What is natural cycle IVF?
Natural cycle IVF is a treatment for infertility that uses the same process as conventional IVF, but does not involve the use of hormonal stimulation of the ovaries to produce multiple eggs.
If male infertility is a concern, intracytoplasmic sperm injection (ICSI), where healthy sperm is injected directly into the egg, may be used for the fertilization process.
If the fertilized egg (embryo) reaches the blastocyst stage (approximately five days later) and is healthy, the embryo is then transferred to the woman’s uterus for implantation where it can develop into a pregnancy.
Natural cycle IVF with in vitro maturation (IVM)
An alternative to performing natural cycle IVF is to trigger ovulation and perform immediate egg collection. Mature eggs can be fertilized immediately and any immature eggs can be matured in the laboratory. Once they have matured, they too can be fertilized.
All the fertilized eggs are then left to develop and one best embryo can then be chosen for transfer. This treatment is sometimes called natural cycle IVF/IVM.
Modified natural cycle IVF
30% of women prematurely ovulate before egg collection. Hormones are usually administered to avoid this, but because only one mature egg is normally collected, the pregnancy rate per started cycle is still usually less than 20%.
Modified natural cycle IVF with in vitro maturation (IVM)
Similarly to natural cycle IVF/IVFM, the aim is to collect a mature egg for fertilization and a number of immature eggs, which can then by matured by IVM then fertilized. This process is called modified natural cycle IVF/IVM.
Younger patient pregnancy rates per started cycle are over 40-45%.
When is natural cycle IVF recommended?
- Need or desire for a medication-free IVF cycle (such as those with PCOS)
- Poor ovarian reserve (a low number of remaining eggs in the ovaries)
- Peri-menopause (the period of a woman’s life right before menopause)
- Poor response to ovarian stimulation by hormonal injections in a previous standard IVF cycle
- Women with normal egg reserves who want a lower-cost approach to IVF
Natural cycle IVF is not an option for women who do not ovulate, but it may be a good option when male factor infertility is the only diagnosed cause of infertility.
Risks of natural cycle IVF
Natural cycle IVF has lower success rate because the chances of having a healthy egg that responds to fertilization and develops into a healthy embryo are lower with fewer eggs to choose from, compared with the typical 15 eggs produced and collected during standard IVF.
Natural cycle IVF with IVM may be done in consecutive menstrual cycles, whereas conventional IVF cycles can only be performed at two to three month intervals to allow the hormones for stimulating the ovaries that had been given to be eliminated from the body before the next cycle begins.
Advantages of natural cycle IVF
The total cost of natural cycle IVF may be significantly lower than conventional IVF because the patient does not need to pay for ovulation stimulation medication. There is also less stress on the woman’s body than conventional IVF due to absence of hormonal injections, plus fewer office visits for monitoring the ovaries.
Also, there are no side effects related to ovarian stimulation, which include bloating, mood swings, and a condition known as ovarian hyperstimulation syndrome, which can cause abdominal distention, mild or even severe abdominal pain, or weight gain.
Birth weights of babies born to women using natural cycle IVF may be higher compared with regular IVF.