Intrauterine Insemination With Letrozole Versus Intrauterine Insemination in Natural Cycle. A Randomised Controlled Trial
Phase: NA
Conditions: Infertility, Intrauterine Insemination
Sponsor: Peking University Third Hospital

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Intrauterine insemination with letrozole versus intrauterine insemination in 
natural cycle. A randomized controlled trial   
 
 
Protocol ID              letrozole/natural cycle IUI 
Short title                Letrozole or natural cycle in IUI 
Version                  2.0 
Date                    23/02/2018 
Coordinating             Prof. Jie Qiao, PUTH, Beijing, China  
investigator/project leader   Prof. Ben W J Mol, MU, Melbourne, Australia 
Principal investigator(s)     Prof. Rong Li, PUTH, Beijing, China 
  Dr. Shuo Huang, PUTH, Beijing, China 
                        Dr. Rui Wang, UOA, Adelaide, Australia              
Sponsor                 Peking University Third Hospital（PUTH） 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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TABLE OF CONTENTS 
SUMMARY .............................................................................................................................. 4 
1. INTRODUCTION AND RATIONALE ............................................................................... 5 
2. OBJECTIVES ....................................................................................................................... 5 
3. STUDY DESIGN .................................................................................................................. 6 
4. STUDY POPULATION ........................................................................................................ 6 
5. TREATMENT OF SUBJECTS ............................................................................................. 7 
6. METHODS ............................................................................................................................ 8 
7. SAFETY REPORTING....................................................................................................... 10 
8. STATISTICAL ANALYSIS ............................................................................................... 12 
9. ETHICAL CONSIDERATIONS ........................................................................................ 14 
10. ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION ...................... 15 
11. REFERENCES .................................................................................................................. 16 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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LIST OF ABBREVIATIONS AND RELEVANT DEFINITIONS 
AE    Adverse event 
AFC   Antral follicle count 
AMH  Anti-mullerian hormone 
BMI   Body mass index 
DCE   Discrete choice experiments 
ICER  Incremental cost-effectiveness ratio 
OHSS  Ovarian hyperstimulation syndrome 
OPR   Ongoing pregnancy rate 
PCOS  Polycystic ovary syndrom 
RCT   Randomised controlled trial 
SAE   Serious adverse event 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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SUMMARY 
Rationale Intrauterine insemination (IUI) is the treatment of first choice for couples 
with unexplained and mild male factor infertility in many countries, but it is 
controversial whether ovarian stimulation improves fertility outcomes. In recent 
retrospectively collected data, we found that in couples with unexplained and mild 
male factor infertility undergoing IUI, ovarian stimulation with letrozole increased 
live birth rate as compared to natural cycle IUI without substantially increasing the 
multiple pregnancy rate. We therefore perform a randomized clinical trial (RCT) on 
the subject in the Centre of Reproductive Medicine, Peking University Third Hospital, 
Beijing, China. 
Objective To test the hypothesis that in couples with unexplained or mild male factor 
infertility scheduled for an IUI program ovarian stimulation with letrozole increases 
the live birth rate as compared to natural cycle treatment. 
Study design Randomized controlled trial. 
Study population Women diagnosed with unexplained or mild male factor infertility 
scheduled for treatment with IUI. 
Intervention Women will be randomized for ovarian stimulation with letrozole or to 
natural cycle IUI. In the group allocated to ovarian stimulation, women will receive 
oral tablets letrozole 5 mg daily from cycle day 3-5 for 5 days. We will treat the 
couples for 3 cycles, with a time horizon of 4 months. 
Main study parameters/endpoints 
Primary outcome is ongoing pregnancy leading to live birth. Secondary endpoints are 
clinical pregnancy, multiple pregnancy, miscarriage rates, pregnancy complications 
and patients’ costs. 
Nature and extent of the burden and risks associated with participation, benefit 
and group relatedness 
The strategies compared are already broadly applied in current practice. No additional 
risks are expected. There is no benefit for participants, but the results may benefit 
future subfertile couples 
 

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1. INTRODUCTION AND RATIONALE 
In many areas around the world, intrauterine insemination (IUI) is the treatment of 
first choice for couples with unexplained and mild male factor infertility due to its 
simplicity, ease of management, and relatively low cost(1)(2). While IUI can be 
applied in the natural cycle, in many settings ovarian stimulation is applied with the 
aim to establish multiple follicular growth. Multiple follicular growth is thought to 
increase the chances of pregnancy and live birth, but bears at the same time the risk of 
multiple pregnancy (3). It is therefore controversial whether ovarian stimulation 
improves fertility outcomes to the couples without female ovulation disorders in an 
IUI program(4,5). Various stimulation protocols have been applied, but there is still 
no consensus on the optimal protocol for ovarian stimulation in an IUI program(6,7).   
We found in a retrospective cohort study that ovarian stimulation with letrozole 
significantly increases the live birth rate as compared to natural cycle IUI without 
substantially increasing the multiple pregnancy rate in IUI program for unexplained 
and mild male factor infertility. Also, letrozole was found to result in similar 
pregnancy and live birth rates for a lower multiple pregnancy rate than Clomid or 
letrozole. 
We therefore plan to perform a randomized clinical trial (RCT) on the women with 
unexplained and mild male factor infertility in IUI program in Centre of Reproductive 
Medicine, Peking University Third Hospital, Beijing, China. We aim to test the 
hypothesis that in couples with unexplained or mild male factor infertility scheduled 
for an IUI program ovarian stimulation with letrozole increases the live birth rate as 
compared to natural cycle treatment. 
 
2. OBJECTIVES 
Primary Objective: 
To test the hypothesis that that in couples with unexplained or mild male factor 
infertility scheduled for an IUI program ovarian stimulation with letrozole increases 
the live birth rates over IUI in the natural cycle 
We aim to answer the following questions: 

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least one semen analysis 
 
4.3 Exclusion criteria 
A potential participant who meets any of the following criteria will be excluded from 
study participation: 
 - Woman with double sided tubal pathology 
- Women with irregular cycles, PCOS or other endocrine disorders 
 - Man with impaired semen quality: sperm concentration lower than 5 million per 
millilitre or progressive motility sperm less than 10% 
 - Women younger than 20 years old 
 
4.4 Sample size calculation 
Our sample size is based on an cumulative live birth rate. We anticipate an 18% 
pregnancy rate after 3 cycles natural cycle IUI. We presume that the clinical relevant 
difference is 8%. To test the hypothesis that IUI with letrozole increased the 
pregnancy rate to 26% as compared to natural cycle IUI, we need to include 483 
women per arm (total 966). (two sided-test, alpha .05, beta .80, 15% loss to 
follow-up). Firstly we will collect 100 women for a pilot study. 
5. TREATMENT OF SUBJECTS 
5.1 Investigational product/treatment 
All women sighed informed consent are seen for a baseline visit with a transvaginal 
ultrasound at the third day of the menstrual cycle, at the first treatment cycle. At this 
first monitoring the antral follicle count will be measured and registered. Women are 
not allowed to continue if one (or more) ovarian cysts of >15 mm is seen. These 
women are treated further according to local protocol.  
Eligible women will be randomly allocated to either 3 cycles of IUI with letrozole or 
IUI in natural cycle. 

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Medication will be perscribed by the treating physician. 
 
Intervention  
After randomisation, women will receive instructions to start daily oral tablets with 
5mg letrozole for 5 days or without stimulation. Medicine therapy is started on day 3, 
4 or 5 of the menstrual cycle depending on the length of the menstrual cycle and 
stopped after 5 days of daily intake of two tablets of 2.5 mg. 
Subsequently further transvaginal ultrasounds will be scheduled to monitor follicle 
growth in both groups. As soon as at least one dominant follicle with a mean diameter 
of >18 mm is present, with a maximum of in total three follicles >15 mm ovulation 
will be triggered using 10000 IU hCG. At the final ultrasound the total number of 
follicles and their diameters will be measured and registered. 
Ovulation triggering will be withheld if more than three follicles with a diameter 
of >15 mm are seen. In this case, the couples are also strictly advised to have barrier 
protected intercourse.Intrauterine insemination is scheduled 36-42 hours after 
ovulation triggering. 
On the day of insemination the male partner will provide a semen sample by means of 
masturbation after a minimum of two days of sexual abstinence. The semen will be 
subjected to density gradient centrifugation and/or washing according to local 
laboratory protocol.Women who will not conceive will be scheduled for the second 
and subsequent insemination cycles, and will keep the same stimulation regimen up to 
3 cycles after randomisation.  
6. METHODS 
6.1 Study parameters/endpoints 
6.1.1 Main study parameter/endpoint 
Ongoing pregnancy resulting in live birth, conceived within 3 cycles IUI after 
randomisation in a time horizon of 4 months. In calculation, we will take the 

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calculated moment of conception leading to the live birth 
6.1.2 Secondary study parameters/endpoints (if applicable) 
 1. Number of cycles with mono-follicular growth 
 2. Number of cycles with Multiple follicular growth 
 3. Number of cancelled cycles due to the occurrence of >3 follicles >15 mm 
4. Time to conception leading to live birth 
5. Clinical pregnancy 
6. Miscarriage  
7. Multiple pregnancy (reported as twins and higher order multipl 
8. PregNANCY COMPLICATIONS 
9. Direct and indirect costs 
 
Counselling 
Women eligible for participation in the study will be invited for additional counselling 
by a research nurse, to ensure that they are fully informed on the nature of the study 
by means of written information (Participant Information Form). Women who agree 
to participate will be asked to sign a written informed consent of which they will 
receive a copy. Consenting eligible women will be randomly allocated to one of the 
two strategies at the baseline visit of the first treatment cycle. 
 
6.2 Randomisation, blinding and treatment allocation 
Randomization will be performed centrally with the use of envelope method. 
The study will be completed 4 months after randomisation, with a maximum of 3 
cycle attempts. According to local protocol, participants may be offered more IUI 
cycles, with medication to their preference after the 4 months study period, or proceed 
to IVF immediately. 
The study will be open. 
 
6.3 Study procedures 
 

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Data collection 
The study will be performed by Reproductive Centre of Peking University Third 
Hospital that is familiar with randomised clinical trials. This has resulted in an 
infrastructure with research nurses, a secretary office for the handling of ethical 
approval, the use of web-based data-entry and collaborate analysis. All data will be 
registered in a case record form (CRF). 
 
Baseline characteristics 
From participant history 
Duration of infertility, parity, referral status, weight, length, smoking. semen-analysis, 
tubal status 
 
Ultrasound 
We will record the basal antral follicle count using sonography and record the number 
and measurements of the total follicles seen at the final ultrasound just before or at the 
day of ovulation triggering. 
 
6.4 Withdrawal of individual subjects 
Subjects can leave the study at any time for any reason if they wish to do so without 
any consequences. The investigator can decide to withdraw a subject from the study 
for urgent medical reasons. 
7. SAFETY REPORTING 
7.1 Section 10 WMO event 
In accordance to section 10, subsection 1, of the WMO, the investigator will inform 
the subjects and the reviewing accredited METC if anything occurs, on the basis of 
which it appears that the disadvantages of participation may be significantly greater 
than was foreseen in the research proposal. The study will be suspended pending 

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further review by the accredited METC, except in so far as suspension would 
jeopardise the subjects’ health. The investigator will take care that all subjects are kept 
informed. 
7.2 AEs, SAEs and SUSARs 
7.2.1 Adverse events (AEs) 
Adverse events are defined as any undesirable experience occurring to a subject 
during the study, whether or not considered related to IUI in natural cycle or IUI with 
letrozole. All adverse events reported spontaneously by the subject or observed by the 
investigator or his staff will be recorded. 
Expected events will be reported by line listing once a year: 
- Allergic reaction to medication 
 - Pregnancy related complications 
7.2.2 Serious adverse events (SAEs) 
A serious adverse event is any untoward medical occurrence or effect that at any dose: 
 - results in death; 
 - is life threatening (at the time of the event); 
 - requires hospitalisation or prolongation of existing inpatients’ hospitalisation; 
 - results in persistent or significant disability or incapacity; 
 - is a congenital anomaly or birth defect; 
 -any other important medical event that may not result in death, be life threatening, 
or require hospitalization, may be considered a serious adverse experience when 
based upon appropriate medical judgement, the event may jeopardize the subject or 
may require an intervention to prevent one of the outcomes listed above. 
The sponsor will report within 15 days after the sponsor has first knowledge of the 
serious adverse reactions. 
SAEs that result in death or are life threatening should be reported expedited. The 
expedited reporting will occur not later than 7 days after the responsible investigator 
has first knowledge of the adverse reaction. This is for a preliminary report with 
another 8 days for completion of the report. 
7.3 Follow-up of adverse events 

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All AEs will be followed until they have abated, or until a stable situation has been 
reached. Depending on the event, follow up may require additional tests or medical 
procedures as indicated, and/or referral to the general physician or a medical specialist. 
SAEs need to be reported till end of study within the Netherlands, as defined in the 
protocol. 
8. STATISTICAL ANALYSIS 
Step 1: Summarizing trial data. 
Baseline data and outcome data will be separately summarized. For continuous 
variables, we will examine the distribution of the observations, and if normally 
distributed then we will summarize them as means with standard deviations (SDs). If 
they are not normally distributed, then medians and inter-quartile ranges (IRQs) will 
be reported. For dichotomous data, we will provide proportions (or percentages). In 
addition to the baseline and outcome data, we will also summarize the recruitment 
numbers, those lost to follow-up, protocol violations and other relevant data. 
Step 2: Inter-group comparisons. 
The analysis of all outcomes will be done on an intention to treat basis. 
The effectiveness of IUI with letrozole versus IUI in natural cycle will be expressed 
as a rate ratio for live birth with corresponding 95% confidence intervals. A formal 
test of the difference in rate will be performed using chi-square test statistics. The 
effectiveness over time will be evaluated in life tables and differences in live birth 
over time will be evaluated using the log-rank test. Further dichotomous outcomes 
will be analyzed using either Fishers Exact Test or chi-square as appropriate. For 
continuous outcomes we will use t-test if the observations in each trial arm are 
normally distributed, and if non-normally distributed, then Mann-Whitney-U test will 
be employed. Although p-values will be reported, the focus will be on providing 95% 
confidence intervals around point estimates as these are more useful in interpreting 
the findings of the trial. 

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Step 3: Adjustments and sensitivity analyses. 
If randomization fails to achieve balanced groups, then we will perform secondary 
analyses in which we will adjust for unbalanced prognostic factors using procedures 
such as logistic regression. If the primary unadjusted analysis and secondary adjusted 
analysis are discordant, we will give greater weighting to the primary analysis in the 
interpretation of trial findings. For issues such losses to follow-up, missing data, and 
protocol violations, we will attempt sensitivity ("worst-case scenario") analyses to 
explore the effect of these factors on the trial findings. As a secondary analysis, we 
will adjust for missing data using imputation techniques to explore the effects of such 
imputations on the trial findings. The effect of baseline characteristics on the primary 
outcome will be explored using logistic regression analysis. In sub analyses the 
association between follicular growth and live birth will be evaluated. 
Details of the analysis will be described in a separate statistical analysis plan, that will 
be developed during the study, and finalized before data lock. 
 
Interim Analysis 
Interim analysis will be done after completion data recruitment of the first 50 
participants. An independent Data Safety Monitoring Committee (DSMC) will be 
invited. The DSMC will be asked to assess the endpoint ongoing pregnancy, as data 
on live birth will not be available. Also, the DSMC will be provided insight in the 
SAE’s that have occurred. The continuation of the study will depend on the advice of 
DSMC. A formal stopping rule will be formulated in the separate statistical analysis 
plan. 
 
Economic evaluation 
An economic analysis will be performed alongside the clinical trial. The economic 
analysis will be performed from a healthcare perspective. Depending on the outcome 
of live birth rates in both groups, the economic analysis will be a cost-minimization of 
cost-effectiveness analysis. 
Cost-effectiveness of each strategy will be presented as cost per live birth and costs 

14 
 
pre clinical pregnancy. Robustness of the results for various assumptions and 
parameter estimates will be explored in sensitivity analysis outcomes and will be 
expressed in ICER graphs and cost-effectiveness acceptability curves. A decision 
model will be used to evaluate the optimal strategy. 
A distinction will be made between direct costs (costs like medical interventions and 
other healthcare costs like medical appliances) and indirect costs (costs of 
productivity loss or time loss costs). Costs will be measured in a subsample of 
participants. 
9. ETHICAL CONSIDERATIONS 
9.1 Regulation statement 
The study will be conducted according to the principles of the Declaration of Helsinki 
(WORLD MEDICAL ASSOCIATION DECLARATION OF HELSINKI) Ethical 
Principles for Medical Research Involving Human Subjects Version Edinburgh, 
Scotland, October 2000, with Note of Clarification on Paragraph 29 added by the 
WMA General Assembly, Washington 2002 end Note of Clarification on Paragraph 30 
added by the WMA General Assembly, Tokyo 2004 and in accordance with the 
Medical Research Involving Human Subjects Act (WMO) and other guidelines, 
regulations and Acts. 
9.2 Recruitment and consent 
Women eligible for participation in the study will be invited for additional counselling 
by a research nurse, to ensure that they are fully informed on the nature of the study 
by means of both oral and written information (Participant Information Form). 
Women who agree to participate will be asked to sign a written informed consent of 
which they will receive a copy. 
9.3 Benefits and risks assessment, group relatedness 
The strategies compared are already applied in current practice. No additional risks 
are expected. Women will not benefit by participating in this study, but the results 

15 
 
may prove beneficial for future couples who will undergo IUI. 
10. ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION 
10.1 Handling and storage of data and documents 
Data will be collected in a registration system. Data will be collected and entered in 
the system by local research nurses. Data monitoring will be done by principal 
investigators. 
Data handling will be done anonymously, with the participant code only available to 
the local investigator and the research nurse working in the local centre. Participants 
will be asked for informed consent. 
10.2 Amendments 
Amendments are changes made to the research after a favourable opinion by the 
accredited METC has been given. All amendments will be notified to the METC that 
gave a favourable opinion. 
A ‘substantial amendment’ is defined as an amendment to the terms of the METC 
application, or to the protocol or any other supporting documentation, that is likely to 
affect to a significant degree: 
 - the safety or physical or mental integrity of the subjects of the trial; 
 - the scientific value of the trial; 
 - the conduct or management of the trial; or 
 - the quality or safety of any intervention used in the trial. 
All substantial amendments will be notified to the METC and to the competent 
authority. 
Non-substantial amendments will not be notified to the accredited METC and the 
competent authority, but will be recorded and filed by the sponsor. 
10.3 Annual progress report 
The sponsor/investigator will submit a summary of the progress of the trial to the 
accredited METC once a year. Information will be provided on the date of inclusion 

16 
 
of the first subject, numbers of subjects included and numbers of subjects that have 
completed the trial, serious adverse events/ serious adverse reactions, other problems, 
and amendments. 
10.4 End of study report 
The investigator will notify the accredited METC of the end of the study within a 
period of 8 weeks. The end of the study is defined as the last participant’s last visit. 
In case the study is ended prematurely, the investigator will notify the accredited 
METC within 15 days, including the reasons for the premature termination. 
Within one year after the end of the study, the investigator/sponsor will submit a final 
study report with the results of the study, including any publications/abstracts of the 
study, to the accredited METC. 
10.5 Public disclosure and publication policy 
No specific arrangements will be made between any sponsors and the investigators 
concerning the public disclosure and publication of the research data. According to 
statement publication policy of the CCMO the results of this study will be published. 
Publication will not only include positive results but also negative results. 
11. REFERENCES 
1.    The ESHRE Capri Workshop. Intrauterine insemination. Hum Reprod Update  
2009;15(3):265–77.  
2.  
Merviel P, Heraud MH, Grenier N, Lourdel E, Sanguinet P, Copin H. Predictive 
factors for pregnancy after intrauterine insemination (IUI): An analysis of 1038 
cycles and a review of the literature. Fertil Steril 2010;93(1):79–88.  
3.  
Liu J, Li TC, Wang J, Wang W, Hou Z, Liu J. The impact of ovarian stimulation 
on the outcome of intrauterine insemination treatment: an analysis of 8893 
cycles. BJOG An Int J Obstet Gynaecol 2016;123:70–5.  
4.  
Goverde AJ, McDonnell J, Vermeiden JPW, Schats R, Rutten FFH, 
Schoemaker J. Intrauterine insemination or in-vitro fertilisation in idiopathic 

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subfertility and male subfertility: A randomised trial and cost-effectiveness 
analysis. Lancet 2000;355(9197):13–8. 
5.  
Diamond MP, Legro RS, Coutifaris C, Alvero R, Robinson RD, Casson P, et al. 
Letrozole, Gonadotropin, or Clomiphene for Unexplained Infertility. N Engl J 
Med. 2015;373(13):1230–40.  
6.  
Hansen KR, He ALW, Styer AK, Wild RA, Butts S, Engmann L, et al. 
Predictors of pregnancy and live-birth in couples with unexplained infertility 
after 
ovarian 
stimulation--intrauterine 
insemination. 
Fertil 
Steril 
2016;105(6):1575–1583. 
7. Veltman-Verhulst SM, Hughes E, Ayeleke RO, Cohlen BJ Intra-uterine 
insemination for unexplained subfertility,Cochrane Database of Syst Rev 
2016;2:CD001838. doi: 10.1002/14651858.