Uterus

The uterus (also called the womb) is a hollow, muscular organ in the lower abdomen where a baby grows during pregnancy. When you're not pregnant, the uterus builds up a lining of blood and tissue each month — and if no pregnancy happens, that lining sheds. That's your period.

• The uterus is where a pregnancy develops. It's also called the womb.
• It's roughly the size and shape of an upside-down pear when not pregnant, but stretches massively during pregnancy.
• The lining (endometrium) builds up each cycle and sheds as a period if no pregnancy occurs.
• The cervix connects the uterus to the vagina. The fallopian tubes connect it to the ovaries.
• IUDs and IUSs sit inside the uterus as a method of contraception.

[DIAGRAM: Labelled cross-section of the uterus showing endometrium, myometrium, cervix, and connection to fallopian tubes]

What it does

Each menstrual cycle, hormones (mainly oestrogen and progesterone) tell the uterus lining to thicken with blood vessels and tissue. This prepares it in case a fertilised egg arrives and needs to implant. If an egg is fertilised and implants successfully, the lining stays and becomes part of the support system for the developing pregnancy. If not, progesterone drops, the lining breaks down, and it leaves the body through the vagina — that's a period.

During pregnancy, the uterus expands from the size of a pear to large enough to hold a full-term baby. The muscular walls (myometrium) are what contract during labour to push the baby out.

The parts

• Endometrium — the inner lining that builds up and sheds each cycle
• Myometrium — the thick muscular wall that contracts during periods (cramps) and labour
• Cervix — the narrow lower end that opens into the vagina
• Fundus — the rounded top part, where the fallopian tubes connect

Things people ask about the uterus

Why do period cramps happen?

The uterus contracts to shed its lining. These muscle contractions are what cause cramping. Stronger contractions mean more pain. Ibuprofen helps because it reduces the chemicals (prostaglandins) that trigger the contractions.

Can the uterus be removed?

Yes — this is called a hysterectomy. It's a major surgery only done when medically necessary (for conditions like severe endometriosis, cancer, or heavy bleeding that doesn't respond to other treatment). It's very rare in young people.

Is the uterus the same as the vagina?

No. The uterus is an internal organ deep in the pelvis. The vagina is the canal that connects the uterus (via the cervix) to the outside of the body. They're connected but separate structures.

Where to get help

• Your GP — for very heavy periods, severe cramps, or any concerns about the uterus.
• NHS 111 — for advice if you're unsure whether symptoms need medical attention.

The uterus is an organ inside a girl's or woman's body, deep in the lower tummy. It's also called the womb. It's roughly the size and shape of an upside-down pear.

Its main job is growing a baby during pregnancy. But even when someone isn't pregnant, the uterus is busy. Each month, it builds up a soft lining of blood and tissue on the inside, getting ready in case a pregnancy starts. If no pregnancy happens, the lining isn't needed, so it comes away and leaves the body as blood. That's what a period is.

The muscles in the wall of the uterus are what cause period cramps. They squeeze to push the lining out. Stronger squeezing means more pain. Painkillers like ibuprofen can help because they reduce the squeezing.

During pregnancy, the uterus stretches from the size of a pear to big enough to hold a full-sized baby. During birth, the muscles contract to push the baby out.

The uterus is not the same thing as the passage between the legs (the vagina). They're connected by a narrow opening called the cervix, but they're separate parts.

Some types of long-lasting birth control (like the coil) sit inside the uterus.