07 3188 5000
Most Popular Posts
Dr Bryan Kenny expert answers powered by Healthshare
Weight and Fertility
Fertility Obstetrics 

How does weight affect fertility?


Weight has always been a sensitive subject for both men and women. While weight can affect self-esteem and physical appearance, an unhealthy weight can also affect fertility in both men and women. For women, an unhealthy weight could affect her fertility, her response to treatment, the course of pregnancy and the child’s health. Having an unhealthy weight means being underweight or overweight.


The impact of weight on fertility for men


An unhealthy weight also impacts fertility in men.. Studies have shown that severe obesity in men impacts fertility due to hormonal imbalances linked to production of sperm, the sperm motility, and low sperm count.


The impact of weight on fertility for women

  • Overweight

The ovaries are the primary site of production for estrogen but about 30% of the estrogen produced in the body are produced by fat cells. A person who has an healthy weight has high chances of producing a healthy amount of estrogen.


A person who’s overweight has additional fat cells that will produce more estrogen than your body requires. It. While you may think having extra body fat and then extra estrogen should be a good thing for fertility, the body doesn’t work that way.


Excess estrogen could prevent regular ovulation or even totally hinder ovulation. About 40% of obese women have irregular menstrual cycles that by extension negatively impacts their chances of getting pregnant. Women who are severely obese with BMIs of around 35 to 40 may have a low reduced chance of conceiving compared to women who have a BMI of less than 29.


Women who are overweight but still have regular periods aren’t necessarily guaranteed to fall pregnant easily as studies have shown that overweight women do not easily get pregnant even if they have normal menstrual cycles.


Being overweight also negatively affects the success rates for fertility treatments. If an obese woman falls pregnant through fertility treatment or natural conception, she has a higher chance of having a miscarriage or the baby having birth defects. These women are also at risk of developing pre-eclampsia and pregnancy induced diabetes.


Being obese or overweight has also been associated with endocrine and hormonal conditions that may decrease fertility such as insulin resistance, excess testosterone and PCOS.


People who are overweight could improve their fertility and increase their chances of getting pregnant by losing weight. It has been shown that more women that achieved significant weight loss have had higher pregnancy and live birth rates when compared to women who were not able to achieve any significant weight loss.


  • Underweight

A woman with very low BMI (usually below 18.5, although the threshold may differ depending on other factors) also tend to have irregular periods. Having irregular cycles means having irregular or no ovulation that could make it difficult to conceive.


While most women would do anything to avoid it, gaining weight is one straightforward solution to reduced fertility due to being underweight. The first thing you should try before any other treatment is to try gaining weight. However, it is important to know that the weight gain should be that of fat and not muscle since it’s fat that helps in estrogen production. So you shouldn’t gain weight by gaining muscle.


We all have different body types. Some women are lean and would conceive with ease while some other fit women would have difficulty letting go of some of their fitness just to get some regular cycles. The plan will most likely be that you work towards achieving a minimum BMI of 18.5 and more preferably 20 to 24 which is the BMI range thought to be the best for conceiving..


You can make an appointment with Dr Kenny on 07 3188 5000.

This article is written to be informative and does not substitute seeking a professional consultation from a medical professional.

Consulting Rooms
Consulting Rooms

Greenslopes Obstetrics & Gynaecology is closely aligned with the Greenslopes Private Hospital which opened Brisbane’s newest maternity facility in February 2013.

Pregnancy Pearls
Pregnancy Pearls

There are many questions and common issues that arise during pregnancy. Here are some short and helpful articles on many common pregnancy issues.

Pregnancy Checklist
Pregnancy Checklist

Congratulations on your pregnancy! If you would like some help thinking through some of the things you need to organise, I've put together a checklist to make sure the important things aren't missed.

To speak directly with a team member please call 07 3188 5000