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Using Ovulation Tests to Predict Fertility

Using Ovulation Tests to Predict Fertility

Ovulation tests - or ovulation predictor kits (OPKs) - are excellent tools for predicting ovulation, a woman's most fertile time during her menstrual cycle. Unlike BBT charting, ovulation tests anticipate ovulation - not just confirm that ovulation has taken place.

Ovulation tests work by detecting luteinizing hormone (LH). Just preceding ovulation, women experience an "LH surge" - a sudden, dramatic, and brief rise in the level of luteinizing hormone. Ovulation tests detect this LH surge, allowing you to accurately predict when you will ovulate. A positive result on an ovulation test means that the woman will most likely become fertile over the next three days - with peak fertility at 36 hours following the LH surge.

How do OPKs Work?

Luteinizing Hormone, the LH Surge, and Ovulation

At the beginning of the menstrual cycle, the body begins to produce follicle stimulating hormone (FSH). FSH facilitates the formation of a follicle on one of the ovaries. The follicle contains and nurtures the egg. When a follicle has adequately matured, a surge of Luteinizing Hormone (LH) causes the follicle to burst and release the egg into the fallopian tube - the moment of ovulation.

Throughout the menstrual cycle, a small amount of LH is produced - but during the middle of the cycle LH briefly and dramatically increases. Elevated quantities of luteinizing hormone facilitate ovulation - and OPKs detect this LH surge through anti-LH antibodies contained in the sensitive testing membrane of the test.

The LH surge is, alas, very brief - and in order to detect the LH surge, a woman needs to test at the right time of the month - and the right time of day. As LH is produced by the body in the morning, mid-afternoon is considered the ideal time to test.

Once the LH surge has been detected, successful fertilization is most likely to take place one to three days following the LH surge - with peak fertility at 36 hours post-LH surge. Since this ovulation "window" only opens once per month (and the unfertilized egg has a short 24-hour life-span) predicting ovulation accurately is very helpful when trying to become pregnant. Below, you will find information on getting the most out of your ovulation tests (and visit our Ovulation Test FAQ for more testing tips).

Advanced Testing Tips and Facts: Answering Common Questions about OPKs

Using OPKs and Interpreting Ovulation Test Results

Ovulation tests come in two formats: test strips and midstream tests. To use the ovulation test strip, you fill a container with urine and hold the test strip in the container for several seconds. With midstream tests, you hold the test in your stream of urine. Both test formats are equally reliable. Always read ovulation test kit instructions carefully.

With most home ovulation testing products, the "reaction time" of the test is five minutes. At five minutes, you can interpret the tests. All tests have a "control" color band (or color line) that indicates whether the test is working or not. Also, the control band provides a color/intensity baseline by which to interpret the "test" band results. The "test" color band indicates a positive or negative result (please refer to the graphic below).

A positive result (indicating an LH Surge) is indicated by a test band that is of equal or greater intensity (equal or darker) than the control band. A negative result for the LH Surge is indicated when the test band is of lesser intensity (lighter) than the control band or cannot be seen. A negative result means the LH level of the urine sample is at or near its normal level and that the LH surge is not in progress. Remember, there is always some quantity of LH in your system, so a light color band in the test region is NOT an indicator of a positive result.

 

Ovulation Predictor Kits

How do I Determine when to Begin Testing?

To determine when to start testing, you must first do a little calculating. Use the Cycle Chart below to figure out when to begin testing for your LH surge.

First, determine the average length of your menstrual cycle. The length of the menstrual cycle is the number of days from the first day of menstrual bleeding to the day before bleeding begins on the next period. Determine the usual length of the menstrual cycle over the last few months. Then, refer to the Cycle Chart to determine on which day of the menstrual cycle to begin testing.

Your Cycle Length

Day to Begin Testing

21 days Day 5
22 days Day 6
23 days Day 7
24 days Day 8
25 days Day 9
26 days Day 10
27 days Day 11
28 days Day 12
29 days Day 13
30 days Day 14
31 days Day 15
32 days Day 16
33 days Day 17
34 days Day 18
35 days Day 19
36 days Day 20
37 days Day 21
38 days Day 22
39 days Day 23


Read More About:

> Ovulation Test FAQ: Testing Tips and Tricks
> Saliva Based Ovulation Predictors
> Ovulation FAQ: Frequently Asked Questions About Ovulation
> Pregnancy Testing
> OvaCue Product Review

Comments

I USED MY OPK SATURDAY MORNING @ 6AM AND RECEVIED A POSITIVE. LATER THAT DAY ABOUT 1PM I STARTED HAVING VERY SEVER OVULATION PAINS WHICH I GET EVERY MTH. IT'S AS IF THE EGG BURST OUT AT THAT MOMENT I GUESS. ANYWAY I HAD SEX ABOUT 1AM SATURDAY MORNING. IM WONDERING IF SATURDAY WAS MY ACTUAL DAY I OVULATED.

Anonymous - Nov 08, 2009
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I've been having positive OPK results for 6 days now. My temperature started to rise yesterday, when I got my first negative (or close to negative: the two lines seem to be the same color, but the control line is slightly thicker...). Does anyone know what it means? I never had positive results before, even when I was on clomid...

Lallala - Nov 01, 2009
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Is it normal to have a positive test results for 5 days on an ovulation test?

Anonymous - Oct 09, 2009
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Ive been taking Clomid for the last 5 days, today is Day 7.
When should i start testing? my last cycle was 27 days and the one before that, 35 days.

babybliss - Sep 22, 2009
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They also turn positive if you're pregnant. Or the test could be faulty, or you misinterpreted the results.

Anonymous - Aug 08, 2009
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Um...I have been charting my BBT and started on 7-29-09. I took my temp this morning it dropped to 96.8 and so I used an OPK...said positive....I am on cycle day 6...what is the deal...and my cycle is 33 days long.

Anonymous - Aug 03, 2009
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First Day of Last Period:
Cycle Length:
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Luteal Phase Length:
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Ovulation:
Due Date:
Fetal Age:

Note that you are most likely to get pregnant if you time your lovemaking to occur on the days right before - and on - your ovulation date. Keep in mind that the projected ovulation date above is simply a “best guess” estimate based on your cycle date information. The most accurate way to pinpoint your most fertile time is through the use of urine-based ovulation tests or with a fertility monitor. We have partnered with Early-Pregnancy-Tests.com, the Internet’s leading supplier of preconception products since 2001, to offer low-cost, FDA-approved pregnancy and ovulation tests – with free same-day shipping.

 

Now that you’ve calculated your ovulation date using our ovulation calculator, we have a number of other helpful tools you can use to help increase your chances of conceiving.

 

  • Create your own personalized ovulation calendar! You can even provide an email address so that you receive email alerts of your most fertile days, when you can begin testing for pregnancy, and more.
     

  • Create your own personalized fertility chart! This is a highly accurate way to pinpoint your ovulation date that relies primarily on basal temperature charting. (Visit Early-Pregnancy-Tests.com for an accurate, inexpensive basal thermometer.)
     

  • Connect with others at our online community! If you have questions about trying-to-conceive – or if you just want to vent a bit – we have a wonderful, vibrant community of people who’d just love to hear from you.

Find your most fertile time.
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