Fetal Scalp Stimulation Versus Fetal Blood Sampling in Labour
- Conditions
- Intrapartum Fetal Distress
- Interventions
- Diagnostic Test: Fetal Blood Sampling (FBS)Diagnostic Test: digital Fetal Scalp Stimulation (dFSS)
- Registration Number
- NCT05306756
- Lead Sponsor
- University of Dublin, Trinity College
- Brief Summary
Pregnant women have routine monitoring of the baby's heart rate when in labour. Women with complicated pregnancies require continuous monitoring using an electronic recorder called a CTG. The CTG produces a paper based recording which is interpreted by the midwife as showing normal, suspicious or abnormal features of the baby's heart rate. Babies quite commonly demonstrate abnormal features from time to time during the course of labour. In some cases the abnormal features are of sufficient concern to warrant delivery by emergency caesarean section. In most of these cases the baby is born in good condition and the question arises whether the caesarean section was unnecessary. In order to reduce the chance of an unnecessary caesarean section additional "second-line" tests can be offered. One such test is where a small drop of blood is taken from the baby's scalp. This test involves an internal examination with an instrument to visualise the baby's head and a small scratch to the baby's scalp. The blood is tested for acid which is an indicator of whether or not the baby is receiving enough oxygen. The test is called a fetal blood sample or FBS. An alternative test is where the doctor or midwife performs a vaginal examination with two fingers and gently rubs the baby's scalp in an attempt to cause an increase in the baby's heart rate. This is a healthy response suggesting that the baby is receiving enough oxygen. The test is called digital fetal scalp stimulation or dFSS. These two "second-line" tests have never been compared in a properly conducted head-to-head comparison. This study aims to compare dFSS and FBS in a large clinical trial completed within four of Ireland's largest maternity hospitals. This trial will generate important evidence of direct relevance to clinical care and patient outcomes.
- Detailed Description
Continuous electronic fetal heart rate recording with cardiotocography (CTG) is a standard approach to monitoring fetal wellbeing in labour and is recommended for high-risk pregnancies. The aim is to identify fetal compromise early and intervene in order to reduce serious adverse events such as cerebral palsy and perinatal death. CTG abnormalities are relatively common and can lead to the decision to deliver by emergency caesarean section. In most cases the fetus is subsequently found to have been compensating for the stress of labour and is not actually compromised. Fetal blood sampling (FBS) is a second-line invasive test that provides information on the acid-base status of the fetus, reflecting hypoxia. It is used to provide either reassurance that labour can continue, or more objective evidence that delivery needs to be expedited. Clinical guidelines in the United Kingdom and Ireland have treated FBS as a gold standard test. Recent studies have questioned the validity and reliability of FBS, and also the logistic challenges of achieving a result in a timely manner. Fetal scalp stimulation (dFSS) by digital rubbing is an alternative less invasive test of fetal wellbeing in labour and is recommended in preference to FBS in US guidelines. This research aims to compare digital FSS and FBS in women with term singleton pregnancies and an abnormal intrapartum CTG, where additional information on fetal wellbeing is required. A multi-centre randomised controlled trial will be conducted. The clinical outcomes of interest will include caesarean section, assisted vaginal birth, low Apgar scores, cord blood acidosis, and admission to the neonatal unit. This trial will generate important evidence of direct relevance to clinical care and patient outcomes.
Recruitment & Eligibility
- Status
- TERMINATED
- Sex
- Female
- Target Recruitment
- 40
- Nulliparous women
- Singleton pregnancy
- Cephalic presentation
- Gestational age 37+0 weeks or greater
- Abnormal CTG that requires second-line testing (FBS or dFSS)
- Contraindication to FBS
- Limited understanding of English
- At the discretion of the responsible obstetrician in cases where there is urgency
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Fetal Blood Sampling (FBS) Fetal Blood Sampling (FBS) Fetal capillary blood samples will be collected in heparinised tubes and analysed in the delivery suite using the locally available gas analyser. The result of the first technically reliable sample, or the lowest reliable sample if multiple samples are tested, will be interpreted and acted upon according to the protocol, taking account of the clinical circumstances and the stage of labour: pH ≥7.25 normal, continue and if indicated repeat in 60 minutes; pH 7.21-7.24 borderline, repeat in 30 minutes; pH ≤ 7.20 abnormal, deliver. digital Fetal Scalp Stimulation (dFSS) digital Fetal Scalp Stimulation (dFSS) The examiner will stimulate the fetal scalp digitally with the index and middle finger over a period of 30-60 seconds.The CTG will be observed over a 5-10 minutes interval after the dFSS and if a fetal heart rate acceleration (\>15 bpm for 15 seconds) is observed the test will be considered normal. If there is an episode of normal variability (5-25 bpm) but there is no clear acceleration, the test will be considered borderline. If there is no FHR acceleration and no episode of normal variability with ongoing abnormal features, the test should be interpreted as abnormal in the same way as an abnormal FBS result. FHR acceleration normal, if indicated repeat in 60 min; Uncertain acceleration/ normal variability borderline, repeat in 30 minutes; No Acceleration/ongoing abnormal features abnormal, deliver.
- Primary Outcome Measures
Name Time Method Caesarean section (CS) at birth All caesarean sections will be in labour in the context of an abnormal CTG
- Secondary Outcome Measures
Name Time Method Spontaneous Vaginal Birth (SVB) at birth unassisted birth
Decision Delivery Interval (DDI) for AVB >15 minutes during labour up until time of birth Decision delivery interval prolonged
Major obstetric haemorrhage >1000mL up to 24 hours after birth postpartum haemorrhage
Obstetric Anal Sphincter Injury (OASI - all degrees) at birth injury either spontaneous or with episiotomy
Assisted vaginal birth, primary indication poor progress at birth Poor progress in second stage of labour
Abnormal neurological examination prior to discharge at time of hospital discharge, assessed up to 28 days after birth clinical assessment recording abnormal findings - tone, reflexes, gag
Perinatal death up to 7 days of age intrapartum or early neonatal death
Caesarean section, primary indication poor progress at birth Poor progress in first or second stage of labour
Caesarean section, failed attempt at assisted vaginal birth at birth Failed vacuum or forceps in second stage of labour
Assisted vaginal birth, primary indication fetal concerns at birth abnormal CTG, or meconium, or low pH on FBS
Late perinatal death 8-28 days of life after 7 days up to 28 days of age
pH umbilical artery <7.00 or Base Excess artery <-12.0 immediately after birth arterial cord blood acidosis
Admission to neonatal unit (NNU) from birth up until 28 days admission all causes
Therapeutic hypothermia indicated within 6 hours of birth treatment for encephalopathy
Caesarean section , primary indication fetal concerns at birth abnormal CTG, or meconium, or low pH on FBS
Assisted vaginal birth (AVB) (all cases) at birth Vacuum or forceps or sequential (vacuum and forceps)
Decision Delivery Interval (DDI) for emergency CS >30 minutes during labour up until time of birth Decision delivery interval prolonged
Number of inconclusive/uninterpretable dFSS procedures during labour up until birth no clear acceleration or variability borderline
Neonatal encephalopathy (as defined by authors) from birth up until 28 days protocol definition
Maternal acceptability of procedure (defined by questionnaire) from birth up to 7 days after birth acceptability
Apgar score at 5 minutes <7 age 5 minutes low Apgar score at 5 minutes
FBS related injury/complication to baby (as reported on neonatal examination) at birth or with first 7 days of life traumatic injury or abnormal bleeding
Referral to perinatal mental health services from birth up to six weeks after birth psychological symptoms warranting referral
Number of second-line tests (dFSS or FBS) during labour up until birth each event (rather than samples taken)
Number of failed FBS procedures during labour up until birth no sample or reliable result achieved
Trial Locations
- Locations (1)
Coombe Women & Infants University Hospital
🇮🇪Dublin, Ireland