You will be provided with the titles and abstracts of a collection of medical RCT reports studying a clinical question -- for instance, the efficacy of an intervention on some medical outcome. Please write a few sentences synthesizing the findings of these reports, which could serve as a conclusion section for a systematic review article. Your response should not include any other text. The RCT reports are below.



Title 1:
Outcome of in vitro fertilization after transabdominal ultrasound-assisted embryo transfer with a full or empty bladder.
Abstract 1:
The use of ultrasound guidance has proven to be a key factor in performing embryo transfer in a gentle and atraumatic manner. However, despite the lower incidence of brusque maneuvers, bladder distension has not shown any positive impact on the IVF success rate.


Title 2:
Removal of cervical mucus: effect on pregnancy rates in IVF/ICSI.
Abstract 2:
Cervical mucus may cover the embryo transfer catheter during passage of the cervical canal, interfering with the correct placement of the embryo(s) into the uterine cavity. The effect of removal of cervical mucus prior to embryo transfer in IVF/ intracytoplasmic sperm injection (ICSI) on live birth rate was studied. The study was set up as a single blind randomized controlled trial. Couples undergoing IVF/ICSI were randomly allocated to either removal of cervical mucus prior to embryo transfer, or a mock procedure. Randomization was done with stratification for age, cycle number and method of treatment. Primary outcome was live birth rate. A total of 317 couples were included and underwent 428 cycles, of which the outcome of 3 cycles was unknown. Baseline characteristics of both groups were comparable. Live birth occurred in 52 of 220 (24%) cycles in the treatment group and 42 of 205 (21%) cycles in the control group (risk difference 3%, 95% confidence interval-5- 11%). It is unlikely that removal of cervical mucus prior to embryo transfer has a significant effect on live birth rate. A small effect, however, cannot be excluded.


Title 3:
Flushing the endometrium prior to the embryo transfer does not affect the pregnancy rate.
Abstract 3:
This study aimed to determine whether direct flushing of endometrial cavity with culture media just after cervical irrigation at the time of embryo transfer has any effect on pregnancy rates. A total of 240 women were prospectively randomised; one group of patients (group 1) underwent intrauterine direct flushing of endometrial cavity with culture media just after cervical irrigation at the time of embryo transfer as detected by transabdominal ultrasound and the other group of patients (group 2) had cervical flushing but did not undergo intrauterine flushing. Pregnancy (positive human chorionic gonadotrophin) rates were 57.5% and 62.9% for group 1 and group 2, respectively. Clinical pregnancy (positive fetal heart rate) rates were 45.2% and 51.4% for group 1 and group 2, respectively. Implantation rates were 20.0% and 21.2% for group 1 and group 2, respectively. Ongoing pregnancy (>12 weeks of pregnancy) rates were 47.9% and 47.2% for group 1 and group 2, respectively. There were no significant differences in pregnancy rates, clinical pregnancy rates, implantation rates and ongoing pregnancy rates between the two groups. In conclusion, even direct flushing of media into the uterine cavity neither improves nor adversely affects the pregnancy rate.


Title 4:
Cervical dilatation has a positive impact on the outcome of IVF in randomly assigned cases having two previous difficult embryo transfers.
Abstract 4:
The difficulty of embryo transfer has been reported to affect success rates in some centres, but not in others. Cervical dilatation has been proposed as a means to overcome difficult embryo transfer, but consistent criteria for patient selection are lacking. In a prospective randomized study, we examined the influence of cervical dilatation 1-3 months before embryo transfer on the outcome of IVF in cases having difficult embryo transfer in two previously failed IVF cycles.
                Two alternative methods of embryo transfer preparation were evaluated in 283 randomly assigned women having difficult embryo transfers in two previously failed IVF attempts. Randomization was made using a computer-generated random number table. Cervical dilatation before starting any IVF treatment was used in 145 cases, and no dilatation was performed in 138 cases.
                The cervical dilatation group yielded a significantly higher pregnancy rate than the non-dilated group (40% versus 24%; P < 0.01). Likewise, the implantation rate (24.1% versus 14.9%; P < 0.01) and the live birth rate (34.48% versus 19.56%; P < 0.01) were significantly higher in the dilatation group than in the non-dilated group.
                In patients with prior difficult embryo transfer, cervical dilatation 1-3 months before embryo transfer lead to an improved pregnancy rate.
                Copyright 2004 European Society of Human Reproduction and Embryology


Title 5:
Effect of bladder filling on embryo transfer.
Abstract 5:
We have investigated a claim that bladder filling, by straightening an anteverted uterus into line with the vagina, might facilitate embryo transfer through the cervix after in vitro fertilization. In a randomized controlled trail in 66 women with and 76 without a filled bladder, we found no significant differences in difficulties encountered at embryo transfer or in the chance of pregnancy.
On the basis of the evidence in this review, no specific implications for practice are made. It is recommended, in general, that more, larger studies are done on ET preparation techniques. The studies need to be of a higher quality with better explained methods, more specified inclusion and exclusion criteria, and more participants.