I find that I need more insulin and have a much more difficult time keeping my blood glucose in the normal range during the week before I get my period.

I have been increasing my basal insulin by 1 unit during the last week of my menstrual cycle, and I have to take extra bolus insulin to get my blood glucose into a normal range.

“Luteal Phase Insulin Resistance”

That’s the scientific term for that I’m describing here.  On average, a woman’s menstrual cycle lasts 28 days.  Day 1 is the day that a woman gets her period.  The time period after ovulation and before menstruation (approx. days 14 through 28) are considered the “luteal phase.”  During this phase, the level of the hormone progesterone increases.  This increased progesterone causes insulin resistance.

Hormone levels during the Menstrual Cycle

Talk to your doctor about how to adjust your insulin or medication during this time period

Female hormones are just one factor that can change how your body responds to insulin.  If you are seeing patterns that correlate with your menstrual cycle, it’s a good idea to discuss that with your doctor to see what their advice is.

This luteal phase insulin resistance may also happen at the same time as other PMS symptoms.  Eating extra carbs because of food cravings can be another cause.  But personally I’ve found that even if I follow a very restrictive diet, I still need to increase my insulin dosage during the week before I get my period.

Compare these 2 days….. It’s not my fault!

It’s hormones I’m fighting against!

My Freestyle Libre CGM Graph while in the Luteal Phase

Articles about the effect of Menstrual Cycle on Insulin Sensitivity

• Menstrual cycle effects on insulin sensitivity in women with type 1 diabetes: a pilot study. This is a small study of just 5 people.  It found that 3 out of 5 women had a decline in insulin sensitivity during the luteal phase.  So this doesn’t effect all women the same way.   This conclusion is in line with other anecdotal conversations I’ve read about.   Individual differences may be very important here.
• 5 Things Women Need to Know about Diabetes and Their Period – This article discusses the luteal phase thing, as well as the effects of birth control pills, and has some other interesting information.
• How My Fertility Charts Help Me Customize My Type 1 Diabetes Treatment – WOW!  It sounds like it’s possible to graph your basal body temperature and see when ovulation happens, which in turn can help you predict when you may need more insulin
• Longitudinal Study of Insulin Resistance and Sex Hormones over the Menstrual Cycle: The BioCycle Study – Scientists studied healthy females and found some variation in insulin resistance that correlated with the menstrual cycle.
• Insulin Requirements throughout the Menstrual Cycle
• Fluctuations of Hyperglycemia and Insulin Sensitivity Are Linked to Menstrual Cycle Phases in Women With T1D – This study found that hyperglycemia risk (high blood glucose) increased during a woman’s cycle, while total daily insulin, carbohydrates, and calories stayed the same.
• Variability of Glycemic Outcomes and Insulin Requirements Throughout the Menstrual Cycle: A Qualitative Study on Women With Type 1 Diabetes Using an Open-Source Automated Insulin Delivery System This study interviewed women to see how they adjusted to changing insulin requirements.  It suggests that medical device manufacturers of insulin pumps should be taking cycle day into account to help with keeping blood glucose levels stable throughout the menstrual cycle.  Interestingly, people had varying experiences.

Can tea help balance things?

Years ago, before I was diagnosed with diabetes, I tried this “Sugar Balance & Women’s Tonic with Dong Quai” tea.   I didn’t have diabetes at the time (I know because I did get my glucose levels checked, and they were fine!), but yet I felt weird around PMS time and I remember thinking that this tea did help my with my moods.  I didn’t monitor my blood glucose back then, so I don’t know if this has a measurable effect on glucose levels.   If I try it again, I’ll let you know!  But mostly I just wanted to mention it, as traditional Chinese herbal remedies like this Triple Leaf Tea may help out someone!