A home fertility monitor is a small reader that clips onto a phone and measures fertility hormones in a urine test strip, so that a woman can track her menstrual cycle at home. It is also called a fertility tracker or an ovulation monitor. The phone app charts the hormone levels across the cycle and shows the days on which she is most likely to conceive.
A woman's cycle is controlled by hormones. Oestrogen rises as an egg matures. A sharp rise, or surge, of luteinising hormone (LH) means that the egg will be released within about 24 to 36 hours. The release of the egg is called ovulation. After ovulation, the hormone progesterone rises, and a substance made from it, called PdG, appears in urine. A simple ovulation test from a chemist shows only whether LH is high or not, as a line that appears or does not. A fertility monitor measures the actual amount of each hormone.
The reader works through the phone's camera. Say a 31-year-old architect in Kochi has been trying to conceive for eight months. Each morning from day 6 of her cycle, she dips a strip in urine and slides it into the reader on her phone. The camera photographs the strip, and the app measures how dark each test line is. From the darkness, it calculates the level of each hormone. On day 12 her oestrogen begins to rise. On day 14 her LH jumps from 6 to 45 units. The app marks days 14 and 15 as her most fertile days. A few days later, her PdG rises, which confirms that ovulation actually happened.
The app keeps a chart of several cycles. Each reading carries its date, so the chart is time series data. If her cycles are irregular, or if ovulation is not confirmed month after month, the chart is useful evidence for a gynaecologist. She can share it in a consultation through a telemedicine app. She can also share it with an online clinic for women's health, a kind of direct-to-consumer telehealth.
The monitor is one form of remote patient monitoring, used by the patient herself. It does not diagnose infertility. It measures hormones and shows the pattern, and a doctor interprets the pattern.