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How many pounds do you have to be to get your first period?


The age at which a girl gets her first period is called menarche. This major milestone in puberty typically occurs between the ages of 10 and 16, but it can happen earlier or later depending on various factors like genetics, body weight, and overall health. Many girls wonder how their weight might impact when they start menstruating. This article will examine the relationship between body weight and the onset of menstruation, and provide an overview of how many pounds a girl typically needs to be before getting her first period.

Typical Weight Range for First Period

There is no single “magic” weight that triggers a first period. Menarche occurs as a result of complex hormonal changes that accompany puberty. However, body fat does play a role. Girls require adequate energy reserves in the form of body fat to begin menstruation. Below are general guidelines for weight ranges that are often associated with starting periods:

– 90-115 lbs for average height girls of 5’0″ to 5’7″.

– 100-130 lbs for taller girls over 5’7″.

These ranges are not definitive – some girls may start their periods at weights below or above those. But having enough body fat is one factor that contributes to the onset of menstruation. Girls who are underweight due to conditions like anorexia may not start their periods until they achieve higher weight.

Body Mass Index

A measurement that is sometimes used in assessing weight in relation to first periods is Body Mass Index (BMI). BMI takes into account both height and weight. According to the Center for Young Women’s Health, a BMI of at least 17 kg/m2 is often needed for menstruation to begin. This would equal about:

– 100 lbs for a height of 5’0”
– 107 lbs for a height of 5’2”
– 114 lbs for a height of 5’4”
– 120 lbs for a height of 5’6”
– 127 lbs for a height of 5’8”

So using BMI as a guide, girls tend to need a BMI approaching the 17 kg/m2 or higher before getting their first period. However, many girls start menstruating at lower BMIs, while others may meet the BMI threshold but still experience delayed menarche. BMI is only one piece of the puzzle when it comes to predicting first periods.

Other Factors Influencing First Period Onset

While weight and BMI provide some useful guidelines, there are other factors that influence when menstruation begins:

Genetics

Genetics play a significant role. Girls often start menstruating around the same age as their mother and other female relatives. If a girl’s mother started menstruating relatively early, she is more likely to as well.

Body Fat Distribution

Where body fat is distributed can matter. Girls require adequate body fat not just overall, but specifically in the pelvic area. Pelvic fat aids pubertal development and onset of menses.

Nutritional Status

Good nutrition supports hormonal function. Getting adequate calories, protein, vitamins and minerals from a balanced diet provides the necessary building blocks for growth and development. Girls who are malnourished may experience delayed periods.

Physical Activity

Extreme amounts of physical activity from sports, dance or other pursuits may be associated with later menarche. This could be related to lower body fat and nutritional deficits. Moderate activity levels are ideal.

Environmental Factors

Environmental influences like exposure to chemicals, smoking, and stress can all potentially impact hormone levels and timing of first periods. Positive environmental factors support normal menstrual cycles.

Medical Conditions

Certain medical conditions that affect hormone levels or organs like the hypothalamus, pituitary gland, ovaries and uterus may delay menarche. Examples include celiac disease, diabetes, and thyroid disorders. Treating underlying medical issues can support normal timing of first periods.

Signs Periods are Coming Soon

Along with tracking weight changes, girls can watch for other signs that periods are on the way:

– Breast development
– Appearance of underarm and pubic hair
– Discharge from the vagina
– Cramps or headaches
– Mood changes
– Skin changes like acne

These signs of puberty typically precede the first period by 6 months – 3 years. Tracking symptoms along with weight provides clues about when menstruation may start.

When to Seek Evaluation

Most girls will start their periods sometime between the ages of 10 and 15. But menarche before age 10 or absence of periods by age 15 warrants medical evaluation. Doctors can run tests to check for issues like hormone imbalances, or structural problems that could be delaying menstruation. Early intervention improves outcomes.

Starting Periods at a Healthy Weight

While specific weight thresholds don’t definitively trigger periods, adequate body mass helps facilitate normal menstruation. Girls require sufficient calories, nutrition and body fat as the foundation for development. However, being overweight comes with its own health risks. Experts advise aiming for a weight in the healthy range based on height and BMI percentiles. Reaching this goal while following an overall healthy lifestyle supports timely onset of periods.

Healthy Lifestyle for First Periods

Along with focusing on achieving a healthy weight, girls can adopt these practices to help periods arrive on time:

– Eat a nutritious diet with plenty of whole foods
– Stay active with regular exercise
– Get enough sleep and manage stress levels
– Avoid smoking, drugs and alcohol
– Limit exposure to endocrine disruptors like plastics
– See a doctor regularly and discuss period onset
– Track body changes like height, weight and symptoms

Setting these healthy habits in place from an early age benefits overall wellness and development – including the start of menstruation.

What to Expect with First Period

Getting that first period is a memorable event for most girls. Here’s what to expect and do when the time comes:

Blood Flow

The first period often starts off light. Blood flow may be spotty at first and come and go. Cycles are very irregular initially but become more predictable. It can take 1-2 years after menarche for cycles to regulate.

Prepare Menstrual Supplies

Have pads, tampons and pain reliever on hand. Use pads for the first few periods until comfortable with tampon insertion. Overnight pads are ideal for heavier nighttime flow.

Track the Timing

Note the first day of bleeding on a calendar. This helps establish cycle length and predict when future periods will start. Period tracking apps are very helpful for this.

Manage Discomfort

Cramps, bloating and back pain are common with periods. Over-the-counter medications, heating pads and relaxation techniques help. The pain often improves after the first few cycles.

Maintain Hygiene

Practice good hygiene during periods. Change pads/tampons regularly, avoid excessive moisture and irritation, and keep the vulvar area clean. Showering daily is recommended.

Be Prepared

Having extra pads/tampons, a change of clothes, and painkillers available at school and outside the home allows handling periods discreetly until a regular routine is established.

When to See a Doctor

Most girls get their first period without complications. But it’s a good idea to make an appointment with a pediatrician or gynecologist for an initial exam, especially if:

– Periods haven’t started by age 15
– Bleeding is excessively heavy right away
– Periods are extremely painful
– Flow lasts more than 7 days
– Abnormal discharge occurs between periods

The first OB-GYN visit usually happens between ages 13-15. Early check-ups help ensure that menstrual cycles are off to a healthy start.

The Takeaway

Body weight isn’t the sole determining factor for getting that first period. But having adequate fat stores signals to the body that conditions are favorable for menstruation. Girls require sufficient weight gain for their height as puberty progresses, typically reaching about 90-120 pounds before starting menses. However, genetics, lifestyle habits, and health status all contribute too. While waiting for their periods, girls should focus on following an overall healthy routine. Then when that excitement of first blood finally arrives, they can be prepared and celebrate this sign of maturation!