Basal Body Temperature (BBT)

After two months of just casually ttc (ttc - trying to conceive), I decided to take a more deliberate approach. I went to the local Walgreen's and bought a digital thermometer for $5. I made sure that the thermometer has accuracy of one tenths of a degree. But you don't really need a fancy "ovulation thermometer" that cost twice or three times as much.

Throughout a woman's monthly cycle, her body temperature changes according to her hormonal variation. At the beginning of the cycle, during menstruation and prior to ovulation, a woman's body temperature is low. At the moment of ovulation, her body temperature takes a dive. Immediately after ovulation and throughout the rest of her cycle, the body temperature jumps by about 0.5 degrees F. This is the bi-phasic pattern of a woman's body temperature in one cycle. At the end of the cycle, her body temperature drops drastically again, signifying the onset of her next period. Therefore, charting this body temperature will allow a woman to tell if she's actually ovulating. So intercourse should take place prior to ovulation so that the sperm will be waiting for the finicky egg the second it is released (ovulation).

In order to properly track your basal body temperature (basal - lowest) you have to take your temperature first thing you open your eyes in the morning, before you get out of bed. So I kept my thermometer on my nightstand. There are a lot of software you can buy to help track your basal temperature, but since I know how to use Excel, I simply plot my BBT. I also keep track of when we had intercourse. I didn't bother with tracking my vaginal discharge but many women do so on the same chart. This chart is actually my April BBT chart. The circle is the day I think I ovulated (based on my BBT and other ovulation symptoms). The red triangles are our "love days". The pink region of the plot represents my period. The tan region represents when my next period should start. I have a regular cycle of 27-18 days. Based on the temperatures, I was able to determine a cover line (red line that separates pre- and post-ovulation).

During my charting period, I browsed hundreds of other womens' BBT charts, some ended up with a BFP (BFP - big fat positive) and some ended up with a BFN (BFN - big fat negative). I must admit to being a little obssessed with how my chart was comparing to other women's. Check out tons of other BBT charts here. So what happened to the right of my chart? I'll share the results in another post.