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Ovulation Prediction Kits (OPKs)


How do Ovulation Prediction Kits (OPKs) work?

Ovulation Prediction Kits have become quite popular and can be quite useful to help you find your fertile time.

Recently "Advanced OPKs" became available as well as Fertility Monitors using the same sticks. These advanced sticks actually measure both Estrogen and LH and provide more advanced notice of ovulation. See below for more details.

Standard OPK

OPKs work by measuring the presence of Luteinizing Hormone (LH) in your urine. A surge of LH, which is sent to your ovary, causes your ovary to produce enzymes which in turn cause the dominant follicle to rupture and release the egg into the Fallopian tube. This is ovulation and it is expected to occur within 24 hours of the surge of LH. An OPK is thus expected to be positive the day before you ovulate.

Advanced OPK

Advanced OPKs measure your estrogen level and LH levels.

LH detection provides the same information as the standard OPK. It gives you between 12 hours and 48 hours advanced notice of your ovulation. This corresponds to the Peak/Solid Smiley display.

Using the Estrogen detection capability, these sticks/monitors can also give you a few more days notice of your fertile window (High/Flashing Smiley display).

An advanced OPK displays a Low, High (flashing smiley) and Peak (solid smiley) fertility status based on your hormone levels. Enter this result in the corresponding data entry field (Monitor/Advanced OPK) on Fertility Friend (under Tests).


Following a few guidelines can help you get the most out of your OPK:

Reading a standard OPK and line intensity

Standard OPKs are only calibrated for positive or negative results.

The test is positive if the test line is as dark or darker than the control line when read within the time limits that the OPK instructions recommend.

If you have difficulty gauging the line intensity, we recommend that you use the Line Reader tool included with the Lightbox feature available in the App (More menu/Lightbox) and the web site (menu Data).

Multiple OPK tests in a single day

If you are testing two times a day to better catch your LH surge you can now use the new OPK AM and OPK PM data entries to record it accurately.

To add these fields to your data entry form, tap the customize tab on the data entry screen and select Add Optional Tests.

If you are using the web site, select the "Tests" tab on the data entry dialog and use the "Add/Remove signs" link.

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