TLT makes early research breakthrough in foetal heart monitoring

23 February 2012

Tarilian Laser Technologies, which has developed a unique optical sensor platform for blood pressure measurement, has now made a further innovation with the development of a ground-breaking early research prototype for a foetal heart monitoring sensor.


The foetal heart rate (FHR) has been used as an indicator of foetal well-being for over 160 years, becoming 'a routine part of clinical practice' in obstetrics around the world. Currently there are two principal methods of foetal heart monitoring: intermittent auscultation and continuous monitoring.

Intermittent auscultation

This is a recommended method of measuring the foetal heartbeat if it has been a “trouble free pregnancy” and would normally be taken at 15-minute intervals during the early stage of pregnancy and every 5 minutes or once every contraction in the later stages. Intermittent auscultation is carried out using either a Pinard stethoscope or a hand held Doppler monitor. This equipment is also used in prenatal care in outpatient clinics and the GP surgery.

Continuous monitoring

For reasons relating to the health of the foetus, continuous monitoring may be required using an electronic heart rate monitor. Two types of monitors are commonly used:

  • Cardiotocograph (CTG): this usually involves the use of an ultrasound transducer to monitor the baby's heart rate and a pressure transducer to monitor uterine contractions, both of which are linked to a recording machine. This is usually undertaken continuously in labour, although occasionally it is used intermittently during labour.
    A current problem with continuous monitoring is the impractical size of the monitoring machines. In most units, CTG requires the mother to wear a belt across her abdomen while monitoring is being conducted, which restricts her mobility.
    An alternative means of monitoring the baby's heart rate with the CTG machine is to attach an electrode directly to the baby's presenting part, usually its head. This form of continuous monitoring is known as 'internal CTG' and requires a ruptured amniotic sac (either spontaneously or artificially) and a scalp electrode (clip) attached to the baby's head, also reducing the mother’s mobility.

Certain patterns of electronically monitored FHR recordings are strongly associated with specific changes in foetal condition. However, not infrequently, uncertainty exists in respect to interpretation. Unnecessary operative interventions might be the result of incorrect interpretation and overestimation of the diagnostic potential of electronic FHR monitoring. Whereas certain FHR patterns are sensitive indicators of foetal hypoxia, the specificity is low.

It is rarely possible to quantitate hypoxia on the basis of FHR records alone and information derived from FHR records only represents one piece of information which always has to be interpreted in the context of the clinical situation.


Tarilian Laser Technologies intends to target its sensor for both intermittent auscultation and continuous monitoring markets.
The company's proposed device has several unique selling points compared to other devices currently available, either for intermittent auscultation, or continuous monitoring, or both:

  • Novel technique: the device would distinguish itself from most other intermittent auscultation devices in that it uses neither invasive Doppler ultrasound, nor is it a simple sound wave amplifier. It utilises a unique optical technique delivery a continuous beat to beat fetal heart rate measurement.
  • Non-invasive foetal monitoring: the device would be the world's first passive truly non-invasive foetal monitor. Doppler devices require the use of ultrasound, whereas the optical-sensor-based device would not transmit any energy at all into the maternal abdomen, the amniotic sack, the foetus and placenta in any way. Currently, the effects of "bombarding" a foetus with energetic ultrasound waves are not fully known, and some clinicians and researchers have expressed concern over the matter.

The TLT sensor also offers the following advantages:

  • Increased mobility: the main problem with current continuous monitoring devices is the reduced mobility for the woman being monitored. The Tarilian sensor can be miniaturized and will be a small “elastoplast”-type small sensor that does not require the use of a belt or electrodes attached to the mother/baby during labour.
  • Increased sensitivity with foetal and maternal monitoring: It is important to be able to distinguish the fainter foetal heartbeat from the maternal heartbeat. This requires high detection sensitivity and differentiating software, which TLT has.
  • Continuous beat-to-beat measurement: The TLT sensor is non-invasive and be used continuously without concern.
  • Not position sensitive: Doppler devices currently strive to obtain the widest beam profile possible in order to increase the area in which you can place the monitor and still detect the foetal signal. Hence they are effectively position sensitive. The Tarilian device, however, very is small and easily can detect a signal over a much larger range of positions, easing use and minimising the chance of error.
  • No gel required: disposable sensor — almost akin to a foetal cardiovascular lab on a small elastoplast.
  • Perfect technology for wireless connectivity.

Global market

According to Life Science Intelligence, globally, the 2008 market for products used to monitor and treat neonatal and perinatal patients was $1.2 billion and should grow to reach over $1.5 billion by 2013. A recent Frost & Sullivan report reveals that the market is growing in the EU due to a combination of higher awareness among expectant mothers about the advantages of sophisticated monitoring, as well as the non-invasiveness and greater safety offered by new prenatal diagnostic techniques. The need for better accurate systems has increased further as the progress in fertilisation technology and trend towards pregnancies at later stages in life, has led to an increased rate of multiple pregnancies and more chance of a mother delivering prematurely. As the number of premature births rises, the demand for neonatal monitoring devices has risen concomitantly.

Future development

In 2009, TLT won a significant grant from the East of England Development Authority (EEDA) for its early research into this application. Subsequent to the successful completion of this proof-of-principle research, TLT is now committed to the forward development of further prototypes and full clinical assessment.

Commenting on the success at TLT, Dr Sandeep Shah, CEO of TLT, stated, "The key sets of historical innovations in obstetrics occurred many many years ago with the giant figures of Joseph Lister and Ignaz Semmelweis in the 1800s; through to the last century with Ian Donald and Tom Brown and their discoveries around ultrasound.

"The TLT Team here are very excited about this ‘new century development’ and the potential we have of further improving global outcomes in pregnancy with our unique optical sensor that can be simply applied by the mother and deliver very powerful data about the baby to the midwife and doctor, including continuous beat-to-beat foetal heart monitoring.

"The telemetric opportunities are also powerful and we have opened discussions with a number of international companies to take this forward, as we launch our latest new division of TLT Sapphire, and a powerful new paradigm in foetal medicine.”



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