Soft versus firm embryo transfer catheters for assisted reproduction: a systematic review and meta-analysis.
BACKGROUND
The true impact of the embryo transfer catheter choice on an IVF programme has not been fully examined. We therefore decided to systematically review the evidence provided in the literature so that we may evaluate a single variable in relation to a successful transfer, the firmness of the embryo transfer catheter.


METHODS
An extensive computerized search was conducted for all relevant articles published as full text, or abstracts, and critically appraised. In addition, a hand search was undertaken to locate any further trials.


RESULTS
A total of 23 randomized controlled trials (RCT) evaluating the types of embryo transfer catheters were identified. Only ten of these trials, including 4141 embryo transfers, compared soft versus firm embryo catheters. Pooling of the results demonstrated a statistically significantly increased chance of clinical pregnancy following embryo transfer using the soft (643/2109) versus firm (488/2032) catheters [P = 0.01; odds ratio (OR) = 1.39, 95% confidence interval (CI) = 1.08-1.79]. When only the truly RCT were analysed, the results were again still in favour of using the soft embryo transfer catheters [soft (432/1403) versus firm (330/1402)], but with a greater significance (P < 0.00001; OR = 1.49, 95% CI = 1.26-1.77).


CONCLUSIONS
Using soft embryo transfer catheters for embryo transfer results in a significantly higher pregnancy rate as compared to firm catheters.
Abou-Setta
Ahmed M
AM
The Egyptian IVF-ET Center, 3, Street 161, Hadayek El Maadi, Cairo 11431, Egypt. abousetta_md@hotmail.com
Al-Inany
Hesham G
HG
Mansour
Ragaa T
RT
Serour
Gamal I
GI
Aboulghar
Mohamed A
MA
D002404:Catheterization / Q000295:instrumentation*; D004624:Embryo Transfer / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D006801:Humans; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D016032:Randomized Controlled Trials as Topic; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods