A recent Healthline article on medications that can raise blood sugar and impact Type 2 diabetics included hormonal contraceptives on its list of common culprits. Surprised? Are you wondering why the synthetic estrogen and progestin in hormonal birth control (HBC) might negatively interact with glucose and insulin?
It’s no secret that hormones are pretty important for overall health. With diabetes, a person is either unable to produce their own or sufficient insulin (Type 1 and Type 2 diabetes) or their cells can become less responsive to insulin (Type 2 diabetes). In short, the body is unable to create and/or respond to a vital hormone. Similarly, with hormonal birth control use, the body’s own production of vital reproductive hormones (estrogen and progesterone) is suppressed and replaced with synthetic versions. It therefore shouldn’t come as any surprise that combining the two situations (problems with insulin and manipulating reproductive hormones with medicine) can both exacerbate existing health problems and create new ones. In this article, we’ll unpack why— though it doesn’t cause diabetes— hormonal birth control does affect blood sugar levels, especially in women who already have diabetes.
How does uncontrolled blood sugar impact pregnant moms and babies?
Uncontrolled high blood sugar is a known risk factor for complications in pregnancy that can affect both mom and baby. When the mother’s blood sugar is too high, the baby will also be exposed to higher-than-normal amounts of sugar. This can cause babies to be larger-than-normal, also known as having macrosomia. Babies with macrosomia are at increased risk of sustaining nerve injury during the birthing process, which could be permanent. Their mothers are at increased risk of experiencing severe tears or other birth trauma due to the babies’ size.
After birth, babies with macrosomia are more likely to experience extremely low blood sugar episodes and/or to have breathing difficulties. Later on in life, these individuals are more likely to become obese and to develop Type 2 Diabetes. The Centers for Disease Control and Prevention (CDC) notes that poorly controlled blood sugar during pregnancy can also cause increased risk of miscarriage, stillbirth, birth defects, preterm birth, and having a Cesarean section.
How do female reproductive hormones impact insulin and glucose?
We know that different hormones in the body interact with one another in complex ways, and insulin and the reproductive hormones are no exception. As we see in polycystic ovary syndrome (PCOS), insulin resistance, which women with prediabetes or Type 2 diabetes also experience, tends to go hand-in-hand with fertility issues like delayed ovulation, a deficiency of fertile-type cervical mucus, tail-end brown bleeding, and breakthrough spotting. In addition to insulin levels affecting ovulation and the reproductive hormones, the reproductive hormones themselves affect blood sugar, especially in women who have diabetes. This interplay between the reproductive hormones, insulin, and glucose levels might make managing glucose levels more difficult at different points in diabetic women’s cycles, as this woman with undiagnosed Type 1 diabetes experienced.
Why might diabetic women be encouraged to go on hormonal birth control?
Some women may be encouraged by their healthcare providers to go on hormonal birth control indefinitely in order to avoid such significant fluctuations in insulin and glucose levels as may occur over the course of a natural ovulatory cycle.
Women may also be encouraged or choose to go on birth control for actual pregnancy prevention. We know that pregnancy puts unique stresses on the female body, and we saw above that some of those stressors may be exacerbated in women with diabetes. Furthermore, some medications that are used to treat comorbidities of diabetes, such as ACE inhibitors to treat kidney disease, are not safe to use while pregnant. While women with diabetes can certainly go on to have healthy pregnancies and babies, some may desire to temporarily postpone pregnancy in order to make a medication or lifestyle change to get blood glucose levels under control before conception.
How might hormonal birth control cause high blood sugar?
While doctors might prescribe hormonal birth control (HBC) for women with diabetes for the reasons above, birth control does affect blood sugar too.
The University of Colorado states on their OB/GYN site that the estrogen in HBC can increase blood glucose levels and increase the need for insulin. CU also cautions that since diabetics are already at an increased risk for heart attack, special consideration should be taken when using HBC, as HBC can also increase risk for cardiovascular disease. Furthermore, while noting that some studies around HBC and diabetes have been inconclusive and there is a need for more research, certain studies indicate that taking HBC for more than two years can increase the risk of developing diabetes-related damage to the kidneys, retina, and nerves. The World Health Organization does not recommend HBC for diabetic women who already experience kidney, retina, nerve, or cardiovascular disease, as highlighted in this journal article [1].
This 2014 research article suggested that birth control could cause high blood sugar due to the influence of the synthetic estrogen, the synthetic progestin, or the particular ratio of estrogen-progestin in HBC [2]. The authors conduct a detailed analysis of research, especially studies on animals such as rats or mice, into how too high or too low levels of female sex steroids can negatively affect the body’s production of insulin or response to glucose.
Healthline highlights the different forms of contraception available to women with diabetes along with specific considerations and quotes from women with diabetes who have tried each method. With the Pill, hormonal IUDs, and Nexplanon, women reported increased insulin resistance to varying degrees, but this side effect seemed especially common with the Pill. Vaginal rings did not seem to impact blood glucose levels, but are not considered safe for people with diabetes-related kidney, retina, nerve, or cardiovascular disease. Some birth control methods, such as Depo-Provera, are associated with weight gain, which can worsen diabetes. Also, since birth control can elevate blood glucose levels and increase insulin resistance, the increased blood sugar circulating through the body may put HBCs users at a higher risk for yeast infections.
Yes, birth control does affect blood sugar, but women with diabetes have another option for pregnancy prevention
Women with diabetes needn’t feel that their only options for preventing pregnancy are to struggle with insulin resistance on hormonal birth control or to use a non-hormonal, but still risky, method of contraception like a copper IUD. There are a variety of methods for understanding your fertility, and using a sympto-hormonal option like the Marquette Method with a ClearBlue fertility monitor or a Mira monitor can allow women to quantitatively measure their estrogen and LH levels at home, which might be a particularly appealing type of fertility awareness method (FAM) experience for women struggling with diabetes.
Why might using fertility awareness be especially important for women with diabetes?
Although this is an area where more research is needed, this article suggests that women whose periods start at age 14 or older, who have more menstrual cycles overall, who reach menopause after age 52, who have an overall longer timespan between first period and last period (onset of menopause), and/or who breastfeed have decreased risk for developing type 2 diabetes later in life. Certainly, women cannot control when they experience menarche (first period) or menopause (last period), but by utilizing fertility awareness they can “have more menstrual cycles overall” compared to women who are not ovulating because they’re on hormonal birth control.
We know that women need their periods (more accurately, the whole of their cycles!), and this is especially true for women with diabetes. Regarding Type 1 diabetes, which is considered an autoimmune disease, we know that estrogen plays an important role in autoimmunity and that birth control is thought to worsen autoimmune disease. For women with Type 2 diabetes, too-high insulin levels are associated with long, irregular cycles and may be a sign of other hormone imbalances. Rather than further upsetting their endocrine systems through hormonal birth control use, women with diabetes can learn about their menstrual cycles and fertility to understand how best to manage blood glucose levels at different points in their cycles, for accurate evaluation and potential treatment of concomitant fertility issues or other hormone imbalances, and to avoid the other health risks of hormonal birth control.
Yes, birth control does affect blood sugar. Fortunately, women with diabetes have non-hormonal options for pregnancy prevention and health monitoring that won’t exacerbate their blood sugar issues.
References:
[1] Robinson A, Nwolise C, Shawe J. Contraception for women with diabetes: challenges and solutions. Open Access J Contracept. 2016 Mar 3;7:11-18. doi: 10.2147/OAJC.S56348. PMID: 29386933; PMCID: PMC5683149. [2] Cortés ME, Alfaro AA. The effects of hormonal contraceptives on glycemic regulation. Linacre Q. 2014 Aug;81(3):209-18. doi: 10.1179/2050854914Y.0000000023. PMID: 25249703; PMCID: PMC4135453.Additional Reading:
Do you get frequent yeast infections? How your birth control might be to blame, and how FAM can help
How fertility awareness can help women with Type 1 Diabetes
Birth control’s link to autoimmune disease?
The link between irregular cycles, birth control, and early death
