Once the embryo reaches the blastocyst stage, some 5 to 6 days after fertilization, it hatches out of its zona pellucida and begins the process of implantation within the uterus. In nature, fifty percent of all fertilized eggs are lost and fail to implant.
How Many Embryos Are Transferred?
Most clinics can currently only transfer two embryos. This will increase the possibilities of a successful pregnancy however limits the chance of triplets and multiples. In previous years there was very little regulation round the numbers of embryos that may well be transferred. currently there are generally more responsible practices being conducted in fertility clinics.
The other issue is that the chance of successful pregnancies from fertility treatments overall has increased.
Embryo Transfer Options
Generally there are two options for embryo transfer; either a natural cycle or programmed frozen embryo transfer. for women who are ovulating normally, the embryo transfer is timed to take place 2-3 days after they need ovulated, depending on how old the embryos were after they were frozen.
With a programmed frozen embryo transfer, natural ovulation is suppressed through taking oestrogen. This has the additional benefit of thickening the female internal reproductive organ lining in preparation for an embryo to implant. Progestin pessaries or gel also are wont to facilitate to create up the female internal reproductive organ lining. It’s common for ladies to use these for around two weeks before the transfer procedure. Around 4-5 days once using the progestin pessaries, the embryo transfer is finished.
What is Freezing Embryos?
The process of freezing embryos for later use isn’t simply a matter of putting them in an exceedingly deep freeze and hoping for the best. First they’re dehydrated so the chance of damage from ice crystals forming is minimised. Then the embryos are cooled to minus one hundred forty degrees and cryopreserved in liquid nitrogen until they’re required.
Thawing takes around 1-2 hours. It’s important that the embryos are frozen at a precise time in their development. This can be commonly after they are at a four or eight cell stage of cell division. This can be because they have become a little more stable by this stage and there’s less probability of them being broken during the freezing and thawing stages.