In vitro oocyte maturation (also known as IVM, or IVM) is a procedure in which immature eggs mature in vitro, i.e. in the laboratory.
To perform this procedure, the most common is that the patient does not undergo a hormonal treatment of ovarian stimulation (if she receives it is at low doses) and this is one of its main advantages.
However, IVF laboratories do not perform IVM routinely and can be thus considered an experimental technique.
Below you have an index with the 8 points we are going to deal with in this article.
Definition of in vitro maturation (IVM)
In vitro maturation is an assisted reproductive technology by which immature eggs are matured in the laboratory until they reach the stage of maturity, also known as metaphase II.
The IVM process consists of incubating the immature oocytes for a period of time that usually ranges from 24 to 48 hours in a culture medium with controlled conditions.
The main difference compared to classic IVF cycles is that in IVM the patient does not receive (or receives at very low doses) the previous hormonal treatment. Therefore, IVM does not require ovarian stimulation, unlike regular IVF cycles.
This is one of the main advantages of IVM, as it minimizes the risk of ovarian hyperstimulation syndrome that can occur as a consequence of ovarian stimulation.
IVM is a technique that avoids ovarian stimulation and thus reduces the risk of ovarian hyperstimulation. Therefore, some of the situations in which IVM would be indicated are the following:
- Women with polycystic ovarian syndrome (PCOS) or polycystic ovaries. IVM is suitable as a fertility treatment for PCOS, as these patients have a high follicle count (the structures where the eggs are located in the ovary) and a higher risk of ovarian hyperstimulation with conventional IVF.
- Patients at risk of ovarian hyperstimulation or who wish to avoid ovarian stimulation to reduce the discomfort and costs associated with medication.
- Fertility preservation. IVM is an alternative for patients who cannot undergo ovarian stimulation because of a hormone-dependent tumor or because they should not delay the start of cancer treatment. If ovarian stimulation can be performed, IVM of immature oocytes can increase the number of oocytes available for preservation. In addition, IVM can also be performed in conjunction with ovarian tissue preservation.
- Low responder patients. In these patients, it is common to cancel a classic IVF cycle (with ovarian stimulation) due to low response, but obtaining immature oocytes and their IVM can be an alternative to cancellation.
Another option for patients with low response is to perform a "rescue" IVM. In this case, the cycle begins with the ovarian stimulation of a classic IVF cycle. All eggs are collected by ovum pick-up and IVM is performed on the immature oocytes to "rescue" them. The aim is to add them to the oocytes already obtained in a mature state in order to increase the chances of gestation of these patients.
Advantages of IVM
The IVM technique offers a number of advantages that have been mentioned throughout the article and are summarized as follows:
- It does not require ovarian stimulation, thus reducing the risk of ovarian hyperstimulation syndrome.
- Reduces discomfort, costs and time in a fertility treatment.
- It offers an alternative for preserving fertility when ovarian stimulation is to be avoided.
Currently, IVM is very restricted to special cases. The following are some of the reasons why IVM has not become popular:
- It is considered an experimental technique.
- It is not optimised because some of the problems it was supposed to solve, such as ovarian hyperstimulation, can be addressed in other ways.
- There are no realiable results to support the use of IVM versus classic IVF in patients with PCOS.
- It presents worse results in assisted reproductive technologies and a higher rate of miscarriage.
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In general, the obstetric and perinatal outcomes of babies born after IVM are good. However, there are few studies and, moreover, they follow-up the newborns only for a short period.
For all these reasons, IVM is not currently an alternative to classic IVF in cases where ovarian stimulation is not recommended. On the contrary, IVM does have a lot of potential in fertility preservation.
FAQs from users
What are the benefits of in vitro maturation of oocytes?
IVM (In Vitro Maturation) of oocytes is a technique that has been known for more than 20 years, but its clinical application remains very limited. The pregnancy rate results when IVM is applied are still worse than with IVF.
However, there are some cases where IVM can provide advantages over IVF:
- To optimize the performance of patients with low response. There are cases in which women respond less than expected to ovarian stimulation, so there are small follicles that do not grow with medication. These follicles can be aspirated along with the rest of the large follicles on the day of the puncture resulting in obtaining immature oocytes that could be matured in vitro to obtain more embryos after IVF.
- For women to whom the administration of gonadotropins for ovarian stimulation is contraindicated..
- For patients with polycystic ovaries and high risk of ovarian hyperstimulation using gonadotropins.
- For oncologic patients or patients with other pathologies that require urgent fertility preservation.
In the cases mentioned above, IVM is becoming more important, since it would allow us to increase the number of oocytes to be preserved without having to wait longer and without having to undergo more hormonal treatment before proceeding with the treatment of the disease.
Is in vitro maturation a good option for women with PCOS?
Women with polycystic ovarian syndrome (PCOS) may consider IVM as a possible option.
PCOS patients have a higher follicle count and also an increased risk of ovarian hyperstimulation syndrome.
Since the IVM technique does not require ovarian stimulation, the risk of hyperstimulation is minimized. This makes IVM a perfect fit for the treatment of patients with PCOS.
However, there is not enough evidence to recommend IVM over conventional IVF treatment for PCOS patients. In addition, there is also no clear evidence showing better results in terms of pregnancy rates of IVM versus conventional IVF in PCOS cases.
Suggested for you
We have discussed ovarian hyperstimulation syndrome throughout the article. Here you can learn more about this topic: What is ovarian hyperstimulation syndrome (OHSS)?
If you need more information about PCOS, click here: Polycystic ovary syndrome (PCOS): causes, symptoms, and treatment.
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