Quantity and quality of eggs for successful IVF

number of eggs for IVF

A common question among IVF patients is how many eggs are needed for IVF and whether the number of eggs obtained from the ovarian puncture is sufficient.

Although only one embryo is needed to achieve pregnancy, a larger number of eggs increases the chances of obtaining high quality embryos and thus the possibility of pregnancy. However, the quality of the eggs is as important as their quantity, as having many low-quality or immature eggs is not beneficial.

Let’s start at the beginning:

number of eggs for IVF

What are antral follicles and how important are they in fertility?

Antral follicles are small fluid-filled structures in the ovaries, visible by ultrasound at the beginning of the menstrual cycle. Their number gives an estimate of a woman’s ovarian reserve, an idea of her fertility.

They are important because each one has the potential to develop an egg that could be fertilised. Therefore, a higher number of antral follicles indicates a greater ovarian reserve, which is a positive factor in fertility treatments such as IVF.

How many follicles are needed to get pregnant?

number of eggs for IVF

To achieve pregnancy through IVF, there is no specific number of follicles required, as even a single follicle can produce a viable egg for fertilisation.

However, generally, fertility specialists seek to obtain several follicles to increase the chances of success, as not all follicles will produce viable eggs and not all eggs will be successfully fertilised.

The optimal number may vary depending on each woman’s individual circumstances, including her age and ovarian response.

Estimating the number of eggs for IVF

In in vitro fertilisation (IVF) treatments, ovarian stimulation is used to promote the growth of multiple ovarian follicles, as opposed to the single follicle that would develop naturally.

This process increases the chances of collecting several mature eggs, which can improve the chances of success in achieving a pregnancy.

Although there is no specific number of eggs that guarantees pregnancy, factors such as the quality and quantity of eggs collected are crucial.

óvulos para FIV

Results or response to ovarian stimulation

Each woman’s response to ovarian stimulation in IVF-ICSI cycles varies according to factors such as medication and fertility status.

Three groups can be identified:

  • Low responders, with a maximum of 3 eggs obtained, usually due to low ovarian reserve.
  • Normal responders, with 4-15 eggs obtained.
  • Hyper-responders, who can obtain more than 15 eggs, often young women with no fertility problems.

It is crucial to follow up ultrasound and laboratory tests during stimulation to adjust medication according to ovarian response.

óvulos para FIV

What follicular size is ideal for egg collection?

The growth of ovarian follicles is monitored through transvaginal ultrasound by the gynaecologist to determine their maturity. A follicle is considered mature enough to contain an egg ready for fertilisation when it reaches a size of 16-20 mm.

Egg retrieval, or follicular puncture, is then scheduled approximately 34-36 hours later. Thus, follicle size serves as an indicator to predict the number of mature eggs that can be retrieved at the ovarian puncture.

Oestradiol blood levels

It is possible to predict the number of mature follicles from the level of oestradiol measured in a blood test as the amount of oestradiol in the blood can indicate the maturity of the ovarian follicles, with each corresponding to a range of 200-300 pg/ml oestradiol.

For example, an oestradiol level of 3000 pg/ml might suggest that approximately 15 eggs are expected to be retrieved during follicular puncture.

endometriosis y tratamientos

Egg retrieval: follicular puncture

This procedure aims to collect eggs at optimal maturity, suitable for fertilisation.

However, the number of mature eggs retrieved may be lower than expected because not all follicles contain mature or retrievable eggs, directly impacting the chances of successful fertility treatment.

How many eggs are needed for successful IVF?

The number of eggs obtained after IVF is an important factor, but not the only determinant of success. The quality of the eggs is equally crucial and varies according to each woman’s specific situation, including her age and ovarian response.

Ideally, obtaining at least 8 to 15 eggs can increase the chances of success, allowing the best embryos to be selected for transfer. However, success stories can occur even with a smaller number of eggs, emphasising quality over quantity.

A larger number of eggs offers more opportunities to select the best eggs for fertilisation, increasing the chances of achieving a pregnancy. However, even with a smaller number of high-quality eggs, positive results can be achieved.

It is essential to focus on quality and personalised treatment according to the specific needs of each patient.

The importance of egg quality

The quantity of eggs collected in IVF is important, but it is not the only critical factor. Although having more eggs may increase the chances of obtaining quality embryos and thus improve the chances of pregnancy, the quality of the eggs is critical.

It is not beneficial to obtain a high number of eggs if they are not of good quality or maturity. The key is to find a balance between quantity and quality to maximise the chances of successful treatment.

Not all fertilised eggs will progress to the blastocyst stage, so obtaining high quality eggs is critical to increase the chances of reproductive success and allow for future embryo transfers.

number of eggs for IVF

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