Girls Getting their Menstrual Cycle Earlier- Why?

When I was 8 years old, a friend of mine got her period. She was a tall, broad chested and fit young lady. Everyone in class was talking about it as it was too young for a girl her age to start her menstrual cycle. Since she was young, she used to stain her clothes very often and had bad period cramps that required her to stay home every 2-3 days in that week-long cycle.

During our grandparent’s time, an average girl started menstruating between 15-17 years old. In my time, it was 12-13 years old. In the most recent data from the Centres for Disease Control and Nutrition Examination Survey, the average age of menstruation has dropped from 14 years old to 12 years old in just a century.

Why is this happening?

Well, many parents claim that children who eat a lot of chicken get their menstrual cycle earlier. Also, girls who have higher BMI get their periods earlier too.

Are these facts true?

Hormones in animals

Hormones are injected into bovines and chicken to enhance growth of the animal for fast slaughter and to increase milk production.

Many of the hormones used are illegal hormones however six steroid hormones have been approved by FDA for cattle use. They are estradiol, progesterone, testosterone, zeranol, trenbolone acetate and melengestrol acetate. These steroid hormones are released into the animal from a pellet that is implanted under the skin of the ear.

Below is the function of these hormones:

Meat: The function of these steroid hormones is for rapid growth of muscle, increase in weight of cattle and also to produce leaner meat.

Dairy Products: Bovine growth hormone is injected into cattle to increase milk production.

• Milk contains hormones like prolactin, corticosteroids, and oestrogens. Processing methods can concentrate these hormones- for instance, butter and cheese may have higher levels than milk. Approximately 75% of dietary exposure to oestrogens comes from dairy products, with eggs and meat contributing to the remainder.

Other factors that contribute to the early onset of puberty (also known as precocious puberty) in girls are:

1. Increased Body Fat / Obesity

• Higher fat levels in obese young girls increase oestrogen production from fat tissue – which can trigger earlier puberty.

2. Genetics

• Ladies in the family who experience early puberty can influence the onset age of puberty in the subsequent generations.

3. Environmental Chemicals (Endocrine Disruptors)

• Exposure to chemicals like phthalates, bisphenol A (BPA), pesticides, and other endocrine disruptors (hormone-mimicking substances) can interfere with normal hormone regulation. This may result in an early on start of puberty.

4. Diet

• High intake of processed foods, red meats, and sugary snacks is linked to earlier puberty.

5. Psychological Stress and Family Environment

• Stress at home, family issues or trauma can affect hormone levels and accelerate puberty.

6. Medical Conditions

• Certain rare brain or hormonal disorders can cause early puberty (e.g., tumors in the pituitary gland or hypothalamus).
• Thyroid disorders or congenital adrenal hyperplasia are also possible causes.

7. Socioeconomic Factors

• Lower socioeconomic status is sometimes linked to earlier puberty due to factors like nutrition, stress, and environmental exposures.

Girls who start their menstrual cycle early can experience several physical and emotional effects. Here’s what typically happens:

Physical Effects

1. Faster Physical Development
   • In the initial stages, girls may grow taller faster than their peers. But they might stop growing earlier than peers, leading to a shorter adult height overall.
   • Breast development and other secondary sexual characteristics appear earlier.
2. Increased Risk of Health Issues Later
   • Higher risk of breast, ovarian, and endometrial cancers later in life.
   • Greater chance of developing obesity, type 2 diabetes, and cardiovascular diseases.
   • Potential bone density issues.

Emotional and Social Effects

1. Emotional Challenges
   • Early periods can lead to increased anxiety, depression, and lower self-esteem due to feeling different from peers.
   • One may experience body image concerns or embarrassment due ti the appearance of breasts or body hair.
2. Social Impact
   • Girls who menstruate earlier may engage in risky behaviours like early sexual activity or substance use.
   • They might feel out of sync with friends who haven’t started puberty yet.

The early onset of puberty is multifactorial. However, parents can moderate the onset of this early puberty by increasing the consumption of fruits and vegetable intake in their child’s diet. Also, regular physical activity and getting enough sleep is also essential to regulate hormones.

Reference:

1. Merck Manual, Veterinary Manual. Use of Steroid Hormones in Animals.