v Success Rates

IVF and ICSI treatment cycles (own eggs) August 2006 – December 2007

	Treatment	Number of cycles	% Achieving ET/ cycle started	CPR/ cycle started	CPR/ embryo transfer
Female Age <35yrs	IVF	64	82.8%	26.6%	32.1%
Female Age <35yrs	ICSI	94	93.6%	36.2%	38.6%
Female Age 35-37	IVF	50	82.0%	22.0%	26.8%
Female Age 35-37	ICSI	57	94.7%	19.3%	20.4%
Female Age 38-39	IVF	35	82.9%	14.3%	17.2%
Female Age 38-39	ICSI	31	87.1%	6.5%	7.4%
Female Age 40+	IVF	23	60.9%	8.7%	14.3%
Female Age 40+	ICSI	22	91.0%	0.0%	0.0%

Data for Frozen-Thawed Embryo Transfer Cycles (2007)

The table below reflects the data for cycles where the thawing of embryos has been initiated.

Embryo survival rates achieved post-thaw: >80 %

Cycle category	Number of cycles	CPR/ thaw cycle	CPR/ embryo transfer
IVF frozen-thawed ET cycles	14	35.7%	38.5%
ICSI frozen-thawed ET cycles	16	25.0%	25.0%
Overall	30	30.0%	31.0%

Data for Intrauterine insemination treatments (IUI) 2007 – partner’s sperm

	Number of treatments	CPR/ IUI treatment
Female age <36	123	20%
Female age 36-39	132	16%
Female age 40+	35	14%
Overall	290	17%

Understanding Success Rates

ET = ‘embryo transfer’

CPR = Clinical Pregnancy Rate (fetal heartbeat detected on ultrasound)

Treatment cycle…. means the start of drugs with a view to performing an IVF treatment. This is the definition used by the Human Fertilisation and Embryology Authority (HFEA) and is the basis on which license fee charges are made in the UK. Some cycles may not be completed due to failure to respond to drugs prior to planned egg collection, failure to obtain eggs, or failure of eggs to fertilise or embryos to develop in the laboratory.

Interpreting Success Rates

Different Fertility Clinics may express their results in different ways, apply different selection criteria and offer IVF or ICSI to couples at different points in their investigations or treatment algorithm. For this reason the HFEA recommends that comparative success rate data should not be represented as a ‘league table’ and that the data may be misleading when used to try to indicate the chance of success that an individual couple may have with IVF at one centre versus another. This major difference between clinics is readily illustrated by examining the differences in the numbers and proportion of Intrauterine insemination (IUI) pregnancies to IVF pregnancies between clinics.