Oocyte freezing explained

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What is Oocyte freezing?

Oocyte freezing is a process of preserving unfertile, viable eggs to retain female reproductive potentiality for later use. The entire process starts with producing eggs in the ovary through hormonal stimulation and transvaginal salvaging followed by freezing.

The process completes with storing the viable eggs in the medical laboratory.

These frozen eggs are later used for in-vitro fertilization under medical supervision. In this process, post-thaw survived eggs are combined with sperm and then implanted into the uterus to support conceiving.

Potentiality of Oocyte freezing?

Oocyte freezing is recommended for women who have a risk of anticipated fertility because of the administration of chemotherapeutic medications or to preserve fertility for delayed family planning.

This process is also applied to overcome the reproductive issues of male partners, such as insufficient sperm count. Oocyte freezing can be done either through slow-freezing or flash-freezing (vitrification) processes.

However, professionals in this field mostly recommend flash-freezing protocols, because the success rate of pregnancy is more due to increased post-thaw survival eggs.

In the flash-freezing method, an ultra-rapid cooling technology is applied to solidify the oocytes. An application of cryoprotectants prevents solidification of ice crystals. Thus, there is a better scope of post-thaw survival of oocytes in the flash-freezing method.

The research experts confirmed that 4.5% to 12% women can able to become pregnant through flash-freezing protocols and the rate of live birth is 2% to 12% for women in age group of 38 years.

Benefits of Oocyte freezing

Aging is one of the major cause of women infertility. There are several instances of delayed marriage and family planning which increases the chance of women infertility.

Oocyte freezing acts as fertility insurance for such instances and supports women to complete their studies, achieve financial stability, and find a suitable partner. Medical professionals described the following benefits of oocyte freezing process:

  • One of the potential clinical approach to young women, who are under chemotherapeutic treatment and have a risk of developing sterility due to the side effects of the cancer treatment.
  • The women below 38 years of age can avail the oocyte freezing process to give a healthy childbirth with a related genetic sequence of the parents at the advanced age of their life through IVF (in vitro fertilization) and embryo transfer.
  • Oocyte freezing process can reduce the risk of developing ovarian aneuploidy related chromosomal abnormalities in children.
  • Oocyte freezing process is an option for a woman who wants to become a single parent without involving her partner or does not have a partner. Even Oocyte freezing process is an alternative of embryo freezing for women who have some ethical concerns about the status of a developing embryo.

Oocyte freezing associated risk

There are always some risks associated with delaying pregnancy (usually after 35 years of age of the women) for both, mother and fetus. Increased blood pressure (preeclampsia), high blood sugar level (gestational diabetes), cesarean delivery are most common problems associated with advanced age pregnancy of a woman.

Low birth weight, premature delivery, and risk of developing congenital diseases are problems with the offspring. Though, oocyte freezing and IVF process support advance stage pregnancy, but clinical experts always suggest women get pregnant at the right age.

Because this process is not completely safe for every individual. Following are some oocyte freezing associated complications:

  • It has already been mentioned that ovarian stimulation is one of the stepwise process followed in oocyte freezing. Women mostly face mild to moderate ovarian hyper-stimulation related health issues, including headaches, nausea, fatigue, abdominal pain, irritability and breast tenderness due to this process. However, these problems can be overcome with appropriate clinical interventions.
  • Some women may develop severe ovarian hyperstimulation related health conditions, including difficulty in breathing, the formation of blood clots, abdominal pain, vomiting, dehydration etc. These types of symptoms require immediate medical attention. In rare cases, ovarian hyperstimulation can cause death.
  • Ovarian stimulation may increase the risk of breast cancer, ovarian cancer; however, no significant research data is available to date to support this.
  • Advance stage related complications include preeclampsia, gestational diabetes, and cesarean delivery. Low birth weight and premature delivery are also associated with frozen-thawed oocyte induced pregnancy.

Oocyte freezing procedure description

  • Before conducting the oocyte freezing, doctors usually perform blood tests to check the follicle-stimulating hormone and estradiol concentration in blood. A blood sample is collected on the third day of the menstrual cycle. The test reports help to determine the efficacy of the fertility medication on a particular individual.
  • HIV screening test is also performed to isolate preservation of the infected eggs.
  • Multiple oocyte freezing procedures are performed in a step-wise manner after completion of these basic medical tests.
  • Medication for ovarian stimulation and premature ovulation preventing medication can be prescribed at the beginning of the menstrual cycle to produce multiple eggs, instead of a single egg and also to prevent premature ovulation. Vaginal ultrasound is required to perform during the follow-up visit to monitor the maturation of the eggs in the follicles.
  • Usually, follicles are prepared for egg retrieval within 8 to 14 days period after administering medications. Egg retrieval is conducted under medical supervision through transvaginal ultrasound aspiration. Sedative medication is given before conducting the procedure.
  • The collected unfertilized eggs are frozen at subzero temperatures, either by following slow-freezing or flash-freezing method to halt all natal activities and conserve them for future utilization.
  • In case a woman wants to conceive, then her frozen eggs will be thawed and fertilized with sperm in a clinically facilitated laboratory. Then the fertilized eggs are implanted in the uterus.

Oocyte freezing is in use since 1990 for preserving women fertility due to the onset of cancer or chemotherapy-induced decline of reproductive organ functioning.

So, this is not a new medical technique but the public awareness of this technique is less, even sometimes the social acceptance of this process remains controversial due to ethical reasons.

However, the developed society has gradually started accepting oocyte freezing, which can help to retain the reproductive ability of a female and decrease the fertility rate reduction in the modern society.

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