Study question

Is there influenced pregnancy outcome at immediate retrial with rigid catheter after failed soft catheter trial in case of difficult embryo transfer?

Summary answer

Immediate retrial with rigid catheter after failed soft catheter trial in embryo transfer does not affect pregnancy rates.

What is known already

Generally, the soft catheters are associated with higher clinical pregnancy rates than the rigid catheters. But in case of difficult embryo transfer such as severely anteverted(AV) or retroverted(RV)uterus, some clinicians prefer to try rigid catheter for easy transfer other clinicians prefer to try soft catheter firstly, if failed, immediate retrial with rigid catheter. This retrial can increase induction of uterine contractions or damage to the embryos during the transfer process.

Study design, size, duration

A retrospective analysis of first fresh IVF-ET cycles between January2009 and December 2011 was performed. Embryo transfer was performed using either Wallace(SIMS PortexLtd., Kent, UK) and/or TDT set(Laboratoire CCD, Paris, France) catheter. Embryo transfer was performed on day3 for fresh embryos using trans-abdominal ultrasound guidance scanning with a full bladder.

Participants/materials, setting, methods

The embryo transfer performances are divided into two groups as: Group A describes the transfer only with TDT set transfer catheter (n=199).
Group B describes transfer with TDT set transfer catheter after failed Wallace (n=230).
IVF outcomes were statistically analyzed by t test. P value <0.05 was considered statistically significant.

Main results and the role of chance

The 429 embryo transfers performed during the study period resulted in 151 pregnancies (32.5%), of which 130 proved to be ongoing pregnancies (30.3%). An implantation rate of 20.4% was recorded. The mean age of the patients (Group A: 35.5 ± 4.2 vs. Group B: 34.5 ± 4.3), mean number of retrieved oocytes (10.1 ± 6.6 vs. 11.2 ± 7.1), endometrial thickness (10.8 ± 2.5 vs. 10.7 ± 2.3) and the embryos transferred (2.2 ± 0.5 vs. 2.1 ± 0.5) were comparable in two groups. Pregnancy (34.2% vs. 36.1%, p=0.47), implantation (20.3% vs. 20.5% p=0.48) and spontaneous abortion rates (14.7%vs. 13.3% p=0.38) were not significantly different between the both groups.

Limitations, reasons for caution

We did not verify that the pregnancy rate is higher when using only a soft catheter in case of difficult embryo transfer.

Wider implications of the findings

In our results, immediate retrial with rigid catheter after failed soft catheter trial in ET does not affect pregnancy rates. In case of severely anteverted or retroverted uterus, embryo transfer can be sometimes easy to perform successfully by soft catheter, and successful embryo transfer by soft catheter is associated high pregnancy rates. Therefore, in case of severely anteverted or retroverted uterus, first trial with soft catheter in embryo transfer is highly recommended.