In vitro maturation (IVM) is a new technique in assisted reproductive technology in which immature eggs are collected from the ovaries and matured in the laboratory before being fertilized.

IVM of human eggs was first introduced in 1965 but the first successful pregnancy from IVM was not reported until 1991. Since then, IVM has advanced significantly to become an infertility treatment options in recent years.

How Does IVM Work?

First, the patients undergo blood tests and ultrasound at the start of the IVF cycle to determine the best time for collecting the immature eggs. Only a minimal hormone stimulation of the ovaries (or no stimulation in some cases) is required depending on which regimen is used by the fertility doctor.

When the best time to collect the immature eggs is determined, usually when the egg diameter is between 6 mm and 12 mm, the immature eggs are collected transvaginally using a small ultrasound guided needle. Patients are provided local anesthesia or general anesthesia to reduce discomfort during this process.

The collected immature eggs are matured in the laboratory under specific environment for 24 to 48 hours. Once the maturation is complete, the matured eggs are fertilized with sperm using intracytoplasmic sperm injection (ICSI) and incubated to become embryos or the mature eggs can be frozen and preserved for future use.

After the embryos grow to a certain stage and ready for transfer, the embryo(s) are transfer into the uterus for implantation and pregnancy is confirmed through blood tests.

What are the advantages of IVM?
  • Less side effects. IVM eliminates complications from stimulation drugs, especially OHSS.
  • Less cost. IVM reduces the need for hormone stimulation drugs and frequent sonographic monitoring compared to conventional IVF.
  • Less time. IVM requires no need to prepare patients before starting fertility treatment and the procedure can be performed urgently, irrespective of the phase of the menstrual cycle without affecting the quantity and maturation rate of the eggs. 
What are the disadvantages?

Not Enough Data to Confirm Its Efficiency and Safety

Although IVM appears to be a promising technique, it is a relatively new procedure and there is still no strong evidence from randomized clinical trials to confirm its efficiency compared to IVF. A few observational studies in groups of women with PCOS found a high maturation rate of eggs up to 80.3% and clinical pregnancy rates from 21.5% to 50% per cycle.

One of the debates with IVM is the long-term safety of the child’s development and health. As less than 3000 children have been born through IVM, there is limited data regarding the developmental and health outcomes of the children. Currently, studies from a number of fertility centers have shown no differences concerning the risk of congenital defects in children after IVM compared with conventional IVF.

Who would benefit from IVM?

IVM was first proposed to be used in women who are at risk for ovarian hyperstimulation syndrome (OHSS) but now the indications for IVM have expanded. There are a few broad groups of patients who may benefit from IVM:

  • Women with polycystic ovarian syndrome (PCOS) who are at high risk for OHSS.
  • Fertility preservation in cancer patients who cannot undergo ovarian stimulation (i.e. patients with hormonally sensitive cancers) and/or cannot delay their cancer treatment.
  • Situations where no suitable standard fertility treatment exists; such as oocyte donation, FSH resistance, and other contraindications for ovarian stimulatory drugs.

IVM technology has continued to improve since the first IVM-induced pregnancy in 1989 and has shown great promise to making IVF safer and easier on the women. However, as a relatively new procedure, there are many unknowns in regards to the long-term health of the child born through IVM or its efficacy compared to other established fertility treatments. One should fully understand the risk and benfits of IVM before considering this option.



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