Diabetes and the Menstrual Cycle
Hormonal changes across the menstrual cycle influence glucose metabolism, insulin sensitivity, and energy regulation. For women living with diabetes, these fluctuations add another layer of complexity to daily management and long-term health.
The Menstrual Cycle and Hormonal Influences
The menstrual cycle typically spans 28 days and is divided into the follicular, ovulatory, luteal, and menstrual phases. Key hormones shift throughout this cycle:
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Follicular phase (days 1–14): Estrogen levels rise, improving insulin sensitivity.
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Ovulation: A surge in luteinizing hormone and peak estrogen occurs.
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Luteal phase (days 15–28): Progesterone dominates, reducing insulin sensitivity and sometimes increasing insulin resistance.
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Menstruation: A rapid decline in both estrogen and progesterone occurs, often improving insulin sensitivity but also creating a risk of hypoglycaemia for women with diabetes.
For women who don’t have diabetes, these changes are generally well tolerated. But for women with diabetes (any type), the hormonal rhythm can really complicate blood glucose management.
Diabetes and the Menstrual Cycle
Type 1 Diabetes (T1D)
International research shows that many women with T1D notice a rise in blood glucose during the luteal phase, likely due to the effect of progesterone on insulin resistance. Insulin requirements may increase by 10–20% during this time. With the sudden drop in hormones at menstruation, the opposite problem can occur: increased insulin sensitivity and risk of hypoglycaemia. Although New Zealand-specific studies are limited, anecdotal reports suggest similar challenges for women here.
Type 2 Diabetes (T2D)
T2D is more common in Māori and Pacific women than in Pākehā women, with prevalence estimates around 10–12% for Māori women and up to 20% for Pacific women, compared to 5–6% in the overall population. Insulin resistance, already a hallmark of T2D, may be further amplified during the luteal phase of the menstrual cycle. Compounding this, conditions such as polycystic ovary syndrome (PCOS)—which is linked to insulin resistance—are more common among Māori and Pacific women. This dual burden increases the complexity of metabolic and reproductive health management.
Menstrual Irregularities and Reproductive Health
Menstrual irregularities are more common in women with diabetes. Women with T1D may experience delayed periods, irregular cycles, or premature menopause, while those with T2D face higher rates of PCOS.
In New Zealand, these issues intersect with broader inequities in reproductive health. Māori and Pacific women experience greater barriers to accessing culturally safe gynaecological and endocrine services. Stigma around menstruation—particularly in some Pacific cultures, where it may be considered tapu (sacred or restricted)—can limit open discussion, leaving women without adequate support
Management Approaches in Aotearoa
Cycle Tracking and Glucose Monitoring
Digital health tools, such as continuous glucose monitoring (CGM), provide opportunities for women to track blood glucose alongside menstrual cycles. However, in New Zealand these tools are not widely integrated into routine diabetes care, other than for women with type 1 diabetes as of (1st October 2024). Making CGM more accessible, particularly for Māori and Pacific women, could support self-management and early intervention.
Insulin and Medication Adjustment
Emerging evidence supports adjusting insulin dosing according to cycle phase, particularly increasing basal insulin during the luteal phase. However, there are no standardised clinical guidelines in New Zealand for this practice, meaning women often rely on trial and error.
Hormonal Contraception
Hormonal contraceptives, including long-acting reversible contraception (LARC), are increasingly used in Aotearoa. They may stabilise menstrual cycles but can also alter insulin sensitivity, and their effects vary across individuals.
Last updated September 2025
