Periods and Bones: How Menstruation Affects Your Lifelong Bone Health

Your period and your bones may not seem related, but they share common foundations for healthy function. Having regular periods is a sign that your body is getting the fuel and hormones it needs. Those same things can also help keep your bones strong.

The hormone estrogen is especially important for both regulating the menstrual cycle keeping bones healthy and strong. When estrogen is low, which can happen during menopause or if a person is not having periods, bone loss can quicken.

Normal and Irregular Periods– And Why Irregularity Can Be a Red Flag for Bone Health

A typical period (the time you bleed) lasts two to seven days, with the heaviest flow usually occurring during the first three days. A normal menstrual cycle (counted from the first day of one period to the first day of the next) is anywhere between 21 and 35 days. If the frequency or length of your period falls outside of these ranges, or if your period is extremely heavy, you should reach out to a healthcare provider.

Amenorrhea is the clinical term for not having a period. If your periods stop for three months or more without an explanation, called secondary amenorrhea, you should reach out to your healthcare provider. Consistently missing your period can be a sign that you’re also at risk for lower bone density. It’s important to talk to your provider if you notice any irregularities in your cycle to prevent long-term conditions like osteoporosis.

Functional Hypothalamic Amenorrhea (FHA): Stress, Under-Fueling, and Over-Training

One reason periods may stop is called Functional Hypothalamic Amenorrhea (FHA). This occurs when a part of the brain called the hypothalamus stops sending the hormones needed for periods. This can happen when someone is not eating enough, is very stressed, has an eating disorder, or a mix of these things.

Doctors only diagnose FHA after ruling out other causes for missed periods. This means they may test for thyroid problems, pituitary issues, pregnancy, or other causes of missed periods first. To treat FHA, doctors often focus on helping the body get enough energy again by improving nutrition, reducing stress, and adjusting exercise. Sometimes hormone treatment is also recommended.

The female athlete triad is a related health problem made up of three parts: not getting enough energy (sometimes because of disordered eating), missing or irregular periods, and weak bones. It often happens in athletes who train very hard but do not eat enough to replace the energy they use. It’s more common in sports that focus on appearance or being very lean, like ballet or running.

When the body does not get enough energy, hormones become unbalanced and bones get weaker. This raises the risk of stress fractures. Finding the problem early can help prevent long‑term bone damage. Athletes who never start having periods as teens, often miss or skip periods, stop having periods for three months or more, have repeated stress injuries, or restrict their eating should be checked by a healthcare provider.

Contraception, Menstrual Suppression, and Bone Health

Some people choose to use birth control or hormonal medication to skip or stop periods. There are several different options for this, and experts agree they are safe to use and do not impact future fertility. However, one of these options may cause temporary drops in bone mineral density if used for a long time. This is the depot medroxyprogesterone acetate (DMPA) injection, also called the Depo shot. It’s not clear how much long-term fracture risk might be impacted after being on the Depo shot, so it’s important to talk about the benefits and risks with your healthcare team before choosing this option.

Special Life Stages that Affect Periods and Bones

Just like your period changes throughout life, so do your bones! The teen and young adult years are the most important time for building bone mass through nutrition (consuming enough calcium and vitamin D) and weight-bearing activities like running and walking. Healthy habits in your teens and 20s help establish good bone density and protect your bones for the rest of your life.

During pregnancy and breastfeeding, it’s normal for bone mineral density to temporarily drop. This is because a woman can “donate” calcium from her own bones to her growing baby during pregnancy and breastfeeding. After weaning, bone levels usually return to normal. Pregnancy and breastfeeding do not usually increase a person’s long-term risk of osteoporosis, unless there are multiple back-to-back pregnancies in a short period of time.

After menopause, estrogen levels fall drastically. Since estrogen is a hormone responsible for protecting bones, this stage of life includes faster bone loss. Building strong bones early in life can help prevent osteoporosis later.

Daily Habits to Support the Menstrual Cycle and Bone Strength

Bones like stress – the healthy kind that comes from exercise. The more weight bones carry, the stronger they can get. Weight-bearing activities, or any activity where your body holds up its own weight, are good for bone strength. This includes running, walking, dancing, and most sports. Things like swimming or biking don’t count, because something else (like pool water or a bicycle) is holding up your body weight, not your bones. Muscle-strengthening exercises like lifting weights and using resistance bands can also be helpful.

Your body also needs energy every day to function properly and engage in all that exercise! Not eating enough, especially if you’re very active, can weaken bones and disrupt hormone levels. It’s crucial to match your calorie and protein intake to your activity, and especially important to get enough calcium and vitamin D.

Teens (ages 14 to 18) need 1,300 mg of calcium a day. Adults (ages 19 to 50) require 1,000 mg daily. Vitamin D consumption is just as important because it helps the body absorb calcium. Focus on a balanced diet including foods like dairy, fortified foods, dark leafy greens, and fish with bones. Try to get calcium and vitamin D from food before discussing supplements with your healthcare provider.

Iron and vitamin D are especially important for teens and people who menstruate. Low levels of both micronutrients are common and can affect a person’s health and energy.

Avoiding smoking and limiting alcohol are beneficial regardless of what life stage you are in. Both weaken bones over time.

When to Seek Medical Advice

Some red flags and signs that you should contact your healthcare provider include:

  • Not getting your first period by age 15 (primary amenorrhea)
  • Missed periods for 3 months or more (secondary amenorrhea)
  • Recurrent stress fractures
  • Rapid weight loss
  • Eating disorders or disordered eating
  • Plans to start or stop hormonal medication, including DMPA (Depo shot)

At a visit, expect your healthcare team to ask about medical and menstrual history, nutrition, and activity. Your provider may order lab tests like bloodwork to rule out other causes. Depending on your age and risk factors, a bone density test (DXA) may also be recommended.

Note on who menstruates

Not all women menstruate, and not all people who menstruate are women. Bone-protective habits and evaluation apply to any person with periods or estrogen changes that affect bone health. Clinical guidance should be personalized to the individual.

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