The Process

The egg freezing program at Advanced Fertility Center of Texas is under the direction of Dr Dmitri Dozortsev. Our IVF team utilizes the latest cryopreservation technique called vitrification, which takes advantage of ultra-rapid cooling.

This cooling is so fast that ice crystals do not have time to form when water goes inside the egg, as the formation of ice crystals can damage the chromosomal plate. This technique has allowed our doctors to improve the frozen egg pregnancy rates without inducing irreversible damage to oocytes (eggs). Our successful techniques for freezing/thawing and fertilizing the eggs and implanting the embryos has led to pregnancy rates equivalent to those in a fresh IVF cycle. Retrieved eggs can be stored for several years.

Benefits of egg freezing

Egg freezing can be beneficial when women are undergoing certain types of reproductive surgery and/or chemotherapy or radiation therapy for cancer treatment. Many types of chemotherapy as well as radiation therapy targeting the pelvis or the ovaries may result in irreversible damage to the eggs (oocytes) contained within the ovarian follicles. Even if those eggs do not die, their genetic material may be damaged beyond repair.

Some patients do not want to create any “extra” embryos that may be potentially discarded and desire that every embryo be transferred. In such cases, we can fertilize a fraction of the oocytes and the remaining eggs could be frozen.

Women who postpone their pregnancy but desire to retain their full reproductive potential can also benefit from egg freezing. Many women today need to postpone having children for a variety of reasons. Yet, after the age of 35 a woman’s fertility begins to decline, and after the age of 40 pregnancy rates decrease substantially.

Furthermore, the chance of having a chromosomally-affected child increases exponentially between the age of 40 and 45 due to the decline in egg quality, yet a women’s ability to carry the pregnancy to term is retained well past the age 0f 50. Furthermore, when eggs are frozen at 30 years old and transferred at 50, the pregnancy rates will be that of a 30-year-old woman.

A world-wide database for egg freezing outcome is an ongoing project. Between 1986 and 2008, there were close to 1000 live births with only 1.3% birth abnormalities, which is the same rate for congenital abnormalities occurring in naturally-conceived infants.

Ovarian tissue preservation

The advantage of ovarian tissue preservation is that the tissue can be implanted back into the patient at the right time, and allow patients the opportunity to conceive on their own or with the aid of fertility treatments. Ovarian tissue transplants also allow patients to resume their menstrual cycles and restore the normal hormone levels associated with the menstrual cycle.

The life of the transplants is often 2-3 years. If patients are unable to conceive on their own with the transplant, they may undergo fertility treatments including IVF to conceive. In the future, women may be able to have their eggs removed from the preserved tissue, matured outside of the body (in vitro maturation), fertilized and transferred back to the uterus.

Currently, Advanced Fertility Center of Texas is collaborating with one of the top experts in fertility preservation and ovarian tissue preservation, Dr Sherman Silber of St Louis, MO.

Types of Chemotherapy

High-risk chemotherapy drugs:

  1. Cyclophosphamide
  2. Busulfan
  3. Nitrogen mustard
  4. L-phenylalanine mustard
  5. Procarbazine
  6. Melphalan
  7. Cholarambucil

Intermediate-risk chemotherapy drugs:

  1. Doxorubicin
  2. Vinblastine
  3. Cytosine arabinoside (Ara-C)
  4. Cis-platinum
  5. Carmustine
  6. Lomustine
  7. VP-16 (etoposide)

Low or no risk chemotherapy drugs:

  1. Methotrexate
  2. 5-Fluorouracil
  3. Vincristine
  4. Bleomycin
  5. Actinomycin D

Effects of Radiotherapy

Both the ovaries and the testes can be damaged by radiation used to treat cancer. The amount of damage depends on the area of the body radiated, the total dose of radiation and the frequency of radiation.

Patients who receive radiation can have a temporary decrease in fertility, permanent damage (decreased egg or sperm count) or become completely infertile (early menopause or failure to produce sperm). Radiation therapy is more damaging to the ovary than chemotherapy, and a single dose of radiation is more toxic than fractionated (divided) doses.

Radiation to the ovary can cause a temporary loss (6-9 months) of the menstrual cycle, and premature ovarian failure (early menopause) can be caused by as little as 2Gy of radiation. Patients in their late 30s and early 40s are more susceptible to ovarian damage from radiation and more often affected by lower doses of radiation.

High-dose abdominal irradiation and total body irradiation for childhood cancers can impair uterine function, growth, and blood flow. Fertility can also be impaired by head irradiation and disruption of the hypothalamic–pituitary–gonadal axis, leading to reduced production of follicle stimulating hormone (FSH) and luteinizing hormone (LH), which are responsible for egg maturation and ovulation.

If you have further questions please call (713)467-4488, we would love to tell you more about the process.