In vitro fertilization, the forming of embryos outside of the body and then reintroducing the strongest ones into the mother’s body in hopes of achieving a successful pregnancy, was successfully performed in 1978 after many failed attempts. This first success paved the way for millions of couples throughout the next decades to become parents.
Since that time, IVF procedures have generally been done with ovarian stimulating drugs. These medications cause a woman’s ovaries to prepare and release multiple eggs during a cycle rather than just a single egg. The hope is that with multiple eggs released and the best embryos re-inserted during the implantation procedure, pregnancy will be more likely to result than with a single egg. That said, the first successful in vitro treatment was actually done using the natural cycle method.
Natural cycling in vitro does not use ovarian stimulating medications. Instead, this procedure works with a woman’s regular menstrual cycle in hopes of harvesting her natural production. As studies help doctors gain more insight into how ovarian drug stimulation affects patients, more are opting to try the natural method or try only mild stimulation medications. This is especially the case amongst women who are trying for a pregnancy into their 40s.
While not everyone is a good candidate for natural cycle, here are a few signs one might want to consult her fertility specialist about whether she would be a good candidate.
- Women who have low ovarian reserve – a lower number of healthy eggs – which can be determined through hormone testing, may be better served to try this method.
- Women who have been unsuccessful trying with standard ovarian stimulation drugs. While these poor responders may not have success with natural cycle IVF either, it can be a good option to consider before turning to oocyte donation.
- Woman who are at high risk for or have developed ovarian hyperstimulation syndrome – especially if the woman in question has been hospitalized due to OHSS before.
- Women who have any contraindications to using traditional stimulation, such as women who have a history of cancer or those who are allergic to the standard medication options.
There are also some real advantages to no stimulation or mild stimulation IVF. Many couples, for instance, find even considering fertility treatment completely off the table due to budget concerns. The great news is, using natural cycling is a much more affordable alternative. Not only are there no or very low medication costs, but the IVF cycle is often cheaper itself. Women who prefer not to use lots of medicines or who prefer a natural approach will also this method’s ability to let them maintain their natural balance and the risk of short and long term side effects are much more minimal, too. This is especially true for ovarian hyperstimulation syndrome, which can become quite serious. This method can be routinely repeated the next month after a failure, while it is common to be advised to wait two or three months between cycles using standard levels of ovarian stimulating drugs. Some evidence is now suggesting that stimulating drugs may actually make a woman less likely to positively respond to fertility treatment by having a negative impact on the endometrium – which can impact overall success rate. Likewise, some evidence is beginning to show that natural cycle embryos may at less risk for genetic abnormalities due to the minimal (or entire nonuse of) stimulating medications.
That said, natural cycle treatment also has disadvantages and drawbacks and is not a good option for everyone. Studies do consistently show that success rates are higher in traditional methods as compared to the natural cycling method and only about 50% to 70% of cycles have an embryo that will be considered a good candidate to be transferred back into the womb. There are also no surplus embryos to preserve for later use – each pregnancy will, thus, require another cycle.