, time interval abnormal FHR to birth, caesarean section, bag mask ventilation, Apgar score <7 at 1 and 5 min, fresh stillbirth, early neonatal death, admitted to neonatal area, adverse perinatal outcome)
Byaruhanga et al, 2015, Uganda [18]	Compare the effect on maternal and neonatal outcome of IA with Doppler device vs. IA with Pinard	RCT 1971 women with a singleton pregnancy, in a cephalic position with gestational age > 37 weeks (992 Doppler device, 979 Pinard)	Description of IA practices (device, frequency, timing, duration, how FHR was counted, definition of normal baseline, definition of abnormal FHR, assessment of maternal pulse) Effects of Doppler device vs. Pinard (detection of abnormal FHR, Apgar score < 7 at 5 min, admission to special care unit, neonatal encephalopathy, caesarean section)
Mahomed et al, 1994, Zimbabwe [26]	Compare the effect on maternal and neonatal outcome of IA with Doppler device by a research midwife, Pinard by a research midwife, Pinard by midwife on duty or intermittent CTG	RCT 1255 high- and low-risk women with a singleton pregnancy, in a cephalic position, gestational age >37 weeks, singleton, cephalic present, with normal FHR at admission were included (312 Doppler device by research midwife, 310 Pinard by research midwife, 315 Pinard by midwife on duty, 318 intermittent CTG)	Description of IA practices (device, frequency, timing) Effects of Doppler device vs. Pinard (duration of labour, caesarean section, assisted vaginal delivery, spontaneous vaginal delivery, Apgar score <6 at 5 min, fits in neonatal unit, hypoxic encephalopathy, stillbirth or neonatal death)
Studies assessing the accuracy of IA
Simpson et al, 1999, Canada [24]	Investigate if the accuracy of auscultation could be improved with the use of a heart rate meter	Accuracy study 15 experienced nurses and 15 obstetric residents were asked to assess six FHR recordings/traces by counting alone, counting with the help of a meter and visual assessment	Description of the accuracy of baseline variability, periodic changes and if the FHR pattern was assessed as reassuring or non-reassuring when counting alone and counting by the help of a meter
Strong & Jarles, 1992, USA [36]	Evaluate current practice of auscultation on the detection of decelerations	Accuracy study 120 nurses and physicians were asked to assess an intrapartum FHR recording containing a deceleration	Description of accuracy of baseline, deceleration nadir and deceleration duration
Miller et al, 1984, USA [30]	Define what characteristics of FHR and FHR patterns can be recognised by IA	Accuracy study 16 nurses and 16 physicians were asked to assess eight intrapartum FHR recordings containing a contraction	Descriptions of accuracy of baseline, accelerations without periodic change and non-uniform), saltatory pattern, decelerations (early, variable, late with good variability and late with diminished variability
Day et al, 1968, Australia [35]	Determine accuracy and usefulness of clinical measurement of the FHR	Accuracy study A trained midwife, a resident obstetrician and two medical students did clinical auscultations (126 observations in 90 women)	Descriptions of auscultation errors (random error, error biased towards normality, error based on inability to count during contractions)