Egg Freezing for Fertility Preservation


Q1. Is egg freezing only recommended to women below 35?
Medical research has shown that the ovarian reserve and egg count are optimal in women below the age of 35. Therefore those who intend to have their eggs frozen should do so before 35. This does not mean that egg freezing is not suitable for women above 35. Based on clinical experience, the egg reserve or egg count remains good in many women above 35. Medical consultation is thus recommended if you are thinking about egg freezing.
Q2. Under what situation is egg freezing not recommended?  
Egg freezing is suitable for healthy women with no chronic illness. Physical and gynaecological examinations will be performed to determine if one is suitable to undergo the egg freezing procedures. Ovary assessments will also be conducted to estimate the potential yield of oocytes and chance of future pregnancy.
Q3. Is there any difference between frozen and fresh eggs?
Egg freezing is a technology to put the women’s eggs in -196°C liquid nitrogen for long term storage. The woman has the option of thawing the frozen eggs for in-vitro fertilization when she wants to get pregnant in future. Vitrification is the most commonly used method for egg freezing after year 2000. In this technique, cryoprotectants are used to draw water out of the eggs. The egg is then rapidly cooled to -196°C to prevent formation of ice crystals and preserve the eggs. The survival rate of vitrified eggs is over 90% after thawing. The pregnancy rate is comparable to that of fresh oocytes.
Q4. What are the procedures of egg freezing?
The whole egg freezing process takes about two weeks and involves two main phases. The first phase is to produce multiple eggs by ovarian stimulation, in which hormone injections are usually given for about 10 days. Ultrasound examination is performed regularly to monitor oocyte maturation and determine the best time for egg collection. The next phase is egg retrieval. The procedure usually takes about 30 minutes, during which a needle is inserted through the vagina to reach the ovaries and take out the mature eggs. Egg retrieval is carried out under ultrasound guidance and anaesthesia, it is a painless procedure.  
Q5. Does egg retrieval cause side effects?
Egg retrieval is a minor surgery. While a needle is used for egg removal, the risk of bleeding or bacterial infection due to organ or blood vessel injury near the ovaries is very low. The procedure is usually completed within 30 minutes and patients can be discharged after 3-hour observation. Side effects are uncommon during the ovarian stimulation phase. With proper medication and regular monitoring, the chance of developing Ovarian Hyperstimulation Syndrome (OHSS) is not high. While some women may experience minor swelling during the stimulation phase, the condition usually resolves after egg retrieval and resumption of normal menstrual cycle.
Q6. Will egg freezing cause early menopause?
Some women may worry that egg freezing will exhaust their egg reserves and cause early menopause. Don’t panic about this. With normal ovarian reserve, a woman can develop around 10 to 20 egg follicles each month. Only one follicle becomes mature for the possibility of pregnancy in a normal cycle, whereas in an egg freezing cycle, the rest of the egg follicles are also stimulated to reach maturity so that more eggs can be harvested. In other words, all the eggs obtained in an egg freezing cycle are from the current not the future cycles.

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