I have had type 1 diabetes for 26 years and am well controlled using an insulin pump. I have had recurring problems with irregular periods, hair growth and acne. I am trying to have a baby and was diagnosed with PCOS. I was put on 2000 mg/per day of metformin, in addition to my pump, to help regulate my condition. It has been two months and my insulin levels have not dropped and, so far, no period. How common is PCOS in type 1 diabetics? Have other type 1 diabetics who have PCOS been treated successfully with metformin? Incidentally, I take on average 30 units of insulin a day and I am not overweight.

PCOS is the most common cause for irregular menses in pre-menopausal women. It is not unique to type 1 diabetes where insulin is not present. It is related to insulin resistance which is associated with type 2 diabetes. You may question whether metformin is appropriate in patients with type 1 diabetes. With no response, I would suggest you should talk with your physician about another therapy. This is not because it is the wrong treatment. It is because it has been some time since you started with no benefit. Patients may have type 1 diabetes and still inherit a predisposition to insulin resistance. These patients tend to weigh more and have increased insulin requirements. Obviously, you don’t have these characteristics. It may be time to move on and consider other causes or reshape the treatment. The problem is that other therapies are not so easy to use. Oral contraceptives or medications that cannot be taken with pregnancy are obviously out. Make sure you have been checked for other causes of irregular periods. You should discuss this with your physician.

JTL
Additional comments from Dr. Bill Jones:

I do not know how frequently type 1 diabetes and PCOS occur together. Metformin does appear to improve ovulation presumably by decreasing insulin resistance. I do not know if the actual mechanism for this improvement is well understood. Interestingly, women with just type 1 diabetes usually ovulate without any problems. Your physiologic problems may be more complex. You lack of insulin production on top of increased insulin resistance. Nevertheless, your insulin requirement is not that high. There also may be other hormonal problems such as thyroid dysfunction that may be inhibiting ovulation. Thus, metformin by itself may not be effective. You may require an additional agent such as Clomid to induce ovulation. This warrants further investigation by your doctor.

OWJ