The thyroid is a small gland in the neck that sets the pace of your metabolism. When it runs slow (hypothyroidism) or fast (hyperthyroidism), periods are often the first thing to change — which is why so many thyroid problems are found by a gynaecologist rather than a physician.
Signs the thyroid may be underactive
- Periods becoming heavier, longer, or more frequent
- Weight gain without a change in eating
- Feeling cold when others do not
- Constipation
- Dry skin, hair fall, thinning of the outer eyebrows
- Tiredness that sleep does not fix
- Low mood, slowed thinking
- Difficulty conceiving, or recurrent miscarriage
Signs it may be overactive
- Periods becoming lighter, shorter, or stopping
- Weight loss despite a good appetite
- Feeling hot, sweating more
- A racing or irregular heartbeat
- Anxiety, restlessness, tremor
- Loose motions
Why this matters for pregnancy
Untreated thyroid disease raises the risk of miscarriage, premature birth, and problems with the baby's brain development. Requirements change during pregnancy itself, so anyone with a known thyroid condition needs their levels rechecked as soon as they are pregnant, and monitored throughout.
Testing
A simple blood test (TSH, often with free T4) settles it. Testing is worth discussing with your doctor if you have the symptoms above, a family history, difficulty conceiving, recurrent miscarriage, or are planning a pregnancy.
Treatment
Hypothyroidism is treated with a daily tablet that replaces what the gland is not making. The dose is set by your blood levels and adjusted by your doctor — it is not a fixed number, it changes over time, and it must never be copied from someone else. Take it as instructed, usually on an empty stomach, and keep the follow-up tests; people often feel better and stop, and levels drift back.
Both conditions are common, straightforward to diagnose, and very treatable. The main harm comes from the years they go unrecognised.