Sildenafil Supplementation for Women Undergoing Infertility Treatments: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Vasodilators for women undergoing fertility treatment

BACKGROUND

The rate of successful pregnancies brought to term has barely increased since the first assisted reproductive technology (ART) technique became available. Research suggests that vasodilators may increase endometrial receptivity, thicken the endometrium, and favour uterine relaxation, all of which could improve the chances of successful assisted pregnancy.

OBJECTIVES

To evaluate the effectiveness and safety of vasodilators in women undergoing fertility treatment.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, three other databases, and two clinical trial registries in April 2024, with no language or date restrictions. We also searched grey literature sources and checked the reference lists of relevant articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing vasodilators (alone or combined with other treatments) versus placebo or no treatment or versus other agents in women undergoing fertility treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, extracted data, and calculated risk ratios (RRs). We combined study data using a fixed-effect model and assessed evidence certainty using the GRADE approach. Our primary outcomes were live birth or ongoing pregnancy and vasodilator side effects. Our secondary outcomes were clinical pregnancy, endometrial thickness, multiple gestation, miscarriage, and ectopic pregnancy.

MAIN RESULTS

We included 45 studies with a total of 4404 women. The included studies compared a vasodilator versus a placebo or no treatment (40 RCTs), vasodilators plus another agent versus placebo or no treatment (3 RCTs) or versus oestrogens (3 RCTs). The mean length of follow-up was 15.45 weeks. Overall, the certainty of evidence was very low to moderate. The main limitations were imprecision (low number of events and participants) and risk of bias (lack of blinding in studies that reported subjective outcomes). Vasodilators versus placebo or no treatment Vasodilators may result in little to no difference in rates of live birth or ongoing pregnancy compared with placebo or no treatment (RR 1.21, 95% CI 0.93 to 1.58; I² = 0%; 6 RCTs, 740 women; low-certainty evidence), but probably increase overall rates of side effects (RR 2.14, 95% CI 1.55 to 2.98; I² = 0%; 7 RCTs, 668 women; moderate-certainty evidence). The evidence suggests that 246 per 1000 women achieve live birth or ongoing pregnancy with a placebo or no treatment, and 229 to 389 per 1000 will do so using vasodilators. Vasodilators compared with placebo or no treatment likely increase rates of clinical pregnancy (RR 1.45, 95% CI 1.28 to 1.64; I² = 22%; 25 RCTs, 2506 women; moderate-certainty evidence). Vasodilators compared with placebo or no treatment probably have little or no effect on rates of multiple gestation or birth (RR 1.37, 95% CI 0.73 to 2.55; I² = 0%; 7 RCTs, 763 women; moderate-certainty evidence), miscarriage (RR 1.01, 95% CI 0.59 to 1.74; I² = 0%; 8 RCTs; 829 women; moderate-certainty evidence), and ectopic pregnancy (RR 1.25, 95% CI 0.34 to 4.59; I² = 0%; 4 RCTs, 543 women; moderate-certainty evidence). Most studies found a beneficial effect of vasodilators for endometrial thickness, but the reported effect estimates varied (I² = 93%), from a mean difference of 0.47 mm higher (95% CI 0.90 mm lower to 1. 84 mm higher) to 1.94 mm higher (95% CI 1.37 higher to 2.51 mm higher), and the evidence was very uncertain. Hence, we are unsure how to interpret these results. Vasodilators versus oestrogens Vasodilators compared with oestrogens may have little or no effect on rates of live birth or ongoing pregnancy (RR 0.83, 95% CI 0.30 to 1.33; 1 RCT, 44 women, low-certainty evidence). The evidence is very uncertain regarding the effect of sildenafil compared with oestrogens on clinical pregnancy rates (RR 0.99, 95% CI 0.71 to 1.38; I² = 59%; 3 RCTs, 262 women; very low-certainty evidence), endometrial thickness (RR 1.90, 95 CI 1.15 to 3.13; 1 RCT, 120 women; very low-certainty evidence) and miscarriage rates (RR 0.50, 95% CI 0.05 to 5.12; 1 RCT, 44 women; very low-certainty evidence) AUTHORS' CONCLUSIONS: Among women undergoing fertility treatment, there may be little or no difference in the rate of live birth or ongoing pregnancy in those who receive vasodilators compared with those who receive a placebo or no treatment, and compared with those who receive oestrogens. Compared with placebo or no treatment, vasodilators likely increase rates of clinical pregnancy, but probably also increase overall rates of side effects. The evidence on clinical pregnancy with vasodilators versus oestrogens is very uncertain, and we found no evidence on overall side effects for the comparison of vasodilators versus oestrogens. We are unsure about the effect of vasodilators versus placebo or no treatment and versus oestrogens on endometrial thickness. Vasodilators versus placebo or no treatment probably have little or no effect on multiple gestation or birth, miscarriage, and ectopic pregnancy. Future studies should be adequately randomised and powered to ensure a more accurate evaluation of each treatment, with live births as a primary outcome.

Platelet-rich plasma infusion as an adjunct treatment for persistent thin lining in frozen embryo transfer cycles: first US experience report

PURPOSE

To study effect of intrauterine infusion of platelet-rich plasma (PRP) on endometrial growth in the setting of thin endometrial lining in patients with prior cancelled or failed frozen embryo transfer (FET) cycles.

MATERIALS AND METHODS

Single-arm cohort study of forty-six patients (51 cycles) with endometrial lining thickness (EMT) < 6 mm in prior cancelled or failed FET cycles requesting intrauterine PRP treatment in upcoming FET cycle. The primary outcomes were final EMT in FET cycle and change in EMT after PRP. The secondary outcomes were overall pregnancy rate, clinical pregnancy rate, miscarriage rate, ongoing pregnancy, and live birth rates.

RESULTS

The mean pre-PRP EMT in all FET cycles was 4.0 ± 1.1 mm, and mean post-PRP EMT (final) was 7.1 ± 1.0 mm. Of 51 cycles, 33 (64.7%) reached ≥ 7 mm after PRP administration. There was a significant difference between pre-PRP EMT and post-PRP EMT in all FET cycles, with mean difference of 3.0 ± 1.5 mm. Three cycles were cancelled for failure to reach adequate lining. Total pregnancy rate was 72.9% in our cohort of 48 cycles that proceeded to transfer. Clinical pregnancy rate was 54.2% (26/48 FET cycles); clinical miscarriage rate was 14.3% (5/35 pregnancies). Twenty six women had live birth (18 with EMT ≥ 7 mm and 8 with EMT < 7 mm). Response to PRP was not correlated with any pre-cycle characteristics.

CONCLUSION

We demonstrate a significant improvement in lining thickness and pregnancy rates in this challenging cohort of women after PRP infusion, with no adverse events. Cost-effectiveness of PRP with benefits and alternatives should be carefully considered.

Princeton IV consensus guidelines: PDE5 inhibitors and cardiac health

BACKGROUND

In 1999, 1 year after the approval of the first oral phosphodiesterase type 5 (PDE5) inhibitor for the treatment of erectile dysfunction (ED), the first Princeton Consensus Conference was held to address the clinical management of men with ED who also had cardiovascular disease. These issues were readdressed in the second and third conferences. In the 13 years since the last Princeton Consensus Conference, the experience with PDE5 inhibitors is more robust, and recent new data have emerged regarding not only safety and drug-drug interactions, but also a potential cardioprotective effect of these drugs.

AIM

In March 2023, an interdisciplinary group of scientists and practitioners met for the fourth Princeton Consensus Guidelines at the Huntington Medical Research Institutes in Pasadena, California, to readdress the cardiovascular workup of men presenting with ED as well as the approach to treatment of ED in men with known cardiovascular disease.

METHOD

A series of lectures from experts in the field followed by Delphi-type discussions were developed to reach consensus.

OUTCOMES

Consensus was reached regarding a number of issues related to erectile dysfunction and the interaction with cardiovascular health and phosphodiesterase-5 inhibitors.

RESULTS

An algorithm based on recent recommendations of the American College of Cardiology and American Heart Association, including the use of computed tomography coronary artery calcium scoring, was integrated into the evaluation of men presenting with ED. Additionally, the issue of nitrate use was further considered in an algorithm regarding the treatment of ED patients with coronary artery disease. Other topics included the psychological effect of ED and the benefits of treating it; the mechanism of action of the PDE5 inhibitors; drug-drug interactions; optimizing use of a PDE5 inhibitors; rare adverse events; potential cardiovascular benefits observed in recent retrospective studies; adulteration of dietary supplements with PDE5 inhibitors; the pros and cons of over-the-counter PDE5 inhibitors; non-PDE5 inhibitor therapy for ED including restorative therapies such as stem cells, platelet-rich plasma, and shock therapy; other non-PDE5 inhibitor therapies, including injection therapy and penile prostheses; the issue of safety and effectiveness of PDE5 inhibitors in women; and recommendations for future studies in the field of sexual dysfunction and PDE5 inhibitor use were discussed.

CLINICAL IMPLICATIONS

Algorithms and tables were developed to help guide the clinician in dealing with the interaction of ED and cardiovascular risk and disease.

STRENGTHS AND LIMITATIONS

Strengths include the expertise of the participants and consensus recommendations. Limitations included that participants were from the United States only for this particular meeting.

CONCLUSION

The issue of the intersection between cardiovascular health and sexual health remains an important topic with new studies suggesting the cardiovascular safety of PDE5 inhibitors.

The use of real time strain endometrial elastosonography plus endometrial thickness and vascularization flow index to predict endometrial receptivity in IVF treatments: a pilot study

BACKGROUND

The usefulness of endometrium strain elastosonography (SE) for the evaluation of endometrial receptivity in women undergoing in vitro fertilization (IVF) remains controversial. The objective of this prospective, observational study was to evaluate the correlation between endometrial thickness (EMT) and its related strain (ESR) on the day of ovulation triggering (hCG-d) and in vitro fertilization outcomes. Additionally, 3D Power Doppler vascular indices (3DPDVI) were also analysed.

METHODS

We included all the patients undergoing fresh IVF-single blastocyst transfer cycle from January 2021 to August 2021 at our center. On hCG-d, after B-mode scanning was completed to measure the EMT, the mode was changed to elastosonography to evaluate the ESR (ratio between endometrial tissue and the myometrium below). At the end of examination, the Endometrial Volume (EV) and 3DPDVI (vascularization index [VI], flow index [FI] and vascularization flow index [VFI]), were assessed. Statistical analysis was completed using STATA MP16 software.

RESULTS

A total number of 57 women were included. Based on the EMT on hCG-d, women were divided into two groups, Group 1: <7 mm and Group 2 ≥ 7 mm. Women with EMT < 7 mm had a significantly higher ESR (p = 0.004) and lower pregnancy rate (p = 0.04). Additionally, low ESR values were correlated with high VFI values (rho = -0.8; 95% CI = -0.9- -0.6; p < 0.0001) and EMT ≥ 7 mm could be predicted by low ESR (OR = 0.01; 95% CI = 0.01-0.30; p = 0.008, area under the ROC curve: 0.70). After all, in multiple logistic regression analysis, low values of ESR (p = 0.050) and high values of EMT (p = 0.051) on hCG-d had borderline statistical effects on pregnancy rate.

CONCLUSIONS

The ESR may be useful to improve the ultrasound evaluation of the endometrial quality in infertile women candidates to IVF/ICS. Given the small sample size of our study, the usefulness of strain elastosonography in this patients, needs further investigation.

Effectiveness of phosphodiesterase type 5 inhibitors on the treatment of thin endometrium and pregnancy outcomes: An systematic review

Phosphodiesterase type 5 (PDE5) inhibitors are thought to play a role in increasing endometrial thickness and increasing the success rate of pregnancy outcomes. This study was done to investigate the effects of PDE5 inhibitors on infertile women with thin endometrium and pregnancy outcomes. In this systematic review, all randomized controlled trials (RCTs) and observational studies were retrieved from databases including Institute for Scientific Information (ISI), PubMed, and Scopus by interesting keywords. A checklist was designed to collect necessary data and pregnancy outcomes, and the required items were recorded. PDE5 inhibitors through various mechanisms such as induction of vasodilatory effect through the effect on NO/cGMP signaling on vascular smooth muscle, through regulating cells proliferation and induction angiogenesis by increasing the expression of tumor suppressor factor (p53), and vascular endothelial growth factor A (VEGF-A) and downregulating inflammation by downregulating proinflammatory cytokines, affect endometrial thickness that eventually increases and pregnancy outcomes. Although PDE5s inhibitors increase endometrial thickness by different mechanisms, especially in women with thin endometrial, this does not necessarily mean that they induce a positive effect in all situations. However, their positive effects on pregnancy outcome may be affected by the time of administration, type of infertility treatment, underlying diseases such as pelvic disorders and inflammation. So in this regard, there are still ambiguous aspects that required further RCTs study in this area.