Charting your basal body temperature (BBT) is really important because it can help you identify your fertile days in the progress of a simple graph. However, one question: is vaginal or oral temping more accurate when TTC?
I have the answers.
Technically speaking, you can take your temperature vaginally, orally, or rectally to chart your BBT, but the good news is that thermometers are super accurate, so there's really no need to chart any way other way but orally. Taking your temperature orally is perfectly fine, and a reliable and accurate way to measure temperature. Fertility doctors don't recommend taking your temperature vaginally, because it's just not necessary.
If accuracy is a concern of yours, purchase a thermometer with an extra digit. Most thermometers come with only three, but those designed for fertility awareness often provide extra specificity. Also, take your temperature first thing in the morning to get a more accurate reading. Taking your temperature at the same time each day and getting at least at least three hours of sleep before you measure your BBT are other important steps to take.
On the other hand, if you're a mouth breather, your oral reading could be off. You could consider taking your temperature vaginally if that's the case, but it is not recommended. Try another fertility awareness method before going vaginal. In fact, experts recommend ovulation prediction kits (OPKs) over taking your BBT in any case. Why?
Well, the theory behind taking your basal body temperature (BBT) is that you can use the slight rise in your temperature, caused by a surge of the hormone progesterone, to identify your day of ovulation. According to a review article in Facts, Views, & Vision: Issues In Obstetrics, Gynecology, and Reproductive Health, you can expect your temperature to rise between 0.3 and 0.6 degrees Celsius, or 0.54 and 1.08 degrees Fahrenheit, and to remain high until your period begins. Unfortunately, this means that what you're seeing when you chart is only a retrospective picture of your fertile days--a report, not a prediction.You can use your chart to guess when you'll be most fertile next month, but your prediction won't be perfect. After all, it's not based on real-time information, but only on past data.
All in all, if you want to chart your fertility using your temperature, go right ahead. Anything women can do to demystify their cycle, their fertility, and their fertile days is useful. Just know that there's no reason to take your temperature vaginally--or rectally, for that matter--when you're trying to conceive. An oral temperature works just fine.