HEMO-STIM study - Thrombotic profile of ovarian stimulation protocols in medically assisted reproduction

Are you ready to start treatment with in vitro fertilisation (IVF) and would you like to take part in the research?

We invite you to take part in the HEMO-STIM study described below. 

If you are interested, talk to our team, who will be pleased to discuss this with you.


Infertility affects more than 10% of couples. As a result, nearly 10,000 IVF treatments are performed each year in Switzerland. The hormonal treatments used are effective and allow stimulation of the ovaries and collection of egg cells. 

Some of these hormonal treatment protocols may, perhaps more than others, increase the risk of developing a blood clot in a leg vein, which is called "venous thrombosis". Although, apart from some particular cases, the benefits of ovarian stimulation greatly outweigh the possible risk of thrombosis, this risk is still poorly understood.

Aim of the study

We want to evaluate how the hormonal medicines used in the various ovarian stimulation protocols used during in vitro fertilisation influence blood clotting (coagulation)and in some way make the blood "thicker".

We intend to analyse the blood's coagulation properties before starting the stimulation treatment and during the stimulation. 

Selection of participants

The observation study is being performed with 100 patients at the CHUV and HUG, between 2017 and 2018. 

Participation is open to all women aged 18 to 42 years who are starting an in vitro fertilisation protocol. 

Participation is voluntary. 

Study description

The duration of the study corresponds to an in vitro fertilisation cycle, i.e. about four weeks.

Two consultations are planned, with three blood samples taken (the same as during your IVF treatment follow-up). 

The blood tests taken during the study are specific to coagulation and the hormones involved in reproduction. For example, we measure how the blood forms a clot and how this solidifies.

Advantages for participants

Your participation in the study will not bring you any direct benefit. 

The results of the study may subsequently prove to be important for women suffering from infertility and resorting to IVF.

Possible risks and inconveniences

By participating in the study, you will be exposed to the minor risk of giving blood samples. 

As far as possible, the blood samples will be taken at the same time as those for the stimulation phase of your IVF treatment.

Context of the study

We are not testing any new medicine or any new technology in medically assisted reproduction. 

We are performing this research study in compliance with the stipulations of Swiss regulations in this field. 

The competent Cantonal ethics committee has reviewed and authorised this study.

Data confidentiality

Your personal and medical information are recorded for the purposes of the study. 

Only a limited number of persons may consult your data, in uncoded form, and then only to perform the tasks necessary for the correct conduct of the study. 

Your personal data are recorded in encrypted form and are then examined as anonymous data.

Your name is never published in any way in the reports or publications resulting from this study.

Your contribution to costs

All the examinations performed as part of the study are carried out free of charge. 

Neither you nor your health insurer have to pay any supplementary costs linked to your participation in this study.

Financing the study

Financing has been obtained from the Fonds national suisse (FNS) (Swiss National Science Foundation).


Fertility Medicine and Gynaecological Endocrinology
CHUV Maternity Unit
Av. Pierre-Decker 2
1011 Lausanne
Tél. +41 21 314 32 76
Fax +41 21 314 32 74
 Last updated on 17/08/2018 at 10:46