The effect of maternal methadone use on the fetal heart pattern: a computerised CTG analysis

Abstract

Using a computerised analysis, the cardiotocograph (CTG) from women who use methadone (n = 25) when compared with women who do not use methadone (n = 25) showed a significant reduction in the fetal heart baseline rate, with a significant reduction in number of accelerations and episodes of high variation. The short-term variation, number of decelerations and episodes of low variation were not different between the two groups. The time taken to meet the standardised criteria was not different, and it is possible that a computer-assisted CTG analysis could be more accurate than a naked eye interpretation.Keywords CTG, methadone, pregnancy.Please cite this paper as: Navaneethakrishnan R, Tutty S, Sinha C, Lindow S. The effect of maternal methadone use on the fetal heart pattern: a computerised CTG analysis. BJOG 2006; 113:948-950. IntroductionMethadone is an opiate commonly used in substitution therapy for heroin-dependent pregnant women. It is known to cross the placenta, and previous workers have suggested that changes in the fetal heart parameters can be seen in a nonstress cardiotocograph (CTG). [1][2][3] The evaluation of the CTG is an important tool to ensure fetal wellbeing in these high-risk pregnancies, and if there are consistent predictable changes to the fetal heart pattern, the changes should be identified and taken into account when a woman using methadone has a CTG performed. Interpretational differences between doctors make objective evaluation difficult; however, computer-aided CTG analysis makes an objective evaluation possible.This study was conducted to document any change in fetal heart patterns in methadone-using women compared with women not using methadone when tested with a nonstress CTG and evaluated using a computer-assisted analysis. MethodsThe CTG characteristics from women using only methadone were compared with a gestational-age-matched and paritymatched control group of women who were not using opiates. Women using methadone were recruited from the antenatal clinic at a gestational age between 28 weeks and 40 weeks.Women who had any condition that may affect fetal heart parameters such as medication, hypertension, diabetes, abnormal umbilical artery Doppler waveforms or liquor volume abnormalities were excluded. The control group of women were recruited from those attending a routine antenatal clinic or who had attended the antenatal day unit for a problem unrelated to pregnancy. Their consent was obtained for CTG, Doppler and liquor volume estimation. The CTG analysis was performed objectively using the computerised package by Sonicaid TM Fetalcare Ò (Huntleigh Healthcare Limited, Cardiff, UK) 4 to avoid inter-observer and intra-observer errors. The results were interpreted using SPSS version 9 statistical package (SPSS Inc., Chicago, IL, USA) using Mann-Whitney U test for all parameters. ResultsFifty women were studied, 25 in each group. The mean gestational age in the methadone group was 35.2 weeks and in the control group 35.7 weeks, and majority of the women were nulliparous in ...

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