At what point does an egg spilt for twins

[billysitch]

I have trawled pages of the internet but cannot find a definite time, first day after fertilization, or a week in.

My reason for asking, I had an EPU scan on Friday last week putting us as 8 weeks tomorrow, but it was difficult to detect if there was one or two sacks! Are we in for a shock or am I being a muppet and worried for no reason.

God I wish I had listened at school during sex ed and not been doodling dogdy pictures of the class hunk!

Muchos for any advice or steering in the right direction.

And why is it I only think of the important questions on the way home in the car!

Only identical twins come from one egg. Non-identical twins come from 2 so they would be fertilized at the same time.

When they come from one egg I think the split is very early on. I have seen it on telly (sorry no expert really) but it happens after the first few splits of the cell. I am not sure how quickly the cells divide but apparently, according to Wikipedia can be in the first two days after conception but it can be later here

Good luck with your scan.

Thanks Niecie,
I had read Wiki but missed that bit, think I was scanning!

Just because I have some information in my handbag...

ID twins: always same sex (apart from I think 1 time a while ago when they proved that they could be boy/girl but very very very rare...)

Split within 3 days of fertilisation: 2 placentas.
Split 4-7 days: single placenta, 2 sacs (what I'm having)
Split after 7days: single placenta, 1 sac(most high risk)
Split afer 12 days: siamese twins.

Taken from the Twin to Twin transfusion Syndrome Assocation website: credited to "mulitple pregnancy" in Dwehursts Textbook of Obstetrics and Gyneacology, and also from Professer Nicolaides of the Harris Birthright Centre in London.

2 eggs: non identical twins so always 2 placentas.

Poorbuthappy - you are a star, clear and concise, marvellous thank you oh and good luck. x