After the last time I said anything about this topic (and for which I was given a shot), and before I open my yap this time, I decided to scan the Web for more information. Here is a current summary of the information which I gleaned:
In Real Life, Vaginal temp taking appears to have two common purposes: a) It is used in an attempt to determine the Core temperature of a woman who is trying to estimate when ovulation occurs during her (monthly) menstrual cycle. (This could be for either avoiding, or (more likely) promoting pregnancy.) For this purpose, it is attempting to determine the lowest body temperature of the day, assumed to be immediately after sleep cycle, and before any physical exertion of any kind. 6:00 A.M. is a commonly suggested time. The EZ Fertility site gives a reasonable description of the use, as Wikipedia does of the monthly variation in the Core temperature. b) The other typical use is of determining the Core temperature of a body. This is an alternative to 'rectal'. (As the body cools at a certain rate, if the temp is in range, the M.E. can estimate the time of death.)
As most women seeking to become or avoid pregnancy aren't likely to have their gynecologist on a sleepover, it is highly unlikely that a doctor would be called upon to use this procedure. Vaginal is recommended for the basal taking, as it is a lot less likely to be influenced by external factors (see the EZ site). When used for this purpose, it is necessary to use a more accurate thermo, one that reads to the 1/100th of a degree. There are digital thermos with the extra digit available online for less than $20. There are also glass thermos (with no mercury), but I couldn't get a look at any of them.
So, three things must be concluded:
1) Because a woman's core temp can vary depending on the time of the month, a blanket statement of whether it is higher or lower cannot be made.
2) As this temperature cycle depends on hormones, a woman taking any type of hormonal contraceptive invalidates the legitimacy of these observations, as the externally assumed hormones will override the body's natural hormones. And
3) It can still be an excellent addition to a play doctor's set of procedures.
Happy days,
Cos.