Monday November 9 2009
A foetal heart monitor in use
Doctors have warned that home foetal heart monitors “are potentially dangerous to the mother and baby's health”, reported The Guardian.
The newspaper describes the case of a woman who noticed her unborn baby was moving less than usual, but who could hear a heartbeat on her home monitor and so did not seek medical attention. When she did go to hospital, doctors found that the foetus had died. The doctors suggest she may have detected her own heartbeat on the monitor.
It is not clear how often such problems occur. It is also not possible to say exactly when the foetus died and whether the baby could have been saved if the woman had sought medical attention sooner.
It is important that the limitations of home foetal heart monitors are made clear to users. Pregnant women who are concerned about their baby’s health should seek medical advice and not rely on a foetal heart monitor.
Where did the story come from?
The article was written by Abhijoy Chakladar and Hazel Adams from Brighton and Sussex University Hospitals NHS Trust. It did not receive any specific funding. The paper appeared as a feature in the peer-reviewed British Medical Journal (BMJ).
The news coverage of this story is generally balanced. It mentions the fact that this article focuses on a single case and refers to another case published earlier in the BMJ. However, the claim in an article in The Independent that the devices “could be death traps for the unwary” is sensational.
BBC News importantly notes that the article’s author is “quick to point out that stillbirth is a rare event and pregnant women should not be unduly alarmed”.
What kind of research was this?
This brief article discusses the authors’ concerns about using at-home foetal heart monitoring devices. It describes a particular case that prompted their concerns.
As the article only mentions one case, it is not possible to estimate how common any potential risks of foetal home monitoring are.
What did the research involve?
The researchers describe a case that they saw in their own obstetric unit and refer to another similar case that was described in a previous issue of the BMJ. They also looked online to see what kinds of foetal heart monitors were available and what warnings the manufacturers’ and retailers’ websites carry.
What were the basic results?
The authors describe a woman who went to their labour ward on a Monday after she had been unable to detect her baby’s heartbeat with a foetal heart monitor at home.
The woman was 38 weeks pregnant with her first baby and was fit and well with no history of medical problems. Routine tests during her pregnancy had shown no abnormalities. An urgent ultrasound scan showed that there was no foetal heartbeat. Further tests could not identify why the foetus had died.
The woman had noticed that the baby was moving less than normal on the previous Friday, but had been able to detect a heartbeat on the monitor over the weekend, so did not seek medical help at that time. The authors assume that the woman had heard her own pulse or the flow of blood in the placenta.
The researchers looked online for similar devices and were “surprised by the number of foetal heart monitors available”. They found two main types: sound amplifiers and Doppler ultrasound devices. The authors express their concern that without training, parents can misinterpret the sounds they hear.
They also say that not all retailer websites had appropriate warnings that the devices should not replace medical advice, and some websites say that the devices can be used for “reassurance in between hospital visits and scans”. They say that one website that provides Doppler ultrasound devices emphasised the safety of the devices for the baby’s heath but did not mention the device's limitations or the dangers of delaying seeking medical attention.
The authors say that foetuses vary in how much they move in the womb and this can change considerably during the day. They also note that a recent systematic review suggested that there was not enough research to say for sure whether foetal movement was a good predictor of foetal health. Despite this, most obstetric units encourage pregnant women to come in for assessment if foetal movements reduce.
The authors describe the investigations that are performed once the woman comes in, including foetal heart monitoring, which is interpreted by experienced midwives and obstetricians in the context of the woman’s medical history. They say that “home monitoring devices can give only a snapshot of the heart rate” and do not give other important information for interpreting what a reduction in foetal movement means.
The authors say that they had asked retailers how many foetal heart monitors they had sold or hired out, but had not received a reply.
How did the researchers interpret the results?
The authors conclude that, although the death of the foetus may have been unavoidable, the use of the foetal heart monitor delayed the woman from seeking medical attention. They say, “the untrained use of foetal heart monitors constitutes a risk to the safety of pregnant women and their unborn babies,” and suggest that this risk will “undoubtedly increase as these devices become more popular”. The authors say that, as well as delaying women from going to hospital, the monitors could result in unnecessary visits to the doctor “when [users] cannot hear the foetal heart because of inexperience”.
They suggest that the manufacturers and retailers of these monitors should make the limitations of these devices clear. They also say that “obstetric services need to educate expectant mothers about the limitations and the potentially fatal consequences of untrained use of foetal heart monitors and to present clear guidance about when to seek medical review.”
This article discusses the authors’ experiences and concerns about the use of home foetal heart monitors. As the article only describes a single case that brought the issue to the authors’ attention, it is not clear how often problems such as these have occurred. It is also not clear to what extent websites offering these devices warn of their limitations, or what information is given with the devices.
As the authors note, it is not possible to say if the foetus could have been saved if the mother had gone to hospital when she first felt its movements change. It is also not possible to tell when the foetus died and what the mother would have done had she not had the foetal heart monitor.
It is important that women follow their doctor's advice on what to do if their baby’s movements change, and that if they have concerns about the health of their baby, they seek medical advice and don’t rely on a foetal heart monitor for reassurance.