Two hearts beat as one
Scientists in Germany and the UK have found that a mother's breathing rate affects the synchronisation of her heartbeat with that of her unborn child. The findings, reported in the journal Proceedings of the National Academy of Sciences, were based on a novel mathematical approach that could be used to detect complications early in pregnancy. The foetal heart rate, which is relatively simple to measure, is often used to indicate a baby's motor activity during the second and third trimesters. Previous studies have indicated that a relationship between maternal and foetal conditions can be found based on observation of the foetal heart rate. 'The frequently reported special awareness of a mother for the well-being of her unborn child may be in part attributable to synchronisation of their heartbeats,' said Jürgen Kurths of the Potsdam Institute for Climate Impact Research in Germany. One of the objectives of the study was to see whether a mother's perception of the condition of her foetus has any physiological basis. To do this, they tested whether episodes of foetal-maternal heart-rate synchronisation could be influenced by the pace of the mother's breathing. Six healthy women who were between 34 and 40 weeks pregnant with a single foetus were asked to maintain a given respiratory rhythm (breathing 10, 12, 15 or 20 times per minute) for 5 minutes while lying down. The sessions were separated by a pause of between two and three minutes. A magnetocardiograph was used to record heart activity in both mother and foetus. The non-invasive device detects the magnetic fields generated by the activation of the heart muscle, and does not stress either the mother or foetus. The data showed that compared to normal or slower breathing rates, higher breathing rates lead to a greater number of epochs during which the heartbeat of mother and child were synchronised. 'We were able to show that the cardiac systems of the mother and her unborn child interact,' said Dr Kurths. The synchronisation the authors refer to is not actually a one-to-one mother-baby beat, but a consistent ratio of heartbeats. For example, an episode of synchrony might be characterised by a repetition of three foetal heartbeats to two maternal beats over the course of a few minutes. The interaction between the maternal and foetal cardiac systems was detected using an innovative mathematical technique called 'twin surrogates'. The method involves first generating independent copies of the underlying system, then using 'surrogate data' to statistically identify the synchronisation epochs. 'This method improves our insight into the prenatal development of the cardiac system and possibly the nervous system,' said Peter van Leeuwen of the University of Witten/Herdecke (UWH) in Germany. 'These exciting results demonstrate the importance of interdisciplinary teams in medicine,' added Dietrich Grönemeyer, also from UWH. The findings were an outcome of collaboration between physicians, engineers, mathematicians and scientists. Moreover, the methods used by the team may have practical applications beyond the field of medicine. 'The method can also be applied to investigate so-called 'teleconnections' in the climate system,' said Dr Kurths. These teleconnections are weak but far-reaching interactions, such as the relationship between the El Niño phenomenon in the eastern Pacific and the monsoon season in India. Synchronisation, he explained, defines the way the two systems react to each other and to external influences. It may occur anywhere where two complex systems are coupled. The main finding of the study was that the foetal cardiac system seems to be able to adjust its rate of activation in response to external stimulation. 'A better understanding of how these two independent cardiac systems interact under various physiological conditions will lead to improved insight into normal prenatal development and shed light on the reciprocal perception between the mother and her child,' the study concludes. 'This in turn may be beneficial for foetal surveillance and the detection of pathological conditions during pregnancy.'
Countries
Germany, United Kingdom