Ever since I picked up a copy of Shettles' How to Choose the Sex of Your Baby a few months before ttc my dd, I have been interested in swaying. I desperately wanted a little girl but had always assumed that what you got was pretty much up to chance. Yet here was someone saying there were things you could do to influence the gender of your future child!
Shortly after I found Shettles' book, I started using Fertility Friend for charting and quickly discovered that most people on the swaying board there were (and still are) pretty dismissive about Shettles. That made it hard to decide how to plan my sway. Did I go along with Shettles' theory that cut-offs favored a girl? Or did I go with the theory advocated on FF that it was best to have frequent BD through ovulation? Both theories sounded reasonable, but I didn't want to make the decision about which method to use based on anecdotes and opinions. I wanted some way to test which was most effective.
Then I hit upon what seemed like a great idea to me: FF is filled with hundreds of pregnancy charts that include information about BD timing, cm patterns, and the gender that resulted. I could just look at a bunch of charts and see what timing and cm patterns resulted in the most girls and boys. This started out as a small, relatively informal survey and has grown into a detailed analysis of 500 (and counting) charts.
I have posted my survey results on my FF chart; however, there isn't a whole lot of space there for writing information (occasionally people do actually want to be able to find my chart!). Since a lot of people have indicated some interest in my survey, I thought it might be useful to start this blog, where I would have a lot more space to explain how I've conducted this survey and what results I've found.
The Survey Itself
Virtually all the charts I am using came from the chart gallery at Fertility Friend. (A handful of charts came from other sources, but they are not part of the main study, and I will explain in the relevant sections when I'm using extra charts.)
When I was selecting charts I excluded ones that:
- did not chart cm at all
- were only partially filled in or did not include daily basal body temperature (if just a couple of temperatures were missing I didn't worry, but if temperatures were only included for half the cycle, I excluded the chart)
- indicated IVF/IUI had been used- resulted in multiples (unfortunately, I didn't figure out a good way to automatically exclude pregnancies with multiples, so some might have slipped in - but I excluded any charts I noticed)
- had obvious errors or problems that I felt made the information in the chart questionable (there were only a couple charts I can remember excluding for this reason - in one case, the chart had a 6 or 7 day cut-off and every sign from cm to OPKs to temperature shift to when she got her BFP indicated that ovulation occurred on a different day than the one noted on her chart; in another case, the temperature on the most likely day of ovulation was discarded, which meant the day of ovulation was most likely identified incorrectly)
For all of these charts I kept track of BD and cm patterns on the five days prior to ovulation through the day afterward (so I was looking at 7 days total). (Note: there was one chart that had a 6 day cut-off that I did include because all the signs indicated ovulation had been identified correctly. That is the only chart where I looked at 6 days prior to ovulation in the survey.)
The reason I selected five days as my cut-off is because I read that sperm could only survive for up to five days. So I figured that the BD that would be most influential on a pregnancy outcome would be the BD that occurred five days before ovulation through the day afterward.
O+12
The survey I have done, unfortunately, has nothing to say about O+12. With O+12 it is critical to know the exact time of ovulation - and the exact time for 12 hours after ovulation. Since FF only indicates the day of ovulation, not the time of ovulation, it is impossible to tell if any of the charts are O+12 charts. Also, since most of the people on FF who have gotten pregnant were trying to get pregnant, it is doubtful that there would be many charts with a true O+12 anyway - that is, seven days of abstinence and then BD at least 12 hours after ovulation occurs.
Still, I do think O+12 is an effective girl timing method. The one study in the FAQ on O+12 (http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=7427410&dopt=AbstractPlus) suggests a high success rate for O+12. If I am understanding the numbers correctly (and it is entirely possible I'm not), the study found that for every 1 girl born there were .514 boys born. This would result in a 66.01% success rate for girls. It's just one study, and I don't know how many people were involved in it since only the abstract is available. But still, if correct, that is a pretty impressive figure. And based on what I have found in my study, I think a 65-70% success rate for timing is the highest success rate that can reasonably be expected from timing alone.
So that is it for the introduction to my timing analysis. :) In the following posts, I will start listing the results that I found in my study.