What are the reasons for a late period?

Your period is the faithful guest that you expect monthly from puberty to menopause. Your period can be regular and recur at the same time, or it can be irregular. A late period can be a source of stress and worry for girls and women, especially when there is no pregnancy. In this article I will share the most common reasons for a delayed period, when is a period considered late, how serious a delayed period is, and how to treat it.

Cherifa Sharaf
Published on:Apr 14th 2023 |Updated on:Apr 10th 2024
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The monthly cycle

The monthly cycle lasts between 21 to 35 days, from the first day of the period to the first day of the next one. Your cycle is not just the bleeding during your period, it is a series of physical and mental changes that you go through every month. The period’s length varies from one woman to another. A period is considered delayed after a whole week.

Types of period delays

Primary delay

This is when a teenage girl doesn’t get her period until the age of 15, or five years after the growing of her breasts. The period is also considered late when the girl has other puberty signs such as growing breasts, pubic hair, and an increase in height. About 0.1% of girls have this condition.

Causes for primary period delay

Genital tract defects such as malfunctioning ovaries.

Turner syndrome affects the chromosomes.

The most common cause is an undeveloped uterus, which affects 15% of girls having primary period delay.

Also read What causes Irregular periods during puberty?

 Secondary delay

This is when a period is absent for 3 to 6 months, after having a regular period for a while. This happens for 0.7% of girls and women.

Causes of period delay 

  • Pregnancy is the first thing we investigate when a patient complains of a missed period.
  • Uterine anomalies.
  • Ovarian anomalies such as polycystic ovarian syndrome.
  • Neurological problems.
  • Pituitary gland problems.
  • Thyroid or adrenal gland issues that directly affect hormones.


  • Pregnancy tests.
  • Thyroid hormones tests.
  • Test the levels of prolactin.
  • Check the levels of FSH hormone which is the main indicator of ovarian health.
  • Uterine ultrasound and MRI.

Risks of delayed periods

The hormones produced in the ovary that affect the periods are paramount for growth during puberty and maintain reproductive health, bone, heart, and skin health during adulthood.


To treat a late period, we need to treat the cause. If it is a polycystic ovarian syndrome, we treat it. If the cause is any hormonal imbalance, we treat this with medication. If the cause is due to congenital reasons, we prescribe HRTs which can be effective sometimes. 

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Cherifa SharafObstetrics & Gynecology Consultant

Consultant of obstetrics, gynecology & Infertility, with years of experience in women’s healthcare. Dr.Cherifa is practicing at Qasr El Eyni Hospital/ Cairo University in addition to several other hospitals and centers in Cairo Egypt. She holds a Ph.D. in medicine from Cairo University in addition to the European Diploma of Operative Gynecology from Clermont-Ferrand, France, and Diploma of Management of Infertility from Antoine Béclère Faculty of Medicine Paris, France. Dr. Cherifa is very passionate about providing the appropriate health care to women and believes the overall health of a woman is key to her reproductive and maternal health. She is a strong believer in the importance of raising women’s awareness and educating them about everything related to health in general and reproductive health in particular.

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