I am currently in week 10+4. I am still temping, and for the past 2 days, I noticed a drop in my BBT. I read that "After the first trimester, the woman's body temperature drops to her pre-ovulatory normal as the placenta takes over functions previously performed by the corpus luteum". But isn't it too early for the placenta to take over, at week 10???? Shouldn't it take over at around week 12 to 14???