How to predict the days before your ovulation


Wait, you need to do it BEFORE you ovulate?

Well, maybe. Here are the variables: 1) how long it takes for the egg to be released after the Luteinizing Hormone (LH) spikes, 2) how long it takes for the LH to show up in your urine, 3) how long it takes the sperm to travel 4) how far the sperm have to travel 5) how long the egg can live, 6) how long the sperm can live 7) and of course, which hour you ovulate in the 24 hour period you measured. You might think that peeing on a stick every day should give you enough info. Sorry Charley.

We recommend the OV watch to predict the 4 days before ovulation

Studies show that you're more likely to get pregnant by having intercourse before ovulation. The OV Watch can signal these pre-ovulation days for you. It's not as easy to use as the monitor, but its reviews on Amazon speak for itself.

You wear it like a watch but it has a biochemical sensor that measures Chloride ion surges in your sweat. This occurs before the LH surge, which means the watch will notify you 4 days prior to ovulation. (Fertility monitors give this advance notice when they display a 2 prior to a 3 but you don't know how many 2's there will be in any given month.) A presentation by Dr. JB Stanford reviews scientific data challenging the notion that ovulation is the optimal time for intercourse, adding that the OV Watch reduces stress by opening up the fertile window, can be used with Clomid (clomiphene citrate), and there's no peeing involved.

The only down-side is cost: $100 for the watch + $40/month for the sensors. The other, albeit minor, downside is that it's a bit finicky, beeping and erroring out for no apparent reason. But it's usually fixable and the help-line is truly helpful: 1-866-OVWatch. The video below shows you how to resolve a common issue with the OV Watch which is the "NO DATA" error.



What to do when your OV Watch reads "NO DATA"

Video Tutorial

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Scientific evidence of high fertility rate prior to ovulation

Chart showing peak pregnancies at 2 days prior to ovulation


A study by Dunson, Colombo, and Baird published in the Journal of Human Reproduction took data from 782 couples over time for a total of 5860 menstrual cycles. The authors found that having intercourse 2 days before the ovulation day was the optimal time for getting pregnant. See Figure 1, right. Ovulation was determined by the basal body temperature method.

Read the Full Article from Human Reproduction, Vol. 17, No. 5, 1399-1403, May 2002
Chart showing odds of pregnancy highest on -2, -1, and ovulation day


A study by Wilcox, Weinberg, and Baird published in the New England Journal of Medicine found that the odds of getting pregnant are just as good whether you have intercourse 1 or 2 days before ovulation as they are for the day of ovulation. See Figure 2, left. The bars represent probabilities calculated from data on 129 menstrual cycles in which sexual intercourse was recorded to have occurred on only a single day during the six-day interval ending on the day of ovulation (day 0). The solid line shows daily probabilities based on all 625 cycles, as estimated by the statistical model.

Read the Full Article from New England Journal of Medicine Volume 333:1517-1521 Dec, 1995 Number 23


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