Natural IVF Cycle

The natural IVF cycle is a milder form of IVF, in which the egg normally develops in this cycle is collected, without the use of medicinal ovarian stimulation.

Unlike classic IVF, where hormonal drugs are administered for the recruitment and development of many follicles, in the natural cycle the treatment is based on the body's natural function. The woman's body chooses and develops, as happens in every menstrual cycle, a dominant follicle, from which a mature egg can be obtained.

This method is a simpler and less intrusive approach, which may be suitable for specific women and couples.

However, like any assisted reproduction therapy, it needs the right choice of case, careful monitoring and realistic information about its possibilities and limitations.

What is the Natural IVF cycle?

The natural IVF cycle is the IVF treatment in which there is no intense hormonal stimulation of the ovaries. Instead of seeking to produce many eggs, the goal is to collect one egg that develops naturally in the woman's cycle.

The procedure involves close monitoring of the development of the follicle with ultrasounds and, where necessary, with hormonal tests. When the follicle reaches the appropriate stage, ovulation is planned.

The collected egg is fertilized in the laboratory with sperm of the partner or donor, usually with conventional IVF or microinsemination, as the case may be. If a good quality embryo arises, the embryo transfer to the uterus follows.

In Which women Can it be suggested?

The natural cycle can be an option for many women, but it is not necessarily the right method for everyone. The decision depends on age, ovarian reserve, history of previous efforts, quality of eggs, cause of infertility and personal preferences of the woman or couple.

It can be discussed in cases such as:

  • women who do not desire or cannot receive hormonal stimulation,
  • women with low ovarian response in previous aroused cycles, when the ovarian response to drugs is at most one follicle,
  • women who want a more gentle and natural approach,
  • women who want to avoid the financial burden of arousal drugs,
  • Women with an individual history of breast cancer, now allowed by the oncologist to have children

The choice of the natural cycle must be made after a detailed discussion with the fertility specialist, so that it is clear whether the specific method offers a real benefit in this particular case.

Advantages of the natural IVF cycle

The natural IVF cycle has some important advantages, mainly because it is a milder and less economically aggravating approach.

A key advantage is that the egg matures naturally, within the body's normal hormonal environment. In some cases, this may be important for women who do not respond well to drug stimulation or who produce few eggs even with high doses of medication.

In addition, because intense ovarian stimulation is not used, the risk of hyperstimulation is avoided. The ovaries do not swell from the growth of many follicles, which makes the method milder for the body.

Another advantage is that the endometrium is not exposed to high levels of hormones due to drug stimulation. This is supported by some circles that it could help maintain a more natural environment for possible implantation.

The natural cycle also limits the body's exposure to high levels of estradiol, which may be important for women who desire or need to avoid a heavy hormonal burden.

From a practical point of view, the method reduces the cost of injectable stimulation drugs, as they are either not used or used little, depending on the protocol.

The process is usually simpler, it can be repeated in continuous cycles and the woman often continues her daily activities normally. In some cases, ovulation can be done with little or even without anesthetic intervention, as it usually involves the collection of a single egg.

Also, because a fetus usually occurs and a fetus is transferred, the risk of multiple pregnancy, such as twin or triplet pregnancy, is reduced, which is associated with an increased risk of miscarriages, prematurity and pregnancy complications.

How does the process take place?

The process begins with monitoring the woman's natural cycle. The doctor checks the development of the dominant follicle with transvaginal ultrasounds and, where necessary, with hormonal tests.

When the follicle reaches the appropriate size and the hormonal values show that the egg is approaching maturation, ovulation is planned. In some cases, a pharmaceutical injection may be given for the exact timing of ovulation.

Ovulation is a short process and, since it usually involves a follicle, it can be less invasive than ovulation of an stimulated cycle. The need for anesthesia or intoxication is evaluated individually, based on the case and the comfort of the woman.

The collected egg is transferred to the laboratory, where it is fertilized with sperm from the partner or donor. Depending on the data, conventional IVF or microfertilization can be applied.

If an embryo emerges and develops appropriately, embryo transfer is performed. In some cases, it can be chosen to freeze the embryo and transfer it to the next cycle, depending on the treatment plan.

Natural cycle or classic IVF?

The choice between the natural cycle and classic IVF is not the same for all women.

Classical IVF with stimulation aims to collect more eggs to increase the chances of creating more embryos. This can be important in many cases.

On the contrary, the natural cycle aims for a milder process, with fewer drugs, less burden and utilization of the egg that develops naturally.

The right choice depends on the woman's history, age, ovarian reserve, previous efforts, cause of infertility and the couple's priorities.

The decision must be made after detailed information, without generalizations and without excessive expectations.

Realistic expectations in the natural IVF cycle

The natural cycle may be a valuable option for some women, but it is not a guarantee of success. The probability of pregnancy depends on the quality of the egg, the success of the fertilization, the quality of the fetus, the condition of the endometrium and the overall history of the couple.

Because in each cycle there is usually a single egg, the process requires patience, proper planning and clear information. More efforts may be needed to achieve the desired result.

Responsible medical guidance is not based on the promise of success, but on the honest evaluation of the data and the choice of the method that makes real meaning for the particular woman and the particular couple.

IVF

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Ioannis A. Sklavounos MD MSC DFFP
Obstetrician Surgeon Gynecologist
Specialists & Retrained in Great Britain
T.Senior Clinical Fellow – Liverpool Woman’s Hospital UK

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