It's Blastocycst day

Yep day 5 after Fertilisation is the day our embryos grow up and become blastocycsts. This is the next phase in the cellular development towards becoming a baby and the day before they implant in the lining of my uterus! (I'm very excited).

The Visible Embryo site describes it as:

The pressure of the blastocele expanding in the middle of the blastocyst against the rigid wall of the zona pellucida, creates "hatching" of the blastocyst from the zona around the sixth day after fertilization.

As the blastocyst enters the uterus free from the zona, the outer layer of trophoblast cells secrete an enzyme to erode the epithelial lining of the uterus and allow the blastocyst to implant.

Human chorionic gonadotropin (hCG) is also secreted by the trophoblast cells stimulating the corpus luteum to continue progesterone production. Progesterone maintains the blood rich lining of the uterus. Endometrial glands in the uterus had already begun to enlarge in response to the progesterone stimulated to release by the corpus luteum ("yellow body") which once surrounded the egg as it grew in the ovary almost six days prior.

The uterus is therefore swollen with new blood capillaries and the circulation between mother and blastocyst begins, a process needed for the continuation of pregnancy.

I'm very excited about this as implantation is the critical point - this is the day that it becomes a real pregnancy and my body generates HCG which is the hormone used to detect a pregnancy by a home test kit.

So only a day to go!

I don't feel any different so far, I'm trying to relax and just get through the day - it's hard as I get bored with tv and I'm going to have to find something else to amuse myself with - I'm grateful for the internet, but I tend to find I'm only surfing for sites that tell me about early pregnancy. This morning I was looking at photos of the uterus as I have no idea what a real one looks like (only those diagrams you get in sexual reproduction books!). Someone on the fertility friends board posted that it's like a burger with 2 pieces of met slapped together - the reason why I was looking as it's always a wonder in the back of our minds (by our I mean IVF ladies) that after embryo transfer the 2 little ones will fall out!

I'm assured that's not possible - I'm so glad of that!