Hypothyroidism, which is a low-functioning thyroid gland, is quite common in women; about one in eight will have thyroid disease in her lifetime. Interestingly, there's been little research in understanding how thyroid function may affect sexual function.
The good news is that treatment for hypothyroidism—supplementation of thyroid hormone—is straightforward, and women receiving treatment seem to have little or no increase in sexual issues. Those who are not treated seem to have more issues with desire, lubrication, and orgasm.
As women get older, their risk of having thyroid disease increases. There are both physical symptoms (like weight gain, dry and yellowish skin, hair loss, fatigue, muscle or joint aches and pains) and cognitive symptoms (like slower thinking or speech, memory issues), but at age 50 and thereafter I recommend a screening—simple blood tests—at regular intervals.