This thesis deals with two prediction problems in reproductive medicine. The first is the prediction in infertile couples of the chance to conceive without treatment. The second deals with the prediction of the chance of conception in couples treated with in vitro fertilization (IVF). Chapter 1 introduces the notion of infertility. The difference between the terms infertile and subfertile is explained and the prevalence and the main causes of infertility are summarised. Emphasis is on prognosis in untreated sub/infertility and prognosis in IVF. Next, the methodology is discussed, with emphasis on the development of prediction models and their validation. Chapter 2 investigates the following question: does combining the information of existing models for predicting the chance of pregnancy among untreated subfertile couples result in improved predictions? The original data of three previously published models are used to develop a synthesis model for predicting pregnancy leading to live birth without treatment. The predictors used are duration of subfertility, women's age, primary or secondary infertility, percentage of motile sperm, and whether the couple was referred by a general practitioner or by a gynaecologist (referral status). Because the post-coital test (PCT) was not assessed in one of the studies, a second synthesis model including the PCT is developed, based on the remaining two studies. The ability of the synthesis models to distinguish between women who did and who did not become pregnant (also called ‘discriminative ability’) is compatible to the ability to the original models. The reliability of the predictions by the three-sample synthesis model (also called ‘calibration’ of the model) is somewhat better. Predictions improve considerably by including the PCT in the synthesis model.

E.R. te Velde (Egbert)
Habbema, Prof. Dr. J.D.F. (promotor), National Institute of Public Health and the Environment (RIVM), The Netherlands Organization for Scientific Research (ZON/MW), Velde, Prof. Dr. E.R. te (promotor)
Erasmus MC: University Medical Center Rotterdam

Hunault, C.C. (2006, November 17). Clinical prediction models in reproductive medicine: applications in untreated subfertility and in IVF treatment. Retrieved from