Hypothyroidism or underactive thyroid disease is a condition where the thyroid gland fails to produce enough hormone. Sometimes it can be due to the immune system attacking the thyroid (Hashimoto’s thyroiditis). The thyroid hormone controls metabolism (how fast or slowly energy is used from food), how efficiently calories are burnt, body temperature and heart rate. Deficiency of thyroid gland can cause lots of unpleasant symptoms including depression and anxiety, dry skin and hair, thinning hair, slow heart rate, stubborn weight gain that doesn’t respond to dieting or exercise and excessive fatigue.
Hypothyroidism also affects menstrual periods, fertility, pregnancy and women in the post-natal period.
Menstruation – The most common side-effect of hypothyroidism on the menstrual cycle is very light or irregular periods (ogliomenorrhoea) but a woman can also present with no periods (amenorrhoea) or long and heavy periods (menorrhagia). This disruption to the menstrual cycle is caused by ovulatory dysfunction from the change in hormone regulation between the thyroid and reproductive system.
Very heavy periods can be distressing and affect the quality of a woman’s life. She may flood through her clothing, need very frequent changes of sanitary protection or have to double up on her protection by wearing both a pad and a tampon. She may find it difficult to leave the house, do her job or engage in other activities that she would normally enjoy. Heavier periods can also be more painful than usual and cause anaemia.
Fertility – Hypothyroidism can affect fertility in a variety of ways. Firstly, it can stop or deregulate ovulation so that there is no egg to fertilise or it becomes difficult to know when the fertile phase is. Thyroid hormone works to assist follicle stimulating hormone (FSH) in producing and releasing mature eggs and without sufficient hormone, this vital interaction doesn’t do its job, leading to eggs that cannot be fertilised , or in the case of IVF, early embryos that fail to divide correctly.
Pregnancy – if a woman does manage to get pregnant while she has hypothyroidism, she is at increased risk of giving birth to a child who has developmental delays. A study in 1999 found that 20% of children born to mothers with hypothyroidism had IQ scores of less than 85. The rate was 5% within the healthy population. They are affected in this way because during the first 12 weeks of pregnancy, all of the unborn baby’s thyroid hormone comes from his mother, until he begins to produce his own in the second trimester.
Post-Natal Period – Sometimes women with symptoms of hypothyroidism and even some without can develop inflammation of the thyroid after childbirth that can lead to a drop in thyroid gland. This is called thyroiditis and is usually temporary but can occasionally lead to permanent hypothyroidism.
Heavy periods can also be caused by blood clotting disorders and liver and kidney disease. Full screening and treatment is available at Conception, Birth and Beyond to help every woman with heavy periods find a resolution and enjoy a happy pregnancy and healthy newborn.