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“Did you know that higher weight will lower your chances to get pregnant?”

This is the question many fertility doctors need to ask during the first consultation. Obesity is a global health problem that has impact on many conditions including fertility. The reason to talk about weight should not be underestimated because significantly higher or lower BMI (Body Mass Index) has a negative impact on fertility and may also influence the chances to get pregnant during in vitro fertilization procedure.

It is known that too high or low BMI can cause changes in female hormonal balance which can cause irregular ovulation or even lead to the absence of menstrual periods. Studies have shown that higher BMI may also affect the success of infertility treatment by reducing the quality and number of eggs and lead to the problems in embryo implantation (Kudesia et al., 2018; Rittenberg et al., 2011).

BMI = Body Mass Index, weight (kg)/height (m) x height (m)

There is emerging evidence that also male obesity has a negative impact on male reproductive potential not only reducing sperm quality, but altering the physical and molecular structure of germ cells in the testes and ultimately mature sperm (Nicole O. Palmer et al 2012).

BMI and fertility

Weight factor should be considered while evaluating the reasons of couple´s infertility. Patients should be informed if losing some weight would improve their likelihood of pregnancy. In some cases, a weight loss of 5-10% may already have positive effect on the treatment result and lead to healthy pregnancy (Clark et al., 1995; Pandey et al., 2010).

Issues related to weight are often personal, sensitive and difficult, and bringing up the topic may be unpleasant for patients. But it would be worse not to talk about the weight as the patient might get an unrealistic idea of her chances of having a baby. Keeping the normal BMI is one of the things patients can do themselves to increase their chances to conceive naturally or having higher success rate in IVF.

These are the reasons Nova Vita´s  and Ovumia´s professionals bring up the topic about the overweight. It is important to remember that you and we are on the same side and that we have a common goal: To create a new life.

”Our main purpose is to create a new life”.

Other authors: Elle Talving, Peeter Karits, Candido Tomas, Anna Kivijärvi, Anna Pulkinen


  1. Clark AM, Ledger W, Galletly C, Tomlinson L, Blaney F, Wang X, Norman RJ. Weight loss results in significant improvement in pregnancy and ovulation rates in anovulatory obese women. Hum Reprod. 1995; 10: 2705–12.
  2. Kudesia R, Wu H, Hunter Cohn K, Tan L, Lee JA, Copperman AB, Yurttas Beim P. The effect of female body mass index on in vitro fertilization cycle outcomes: a multi-center analysis. J Assist Reprod Genet. 2018 Aug 21. doi: 10.1007/s10815-018-1290-6.
  3. Lan L, Harrison CL, Misso M, Hill B, Teede HJ, Mol BW, Moran LJ. Systematic review and meta-analysis of the impact of preconception lifestyle interventions on fertility, obstetric, fetal, anthropometric and metabolic outcomes in men and women. Hum Reprod. Vol. 32, No. 9 pp. 1925–1940, 2017.
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  5. Rittenberg V, Seshadri S, Sunkara SK, Sobaleva S, Oteng-Ntim E, El-Toukhy T. Effect of body mass index on IVF treatment outcome: an updated systematic review and meta-analysis. Reprod Biomed Online. 2011 Oct; 23(4): 421-39. doi: 10.1016/j.rbmo.2011.06.018.
  6. Nicole O. Palmer, 1 Hassan W. Bakos, 2 , 3 Tod Fullston, 1 and Michelle Lane 1 , 3. Impact of obesity on male fertility, sperm function and molecular composition.