The benefits of Frozen Embryo Transfer

There is no data to indicate any increased risk of abnormalities due to the freezing and thawing process. In fact, studies* have shown the following benefits when using frozen embryos compared to fresh embryos:

• Less risk of bleeding during pregnancy
• Lower chance of a baby being born underweight
• Less risk of a baby being born premature
• Less risk of death
  

*(Maheshwari et al., review, Aberdeen University, 2012).

There’s also an increasing belief that for certain patients and conditions, it’s beneficial to freeze all embryos in an IVF or ICSI cycle and transfer them at a later date (based on embryos frozen by the vitrification method and not slow freezing).

There are two treatment options to prepare for a frozen embryo transfer and your doctor will discuss these with you. We’ve outlined them both below:

Natural cycle FET
In a natural cycle it’s important that frozen embryos are transferred at the correct time. You’ll be closely monitored using ultrasound scans and advised to use Luteinising Hormone (LH) urine test kits to confirm a normal ovulatory cycle.
Once ovulation has occurred, the frozen embryos will be thawed and transferred into your uterus on the appropriate day.


Medication controlled FET

• If you’re having an FET as part of a hormone-controlled cycle, you’ll start medications to suppress or down regulate your natural hormones – typically from day 21 (of a regular 28-day cycle).
• You’ll be asked to call the clinic on the first day of your period and arrange for an ultrasound scan on day 5, 6 or 7 to check if the hormonal suppression has been effective.
• If the scan is good, then you’ll start medications (Oestradiol valerate tablets – Climaval) to prepare the lining of your womb (the endometrium).
• The development of the endometrium will be monitored using ultrasound scans (typically two). If the endometrium is not thick enough, you may also be asked to start Oestrogen patches.
• The embryo transfer will be arranged once the endometrium is thick enough. At this stage you’ll be asked to start Progesterone supplementation (in the form of pessaries or injection) for luteal phase support. You’ll continue the Oestrogen medications but will stop any ‘down regulation’ medications.