Couple Fertility Treatments | Embryo Freezing


In-vitro fertilisation is an Assisted Reproduction Technology (ART) process whereby eggs are harvested from the woman, after hormonal stimulation of the ovaries, and then fertilised manually in a laboratory by combining the egg with the partner’s sperm. The embryo is then transferred to the uterus.
An IVF treatment is required in cases where the fallopian tubes are blocked or damaged, there is decreased sperm count or sperm motility, there is a history of genetic disorder, women have uterine fibroids, ovulation disorders, when women have had their fallopian tubes removed and other such unexplained infertility.
Sometimes, if there is a problem with the sperm, an Intra-Cytoplasmic Sperm Injection (ICSI) is used along with IVF to further increase the chances of conception. ICSI involves the direct injection of a single sperm into each egg, under microscopic control.

IVF steps vary from one patient to the other but for the most part consist of the following steps:
  • Administering hormone injections to ensure 10-12 days of ovarian stimulation. The medication to be prescribed and dosage are monitored through regular scans and blood tests throughout this period.
  • Usually 36 hours prior to egg collection, on the final day of ovarian stimulation, an hCG injection is administered in order to mature the eggs.
  • Egg collection is conducted at the same time as sperm collection, under sedation or a mild general anesthetic.
  • Insemination or ICSI is conducted on the day of egg collection.
  • Based on the quality and available number of embryos, they are transferred 2-5 days after egg collection.
  • A blood test is performed 14 days after egg collection to determine pregnancy.


Intrauterine insemination or IUI is a fertility treatment procedure, when a catheter is used to place washed, concentrated sperm into the uterus, near the time of ovulation in order to facilitate fertilisation. The main idea is to increase the number of sperm that make it to the fallopian tubes and thereby increase the chances of fertilisation. The procedure is less invasive and also less expensive when compared to IVF. Sometimes doctors prescribe minimal medication to stimulate the ovaries and prepare the uterus prior to the insemination. This helps enhance the chances of success. IUI is a treatment option for couples who have unexplained infertility or very mild factors preventing natural pregnancy. Some reasons for couples to opt for IUI are low sperm count or mobility, the presence of cervical scar tissue from previous procedures, ejaculation dysfunction and a hostile cervical condition. IUI can be highly successful when the recommended 4-6 cycles are done. However, IUIs have a lower success rate than IVF procedures .

For the most part, the steps involved in IUI involve:
  • A blood test and ultrasound in the beginning of the menstrual cycle.
  • Potential prescription of fertility enhancing drugs to stimulate the ovaries.
  • Additional scans so as to assess the readiness of follicles.
  • Administering of an hCG injection roughly 40 hours prior to insemination.
  • Collection of semen, which is then prepared in the laboratory and placed inside the uterus using a fine catheter.


Earlier, IVF treatment involved transfer of embryos on the 3rd day after egg collection. In cases, where many good quality embryos are available on day 3, it may be difficult to decide which are the best ones to put back, and in these circumstances we can now give couples the possibility of opting for blastocyst culture and transfer. In this treatment, the embryos are allowed to grow in the laboratory until they are 5 days old. The appearance of the embryo changes each day, so instead of a group of 6 to 8 cells as seen on day 3, it accumulates fluid in the centre of the embryo and those cells which are going to form the baby (the inner cell mass) fuse together at the side of the embryo. The remaining cells go towards forming the placenta. The blastocyst is a much more advanced structure than the 3-day-old embryo and the real advantage of transferring blastocysts is the high live birth rate associated with blastocyst transfer. Although many couples wish to undergo blastocyst transfer, it can only be used in those patients who have several high quality embryos on day 3 after egg collection and so although we can take a decision in principle to perform transfer on day 5 we can only take the final decision on day 3. For women who wish to get pregnant but are keen to avoid a twin pregnancy, a single embryo transfer using a blastocyst will give them the highest chance.


PGD is a procedure used prior to implantation to help identify genetic defects within embryos. It prevents the transmission of single gene disorders in a family and achieve a healthy pregnancy. The embryos used in PGD are usually created during the process of In Vitro Fertilization (IVF). PGD is performed in the female of embryo biopsy and identifies which embryos are not at increased risk of developing the disease. PGD testing helps couple to build a healthy family, if there is a risk of inheritance or genetic disorder. PGD is done before the pregnancy is established and helps avoid tough decisions and situations.

  • Why PGD Testing ?
    PGD is indicated for couples who have increased risk of having a child with a single gene disorder. Fertile couples who have a known history of a genetic condition in their families can consider PGD testing. Couples who are already undergoing IVF therapy for infertility can consider additional pre-conception screening to identify conditions that their offspring might be at increased risk of developing.
  • Procedure of PGD:
  • Step 1: Stimulation of the ovaries
    In order to create embryos for genetic testing, the ovaries have to be artificially stimulated using hormones to produce several eggs at the same time. Because a significant number of a couple’s embryos are likely to be affected by the genetic or chromosomal abnormality, a large number of embryos need to be created for the best chances of success.
  • Step 2: Collection of eggs from the ovaries
    At the appropriate time, the eggs are removed in during a surgical procedure known as egg retrieval. Once the eggs are removed, they are inspected to determine which are mature and normal appearing.
  • Step 3: Insemination/injection of sperm
    Fertilization during PGD will be done:
    Intracytoplasmic Sperm Injection (ICSI): A single sperm is injected in the centre of an egg. This technique is used for conditions caused by a single faulty gene.
  • Step 4: Fertilisation
    The morning after injection/insemination of the sperm, the embryologist carefully examines each egg to see if fertilisation has occurred.
  • Step 5: Embryo biopsy
    The eggs that were successfully fertilised are grown in the laboratory for 5-6 days when the embryo forms what is called a blastocyst of about 100-150 cells. At this stage trophectoderm biopsy (the cells which will form the placenta) takes place.
  • Step 6: Embryo Testing
    The cells are tested to see if the embryo from which they were removed contains the abnormality that causes the genetic condition.
  • Step 7: Embryo Transfer
    Only those embryos that do not have the specific genetic condition that were tested for will be transplanted into the woman’s uterus. Usually one embryo will be transferred to the uterus at any one time to avoid the possibility of multiple births (more than one baby in a pregnancy).
  • Step 8: Pregnancy Test
    Twelve days after the embryo transfer, the woman is given a pregnancy test.


PGS (Pre-implantation genetic screening) is a technique for testing whether embryos have any problems with their chromosomes, which is thought to be the most common reason IVF treatment fails. PGS is performed on a small embryo biopsy prior to transfer and identifies which embryos are chromosomally normal. Chromosomally normal embryos are the most likely to develop to term and to be born as a healthy baby. PGS testing helps IVF physicians and patients decide which embryos to transfer. This technology is specially developed for analysis of only a few cells or even a single cell as is required for preimplantation genetic testing.

Why PGS ?
  • Increase in implantation rate:
    Some embryos that are chromosomally abnormal will fail to implant into a woman’s uterus. Therefore, by transferring chromosomally normal embryos, PGS by NGS (Next Generation sequencing) can increase the implantation rate.
  • Reduction in miscarriage rate:
    PGS evaluates numerical changes in chromosome numbers and large chromosome imbalances, embryos with chromosome abnormalities will not be transferred. Therefore, especially, in high-risk groups, PGS reduces the risk of miscarriage.
  • Increase in the chance of delivering a healthy baby:
    Some pregnancies with chromosome abnormalities will result in the birth of a child with multiple serious anomalies. Therefore, PGS can increase the chance of delivering a healthy baby by assisting physicians in identifying chromosomally healthy embryos for transfer.
  • Decrease in time to achieve a pregnancy:
    The time to achieve a healthy live-born decreases compared to a regular IVF cycle, avoiding multiple frozen embryo transfers before the transfer of the implanting embryo.


Embryo freezing is relatively a new technique, which is used as a part of the IVF treatment. Embryo freezing offers the opportunity for couples to conceive more than once from a single IVF procedure. During the IVF procedure, fertility drugs are recommended by doctors to stimulate the production of eggs. This usually results in more eggs than required. A couple can choose to store their embryos for future use, should they decide to conceive again without again going through the ovum pick up, and In-Vitro Fertilisation steps of the process. If they later decide not to use the embryos, they may elect to donate them to other couples.

The process of embryo freezing is very simple. The unused embryos are frozen and stored in the tank of liquid nitrogen at -196° Celsius. During the freezing process, a liquid called cryoprotectant is added to protect the embryos. It is not necessary that all embryos will survive the thawing process. Therefore, for the next cycle, your doctor will advise you to have more embryos thawed than needed to be transferred. Another method used for the same is Vitrification. This technique uses very high concentrations of cryoprotectant, usually three or four times higher. Rapid cooling is used to freeze the embryos around 10,000 times faster to prevent the toxicity of the high levels of cryoprotectant and to achieve vitrification. (Vitrification, in simple words, is a process of changing the liquid state into gas formation instead of changing it into solid state that allows cells to be preserved into its existing state).
Normally, embryos can be stored for 10 years and after this its storage will depend on the woman’s medical circumstances and her partner or sperm donor’s medical status.
The success rate of pregnancy using the frozen embryos is similar or slightly lower than that using the fresh embryo.


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