IVF or IUI as first-line treatment in unexplained subfertility: the conundrum of treatment selection markers

Should IUI replace IVF as first-line treatment for unexplained infertility? A literature review

BACKGROUND

Unexplained infertility accounts for 25% of infertility causes in the UK. Active intervention methods, such as intrauterine insemination (IUI) or in vitro fertilisation (IVF), are often sought. Despite the National Institute for Health and Care Excellence (NICE) recommending IVF for unexplained infertility, this recommendation has generated an ongoing debate, with few fertility clinics discontinuing the use of IUI as the first-line management of choice. In contrast to NICE, recent guidance released from the European Society for Human Reproduction and Embryology (ESHRE) in August 2023 supports the use of IUI as first-line. High-quality evidence behind such interventions is lacking, with current literature providing conflicting results.

AIMS

This review aims to provide a literature overview exploring whether IUI or IVF should be used as first-line treatment for couples with unexplained infertility, in the context of current guidelines.

METHODS

The primary outcome used to assess efficacy of both treatment methods is live birth (LB) rates. Secondary outcomes used are clinical pregnancy (CP) and ongoing pregnancy (OP) rates. A comprehensive literature search of 4 databases: Ovid MEDLINE, EMBASE, Maternity & Infant Care and the Cochrane Library were searched in January 2022. Upon removal of duplications, abstract screening, and full-text screening, a total of 34 papers were selected.

DISCUSSION/CONCLUSION

This review highlights a large discrepancy in the literature when examining pregnancy outcomes of IUI and IVF treatments. Evidence shows IUI increases LB and CP rates 3-fold compared to expectant management. Literature comparing IUI to IVF is less certain. The review finds the literature implies IVF should be used for first-line management but the paucity of high-quality randomised controlled trials (RCTs), coupled with heterogeneity of the identified studies and a lack of research amongst women > 40 years warrants the need for further large RCTs. The decision to offer IUI with ovarian stimulation (IUI-OS) or IVF should be based upon patient prognostic factors. We suggest that IUI-OS could be offered as first-line treatment for unexplained infertility for women < 38 years, with good prognosis, and IVF could be offered first to those > 38 years. Patients should be appropriately counselled to enable informed decision making.

Effectiveness and safety of intrauterine insemination vs. assisted reproductive technology: emulating a target trial using an observational database of administrative claims

OBJECTIVE

To compare the effectiveness and safety of 1 cycle of assisted reproductive technology (ART) vs. 3 cycles of intrauterine insemination (IUI).

DESIGN

Target trial emulation using observational data.

SETTING

A healthcare claims database (2011-2015).

PATIENT(S)

The patients were 29,021 women aged 18-45 years with an infertility diagnosis and no history of IUI or ART within the past 12 months.

INTERVENTION(S)

One ART cycle immediately, with no more cycles of ART or IUI within the next 4 months; or 1 IUI cycle immediately, with 2 additional consecutive cycles of IUI within the next 4 months unless pregnancy occurred.

MAIN OUTCOME MEASURE(S)

Live births, multiple births, congenital malformations, preterm births, small-for-gestational-age newborns, large-for-gestational-age newborns, admission to neonatal intensive care unit (NICU), gestational diabetes, preeclampsia, and gestational hypertension.

RESULT(S)

The probability of live birth was 27.3% for ART and 26.3% for IUI. The observational analogue of per-protocol risk difference (95% confidence interval) for ART compared with IUI was 1.0% (-0.1%, 2.2%) for live births, 4.3% (3.7%, 4.9%) for multiple births, 3.4% (2.8%, 4.0%) for preterm births, 1.5% (0.9%, 2.1%) for NICU admissions, and 0.6% (0.2%, 1.0%) for gestational diabetes. The risk differences for the other outcomes were <0.5%. The results of the 2 strategies were similar in women ≤40 years, but in women >40 years the probability of live birth was greater for ART (14.4%) than for IUI (7.4%).

CONCLUSION(S)

Compared with 3 cycles of IUI, 1 cycle of ART was estimated to have a similar probability of live birth but slightly higher risks of multiple gestations, preterm births, and NICU admissions.

Should intrauterine inseminations still be proposed in cases of unexplained infertility? Retrospective study and literature review

OBJECTIVE

Unexplained infertility is defined by the absence of identifiable causes of infertility. The results of randomized studies and meta-analysis regarding the treatment of unexplained infertility are discordant due to methodological problems.

DESIGN

The aim of this study is to compare the clinical pregnancy rate per cycle (CPR/c) in IUI and IVF/ICSI in cases of unexplained infertility, according to the woman's age group and to identify the factors which predict success.

INTERVENTIONS

We performed a retrospective study in two ART centers, comparing overall clinical pregnancy, ongoing pregnancy and live birth rates in IVF/ICSI and IUI. We also compared pregnancy and birth rates according to different female age groups.

RESULTS

855 IVF/ICSI and 804 IUI cycles were compared. We found a significant difference (p < 0.001) in the pregnancy and live birth rates per cycle between IUI and IVF/ICSI, overall and in the different female age groups, except in women aged 40 and over. The greatest chances of pregnancy with IUI are found in women with secondary unexplained infertility, during the first two cycles and with a bi-follicular response to stimulation. In IVF/ICSI, pregnancy rates are higher in women with secondary unexplained infertility, in the first two cycles, in IVF and in women receiving a transfer of two embryos regardless of the embryonic stage.

CONCLUSION

We recommend IVF/ICSI treatment rather than IUI for unexplained infertility (OR CPR/c 4.20 with 95% CI [3.72-4.68]). This is in accordance with NICE, which advises the use of IVF after 2 years.

Expectant Management Before In vitro Fertilization in Women Aged 39 or Above and Unexplained Infertility Does Not Decrease Live Birth Rates Compared to Immediate Treatment

Unexplained infertile couples can have further expectant management before starting assisted reproductive treatments. However, ovarian reserve and in vitro fertilization (IVF) outcomes rapidly decline after 39 years or more. It is thus important to clarify whether a waiting policy is also appropriate for women of advanced age. Couples who had access to a waiting list for approximately 1 year before receiving reimbursed public IVF were compared with those paying for access to immediate treatment. To allow for comparisons between these two strategies, we followed up couples who opted to pay for 1 year after the last embryo transfer from their first cycle. We calculated the proportion of live births in both groups and compared these using logistic regression models and a two-sample Z test for equality of proportions. Six hundred thirty-five couples were evaluated. Out of 359 couples in the immediate group, 70 (19.5%) had a live birth of which 11 after natural conception and 59 after IVF. Out of 276 couples in the waiting group, 57 (20.7%) had a live birth of which 37 after natural conception and 20 after IVF. There was no statistically significant difference between the two strategies in terms of the crude cumulative live birth rate (cLBR). The adjusted odds ratio of 0.69 (95%CI:0.39–1.22) did not change this conclusion as our sensitivity analyses. The cLBR for the ‘waiting before IVF’ and the ‘immediate’ strategies were similar. Further studies are needed to better characterize couples affected by unexplained infertility in order to individualize treatment strategies.

Double versus single intrauterine insemination (IUI) in stimulated cycles for subfertile couples

BACKGROUND

In subfertile couples, couples who have tried to conceive for at least one year, intrauterine insemination (IUI) with ovarian hyperstimulation (OH) is one of the treatment modalities that can be offered. When IUI is performed a second IUI in the same cycle might add to the chances of conceiving. In a previous update of this review in 2010 it was shown that double IUI increases pregnancy rates when compared to single IUI. Since 2010, different clinical trials have been published with differing conclusions about whether double IUI increases pregnancy rates compared to single IUI.

OBJECTIVES

To determine the effectiveness and safety of double intrauterine insemination (IUI) compared to single IUI in stimulated cycles for subfertile couples.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase and CINAHL in July 2020 and LILACS, Google scholar and Epistemonikos in February 2021, together with reference checking and contact with study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included randomised controlled, parallel trials of double versus single IUIs in stimulated cycles in subfertile couples.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

We identified in nine studies involving subfertile women. The evidence was of low quality; the main limitations were unclear risk of bias, inconsistent results for some outcomes and imprecision, due to small trials with imprecise results. We are uncertain whether double IUI improves live birth rate compared to single IUI (odds ratio (OR) 1.15, 95% confidence interval (CI) 0.71 to 1.88; I² = 29%; studies = 3, participants = 468; low quality evidence). The evidence suggests that if the chance of live birth following single IUI is 16%, the chance of live birth following double IUI would be between 12% and 27%. Performing a sensitivity analysis restricted to only randomised controlled trials (RCTs) with low risk of selection bias showed similar results. We are uncertain whether double IUI reduces miscarriage rate compared to single IUI (OR 1.78, 95% CI 0.98 to 3.24; I² = 0%; studies = 6, participants = 2363; low quality evidence). The evidence suggests that chance of miscarriage following single IUI is 1.5% and the chance following double IUI would be between 1.5% and 5%. The reported clinical pregnancy rate per woman randomised may increase with double IUI group (OR 1.51, 95% CI 1.23 to 1.86; I² = 34%; studies = 9, participants = 2716; low quality evidence). This result should be interpreted with caution due to the low quality of the evidence and the moderate inconsistency. The evidence suggests that the chance of a pregnancy following single IUI is 14% and the chance following double IUI would be between 16% and 23%. We are uncertain whether double IUI affects multiple pregnancy rate compared to single IUI (OR 2.04, 95% CI 0.91 to 4.56; I² = 8%; studies = 5; participants = 2203; low quality evidence). The evidence suggests that chance of multiple pregnancy following single IUI is 0.7% and the chance following double IUI would be between 0.85% and 3.7%. We are uncertain whether double IUI has an effect on ectopic pregnancy rate compared to single IUI (OR 1.22, 95% CI 0.35 to 4.28; I² = 0%; studies = 4, participants = 1048; low quality evidence). The evidence suggests that the chance of an ectopic pregnancy following single IUI is 0.8% and the chance following double IUI would be between 0.3% and 3.2%.

AUTHORS' CONCLUSIONS

Our main analysis, of which the evidence is low quality, shows that we are uncertain if double IUI improves live birth and reduces miscarriage compared to single IUI. Our sensitivity analysis restricted to studies of low risk of selection bias for both outcomes is consistent with the main analysis. Clinical pregnancy rate may increase in the double IUI group, but this should be interpreted with caution due to the low quality evidence. We are uncertain whether double IUI has an effect on multiple pregnancy rate and ectopic pregnancy rate compared to single IUI.

Role of the total progressive motile sperm count (TPMSC) in different infertility factors in IUI: a retrospective cohort study

OBJECTIVE

The objective of this retrospective cohort study was to explore the optimal range of the total progressive motile sperm count (TPMSC) for live birth in couples with varying infertility diagnosis undergoing intrauterine insemination (IUI) in a university-affiliated teaching hospital.

METHODS

A total of 2647 couples and 5171 IUI cycles were included between January 2015 and December 2018. Of those, 1542 cycles were performed due to unexplained infertility, 1228 cycles due to anovulation, 1120 cycles due to mild male factor infertility and 122 cycles due to mild endometriosis. The primary outcome measure was live birth rate (LBR). The secondary outcome measure was clinical pregnancy rate (CPR).

RESULTS

The CPR and LBR were highest in patients with a diagnosis of anovulation compared with the other three groups of patients. The CPR and LBR in patients with unexplained, mild male factor and mild endometriosis were comparable. For the patients with mild male factor infertility, the CPR with prewash TPMSC of >75.0 M and postwash TPMSC of 65.10 M was above 10%, statistically significantly higher than other quartiles of TPMSC (p<0.05). The LBR with postwash TPMSC of >65.10 M was statistically significantly higher than other groups (p<0.05). However, in patients with unexplained infertility, the CPR and LBR were not statistically different in quartiles of TPMSC, being less than 10%. Overall, there was only one clinical pregnancy and no live birth in patients >40 years of age.

CONCLUSIONS

In conclusion, the infertility diagnosis plays a significant role for the patient undergoing IUI. Thus, the anovulatory patients benefitted most from IUI, irrespective of TPMSC. For patients with unexplained infertility, TPMSC does not affect the success rate of IUI. Overall,female patients more than 40 years old should not be referred to IUI.

IUI needs fairer appraisal to improve patient and stakeholder choices

Information supporting IVF at the expense of intrauterine insemination (IUI) has become commonplace, but it lacks critical analyses. Data from poorly practiced IUI, without an equivalent comparison to IVF, has been generalised to recommend a total abandonment of IUI in favour of IVF treatment. Our intention with this paper is to reappraise and balance arguments so that patients and stakeholders can have an unbiased informed choice. We provide information that reveals IUI to predominate over IVF in terms of integrated success, risks and cost to deliver one live birth whilst obviating the maternal and neonatal costs. Exceptional cost savings are demonstrated for IUI over IVF for fee-paying agencies and patients with lowered risks of maternal and neonatal care along with other risks including OHSS, fetal reduction and termination of pregnancies. This analysis supports the view that patients and stakeholders can choose IUI instead of IVF in most instances, except with bilateral tubal blockage and severe male factor infertility. It is apparent that fertility clinics need to re-evaluate and reconsider this field, and IUI can be of benefit to both subfertile patients and the stakeholders.

Cervical stenosis and pregnancy rate after ultrasound guided cervical dilation in women undergoing saline infusion sonography

Aim

To assess the effect of ultrasound-guided cervical dilation on clinical pregnancy rates in women with cervical stenosis.

Methods

A prospective case control study was conducted in women with unexplained infertility. These women underwent saline infusion sonography and were suspected of having cervical stenosis if a 7 French Foley’s catheter could not be introduced into the cervical canal. Women with suspected stenosis who agreed to undergo ultrasound guided dilation were included as cases. Those with suspected stenosis who refused dilation were used as controls. Both groups were followed for one year. The primary outcome measure was women who had clinical pregnancy i.e. fetal heart beat present on transvaginal scan during the follow up period.

Results

During the study period, 1097 women who underwent SIS were included. A total of 117 (10.7%) patients had cervical stenosis. No statistically significant difference was there in both groups in terms of mean age (p = 0.617), mean body mass index (p = 0.598), duration of infertility (p = 0.588) and type of infertility (p = 0.167). However, both groups were significantly different in terms of history for risk factors i.e. endometriosis (p <0.001), prior surgery (p <0.001), polyps (p = 0.004) and pelvic inflammatory disease (p = 0.001). Eighty-nine women agreed to have dilation and were used as cases and 28 women refused and were used as controls. Of the cases, 70.45% conceived as compared to 18.5% of controls. The mean time to conception in months was also significantly lower in cases (8.10 ± 3.43 vs. 11.39 ± 1.97, p <0.001).

Conclusions

Our study shows that ultrasound-guided cervical dilation in women with cervical stenosis can lead to improved conception rates.

Special characteristics, reproductive, and clinical profile of women with unexplained infertility versus other causes of infertility: a comparative study

PURPOSE

To investigate whether women with unexplained infertility (UI) demonstrate different demographic and IVF characteristics compared to those with other causes of infertility.

METHODS

Data on 245 couples that underwent a total of 413 IVF/ICSI cycles were analyzed (UI 114 cycles, 73 women; anovulation (PCO/PCOS) 83 cycles, 51 women; tubal factor 85 cycles, 47 women; male factor 131 cycles, 74 women). Features of UI were compared versus other infertility groups, after adjustment for multiple comparisons. Generalized least squares (GLS) and random-effects logistic regression analysis were also performed.

RESULTS

Live birth rates, consisting of the primary outcome, were similar in all compared infertility groups. Compared to male infertility, UI was associated with woman's older age at cycle, lower body mass index (BMI), and higher follicle-stimulating hormone (FSH). Compared to tubal infertility, UI was linked to lower endometrial thickness at oocyte retrieval and lower BMI; compared to anovulatory infertility related to PCO/PCOS, UI was linked to woman's older age, more frequent smoking, and poorer ovarian reserve tests (FSH and antral follicle count). After adjustment for other types of infertility, woman's age, age at menarche, and FSH levels, anovulatory infertility presented with higher odds of clinical pregnancy compared to UI (adjusted OR = 2.13, 95% C: 1.01-4.52).

CONCLUSIONS

Infertile women with UI undergoing assisted reproduction demonstrate different demographic and clinical characteristics compared to those of other causes of infertility, albeit live birth rates are similar.

Low-dose human menopausal gonadotrophin versus natural cycles in intrauterine insemination for subfertile couples with regular menstruation

BACKGROUND

Women with irregular menstruation should be considered to benefit from the ovarian stimulation. However, most literature did not separate ovulatory disorders from normal menstrual cycles. Our purpose was to assess the superiority of ovarian mild stimulation compared with the natural cycle in IUI for subfertile couples when the women with regular menstruation.

METHODS

A retrospective study in a single medical center in which 2413 couples with 3573 IUI cycles were studied from 2013 to 2018. The results of IUI in natural cycles versus low-dose HMG induced cycles were analyzed.

RESULTS

For young women (age < 35 years) with normal menstrual cycle, HMG induced ovulation combined with IUI can improve clinical pregnancy outcome (13.55% in two follicular induced cycles vs. 7.23% in natural cycles, p < 0.01); even if only one follicle was induced, the clinical pregnancy rate was increased to 10.32% (p < 0.01). When two growth follicles were induced in HMG cycles, a remarkable improvement of the live birthrate (10.28% vs. 5.91% in natural cycles, p < 0.05) was noted. Simultaneously, twin pregnancy rates were increased to 20.69% (p < 0.01). Twin pregnancies showed significantly increased risk of both ectopic pregnancy and preterm birth (p = 0.00 for both). For advanced women (age ≥ 35 years) with regular menstrual cycle, ovulation induction didn't improve clinical pregnancy and live birthrates, while age was the only relevant factor.

CONCLUSIONS

Combining HMG induced ovulation and IUI can improve pregnancy outcome in young women with normal menstrual cycles. 1-2 follicles with diameter ≥ 14 mm served as the purpose of ovulation induction. Further, both twin and ectopic pregnancy rate in HMG cycles with two growth follicles were significantly higher than those in natural cycles were. Therefore, doctors must evaluate the risk before making choices and inform the patients to achieve the best results. For advanced women with normal menstrual cycles, natural IUI cycles were optional.

Observational retrospective study of UK national success, risks and costs for 319,105 IVF/ICSI and 30,669 IUI treatment cycles

OBJECTIVE

To compare success rates, associated risks and cost-effectiveness between intrauterine insemination (IUI) and in vitro fertilisation (IVF).

DESIGN

Retrospective observational study.

SETTING

The UK from 2012 to 2016.

PARTICIPANTS

Data from Human Fertilisation and Embryology Authority's freedom of information request for 2012-2016 for IVF/ICSI (intracytoplasmic sperm injection)and IUI as practiced in 319 105 IVF/ICSI and 30 669 IUI cycles. Direct-cost calculations for maternal and neonatal expenditure per live birth (LB) was constructed using the cost of multiple birth model, with inflation-adjusted Bank of England index-linked data. A second direct-cost analysis evaluating the incremental cost-effective ratio (ICER) was modelled using the 2016 national mean (baseline) IVF and IUI success rates.

OUTCOME MEASURES

LB, risks from IVF and IUI, and costs to gain 1 LB.

RESULTS

This largest comprehensive analysis integrating success, risks and costs at a national level shows IUI is safer and more cost-effective than IVF treatment.IVF LB/cycle success was significantly better than IUI at 26.96% versus 11.49% (p<0.001) but the IUI success is much closer to IVF at 2.35:1, than previously considered. IVF remains a significant source of multiple gestation pregnancy (MGP) compared with IUI (RR (Relative Risk): 1.45 (1.31 to 1.60), p<0.001) as was the rate of twins (RR: 1.58, p<0.001).In 2016, IVF maternal and neonatal cost was £115 082 017 compared with £2 940 196 for IUI and this MGP-related perinatal cost is absorbed by the National Health Services. At baseline tariffs and success rates IUI was £42 558 cheaper than IVF to deliver 1LB with enhanced benefits with small improvements in IUI. Reliable levels of IVF-related MGP, OHSS (ovarian hyperstimulation syndrome), fetal reductions and terminations are revealed.

CONCLUSION

IUI success rates are much closer to IVF than previously reported, more cost-effective in delivering 1 LB, and associated with lower risk of complications for maternal and neonatal complications. It is prudent to offer IUI before IVF nationally.