Monitoring of pregnancy and labour by cardiotocography: 155 cases from the maternity ward of the institut hygiène sociale Hospital in Dakar

Abstract

Objectives: To determine the epidemiological and clinical profile of patients monitored by cardiotocography, to assess the performance of the device in detecting labour abnormalities and to identify factors influencing the results of cardiotocography. Patients and methods: We conducted a retrospective, descriptive and analytical study of labour monitoring and pathological pregnancies using the cardiotocograph at the Maternity Unit of the Institut Hygiène Sociale hospital in Dakar over a two-year period from 1 January 2019 to 31 December 2020. All cardiotocographic tracings were subject to a 2nd blind interpretation by a senior. The results were interpreted using the 2007 classification of the Collège National des Gynécologues et Obstétriciens Français (CNGOF). An APGAR score of less than 7 at 1 minute was defined as neonatal asphyxia. Data were collected from the patients' records and entered on a computerised form. Data analysis was performed using SPSS version 22 software. Results: During the study period, 208 patients were monitored with the cardiotocograph out of a total of 4123 deliveries, i.e. a frequency of use of 5%. Of these, 155 were included in the study (74.5%). These included 118 parturients (76.1%) and 37 pathological pregnancies (23.9%). The epidemiological profile of the patients was that of a woman aged 28 years on average, of low socio-economic status (83.2%), paucigest (48.4%), pauciparous (46.5%), carrying a full-term pregnancy (67.7%) and living outside the South District (72.3%). Ninety-seven FHR tracings contained abnormalities (62.2%). These included 47 pathological FHR tracings (30.1%) and 50 FHR tracings at intermediate risk of acidosis (32.1%). The basic rhythm was most often normal (87.2%). The abnormalities found were bradycardia (4.5%), tachycardia (7.7%) and absent rhythm (0.6%). Variability was mostly normal (78.9%). However, it was reduced in 12.2% of cases. Fifty tracings showed accelerations (32.1%) and decelerations were noted in 49 foetuses (31.4%). These were most often early (16%) or late (7.1%) decelerations. Tocography was mostly normal (60%). The abnormalities noted were dominated by hypertonia (11.7%) followed by hyperkinesia of intensity (7.7%). The majority of patients (54.8%) had given birth by caesarean section and the indications were dominated by the non-reassuring state of the foetus (69.4%). Most of the newborns had an APGAR score greater than 7 at 1 minute (82.7%) and 5 minutes (91.7%). Comparison of the results of the ERCF with the neonatal status revealed 20 true positives, 7 false negatives, 27 false positives and 102 true negatives, giving the ERCF a sensitivity of 74.1%, a specificity of 79.1%, a positive predictive value of 42.1% and a negative predictive value of 93.6% for the diagnosis of non-reassuring foetal status. A bivariate analysis enabled us to identify factors associated with the occurrence of perinatal asphyxia. Basic rhythm abnormalities (p = 0.001) and variability (p = 0.004), hypertension in the pregnant woman (p = 0.034), premature rupture of the membranes of more than 6 hours (p = 0.044) and intrauterine growth retardation (p = 0.013) were significantly associated with the risk of neonatal asphyxia. Conclusion: Cardiotocography is a powerful tool for monitoring labour, but its effectiveness is influenced by the conditions in which it is performed and the qualifications of the operator.