Limitations of randomization for the study of nutrition, lifestyle, and in vitro fertilization success

Limitations of randomization for the study of nutrition, lifestyle, and in vitro fertilization success

VOLUME 114, ISSUE 5, P955-956


David R. Meldrum, M.D., Jamie Stanhiser, M.D., H. Irene Su, M.D., M.S.C.E.


Reflections on "First effective mHealth nutrition and lifestyle coaching program for subfertile couples undergoing in vitro fertilization treatment: a single-blinded multicenter randomized controlled trial" by Oostingh et al.

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Go to the profile of Eline Oostingh
about 2 years ago

We thank the authors for their efforts of writing this editorial on our paper. As we have addressed in our paper, a randomized controlled trial does not represent a real life situation and decreases the generalizability, which is in line with the opinion of these authors. The advantage of a long history of research is that in earlier studies we have shown that our online coaching program www.Smarter is also an effective coaching program for the general as well as vulnerable population [1, 2, 3]. Since placebo effects refer to the effects that occur due to mechanisms such as expectancies of the patient [4], it is indeed likely that a placebo effect occurred by only participating in our coaching program. However, participants in the intervention group showed much larger improvements of inadequate behaviours compared to participants in the control group. This underlines that awareness of inadequate lifestyle behaviours only does not do the trick.

Our study was indeed not powered to investigate clinical outcomes such as pregnancy rates and birth outcomes. However, since these outcomes are of great relevance, we are expanding our study population in order to obtain more data for future analyses. One may argue about the statistical intention-to-treat analysis we have used, but since it is not possible for a participant with adequate behaviour to further improve this behaviour, the coaching was not started on this particular point and so they were not offered the intervention. Therefore, we found use of this statistical method justified.

In an ideal world, implementing a coaching program that covers the full range of behaviours impacting IVF success would be, as the authors stated, most successful. Therefore, with our study we also want to underline the need for cohort studies with a broad range of exposures, unifying measurements and collaboration between study groups in order to obtain big data for robust analyses. However, the challenge will be to find the right balance between the amount of interventions, the quality of data, and high compliance. In this way we can support medical care for (sub)fertile couples wishing to conceive, but at the same time also contribute to the health of current and future generations. At the Erasmus MC, University Medical Centre Rotterdam, Smarter Pregnancy is now incorporated in a blended periconception Lifestyle care approach offering tailored face-to-face counselling in combination with Smarter Pregnancy coaching to these couples. In the end, creating a life course care platform in which multiple disciplines are incorporated to offer integrated care preconceptionally is in our opinion of utmost importance.


Drs. E.C. Oostingh, Dr. M.P.H. Koster, Dr. R.P.M. Steegers-Theunissen

Department of Obstetrics and Gynaecology, Erasmus Medical Center, University Medical Center, Rotterdam, the Netherlands.



  1. Van Dijk et al. Impact of an mHealth platform for pregnancy on nutrition and lifestyle of the reproductive population: a survey JMIR mHealth uHealth 2016 May 27;4(2):e53
  2. Van Dijk et al. Healthy preconception nutrition and lifestyle personalized mobile health coaching is associated with enhanced pregnancy chance. Reprod Biomed Online. 2017 Oct;35(4):453-460
  3. Gootjes et al. Neighborhood deprivation and the effectiveness of mobile health coaching to improve periconceptional nutrition and lifestyle in women: survey in a large urban municipality in the Netherlands. JMIR mHealth uHealth 2019 April 11;7(4):e11664
  4. Evers et al. Implications of placebo and nocebo effects for clinical practice: Expert consensus. Psychotherapy and Psychosomatics 2018 Aug; 87(4):204-210
  5. Van der Windt et al. Impact of a blended periconception lifestyle care approach on lifestyle behaviours: before-and-after study JMIR 2020 Sept 30;22(9):e19378