Impact of Braxton-Hicks contractions on fetal wellbeing; a prospective analysis through computerised cardiotocography.

To estimate the correlation between the maternal perception of Braxton-Hicks contractions (BHC) and foetal wellbeing throughout antepartum computerised cardiotocography (cCTG) parameters, we performed a prospective observational study between April 2019 and March 2020. Non-labouring women with a term pregnancy were recruited. We collected data regarding maternal perception of BHC in the last two weeks before delivery. For each patient, an external computerised cardiotocography (cCTG) was registered. Women were subdivided in accordance with perception or non-perception of BHC. Fifty women were recruited. Women who felt BHC showed higher foetal heart rate (135 bpm vs 128 bpm, p  = .008), lower long-term variability (47.2 ms vs 57.7 ms, p  = .02) and reduced number of accelerations (7.8 vs 11.4, p  = .04). In conclusion, the absence of mother's perception of BHC showed lower baseline foetal heart rate, increased number of accelerations and higher long-term variability related to mothers who perceived BHC.IMPACT STATEMENT What is already known on this subject? BHC are common painful contractions that start in the third trimester. They are random spots of uterine action that happen in the absence of sufficient gap-junction connectivity. BHC have a significant impact on foetal wellbeing. What do the results of this study add? BHC are associated with reduced long-term variability during cCTG examination. Moreover, baseline foetal heart rate seems lower, and accelerations are less frequent when BHC are felt by pregnant women. What are the implications of these findings for clinical practice and/or further research? These findings could be related to a cumulative effect on the uterine flow mediated by BHC. Further researches are needed to state the impact of BHC on the foetal wellbeing.