Healthy Weight and Fertility


As promised, each Thursday, we will now offer you a piece of educational, science, or research related information. The purpose of our #ThursdayThoughts post is to share with you fact-based content that can enlighten and assist you on your fertility journey. Enjoy our post! Helping to Create New Beginnings….

Healthy Weight and Fertility

Maintaining a healthy weight can be beneficial when trying to have a baby.  Women who are underweight, overweight, or obese may find some difficulty trying to conceive.  The World Health Organization (WHO) defines being overweight as having a BMI equal to or greater than 25 kg/m2 and obese as BMI equal to or greater than 30 kg/m2. 1   Women in these categories may have abnormal menstrual cycles and anovulation.  The rate of miscarriage and pregnancy complications are also increased.  Endocrine disorders such as polycystic ovarian syndrome (PCOS), hypothyroidism, and insulin resistance with women who are obese or overweight can further increase the rate of miscarriage. Men who are also overweight or obese can have changes in sperm function.2  It can also cause problems with erection.

Being underweight or having a BMI of less than 18.5kg/m2, has also been shown to affect fertility.  There may be some difficulty with getting pregnant, and the risk of miscarriage is elevated with a low BMI. 3  These women may also experience irregular periods or preterm delivery when they do achieve pregnancy. Although more research is needed, it has been demonstrated that lower BMI in men can negatively influence semen count, concentration, volume, and motility. 4

Diet and exercise has been shown to improve sperm function and chance of pregnancy.2  A small increase or decrease in weight towards a healthier BMI can greatly improve the probability of pregnancy for both men and women.  Incorporating more fresh fruits and vegetables and getting regular, 30-60 minutes of exercise on most days of the week are a couple ways fertility can be enhanced.

For more information regarding treatment and evaluation please schedule an appointment with one of our providers at the Fertility Institute of Hawaii at 808-545-2800 or visit our website


Dağ ZÖ, Dilbaz B. Impact of obesity on infertility in women. J Turk Ger Gynecol Assoc. 2015;16(2):111-117. Published 2015 Jun 1. doi:10.5152/jtgga.2015.15232

Palmer NO, Bakos HW, Fullston T, Lane M. Impact of obesity on male fertility, sperm function and molecular composition. Spermatogenesis. 2012;2(4):253-263. doi:10.4161/spmg.21362

Oliveira JBA. Does low BMI affect ART outcomes?. JBRA Assist Reprod. 2018;22(1):1. Published 2018 Mar 1. doi:10.5935/1518-0557.20180021

Guo D, Xu M, Zhou Q, Wu C, Ju R, Dai J. Is low body mass index a risk factor for semen quality? A PRISMA-compliant meta-analysis. Medicine (Baltimore). 2019;98(32):e16677. doi:10.1097/MD.0000000000016677

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