How Accurate?

Ovulation^? has been monitored by accurately charting resting body temperature since the 1930s. Numerous studies on the method have repeatedly demonstrated that it can detect a woman’s fertile days with 99% accuracy, under controlled conditions where there are no missed measurements and measurements are taken immediately on waking, at the same time every day. Unfortunately, in home use the method has been shown to fall short of these statistics.

The fundamental advance in DuoFertility is continuous body temperature measurement, which eliminates the possibility of missed or miss-timed measurements and therefore provides home users and their doctors with the quality of data that the method is capable of providing.

The inherent problem with conventional body basal temperature (BBT) measurement methods is that waking temperature is used as an estimate of deep sleep resting temperature. Unfortunately, when you wake your body temperature changes faster than just about any point during the night. This means that a small error in the time that you take the measurement can lead to a large error in the temperature measured – without you having any indication that this error has occurred.

In comparison, DuoFertility measures your temperature continuously, and works out when you are sleeping most deeply. The measurement of your temperature is therefore independent of late nights, early mornings, or even interrupted sleep. Only the best quality measurements from up to 20,000 points collected during the night are used in monitoring your ovulation.

What this means is that the “real world” accuracy of DuoFertility at last matches up to the results found for body basal temperature measurement in controlled studies. Several studies have been performed on the accuracy of detection of the fertile window^?, most of which have been done for the purpose of contraception. Dr Marshall performed a study looking at the effectiveness of temperature monitoring to detect a woman's fertile days and found that the success rate was 99%. Other studies have found that it was as successful as 99.3% (Dr Freundl).

By combining additional fertility clues, such as cervical mucus^? and position, it has been shown that this accuracy can be increased even further. For this reason, DuoFertility provides you with the option of entering “fertility clues” if you wish to do so. Some women find the identification of such clues difficult, so they are entirely optional, but if entered they will be used by the algorithms to improve the accuracy of fertility prediction and detection. A study by Dr Frank-Herrmann found the combination of temperature with other fertility clues provided an accuracy of 99.7% in identifying a woman’s fertile days.

With DuoFertility you can finally get the quality of information from controlled studies without changing your lifestyle.

References:

G. Freundl et al., Estimated maximum failure rates of cycle monitors using daily conception^? probabilities in the menstrual cycle^?, Human Reproduction, Vol. 18, No. 12, 2628-2633, December 2003 - Full text

Frank-Herrmann et al., Determination of the fertile window: reproductive competence of women–European cycle databases, Gynecological Endocrinology, Volume 20, Issue 6 June 2005 , pages 305 - 312 - Abstract

Marshall, J., A field trial of the basal-body-temperature method of regulating births., The Lancet, Volume 292, Issue 7558, Pages 8 - 10, July 1968 - Abstract