The success of any IVF cycle is known to be multifactorial, although there is no consensus about the factors that influence the outcome. Now, a new retrospective study elucidates the negative effect of certain key recipient-related parameters, such as increased body mass index (BMI >30 kg/m2), endometrial thickness (<8 mm), and pituitary down-regulation, on IVF outcome in donor oocyte cycles, independent of the age of the recipient. The study results have been published in the current issue of Human Reproduction.
Lionel Dessolle from the Service de Gynécologie Obstétrique et Médecine de la Reproduction, Hôpital Tenon, France, investigated 450 frozen-thawed embryo transfers to identify the predictive factors of treatment success. The study considered IVF cycles carried out using donor oocytes in 198 infertile recipients with a mean age of 35.7 years (±4.5) during the period, January 1992 to December 2006. The mean number of transferred embryos was 1.65±0.5 (range=1-3) and the overall implantation, clinical pregnancy, and delivery rates noted during the analysis were 18%, 30%, and 23%, respectively.
The findings of the univariate analysis showed that the rate of pregnancy was substantially higher in subjects with the following characteristics:
• <35 years of age
• BMI of <30 kg/m2
• Endometrial thickness of ≥8 mm
• Amenorrhea
• Not used gonadotropin releasing hormone (GnRH) analogue for pituitary down-regulation prior to endometrial priming
Based on the study results, the researchers concluded that some of the negative determinants of IVF outcome in oocyte donor cycles include obesity, endometrial thickness of <8 mm, and the administration of GnRH analogue before priming of the endometrium.
In another retrospective analysis, Huang et al (Reproductive BioMedicine Online, 2008) suggested the pulsatility index (impedance of blood flow in the uterine arteries) measured on the day of embryo transfer, and recipient’s age, as good predictors of successful pregnancy outcomes during oocyte donation IVF cycles. The researchers investigated 143 donor cycles where the donors were below 30 years of age. The study results showed an increased rate of implantation and reduced abortion rate in the younger recipients (<34 years) compared to recipients with more advanced age (≥40 years old). Additionally, a substantial increase in the rates of implantation and successful pregnancy outcomes were noted for a pulsatility index of ≤3.0.
Another study by Zenke et al (Fertility and Sterility, 2004) proposed uterine pathology, transfer difficulty, thin endometrium, and the number of high-grade embryos as principal recipient-related predictors of IVF treatment success. Safdarian and Peyvandi (Acta Medica Iranica, 2005) also substantiated the role of the endometrial pattern in predicting the success rate of pregnancy.
In view of several studies indicating the diversity of determinants of IVF outcome in oocyte recipients, further large clinical trials are still required to reach a consensus on the ideal prognostic factors that could aid in customizing treatment strategies.
References
1. Dessolle L, Daraï E, Cornet D, et al. Determinants of pregnancy rate in the donor oocyte model: a multivariate analysis of 450 frozen-thawed embryo transfers. Hum Reprod. 2009 Dec;24(12):3082-9.
2. Huang LS, Lee MS, Cheng EH, et al. Recipient age and pulsatility index affect uterine receptivity in oocyte donation programmes. Reprod Biomed Online. 2008 Jul;17(1):94-100.
3. Zenke U, Chetkowski RJ. Transfer and uterine factors are the major recipient-related determinants of success with donor eggs. Fertil Steril. 2004 Oct;82(4):850-6.
4. Safdarian L, Peyvandi S. Factors affecting the outcome of oocyte donation cycles. Acta Med Iran. 2005;43(2):123-126.
