Natural Cycle IVF. Part 3: It Works

Although I anticipated posting this final part concerning NC-IVF two weeks ago, it took me longer than I had anticipated to pull all the data together and organize it into a coherent discussion of NC IVF. So after much effort here it is....

In December 2006, my partner here at Dominion, Dr. Michael DiMattina, attended the First World Congress on Natural and Minimal Stimulation IVF in London, England. Now, London is not the greatest place to visit in December but DrD came back completely convinced that Natural Cycle IVF was worth trying. The keynote speech was given by none other than Dr. Robert Edwards (Nobel Prize winner and one of the pioneers of IVF--see my previous Blog post). Only 2 Americans were present among the hundreds of fertility physicians from around the world. In January 2007 we launched our Natural Cycle IVF program and since that time Natural Cycle IVF has become an integral part of our fertility treatment options.

At the ASRM meeting in Denver we were peppered with questions from other physicians and nurses and embryologists about our experience with Natural Cycle IVF. Here are answers to the most commonly asked questions...

Question #1: How many other clinics offer Natural Cycle and how many cycles do they perform?

At the ASRM meeting in Denver last month I presented the national data on utilization of NC-IVF across all IVF clinics reporting their results to SART. As is evident from the table below, about 15% of IVF clinics in the US offer NC-IVF, but the average number of NC-IVF cycles performed at those clinics that offer NC-IVF is less than 10. In looking at NC-IVF in 2006 (the year before we started our program) it is evident that we now perform more NC-IVF than all the other clinics in the US combined. Clearly, we are in a unique situation to comment on the addition of NC-IVF to a busy fertility clinic offering comprehensive fertility care and treatments.
Question #2: How much Natural Cycle IVF do you do?

The quick answer is "quite a bit." In 2007, the year we launched the program, we initiated 66 cycles and this year we are on target to initiate about 500 cycles of Natural Cycle IVF. As a result, every year since 2007, the percentage of Natural Cycle IVF in our clinic has increased....from 20% that first year to almost 70% (predicted) for 2010. Question #3: Has the inclusion Natural Cycle IVF impacted your number of cycle of stimulated IVF?

In fact, we still perform a lot of stimulated cycle IVF. We strongly believe that there is a place for both Natural Cycle and Stimulated Cycle IVF within our practice. Our total number of stimulated IVF cycles has remained fairly stable over the past 4 years, which is very interesting given the economy and the higher costs associated with stimulated IVF.



Question #4: What are the pregnancy rates with Natural Cycle IVF?

There are many ways to answer this question. We can look at pregnancy rate per initiated cycle or per successful retrieval or per embryo transfer. Not every patient will make it to retrieval or transfer in Natural Cycle IVF which is different than stimulated IVF (as nearly all patients go to retrieval and transfer since there is more than just the one egg that is produced in a natural cycle).

Shown below then are the pregnancy rates for 416 completed cycles. In patients under 35 years old the pregnancy rate was 35.4% per embryo transfer and for patients 35-39 years old the chance of pregnancy was 41% per embryo transfer (which is not statistically different than the rate for the younger group).

2007-2009 Success Rates for Natural Cycle IVF

Question #5: How many patients who initiate a cycle make it to retrieval and transfer?

Natural Cycle IVF differs from stimulated IVF in many ways. As the cancellation rate is higher in Natural Cycle IVF we knew that patient expectations and the associated financial implications of canceling a cycle would be important to codify. Thus, we have a sliding scale that takes into account cycle cancellation before retrieval (LH surge or ovulation), after retrieval but before fertilization or after fertilization but before embryo transfer (arrested embryo development).

Here is our data for all patients younger than 40 years old (2007-2009):

Question #6: How does NC-IVF compare with stimulated IVF?

In answering this question I compared NC-IVF to the Society for Assisted Reproductive Technologies (SART) data for all IVF clinics reporting to SART for 2007. The implantation rate (pregnancy per ET) was outstanding for NC-IVF (over 35%). So if a patient made it to transfer the odds of pregnancy were excellent. Does that mean that NC-IVF produced better embryos or a better lining or both? It is hard to say, but the concept that Mother Nature may provide a better outcome is certainly intriguing.


Question #6: What about OHSS and multiples?

Well the incidence of OHSS with NC IVF is 0%. One can't have OHSS without fertility drugs so with Natural Cycle IVF there is essentially no risk of OHSS. Multiples are also very rare. The only twin pregnancy we have had so far was a case of identical twins. Interestingly that patient had a child from stimulated IVF with us but was a very low responder with only 3 eggs. She elected to give NC IVF a try and with her first cycle she had a beautiful blastocyst and ended up with identical twins. Go figure..... 3 eggs for thousands of dollars and one baby vs. one egg for a fraction of the cost and twins. Never a dull moment in reproductive medicine.

The reason for the lack of twins is simply the fact that there is almost always only a single follicle, a single egg retrieved and a single embryo available for transfer. Nationally, we still transfer too many embryos as seen below.


This phenomenon then directly influences the multiple pregnancy rate which is over 30% for patients younger than 30 years old and 24% for those patients between 35 and 39 years old. Elective single embryo transfer is attractive to consider but in reality not that many patients will elect to transfer only one embryo. Natural Cycle IVF solves that dilemma for the patient as there is almost always just a single embryo available.


The risk of twins is mainly that of prematurity. Although patients are often thrilled with twins, we are happier with singletons. The pregnancies are less complicated and the outcomes are better.

Concluding Thoughts:

As far as we are concerned, Natural Cycle IVF is here to stay. Our extensive experience has demonstrated that acceptable pregnancy rates can be achieved, especially if NC IVF is integrated into a fertility practice as a viable treatment option and not relegated to use only in extremely poor prognosis patients. In looking at our data from 2007-2009 we inform our patients that if they are younger than 40 years old then they can anticipate the following odds:I cannot emphasize enough how much patients appreciate having this option as a bridge. Many who have failed clomid/IUI or clomid/FSH/IUI are much happier trying NC IVF than full stimulated cycle IVF. Some patients who have known for years that they need IVF have been ecstatic that they have a new option. Some low responder patients with diminished ovarian reserve have pursued NC IVF as opposed to egg donor IVF or adoption. Although success rates in these patients are certainly lower than with donor egg IVF or adoption (we anticipate that 10-12% of these poor prognosis patients may still achieve a pregnancy with Natural Cycle IVF), many patients are not open to alternative pathways to parenting...at least not until they feel like they have exhausted all options.