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Illustration by Marta Pucci

Cycle A-Z

Vaginas 101

by Nicole Telfer, Science Content Producer
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Top things to know about vaginas:

  • The vagina connects the vulva to the cervix

  • In a non-aroused state, the walls of the vagina are collapsed against each other

  • The vagina changes: during sex, throughout the menstrual cycle, and with age and different life stages

People often use the term vagina to refer to the entire female genital region between the legs—but this is incorrect.

Let’s first start with correcting this terminology. The vulva is the correct name for the external parts of the female genitalia. This includes the glans clitoris, labia minora and majora, opening of the urethra and vagina (the introitus), and the surrounding tissue.

What is a vagina?

The vagina is the tube between the vulva and the cervix. This tube is the connection between your uterus and the outside world. The vagina is what babies exit through during birth, and what menstrual blood exits through during your period. The vagina is also used for insertion, such as with a penis, fingers, female condoms, sex toys, tampons, or menstrual cups.

The vagina can also act as a route to other parts of the body. During penis-vagina sex, ejaculate is deposited in the vagina, allowing sperm to enter the uterus through the cervix. The walls of the vagina can also be used as an administrative route for medications and contraceptives, such as intervaginal hormone creams, the hormonal vaginal contraceptive ring, or vaginal suppository medications.

Anatomy of the vagina

It may seem strange that an organ capable of passing an entire baby through it is also capable of holding a small tampon in place for hours. How does that tampon stay in there? If the vagina is just a tube, shouldn’t the tampon fall out?

The vagina is much more than just a tube. When it is in a relaxed state (not aroused), the walls of the vagina are collapsed against each other, flattened by the pressure of the surrounding organs and tissues within the pelvis. During this state, a cross-section of the vaginal canal (the vaginal lumen) can resemble an “H” or a “W” shape, as the walls flatten against themselves (2). From the sides, the vagina offers movable support and pressure, which allow your tampon to stay in place (2,3).

The walls of the vagina are covered by many folds called rugae (3). The walls and folds of the vagina have many purposes, providing both a barrier and access route between the cervix and the outside world. All of these folds allow the vagina to be stretched and expand like an accordion when pressure is applied to the sides (like when a baby’s head is passing through).

The walls of the vagina are composed of different layers of tissue. The surface layers of the vaginal wall are made of mucosal tissue—similar to the tissue that lines your mouth, nose, and digestive tract. Underneath the mucosal tissue are layers of smooth muscle tissue, collagen, and elastin fibers, which give the vagina both structure and ability to stretch (4).

Fluids are released through the walls of the vagina to keep the area moist, and during times of sexual arousal, to increase lubrication. The vagina is also capable of absorbing some substances—such as medications, hormonal creams, or contraceptives—into the body (3).

How the vagina changes with age

The vagina can change a lot throughout a person's life (1,5). An average adult vagina is slightly curved, and can range between 7 to 12 cm in length (1,3,4)—but every body is different, and there’s no such thing as a too small or too large vagina.

The vagina is strongly influenced by hormonal changes throughout the body. During the reproductive years after menarche (the first menstrual period) and before menopause, more layers of tissue are present lining the vagina, due to stimulation from higher estrogen levels in the body (3).

The vagina is also influenced by changing hormone levels during pregnancy. Increased blood flow is directed to the pelvis, causing a deeper color change to the vulva and vagina (5). Throughout a pregnancy, the connective tissue of the vaginal walls progressively relaxes, in preparation for the delivery of a baby (5). After delivery, the vagina and vaginal opening temporarily widen, but 6-12 weeks post-delivery, the vagina returns to its pre-pregnancy size (5).

As people age, the walls of the vagina of the vagina become more relaxed, and the diameter of the vagina becomes wider (1). When it comes to sexual satisfaction, vaginal size does not affect sexual function (6). The perception of vaginal tightness during sex is primarily related to the pelvic floor muscles, which are present around the base of the vagina and not actually how wide the vaginal canal is.

After menopause, when estrogen is lower, the walls of the vagina become thinner and frailer, which can cause symptoms of vaginal dryness and decreased vaginal secretions (5). This may result in discomfort during sex and increase the chances of vaginal irritation or infection (5).

How the vagina changes during the menstrual cycle

The vagina also changes in response to hormonal fluctuations of the menstrual cycle. Around mid-cycle, when estrogen is highest, vaginal tissue becomes thicker and fuller (5).

The cervix, at the top of the vagina, moves and changes shape throughout the cycle. Before and after the fertile window, the cervix is low and can be felt in the vagina, with a firm texture, and the hole in the center of the cervix is closed. During the fertile window, the hole in the cervix opens to facilitate the entrance of sperm into the uterus (7), the cervix rises higher in the vagina, and is softer when touched (8).

A hand holding a phone with the Clue app opened

Use Clue to track all things related to your vagina: bleeding, discharge, sex, and contraception.

How the vagina changes during sex

The vagina can also undergo more rapid changes, such as during sexual activity. When a person with a vagina is sexually aroused, increased blood flow is directed towards the genitals, causing the vaginal tissue to become engorged with blood, and additional lubrication to be produced. This fluid is called arousal fluid.

During sexual excitement, the vagina expands by lengthening and widening in shape. This is called vaginal tenting and ballooning. This shape change happens as the uterus and cervix are drawn higher into the pelvis, which creates more space and moves the cervix farther away from any semen that is ejaculated into the vagina. This allows time for the semen to mix with female genital fluids, stimulating the sperm to undergo the physical changes necessary for fertilizing an egg (9).

The vagina is an incredible organ which changes in response to hormones, life stages, and physical responses. So show your vagina some love, and feel free to tell anyone you want just how amazing your vagina really is.

Article was originally published on Apr. 18, 2018.