Natural Cycle

The Natural IVF Cycle aims at monitoring the normal ovulation of a woman with a regular menstrual cycle without the administration of hormones.


What is the procedure of Natural IVF Cycle?

The developing follicle is monitored by ultrasound every 3-4 days, to determine its rate of development. When the follicle has reached the appropriate diameter (maximum diameter 18-20 mm) combined with a suitable oestradiol level in the blood, predicting the maturity and quality of the contained oocyte, the chorionic gonadotropin (hCG) is administered in order to achieve its final maturation. –36 hours later, the oocyte retrieval is performed, under sedation (twilight anaesthesia) and if present, it is fertilised in the laboratory through micro-fertilisation (ICSI) and transferred into the uterus 3 or 5 days later.

40% of Natural IVF Cycles are cancelled due to the absence of an oocyte, or failed fertlisation and embryo development.

One option in Natural IVF cycles is to undergo a number of cycles, to create and vitrify the embryo created in each cycle for the purpose of creating 2-3 embryos, which will be transferred in a subsequent cycle following appropriate preparation of the uterus, therefore giving a higher chance of pregnancy.

What is the pregnancy rate in Natural IVF Cycle?

Studies have shown that the pregnancy rate in Natural IVF Cycle does not exceed 15%, whereas the corresponding rate in classic IVF –is 50-54% for women up to age 28 and 20% for women age 40. —In nature, the highest rate of pregnancy per cycle in humans is 20-25%. —These rates depend on the woman’s age since at the age of 20, good quality oocytes constitute 80% of existing oocytes, while at the age of 40 it is 15-20%.

What are the advantages of this method?

  • Absence of hormonal stimulation
  • Absence of twin pregnancy (high-risk pregnancy)
  • Avoidance of ovarian hyperstimulation syndrome (OHSS)
  • Experience of natural conception
  • Lesser mental strain, since no medication is administered
  • Reduced cost per attempt

What are the disadvantages of this method?

  • Low rates of pregnancy and live birth per attempt, compared to classic IVF
  • Long-term procedure with multiple egg retrievals and cycle cancellations
  • Increased mental strain due to repeated failures
  • Increased overall cost due to repeated failures

Women able to follow this method:

  • Women under 35 years of age
  • Women of any age who meet the criteria for IVF who do not desire ovarian hormonal stimulation
  • Women of any age who are poor responders— producing less than three oocytes regardless of the stimulation protocol
  • As a last resort before egg donation
  • When there are medical reasons to avoid hormonal stimulation, such as liver or kidney disease, history of breast or ovarian cancer

In conclusion, Natural IVF Cycle is an alternative for women who do not want to take hormones and are willing to accept lower pregnancy rates and increased cycle cancellation rates per attempt, in comparison to classic IVF. The natural cycle is a cost-effective solution if pregnancy is achieved on the first attempt, but not in cases of repeated failures.