New research compares natural IVF cycles versus artificial cycles

A team of Melbourne IVF fertility specialists and researchers have conducted research comparing endometrial preparation for frozen-thaw embryo transfers, finding that pregnancy outcomes for natural cycles are just as good as artificial (or medicated) cycles.  

Dr Genia Rozen, Fertility Specialist at Melbourne IVF said she is confident this new research will help improve patient outcomes.

“I’ve already changed my practice, I try to use natural cycle where possible,” said Dr Rozen.

There are different approaches to prepare the uterus (womb) during a frozen-thawed embryo transfer. A natural cycle is carried out using the woman’s spontaneous ovulation (release of the egg) to produce the hormones which support the transferred embryo.

The artificial cycle overrides natural ovulation, with lining being prepared by sequentially administered estrogens and progestogen. The artificial cycle is necessary for women without spontaneous ovarian function, such as those with premature menopause, and it is also convenient for scheduling purposes.

Dr Rosen said increasingly, and in some centres exclusively, artificial cycle preparation, is being adopted over natural cycle.

“The study provides new insights to our understanding of the optimal endometrial preparation, giving a clearer picture of this complex landscape. Interestingly in our study, the positive bhcg (initial pregnancy blood test) was similar in both groups but the miscarriage risk was higher in the artificial cycles. 

“The research suggests that artificial cycle is perhaps an over simplified replica of the much more complex hormonal and biochemical processes which occur throughout the menstrual cycle and early pregnancy.

“Natural cycles are easier and more acceptable for patients, so improves compliance and tolerability of ART.

“This new research is exciting particularly as the data on optimal endometrial preparation is limited; the most recent Cochrane review on this topic suggested that that there was insufficient evidence to recommend one method over another.

“As IVF lab practices have improved, frozen-thaw embryo cycles are being done more frequently. So it’s important to have results from an IVF centre which does both, for a balanced perspective.

“At Melbourne IVF we have a large ART research program with high patient numbers, giving us lots of scope to explore and interrogate our clinical practice and find ways to fine tune and improve outcomes for our patients.

“Our in-house laboratories place great emphasis on research and development. For each of our patients, we aim to scrutinise and optimise every step of their treatment, to aim for the best outcome possible.

“This research provides further insights to our understanding of the optimal endometrial preparation, important for optimising frozen-thaw embryo transfers,” said Dr Rozen.