Age and Fertility: Why Timing Matters, and When to Consider Egg Freezing
How age affects the chances of pregnancy and the egg reserve, and what egg freezing is and who it suits.
Egg Freezing
Retrieving mature eggs after ovarian stimulation and freezing them by vitrification, to preserve fertility for medical reasons or when delaying pregnancy.
The number and quality of eggs fall with age, and this decline becomes clearer after 35. Egg freezing keeps eggs from a younger age, to be used later when the woman wants to become pregnant.
Who is egg freezing for?
- Medical reasons: before chemotherapy or radiotherapy, or before surgery that may affect the ovaries.
- Low ovarian reserve or an early fall in AMH.
- Endometriosis, which may affect the ovaries over time.
- Delaying pregnancy for personal reasons, such as study, work or marrying later.
The steps
- Assessing ovarian reserve with an AMH test and an ultrasound follicle count.
- Ovarian stimulation with hormone injections for about 10 to 12 days, monitored by ultrasound.
- Egg retrieval under light anesthesia: a short procedure with no incision.
- Freezing the mature eggs by vitrification and storing them in liquid nitrogen at minus 196 degrees Celsius.
The vitrification breakthrough
Vitrification turns the egg into a glass-like state within seconds. This prevents the ice crystals that damaged eggs with the older methods. As a result, egg survival after warming has risen sharply, and frozen eggs now give results close to fresh ones.
When is the best time?
The younger the age at freezing, the higher the chances of pregnancy later. Ideally it is done before 35. After 38 the chances fall clearly, and more eggs are needed.
When you want to become pregnant
The eggs are warmed, fertilized by ICSI, and the embryo is transferred to the uterus. Freezing preserves the chance but does not guarantee a pregnancy. Success depends on the age at freezing and the number of eggs frozen.