Irregular Periods

Before discussing irregular periods, it's important to understand what a normal menstrual cycle looks like.

The time from the start of one menstrual cycle to the start of the next ranges from 20–35 days (ideally 28–31 days).

You should typically use 2–3 pads per day, with minimal clotting, and bleeding should last no more than 8 days.

Mild cramping during the first 1–2 days of your period is generally normal.

Anything outside of what we've described here can be considered an irregular period.

Over an average 30-day span, multiple eggs in the ovaries begin to mature.

During this time, the uterine lining (endometrium) also thickens and develops a richer blood supply.

Among the maturing egg cells (primordial follicles), the most developed one ruptures its follicle and is released from the ovary.

The Journey That Begins in the Ovary

Different biological events occur at each stage of the egg cell's maturation process (ovulation). Each of these events leads to the formation of the next anatomical structure.

A second layer of cells forms as multiple layers of cuboidal cells gather around the egg.

The outer portion of these cells forms a vascularized connective tissue layer (theca externa), while the inner portion forms the inner layer (theca interna).

The inner layer (theca interna) is responsible for secreting the hormones progesterone and estrogen (the female hormones).

Macromolecules within the glycoprotein substance secreted by the multiple layers of cuboidal cells also form a surrounding shell (zona pellucida) around the egg.

This structure — with its inner shell and the multiple layers of cuboidal cells surrounding it — is called the primary follicle.

The inner shell surrounds the egg until it ruptures, distinguishing sperm cells and allowing entry into the egg. It triggers the acrosome reaction, in which enzymes on the sperm cell become active, acts as a sperm-binding receptor, and plays an important role in protecting the embryo until it implants and takes hold in the uterus.

One of the most common misconceptions is the idea that menstrual bleeding represents the shedding of "dirty" blood, or that it is a sign of illness. This is not accurate — in fact, menstruation is not even bleeding in the true sense of an injury.