Consultant dietitian Sarah Keogh explains why hormones are key to a woman’s reproductive health.
Women tend to be very aware of their hormones. We are used to our monthly cycles and the changes they can bring both physically as well as the effects on mood (not to mention the sugar cravings!).
Hormones have control over fertility and our monthly cycles, but they can have a wider effect on the whole of our health – and pregnancy is one area they can really influence.
An estimated one in six couples in Ireland is affected by infertility and it can be heartbreaking to experience. There are so many potential causes of infertility and with some couples, no cause is ever found.
So, can hormones cause infertility?
Imbalances in hormones can affect conception and the progression of a pregnancy. An underactive thyroid has an effect across the board on metabolism and can make it harder to become pregnant.
In recent years, scientists are paying more attention to the link between hormones and fertility and looking at conditions like under-active thyroid and Poly Cystic Ovary Syndrome (PCOS).
Your thyroid produces a hormone called thyroxine, which in turn controls metabolism. Low levels of thyroxine literally slow down the body, so you can feel extremely tired, have dry skin, find your hair is thinning or falling out as well become constipated and gain weight.
People often assume that weight is the only symptom of an underactive thyroid, but it is possible to be slim and still be lacking thyroxine, so don’t rule it out.
One effect of having an underactive thyroid is that it can interfere with the release of an egg from the ovary, making it harder to become pregnant. An underactive thyroid, if it is undiagnosed, can also lead to an increased chance of having a miscarriage.
A number of causes
Underactive thyroid can have a number of causes. In Ireland, the most common cause is a type called Hashimoto’s Thyroiditis. This type of underactive thyroid is caused when the body makes antibodies that attach to the thyroid gland and reduce the amount of thyroid hormone that it can make.
Another cause is low levels of iodine. The thyroid gland needs lots of iodine to work, so it is worth topping up with iodine-rich foods like fish and milk. The soil in Ireland is naturally quite low in iodine, so if you normally don’t eat fish or dairy, you may need to start taking an iodine or kelp supplement. As with any condition, never selfdiagnose!
An underactive thyroid may also be linked to problems with your pituitary gland, which is essentially the control centre for all of the hormones in your body. A simple blood test can rule out (or in) an underactive thyroid and it is generally easily treated by taking thyroxine as a tablet. It also helps if you add 200 micrograms of selenium, as this helps your thyroid hormone to work a little better.
It is important for your GP to know your thyroid is underactive once you become pregnant, as you will need to have the levels of your thyroid hormone carefully controlled for the nine months.
PCOS (Polycystic ovary syndrome)
Polycystic ovary syndrome affects about 10% of women and is a leading cause of infertility. Several hormones are affected in PCOS and women with this condition typically have higher level of male hormones (called androgens) and there can also be issues with insulin levels.
The exact cause of PCOS is unknown, but it can run in families so it might be genetic. Women with PCOS can have very irregular periods or long cycles (more than 35 days between periods). They can also have facial hair and more hair than normal on their legs and chest. Acne can be a problem and women often struggle with weight.
Women with PCOS can find it harder to become pregnant, as the increased levels of male hormones means that fewer eggs are released from their ovaries. They are also more likely to have miscarriages.
In recent years, there has been more focus on managing insulin levels. Women with PCOS seem to be more ‘insulin resistant’ than other people and this can lead to higher levels of insulin in their blood.
Why does this matter?
Higher levels of insulin can be a trigger for the body to make more male hormones, which go on to affect fertility. Higher levels of insulin can also lead to weight gain. Insulin has the effect of ‘switching off’ fat burning, and encouraging the body to store fat. This means that women with PCOS put on more weight and find it much, much harder to lose it compared to everyone else.
Some diabetes medicines that reduce insulin resistance have been used to help women with PCOS, but they have had only limited benefits so far.
One important treatment for PCOS is weight loss and a low-glycaemic index diet. A major cause of insulin resistance is weight gain, so it can become a vicious cycle for women with this condition: the insulin makes them put on weight, which makes them more insulin resistant, so they put on more weight and become even more insulin resistant and so on.
A very low glycaemic index diet is a great way to start reducing insulin resistance and weight. Exercise is also very helpful as it has a huge effect on getting insulin levels down.
What are low-glycaemic index foods?
High-fibre foods take longer to digest and therefore produce a slower rise in blood sugar. The following foods help to keep you fuller for longer. Wholegrain bread, pasta, rice and crackers, new potatoes, basmati rice, unsalted nuts and seeds.
Women with PCOS benefit hugely by working with a dietitian – both for advice on a very low GI diet and support with what can be quite a long process. If you think you may have PCOS, an underactive thyroid, or you are experiencing infertility, do talk to your GP for advice and further testing.
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