If you have a luteal phase defect you probably won't get pregnant, the egg might get fertilized but it won't have enough time to implant in your uterine lining before your body sheds the lining, I guess depending on your definition of miscarriage it might be considered one, but not technically, because your body doesn't begin producing pregnancy hormone until after implantation, so you'd never know the difference, never have a + test. High levels of progesterone, which should be produced after a strong ovulation, keep your temp up and tells your body not to shed the lining yet...(peaks about 7 days post ovulation), if you aren't pregnant, your temps and the progesterone levels should drop at the end of you luteal phase and shed the lining to start over. If you are ovulating but not producing enough progesterone, your luteal phase could be too short as a result. Let me know if i'm confusing you more, i'm not sure that i'm explaining it well.
so anyway, before ovulation, you should have no progesterone. It starts being produced at ovulation and peaks around day 7, which is why it should be tested then ideally, any earlier and you could have a low level that's not really low, and in a day or two after day 7,if you aren't pregnant, it will start declining. Some women do get pregnant with low progesterone but are at risk to miscarry if its not supplemented bc the body may think its time to shed the lining. But normally during pregnancy the progesterone levels stay steady and continue rising.
Me (29) DH (30)
#1-Olivia Caetlyn-9-28-09-9-28-09, 23+2 wks, emergency classic c-section, class I HELLP, IUGR
#2- Lucas Oliver (rainbow baby)- April 2011, 36+2 wks, HELLP and pre-e free! (lovenox and LDA pregnancy)
#3-Matthew, late October 2012...mostly normal, 37 wks, (lovenox and LDA again)
My blog: http://www.butterflies-and-rainbows.blogspot.com/