ArticleModified natural cycle IVF and mild IVF: a 10 year Swedish experience
Introduction
The trend towards single embryo transfer and increasing focus on ‘patient friendly’ IVF has lately led to a growing interest in modified natural cycle IVF (mnc-IVF) and mild IVF (m-IVF). Several countries now have legislation regulating the number of embryos transferred per treatment cycle, and population studies of children born after IVF clearly show the health benefits from treatments leading to deliveries of singletons (Bergh, 2007, Nygren et al., 2007). mnc-IVF and m-IVF are both treatment modalities involving less medical intervention, leading to a reduced number of oocytes retrieved. Stimulation protocols vary between clinics, and until recently there was no consensus on the nomenclature used to describe these treatments. The International Society for Mild Approaches to Assisted Reproduction published guidelines for terminology and description of protocols (Nargund et al., 2007; see also Edwards et al., 2007). Although the nomenclature is now settled, the terminology still encompasses a wide variety of clinical approaches to the mnc-IVF and m-IVF treatments (Verberg et al., 2009a, Verberg et al., 2009b). Treatment strategies for mnc-IVF and m-IVF include FSH stimulation, clomiphene citrate (CC) and use of gonadotrophin-releasing hormone (GnRH) antagonists, as well as luteal phase support administered both vaginally and as injections (Kolibianakis et al., 2004, Pelinck et al., 2006, Teramoto and Kato, 2007). The present study approaches both treatment modalities in a minimalistic way, exploring the potential of IVF as a treatment when there is a demand for less intervention using fewer resources. New studies are still needed to optimize these protocols in an era when IVF clinics meet new challenges in terms of cost-effectiveness, minimal intervention, maximizing results and singleton deliveries. This study presents a 10 year retrospective study describing mnc-IVF and m-IVF in a Swedish private IVF clinic during the years 1996–2007.
Section snippets
Materials and methods
mnc-IVF or m-IVF was offered to selected patients, based on both medical criteria and the woman’s desire for a ‘low interference’ treatment. Medical reasons for the choice of a mild approach included previous history of ovarian hyperstimulation syndrome (OHSS), undesired side effects of drugs during previous full scale treatments, and medical conditions requiring none or low grade hormonal stimulation (e.g. previous breast cancer). Only patients with regular menstrual cycles were accepted. The
Modified natural cycle IVF
The mean age of women undergoing mnc-IVF was 34.2 years and mean cycle day 3 FSH for these women was 8.0 ± 5.1 (1.4–24) IU/l (Table 1). The most frequent causes of infertility were unexplained infertility (28%), tubal damage (21%) and male infertility (16%). ICSI was performed in 31.7% of the treatment cycles. Of the 129 cycles started, 40 (31.0%) were cancelled prior to oocyte retrieval, 17 (13.2%) due to premature ovulation and 23 (17.8%) due to other reasons, including non-medical causes.
Discussion
The results reported in this study are based on consecutive cycles where all patients treated with mnc-IVF (1996–2007) and m-IVF (1997–2007) were included. The retrospective design is due to the limited number of patients who historically have asked for ‘low interference’ IVF. The lack of randomization is an obvious source of bias, where the good prognosis patients were advised to choose mnc-IVF or m-IVF. An increased demand for light stimulation protocols and a paradigm shift towards single
Acknowledgements
This study was supported by an unrestricted grant from the research council at Queen Sophia Hospital, Stockholm, Sweden. The authors are grateful to Mrs Birgitta Berthold for skilful data collection and construction of data sheets.
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Dr Aanesen completed his studies in medicine in 1990 at the Faculty of Medicine, University of Oslo, Norway. After his internship, he started his residency at the Department of Gynaecology and Obstetrics, Karolinska Hospital, Sweden, Stockholm in 1992, and became a specialist in 1997. He has had a research interest in sperm physiology and andrology and received his PhD 1998. Since 2001, Dr Aanesen has been working at the IVF Unit, Queen Sophia Hospital. His present research focuses on intracellular signalling and mild IVF.