Transfer of embryos into the uterus: how much do technical factors affect pregnancy rates?
OBJECTIVE
Our objective was to identify the effect on outcome of (a) ultrasound-assisted embryo transfer, (b) the use of different embryo transfer catheters, and (c) the length of time the patients remain in the supine position after embryo transfer.


METHODS
The setting was a private fertility center.


METHODS
This was a prospective study of 178 in vitro fertilization and embryo transfers (IVF-ET) and 63 frozen embryo replacements (FER).


RESULTS
The pregnancy rate was 28.7% following IVF-ET and 31.8% for FER. Ultrasound-assisted transfer did not affect the outcome (29 vs 30.3%). There was no difference in the performance of the Wallace and Frydman catheters with regard to outcome (30.3 vs 30.7%). Although there was an increase in pregnancy rate as the time interval in the supine position after ET increased, this needs a larger study.


CONCLUSIONS
The parameter studies did not affect the outcome of IVF/ET or FER. Some factors encouraged us to recommend ultrasound-assisted transfer in some cases, and the use of a Frydman catheter for transfer and to encourage the supine position after transfer for longer periods.
London Fertility & Gynaecology Centre, England.
T
T
al-Shawaf
R
R
Dave
J
J
Harper
D
D
Linehan
P
P
Riley
I
I
Craft
D000005:Abdomen / Q000000981:diagnostic imaging; D002404:Catheterization / Q000295:instrumentation; D015925:Cryopreservation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D016683:Supine Position; D013997:Time Factors; D014463:Ultrasonography