Weight and Fertility

Intervention: #3 Weight
Fact Check
  • The best range for fertility is a body-mass index (BMI) of 20 to 24.
  • In women with a BMI of less than 19 and irregular/no menstruation, increasing body weight improves chances of conception.
  • Women who have a body mass index (BMI) of 30 or over are likely to take longer to conceive.
  • In women with a BMI of 30 or over and who are not ovulating, losing weight is likely to increase chances of conception.
  • In men with a BMI of 30 or over, fertility is likely reduced.
  • Participating in a group programme involving exercise and dietary advice leads to more pregnancies than weight loss advice alone.
Research shows that women or men who are underweight or overweight are at greater risk of experiencing infertility. Lower weight is associated with poor quality eggs and less eggs available, as well as increased risk of miscarriage and reduced live birth. Higher weight has been shown to impact conception, pregnancy, and also has impact later in life for the mother as well as child.

Interventions that combine diet and exercise are more effective and can improve 46% of infertility cases. There are 8 factors that must be considered when adjusting nutrition: avoid trans fats, use more unsaturated vegetable oils, turn to vegetable protein, choose slow carbs, drink whole milk, take a multivitamin, get iron from plants and drink water.

The Enhanced Fertility Programme suggests a 5 step strategy to help you adjust your weight and nutrition. The video and the workbook will guide you through the strategy :

  1. Assess: complete the 7 day Food Diary in your workbook. This exercise will help you identify what food, textures and tastes you enjoy, as well as what meal times work best for you.
  2. Plan: complete a 7 day Food Plan in your workbook. This exercise takes into account what you learned about your eating habits in the previous week, as well as what has been proven to make a difference when trying to conceive. The idea is to reach a balanced plan that allows you to follow a healthy diet most of the time.
  1. Intervene: this is the phase when you follow your food plan, try new recipes and foods. You might be practicing mindful eating and introducing moderate daily exercise into your routine. It is important to get support from partners, family, friends or peers to keep the momentum going. Our professional support consultations can also be helpful if you find challenges along the way.
  2. Monitor: the monitoring phase is when you start noticing changes in your body, in response to your nutritional intake. You may notice less bloating, regular bowel movements, or menstrual cycles that are more regular. This is also the phase when you start monitoring your weight once a week. Professional support can help you adjust what is not working for you and help you continue with what is being beneficial.
  3. Maintain: once you reach your fertility zone for weight, you want to maintain your body in that state. In this phase, you will continue following your food plan, with an 80/20 rule, which means you are eating healthily most of the time. Partners, family, friends and peers can help you maintain this phase. Professional support can help you cope with challenges you may face. After some time, you will get used to a new nutritional routine which will come naturally to you. This is when you have reached long lasting change.

Watch the video to learn more about the impact of weight on fertility and reproduction. Download the workbook to follow the 5 step strategy to move you closer to the fertility zone for weight.
Find the Evidence

[1] https://www.ncbi.nlm.nih.gov/pubmed/17978119
[2] https://www.ncbi.nlm.nih.gov/pubmed/18929048
[3] https://www.fertstert.org/article/S0015-0282(14)01771-3/fulltext
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC27536/
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3455453/
[6] https://www.ncbi.nlm.nih.gov/pubmed/18281684
[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5844651/#r8
[8] https://www.ncbi.nlm.nih.gov/pubmed/27887711
[9] https://joe.bioscientifica.com/view/journals/joe/239/3/JOE-18-0199.xml#bib66
[10] https://joe.bioscientifica.com/view/journals/joe/239/3/JOE-18-0199.xml#bib57
[11] https://www.ncbi.nlm.nih.gov/pubmed/21821244
[12] https://doi.org/10.1016/S1472-6483(10)60385-9
[13] https://journals.sagepub.com/doi/10.2217/17455057.4.2.183
[14] https://insights.ovid.com/article/00001703-201412000-00006
[15] https://www.thieme-connect.de/products/ejournals/abstract/10.1055/s-0032-1328877
[16] https://joe.bioscientifica.com/view/journals/joe/239/3/JOE-18-0199.xml#bib35
[17] https://joe.bioscientifica.com/view/journals/joe/239/3/JOE-18-0199.xml#bib58
[18] https://joe.bioscientifica.com/view/journals/joe/239/3/JOE-18-0199.xml#bib39
[19] https://linkinghub.elsevier.com/retrieve/pii/S1701216316328638
[20] https://www.nature.com/articles/0801602
[21] https://www.ajpmonline.org/article/S0749-3797(15)00752-7/fulltext
[22] https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.111.070060
[23] https://joe.bioscientifica.com/view/journals/joe/239/3/JOE-18-0199.xml#bib4
[24] http://centrespringmd.com/wp-content/uploads/2013/05/Fertility-Diet-Study.pdf
[25] https://www.ncbi.nlm.nih.gov/pubmed/17329264
[26] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5826784/