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The Best Fertility Monitor

To get pregnant, you have to be trying at the right time. You can only conceive within what’s known as your fertile window: that period of time when sperm could encounter a fertile egg. Sperm can survive inside a body for four to five days, and an egg remains fertile for between twelve and twenty-four hours after ovulation, so that adds up to a window of only five or six days in each cycle when you can conceive.

There are plenty of different options for you to monitor your fertility and pin down exactly when this fertile window is. Online calculators, hormone tests and temperature measurements are some of the most common, and picking which one is right for you is a tricky task in itself.

OvuSense is here to give you a rundown and help make that choice easier!

Ovulation Calculators

The simplest tool to use, but the most limited, is the online ovulation calculator. All it needs is two bits of information for you: the date you started your most recent period and the usual length of your cycle. Comparing these two pieces of information with its database lets it place you in your cycle and predict when you’ll next ovulate.

Convenient, and non-invasive, this is a tool that is most useful to people with very regular cycles. If you have anything disrupting your menstrual cycle, be it a health issue or just natural irregularity, there’s nothing for the statistics to latch onto and the predictive power is almost nothing.

Hormone Test

Ovulation Prediction Kits (OPKs) work like pregnancy tests: they test your urine for traces of the hormone responsible for ovulation. It’s called the luteinising hormone or LH, and a surge of it 11-21 days into your cycle causes a mature egg to be ejected from your ovaries. OPKs work by detecting this surge in your urine as the hormone leaves your body.

Again, these tests don’t work brilliantly if you have any kind of health condition affecting your fertility or hormones. Your body might simply produce a naturally strong or weak dose of LH, which could cause the test to give a false positive or a false negative.

Basal Body Temperature

Your core temperature is an impressively accurate indicator of ovulation but it’s hard to measure. What you need is your basal body temperature (BBT) – the low temperature your body drops to in rest. This regularly responds to ovulation with a drop before and a raise immediately after in the vast majority of cases, but to get a result that shows this small change you need to take your temperature in the morning, immediately upon waking. Even tiny amounts of activity can raise your temperature, cloaking this signal in noise.

You also need to plot out your temperature over days and weeks, to establish what’s average for you, letting you spot when your body departs from its average temperature. It’s more work, but it has the advantage of being tailored to your body, rather than ‘the average’.

Luckily, OvuSense has a solution that takes the work out of this method: our sensor measures your body temperature through the night to get the most accurate reading possible, and compares it with our algorithm to give you an advance warning of your fertile window with 96% predictive power.