2007 Instituto para el Estudio de la Concepción Humana (IECH) Fertility Center

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Oocytes cryopreservations, a valuable tool for the contemporary woman June 15, 2007 Dra. Astrid Cuevas de la Mora, Dr. José Sepúlveda González Today, contemporary women postpone motherhood for several reasons. Therefore infertility appears to be most frequently, and the principal factor it is the one related to age. The oocyte cryopreservation offers a strategy to preserve excedent oocytes for further use. The most important clinic application of oocytes cryopreservation is on cancer patients whom will be submitted to radiotherapy, chemotherapy or surgery with gonadotoxic effect. The first pregnancy in humans after oocyte cryopreservation was reported by Chen in 1986, using slow cryopreservation technique. This investigator reports a very good percentage of surviving of 80% and 83% of fertilization, in a sample of 40 oocytes. Nevertheless, in the following decade, there were reported a low index of newborns. The progress was slow, particularly by the difficulty in fertilization of cryopreservated oocytes before the intracytoplasmic sperm injection (ICSI) era. Recent studies evaluated the publicated data about efficacy in oocyte cryopreservation, comparing different protocols. The slow freezing protocol had shown a higher efficiency in cryopreservation, with the increment in the number of childbirths of 21.6% per transfer in 1996 to 32.4% between 2002 and 2004. The data about vitrification showed a similar tendency, with a frequency of 29.4% before 2005 and 39% after 2005. The miscarriage rate after oocyte cryopreservation initially appears to be higher. Nevertheless, Oktay in 2006, found a 20% frequency (19/95), very similar to general population rate (15%). In spite of all these advances, there are no long follow up studies reported, lacking for example, the number of cryopreserved oocytes needed for a satisfactory pregnancy. Based on available, we can say that there are needed 20 oocytes in a woman with 35 years or less to achieve a pregnancy.

Oocytes cryopreservations, a valuable tool for the contemporary woman

June 15, 2007

Dra. Astrid Cuevas de la Mora, Dr. José Sepúlveda González

Today, contemporary women postpone motherhood for several reasons. Therefore infertility appears to be most frequently, and the principal factor it is the one related to age. The oocyte cryopreservation offers a strategy to preserve excedent oocytes for further use.

The most important clinic application of oocytes cryopreservation is on cancer patients whom will be submitted to radiotherapy, chemotherapy or surgery with gonadotoxic effect.

The first pregnancy in humans after oocyte cryopreservation was reported by Chen in 1986, using slow cryopreservation technique. This investigator reports a very good percentage of surviving of 80% and 83% of fertilization, in a sample of 40 oocytes. Nevertheless, in the following decade, there were reported a low index of newborns. The progress was slow, particularly by the difficulty in fertilization of cryopreservated oocytes before the intracytoplasmic sperm injection (ICSI) era.

Recent studies evaluated the publicated data about efficacy in oocyte cryopreservation, comparing different protocols. The slow freezing protocol had shown a higher efficiency in cryopreservation, with the increment in the number of childbirths of 21.6% per transfer in 1996 to 32.4% between 2002 and 2004. The data about vitrification showed a similar tendency, with a frequency of 29.4% before 2005 and 39% after 2005. The miscarriage rate after oocyte cryopreservation initially appears to be higher. Nevertheless, Oktay in 2006, found a 20% frequency (19/95), very similar to general population rate (15%).

In spite of all these advances, there are no long follow up studies reported, lacking for example, the number of cryopreserved oocytes needed for a satisfactory pregnancy. Based on available, we can say that there are needed 20 oocytes in a woman with 35 years or less to achieve a pregnancy.