How to Improve Blood Sugar Control During Your Period

As if blood sugar management isn’t hard enough already, adding in the constantly changing hormone levels of a woman’s menstrual cycle seems like a cruel joke. Here's how to get blood sugar control when your hormones are out of control.

diabetes and your periodThe menstrual cycle's hormone levels impact the body's sensitivity to insulin—it's not that you've suddenly developed an inability to count carbs.

Contrary to the basic explanation we all received in the 8th grade, your hormones are changing every single day of the month, and you can bet those hormones impact your sensitivity to insulin, too.

Trying to determine when the hormones of your menstrual cycle impact your blood sugars and how to adjust your insulin doses—in an effort to keep your blood sugars in your goal range—feels nearly impossible to predict. And for each woman, that entire process and reaction can be slightly different, so there isn’t a “one size fits all” plan.

To give guidance about how to make diabetes management less stressful during that “time” of the month (or, more accurately, the whole month),OnTrack Diabetes reached out to Jennifer Smith, RD, CDE from (And Jenny should know since she’s lived with type 1 diabetes for over 30 years!)

The Fab Four: Hormones and Your Blood Sugar Levels

“Every month,” explains Smith, “the body cycles through hormones that are meant to essentially prepare the body for pregnancy.”

There are three phases that your body cycles through the follicular, the ovulatory and the luteal phase.

“The four hormones that regulate your menstrual cycle are estrogen, progesterone, Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). And to a very small extent, testosterone production is a factor here, too,” explains Smith.

Each of these hormones will impact your blood sugars and sensitivity to insulin differently as their production levels fluctuate throughout the entire month-long cycle. Here’s how it breaks down:

  • Days 1-10: Things Could Start Off Rocky
    The first day of your cycle begins on the first day of your period. While some women may experience higher blood sugars and insulin resistance on this day, your insulin sensitivity should return to “normal” for the remainder of your period. The few days following your period are generally insignificant as well in terms of blood sugar challenges.
  • Days 11 - 14 of Your Cycle: Erratic Blood SugarsTypical 
    The “ovulatory phase” is the first part of your cycle where you may notice higher blood sugars and insulin resistance, Smith explains. As your body prepares to release an egg (ovulate), luteinizing hormone, follicle stimulating hormone and estrogen levels all rise, causing a brief but notable spike in blood sugars. “This phase is generally noticed in blood sugars levels for no more than 2 or 3 days at most.”

    ● Days 15 - 20 of Your Cycle: You Can Relax Now But Not For Long
    During this part of your cycle, your LH and FSH levels drop quickly back to normal levels. Estrogen will decrease rapidly as well but as you approach the next phase of your cycle, both the estrogen and especially the progesterone levels begin to slowly rise.

    Days 21 - 28 of Your Cycle: This is High Blood Sugar Territory
    The time of your cycle that you’re probably noticing significant and lasting insulin resistance and higher blood sugars levels are during the 3 to 7 days leading up to the start of your next period.

"During the week before the first day of your period, estrogen and progesterone levels are peaking,” says Smith. “This would be days 21 through 28 of a typical 28-day cycle.”

As these hormones peak in production, your blood sugars become more resistant to your “normal” insulin doses, particularly your background or basal rate insulin. While the increase of progesterone and estrogen are gradual, it can seem like there is actually one day right before your period begins during which your blood sugar spikes dramatically.

Progesterone is also the constantly-increasing hormone during pregnancy that causes insulin needs to persistently rise throughout the last two trimesters.

Preparing for Insulin Resistance During Your Cycle

Considering your hormone levels are in a constant state of flux, don’t let your frustration or confusion get the best of you. Balancing your blood sugars around the hormones of your menstrual cycle is not an easy task, especially considering that not every cycle is the exact same number of days.

Here are a few steps to help you control fluctuating blood sugars around those pesky fluctuating hormone levels:

  1. “Track your period for 3 months using a period app or even an ovulation kit, to determine when you’re likely ovulating and how many days your cycle usually is,” advises Smith. If you’ve never studied your own cycle before—even aside from its impact on your blood sugars—that’s the best place to start. Most women don’t have a need to track when they ovulate and how many days their cycle is until, or if, they begin pursuing pregnancy. Tracking your cycle for a few months can help you know when those days of stubborn high blood sugars are really the result of hormones, not your sudden inability to accurately count carbs. Some good apps to try—One Drop, mySugr, and Clue.
  2. “Watch your blood sugar for two months to establish a pattern and identify just how much your blood sugar rises during the two phases of your cycle that cause insulin resistance,” suggests Smith. Again, you’ll notice insulin resistance and higher blood sugar levels around the time you ovulate and in the days right before your period is expected to begin.
  3. “Experiment with adjusting your insulin doses with the help of your CDE or endocrinologist,” adds Smith. “Most women find they need a 25 to 40% increase in their background insulin during the days before their period starts and around the time they ovulate, whether you’re using a pump or injections.” Generally, she explains, women notice that their fasting blood sugar levels being creeping up and staying up. Some women may notice they need to slightly increase the insulin doses they take for meals, too.

“These are starting places,” explains Smith. It’s important to track for a few months first before making any major changes in your insulin doses. Be patient, try to identify a pattern, and if all else fails, do the best you can while remembering that no one does diabetes management perfectly.