title: Foetal scalp blood sampling during labour for pH and lactate measurements.
abstract: Second-line methods of foetal monitoring have been developed in an attempt to reduce unnecessary interventions due to continuous cardiotocography (CTG), and to better identify foetuses that are at risk of intrapartum asphyxia. Very few studies directly compared CTG with foetal scalp blood (FBS) and CTG only. Only one randomised controlled trial (RCT) was published in the 1970s and had limited power to assess neonatal outcome. Direct and indirect comparisons conclude that FBS could reduce the number of caesarean deliveries associated with the use of continuous CTG. The main drawbacks of FBS are its invasive and discontinuous nature and the need for a sufficient volume of foetal blood for analysis, especially for pH measurement, resulting in failure rates reaching 10%. FBS for lactate measurement became popular with the design of test-strip devices, requiring <0.5 mL of foetal blood. RCTs showed similar outcomes with the use of FBS for lactates compared with pH in terms of obstetrical interventions and neonatal outcomes. In conclusion, there is some evidence that FBS reduces the need for operative deliveries. However, the evidence is limited with regard to actual standards, and large RCTs, directly comparing CTG only with CTG with FBS, are still needed.
authors.affiliation: Department of Obstetrics and Gynaecology, Centre Hospitalier Princesse Grace, Monaco; Department of Obstetrics and Gynecology, Hôpital Trousseau, Assistance Publique des Hôpitaux de Paris, Paris, France. Electronic address: bruno.carbonne@chpg.mc.
authors.forename: Bruno
authors.initials: B
authors.lastname: Carbonne
authors.affiliation: Department of Obstetrics and Gynecology, Hôpital Trousseau, Assistance Publique des Hôpitaux de Paris, Paris, France.
authors.forename: Kelly
authors.initials: K
authors.lastname: Pons
authors.affiliation: Department of Obstetrics and Gynecology, Hôpital Trousseau, Assistance Publique des Hôpitaux de Paris, Paris, France.
authors.forename: Emeline
authors.initials: E
authors.lastname: Maisonneuve
mesh_terms: D000138:Acidosis / Q000097:blood / Q000175:diagnosis*; D001238:Asphyxia Neonatorum / Q000097:blood / Q000175:diagnosis*; D001800:Blood Specimen Collection / Q000379:methods; D002547:Cerebral Palsy; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005311:Fetal Hypoxia / Q000097:blood / Q000175:diagnosis*; D005323:Fetal Monitoring / Q000379:methods; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007743:Labor, Obstetric; D019344:Lactic Acid / Q000097:blood*; D011247:Pregnancy; D012535:Scalp
chemical_list: D019344:Lactic Acid
keywords: cerebral palsy; foetal asphyxia; foetal blood sampling; metabolic acidosis; scalp blood lactates; scalp blood pH