• Ovarian Hyperstimulation Syndrome.
• When surplus embryos are remaining after a fresh transfer, for future use.
• In the case where embryo transfer is deferred.
  • thin endometrial lining.
  • Fluid in the endometrial cavity.
  • Difficult cervical negotiation.
• As an adjuvant to PGD/PGS.
• When embryo transfer needs to be deferred due to unexpected personal, social or medical reasons.

• Vitrification rapid freezing

• Natural cycle.
• Hormone replacement cycle – most commonly used.

  The hormone replacement cycle is of two types:

  • Downregulated cycle with Gn agonist, which can either be in form of daily injections or in form of monthly depot, to suppress the body’s own ovaries from functioning and once that this confirmed by ultrasound, then the uterine (womb) lining is made to grow with help of oral medications, estradiol valerate (2 mg ), which takes approx 2 weeks to grow.
  • Non – downregulated cycle – here the patient is put on an oral high-dose estrogen treatment, tab estradiol valerate (2 mg ), which would work, dually to suppress the ovarian function due to the negative feedback and also help the endometrial lining to grow.
  • Once an adequate uterine lining thickness is achieved, 8 mm, then depending on the stage of development at what the embryos were frozen, the progesterone supplementation is started in form of vaginal pessary, vaginal gel or injection for those many days and then the embryo transfer is undertaken in the luteal phase the estrogen and the progesterone supplementation is continued and the preg test is done 9-14 days post transfer, depending on the stage of transfer.

There is enough evidence and literature to support that the results in selected conditions are better or at par with the fresh transfers. The recovery of the embryos is as high as 80 – 90% if carried out by experts. The implantation rate is approximately 40-50%.

The success rates are optimized by:

• Dedicated frozen thaw cycle program running.
• The expertise of the embryologist in freezing as well as thawing the embryos.
• The uterine endometrial thickness at the time of transfers.

• For how long one can freeze the embryos?
  As long as 10 yrs. The results are not affected by the duration of freezing.
• Which is stage freezing carried out?
  Day 2/3/5 embryos can be frozen. However, freezing, the embryo at the blastocyst stage is recommended.
• Any complications of the procedure?
  In experts hands, they are negligible.
• Are the results not as good as the fresh cycle?
  This is a myth. In Fact, the results are equal or better, when indications & expertise, are optimally matched.
• How long does the process take ?
  2-3 weeks.