Greater BMI, greater miscarriages with ART


Being overweight leads to a greater risk of miscarriage if they used assisted reproductive technology like IVF or ICSI. These findings were reviewed at the 26th annual conference of the European Society of Human Reproduction and Embryology along with a strong recommendation that this information be provided during the counseling given to those women considering ART.

Dr. Vivan Rittenberg, a Clinical Fellow in the Assisted Conception Unit, Guy’s and St. Thomas’ Hospital NHS Foundation Trust, London, and colleagues analyzed all pregnancies after single blastocyst transfer (SBT) performed over a four year period in their clinic. A blastocyst is a five day old embryo ready for implantation. The 318 women were divided into two groups based on the body mass index (BMI). One group was in the normal range while the other had great BMI and included women who registered as obese.

Overall, 26% of all women miscarried before 20 weeks gestation. The miscarriage rate was lower in women with the normal BMI at 22%. Overweight women miscarried at a rate of 33%. After adjusting for variables in the data, the researchers were comfortable asserting that overweight or obese women had more than double the risk of miscarriage using ART.

“Although there is evidence that miscarriage rates are higher in overweight women who conceive spontaneously, there were conflicting views about the effect of increased weight on the outcome of pregnancies occurring after IVF and ICSI,” Dr. Rittenberg said. “The difficulty of interpreting the studies to date is that they are heterogeneous, their thresholds for defining obesity vary, and they assess the outcome in relation to BMI following the transfer of multiple embryos at various stages of development. Our study differs in that we transferred only one embryo at a specific stage of development, and were therefore able to provide clear evidence of the deleterious effect of being overweight on the chances of miscarriage.”

The message is clear: lose weight prior to pregnancy, natural or assisted.

“Overweight women wishing to get pregnant by spontaneous conception are already counseled to lose weight before trying for a baby,” Said Dr. Tarek El-Toukhy, Consultant in Reproductive Medicine at the Assisted Conception Unit, Guy’s and Thomas’ Hospital. “Our findings have shown clearly that women undertaking ART should be strongly encouraged to heed this advice in order that they can have the best possible chance of obtaining and maintaining a pregnancy.”

Source: ESHRE, Medical News Today


The information provided on is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her health professional. This information is solely for informational and educational purposes. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Neither the owners or employees of nor the author(s) of site content take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading this site. Always speak with your primary health care provider before engaging in any form of self treatment. See our Legal Statement for more details.

Fertility Clinics Directory

Find a Fertility Clinic

If you or a loved one is suffering from infertility and needs help conceiving then we are here to offer help in any way we can. We have over 450 Fertility Clinics listed on our Directory. Click here to search for a Fertility Clinic that is right for you.