Use of fetal heart rate monitoring (FHRM) on the labour ward is common but obstetricians are less familiar with its use in theatre for non-obstetric surgery. In comparison, obstetric anaesthesia literature largely supports monitoring as an adjunct to maternal observations. The aim of this study was to systematically review the evidence on intra-operative FHRM during non-obstetric surgery.
Literature was searched between 1966 and 2013 for all reports of FHRM in non-obstetric surgery; multiple sources were searched. All studies were considered; those meeting criteria underwent data extraction and quality appraisal.
Forty-three cases were identified within the literature, the majority either undergoing maternal general (n = 23) or cardiovascular (n = 17) surgery. Cases were identified either from case reports or case series. Several reports discussed changes with fetal heart rate patterns on induction of anaesthesia, including reduced variability. Nearly all cases of FHRM in cardiovascular surgery reported profound fetal bradycardias on initiation of maternal by pass, which often persisted for the duration of surgery. There were three reports of delivery of the fetus as a result of the FHRM; one of these cases was reported as an inappropriate response to reduced variability.
Despite the relatively high numbers of women undergoing non-obstetric surgery during pregnancy, only small numbers are reported in the literature, which may be as a result of literature bias. Practitioners considering FHRM during non-obstetric surgery need to be aware of the reported changes in FHRM with onset of general anaesthesia and maternal cardiopulmonary bypass. Individualisation of the decision to use FHRM is appropriate.