Hum Reprod. 2008 May;23(5):1101-6.
A randomized controlled clinical trial of 2295
ultrasound-guided embryo transfers.
Drakeley AJ, Jorgensen A, Sklavounos J, Aust T,
Gazvani R, Williamson P, Kingsland CR.
Hewitt Centre for Reproductive Medicine,
Liverpool Women's Hospital NHS Foundation Trust,
Crown Street, Liverpool L8 7SS, UK. adrakeley@yahoo.com
Background:
We wanted to test the hypothesis
that using abdominal ultrasound at the time of
embryo transfer to guide replacement, improved
pregnancy rates by at least 5%.
Methods:
An RCT
in a large assisted conception unit. A pilot
study and power calculation suggested that at
least 2000 embryo transfers were required to
demonstrate a difference of 5%, for a test with
80% power and Type 1 error 0.05. Randomization,
data entry and analysis were arranged
independently. Randomization was stratified for
age and fresh/frozen embryo transfer. Analysis
was by intention to treat.
Results:
There was no
difference in clinical pregnancy or live birth
rates between the two groups. The clinical
pregnancy rate for ultrasound-guided embryo
transfer was 22% and for non-ultrasound-guided
embryo transfer was 23% (odds ratio: 0.96; 95%
confidence interval: 0.79-1.18).
Conclusions:
We
set out to determine whether ultrasound-guided
embryo transfer improved clinical pregnancy
rates and live birth rates in assisted
conception. We used an appropriately powered RCT
design. We did not demonstrate a difference.
This outcome is at odds with the UKs National
Institute of Clinical Excellence recommendations
for fertility treatment (Fertility Assessment
and Treatment for People with Fertility
Problems. London, UK: RCOG Press, 2004, 112.)
which used a meta-analysis of four smaller
trials (range 362-800 patients, totalling 2051
embryo transfers) to conclude that ultrasound
should be offered. We suggest that the current
Cochrane review should be updated with data from
our trial and recommend that consideration is
given to accounting for heterogeneity between
the included trials.
Please click on the required question..
