Trying for a baby? It doesn’t matter if it’s your first or the fifth, maintaining a healthy weight prior to conception can really have an impact on the health of your eggs and improve your fertility. There is a wealth of evidence to show that for women greatly above their healthy BMI, fertility can decrease by up to 4% with each BMI point over 29kg/m2. So how does my weight affect the health of my eggs, I hear you say? Well let me show you….
Trying for a baby? It doesn’t matter if it’s your first or the fifth, maintaining a healthy weight prior to conception can really have an impact on the health of your eggs and improve your fertility. There is a wealth of evidence to show that for women greatly above their healthy BMI, fertility can decrease by up to 4% with each BMI point over 29kg/m2. So how does my weight affect the health of my eggs, I hear you say? Well let me show you….
Genetic development
Being above your healthy weight range and holding extra weight particularly around your tummy puts increased pressure on your organs. This additional weight creates inflammation which has the potential to cause trouble for every part of your body, including your ovaries and other reproductive organs. Your ovaries are responsible for the genetic and physical development of your eggs. Chronic inflammation may influence the genetic signalling and makeup of your eggs and their development.
Oestrogen balance
Studies have shown that overweight and obese women are three times more likely to experience irregular menstrual cycles. The release of your eggs, or ovulation, is dependant on a symphony of hormones working succinctly with each other to form a harmonious cycle. One of the main hormones that determine ovulation is oestrogen (you ovulate when oestrogen is at its lowest levels). Each cell of fat is actually able to make oestrogen independently so having a high amount of body fat enables your body to produce excess oestrogen. Higher levels of oestrogen throws out the hormonal balance for your menstrual cycle meaning the what-would-be perfectly playing orchestra becomes an out-of-tune jamming session. Consequently only a very weak signal is sent for cell maturation and therefore ovulation.
Insulin Resistance
You may like to think of the hormone insulin like a delivery truck; collecting glucose, or sugar, from your bloodstream and delivering it to working muscles. Excess fat mass impairs the actions of insulin (picture numerous roadblocks hampering the normal smooth delivery route) and so your body tries to overcompensate by producing more and more insulin. A high level of insulin in the bloodstream has an effect on other sex hormones, progesterone and luteinising hormone, that further contribute to irregular ovulation.
Implantation rates
The data on miscarriage rates indicate that being overweight or obese may be a possible cause for an increased risk of miscarriage. A reduced rate of embryo implantation in the endometrial lining has been put forward as one possible factor however the actual mechanisms behind this hypothesis are still to be confirmed. It has been suggested that the inflammation, insulin resistance and impaired hormonal balance caused by excess fat mass might create an unsuitable environment for optimal endometrial development and/or may generate reduced sensitivity signals for implantation.
So if your BMI is above 29kg/m2 it’s not to say that you will not be able to fall pregnant at all if you don’t lose weight; not at all. I just want to highlight that there is a lot of research into maintaining your healthy weight to provide the best health for your eggs and therefore boost your fertility. Talk to your Accredited Practising Dietitian if your BMI is above 29kg/m2 to discuss strategies and develop a personalised weight management plan for you.