First Period (Menarche)

The order of puberty

In girls, puberty usually begins with breast budding (thelarche). This happens at around 8.5–10 years on average. Next come pubic hair, a growth spurt and, finally, the first period. The period is expected around Tanner stage IV of breast development, that is, after breast tissue has become clearly visible. A period before any breast development is rare and is investigated.

The hypothalamic–pituitary–ovarian axis is quiet during childhood. At puberty, the pulsatile activity of kisspeptin and GnRH neurons increases. LH and FSH rise, and the ovaries produce estrogen. The endometrium thickens and the first bleeding occurs. In the first years, cycles are often anovulatory; regular ovulation settles within 1–3 years.

What to expect with the first period

The amount and length of bleeding vary from person to person. For most girls, the first bleeding is light or moderate and lasts 3–7 days. About 3–6 pads or tampons a day are needed. There may be pain; it usually increases or decreases during the first year. In the first 1–2 years, the cycle length may vary between 21 and 45 days. A gap of more than 90 days, or bleeding that lasts longer than 7 days or soaks a pad in 1–2 hours, needs evaluation.

In early cycles, ovulation does not happen every time. So although the risk of pregnancy may seem low, a pregnancy test should be considered if she is sexually active. Having periods does not prove that ovulation happens regularly every month.

When to see a doctor

The following situations need evaluation:

• No breast development at all by age 13
• No period 3 years after breast development began
• No period at all by age 15
• Breast development or clear signs of puberty before age 8
• A period before age 9
• Cycles still shorter than 21 days or longer than 45 days more than 2 years after the first period
• Bleeding that lasts longer than 7 days, soaks a pad in 1–2 hours or comes with large clots
• Severe pain that prevents daily activities
• Marked hair growth, rapid weight change, milk-like discharge from the breasts or vision problems

These thresholds are consistent with ACOG and pediatric endocrinology guidelines. If there is a family history of late puberty, the waiting time may be somewhat longer; still, the age-15 limit and the age-13 limit for no breast development apply.

Possible causes of a late first period

Causes of primary amenorrhea (never having a period) fall into a few groups:

• Hypothalamic–pituitary: intense exercise, low body weight, eating disorders, chronic illness, stress, some medicines
• Ovarian: Turner syndrome (45,X), primary ovarian insufficiency, polycystic ovary syndrome (later on)
• Anatomical: imperforate hymen, transverse vaginal septum, Müllerian agenesis (MRKH), androgen insensitivity
• Other: thyroid disease, hyperprolactinemia, excess androgens from the adrenal glands

The first step in evaluation is the history, height and weight, Tanner staging, pelvic ultrasound and basic hormones (FSH, LH, estradiol, TSH, prolactin). If needed, chromosome analysis or MRI is planned. SoftCare is not a pediatric endocrinology center; initial gynecological evaluation and referral can be provided.

Early first period

Breast development before age 8 is evaluated for precocious puberty. A period before age 9 is considered early menarche. Causes include central precocious puberty, excess hormones from a peripheral source (adrenal glands, ovarian cyst, exogenous estrogen) and familial early puberty. Bone age, hormone tests and, when needed, a GnRH stimulation test are used to tell these apart. An early period can stop growth in height early; that is why prompt evaluation is recommended.

Irregular cycles in the first years

In the first 1–2 years after menarche, cycles are often irregular. Intervals of 21–45 days are considered normal. After the third year, the interval settles at 21–35 days in most girls. If gaps of more than 90 days, heavy bleeding or severe pain continue, the cause is investigated. Polycystic ovaries, thyroid disease or a bleeding disorder may first appear during this period.

Our approach at SoftCare

At SoftCare Clinic, we provide gynecological evaluation for the first period and for irregular periods during adolescence. The history covers the mother's age at menarche, the growth curve, weight change, exercise intensity and chronic illness. The examination is planned according to age and symptoms; a pelvic exam is not mandatory. The uterus and ovaries can be assessed with ultrasound. Basic hormone tests may be requested.

If delayed puberty, precocious puberty or an anatomical anomaly is suspected, we refer to pediatric endocrinology or pediatric surgery. In case of heavy bleeding or anemia, iron supplements and, if needed, hormonal treatment are discussed. The treatment decision is made after examination and tests.

Appointments: +90 212 241 30 10 · softcareclinic.com

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Medically reviewed by Op. Dr. Şükrü Sanus, Obstetrician & Gynecologist · Last medical review: 2 October 2026