Well, the RE's (reproductive endocronologist) nurse let IM know the reason I have to stay on all my meds until about week 12, even after the betas confirm the pregnancy. It's all because of a little thing called a corpus luteum.
That lovely item #10, well that's the corpus luteum.
A normal pregnancy starts with an egg released from the mother's ovary which travels down the fallopian tube to the uterus where it joins with the sperm and becomes the embryo. This follicle that releases the egg then becomes a temporary estrogen and progesterone ovarian cyst called the corpus luteum. http://en.wikipedia.org/wiki/Corpus_luteum The corpus luteum produces estrogen and progesterone for up to 12 weeks until the placenta develops and takes over its duties. Because we didn't want to fertilize any of my eggs, I was given the Lupron shots to prevent ovulation therefore leaving me with no corpus luteum to produce the necessary hormones that maintain the inner lining of the uterus for the embryo. After 12 weeks the placenta will take over producing the necessary hormones therefore allowing me to discontinue the meds. This will be the point at which my body is allowed to do what it naturally does, completely unassisted. I like the sound of that!
The nurse also informed us that if the betas confirm that I am indeed pregnant, we will have a sonogram two weeks from that date to determine if the pregnancy is a singleton or twins.