Signs of The First Period and Why Many Girls Are Getting Them Earlier

According to recent data from the Centers for Disease Control and Prevention, the average age of a girl’s first period, also known as menarche, in the United States is 12. This can be a scary and confusing time for your child, but you can help give her the support she will need to navigate the changes she'll experience. Research suggests that girls are getting their first periods much earlier than before. Read on to learn more about the factors that are contributing to this change.

First Period or Menarche

The first period is also called menarche. It's the first time a girl menstruates. This important milestone marks the beginning of fertility in a young girl or the beginning of her reproductive years. When a girl gets her first menstrual period, it means that she is physically capable of becoming pregnant and having a baby, unless it is otherwise impossible because of health issues. It's a part of puberty, a stage in the transition from childhood to adulthood.

How First Periods Start

Hormonal changes in the body cause a period to occur. The ovaries release the hormones estrogen and progesterone, which are responsible for the thickening of the lining of the uterus (or womb) and prepare it for fertilization. A girl typically gets her first period after she first ovulates.

Ovulation happens when the ovaries release a mature egg into the fallopian tube. The lining of the uterus thickens in preparation for fertilization of the released egg. If fertilization does not happen, the lining sheds or breaks down. This shedding is how period blood comes about. This cycle continues regularly in most females from the age of the first period until she reaches menopause.

When Do First Periods Usually Begin in Girls?

Typically, the average age most girls get their first period is around 12. However, sometimes it may start a couple of years earlier or later. Some can get their period as early as 9 or as late as 15. There is no set schedule for a girl to begin her first period since every girl's body is different and is working with its own schedule.

Genetic and environmental factors also play a role in determining when girls will get their first menstrual period. Furthermore, body build, physical activity, and chronic illnesses also have the potential to impact the region of the brain that influences when puberty starts and ultimately initiates a girl's first period.

Signs of First Period

Some signs may come before a girl's first period. These include:

• Breast growth, also known as "thelarche," starts 2 to 3 years before the first period. Breast growth is typically the first sign of puberty in girls, often occurring around 9 or 10 (1). Menstrual periods typically start roughly 2 years after breast development.
• Pubic hair development, also referred to as “pubarche”. This is hair growing under the arms and in the private parts. This typically happens 1 to 2 years before menarche.
• Vaginal fluid in underwear. This typically starts roughly six months to a year before a girl's menarche. This fluid will likely be a thin, whitish liquid with little smell. Also, the fluid may change from day to day.
• Changes in body shape and size. Many girls experience their biggest growth spurt roughly 6-12 months before menarche. A girl's height may change fast and then slow, which can indicate that the first menstrual period is close. Additionally, many girls experience changes in body shape, including hips widening and thighs thickening.
• Acne may develop on the face and body.

Still, there is no precise way of knowing when menarche will start in girls. Some may notice spotting in the underwear or abdominal cramps several days before the first period. However, this does not necessarily happen for all girls.

Symptoms of First Periods

Girls may experience certain symptoms leading up to their first period. These include

• Cramping in the belly or lower back
• Pain or achiness in the back or legs
• Bloating
• Tender or sore breasts
• Breakouts (acne/pimple flare-ups).
• Mood swings
• Fatigue/tiredness

During a period, you may notice:

• Red or brown blood on underwear or in the toilet after use. Also, some people may pass small blood clots.
• A small amount of bleeding, with only a few spots before your period ends.
• Or, bleeding that starts light, gets heavier, and then light again before the period ends.

Still, different people experience their first periods differently. Also, first periods are particularly unpredictable.

Frequency After First Period

Throughout the first couple of years after the first period, menstruation may be irregular. It may come at unpredictable intervals. However, over time, periods usually become more regular.

For most, periods tend to arrive roughly every 28 days. Still, the length varies from one female to the next and also from period to period. The menstrual cycle length may vary from 2 to 7 days.

First Periods: Earlier for Racial Minority and Lower-Income Individuals

In the U.S., all racial groups are having their first periods earlier. However, research indicates that young girls in racial minorities and lower socioeconomic statuses are having their first periods earlier than other groups. A recent longitudinal study of 71,341 individuals in the US found that, as birth year increased (younger participants), the average age at menarche decreased and time to regularity increased. The study indicated that the average age at menarche for participants born from 1950-1969 was 12.5 years, while for participants born from 2000-2005, the average age at menarche was 11.9 years (2),

Furthermore, the trend toward earlier menarche was greater among Asian, non-Hispanic Black, and other non-white races, and participants with a lower socioeconomic status.

Why First Periods Are Happening Earlier in Girls

Changes in estrogen signal the body to start a girl's menstrual cycle. Research suggests that first periods are triggered much earlier in girls because of changes in their estrogen levels. Several factors may affect these estrogen levels.

BMI/Obesity

One explanation for why periods might occur at a younger age is that girls today weigh more than they did a generation prior. Their higher body fat percentage correlates to earlier activation of the pituitary gland, which produces the hormones involved in puberty. This increase in body fat percentage may be due to decreased physical activity and a more calorically dense diet. Thus, a high BMI or childhood obesity at the age of menarche could explain this trend.

Environmental Exposure to EDCs

Another possible factor is environmental exposure to endocrine-disrupting chemicals or EDCs. Some common EDCs include phthalates and bisphenol A, both typically found in common consumer household items. Many everyday products, including cosmetics, soaps, shampoos, pesticides, toothpaste, handwashes, food and beverage packaging, toys, and carpets, contain synthetic chemicals that mimic hormones and disrupt the delicate endocrine system.

EDCs appear to mimic estrogen, along with other naturally occurring hormones found in the human body. They are known to disrupt the endocrine system. For instance, EDC-like phthalates, commonly found in plastics, many personal care products, and cosmetics, are endocrine disruptors. One theory is that EDCs may promote weight gain or early puberty by affecting how the cells and the body control metabolism. As a result, they impact estrogen production.

Stress

Also, beyond environmental exposures, stress may also play a role in changing estrogen levels. Stress increases the level of androgens, and more adipose tissue converts the excessive androgens into estrogens, resulting in earlier puberty (3). Chronic stress can impact kids and lead to symptoms of Adrenal Fatigue, the condition where the body is unable to keep up with long-term stress, resulting in various nonspecific symptoms such as mood changes, irregular menses, premature menopause, and unexplained hair loss.

The adrenals produce the reproductive hormones estrogen and progesterone, but when stressed, the Hormone Circuit of the NeuroEndoMetabolic (NEM) Stress Response becomes dysregulated. Instead of producing reproductive hormones, it focuses on producing cortisol. This disruption can lead to irregular periods at any age.

Dietary Patterns

Furthermore, dietary patterns may also factor into the change as well. Research suggests that higher adherence to modern dietary patterns during childhood is linked to accelerated menarche. High intakes of fast foods, meat, milk, fruits, and eggs and low intakes of grains and vegetables characterize this modern dietary pattern. This dietary pattern is potentially implicated in the timing of menarche in any of three ways: high milk intake, high fat intake, and low intake of plant foods (4). Many farmers pump hormones into their livestock to encourage faster growth. Girls are eating more inorganic meats and getting these hormone disruptors into their system when eating unhealthily.

First Periods Timing and Future Health

Research suggests that changes in the timing of the first menstrual period can affect health outcomes later in life. A girl getting her first period at an earlier age has been linked to health issues, such as an increased risk of cardiovascular disease, diabetes, and even early death.

Additionally, it has been associated with a higher risk of several cancers, especially breast cancer, later in life. Experts suggest that girls who have their first period before they turn 12 have a 20% increased risk of developing breast cancer.

However, these are only correlation relationships and do not necessarily show cause. Furthermore, girls who eat a healthy diet, maintain a healthy weight, and avoid environmental contaminants as they age may be able to reduce their risks for many of these negative associations.

The Takeaway

The first period marks many changes in a young girl's life and can be confusing. Today, more and more girls, especially those of color, are getting their periods earlier in life. Factors such as environmental exposure to EDCs, high BMI/childhood obesity, stress, and dietary factors appear to play a role in earlier menarcheal age. Additionally, these factors may increase the risk of developing certain health issues. Addressing these factors by adopting a healthier diet and lifestyle may be the appropriate approach to fixing this issue.

Contact us at +1 (626) 571-1234 if you need help with issues associated with menstruation.