The Uterus

An impressive organ
POWERFUL        STRONG      


“KNOWS”  what to do when there is a baby growing inside it and it knows how to get that baby from the inside to the outside ….

Small, pear shape set of muscles
when not pregnant nestles within the pelvic girdle.

It has three main areas:
The Fundus – which is the layer of muscle at the top of the womb.
The Body – the main chamber where the baby grows and develops.
The Cervix –narrow channel of circular muscles, linking the cervix to the vagina. The cervix has an opening at the bottom for sperm to go in and babies to come out

There are three layers to the uterus: 
The Perimetrium – a thin lining connecting the uterus to the body lining. 
The Myometrium – a thicker middle muscular layer covering the outside of the uterus, located between the perimetrium and the endometrium. The muscular nature of this layer is extremely important for the contractions needed for childbirth. 
The Endometrium – the thinner, inner layer of the uterine wall which builds up every month, preparing for the fertilised egg implantation. When that doesn’t happen the lining sheds, causing the monthly period.

The Myometrium (middle layer of the uterus) has three different layers of muscle within it. 
Each has a different role to play during labour

Don’t you just love the power of 3

All work in harmony when birthing your baby

The outer layer has longitudinal muscle fibres that go down the front and back of the uterus, with the main mass of muscle being at the top. As this layer of muscles contract, they gently push up the circular fibres of the inner layer causing the cervix to dilate (or open) and extra muscle mass to gather at the top of the uterus (the fundus). When the cervix is open enough to allow a baby’s head through (usually considered to be around 10cm) the motion of these longitudinal muscles changes, allowing the extra muscle thickness at the top of the fundus to act as a piston to push the baby out of the uterus and down the birth canal. The middle layer is a mass of muscle fibres all matted together forming figures-of-eight around the uterus’s blood vessels. When these muscles are relaxed the blood flows freely, enabling the baby to receive all the oxygen and nutrients she needs. When they contract, the blood vessels are constricted, temporarily reducing the flow of blood etc. to the baby. 

This may sound scary but this process is actually helping prepare their lungs for life outside of the womb. This restricting of blood flow is also very important because it allows the safe release of the placenta with minimal bleeding. The inner layer consists of circular fibres that go around the uterus, with the main mass concentrated in the lower segment close to the cervix. Their role during pregnancy is to keep the cervix closed and the baby safe. 

Interestingly, when this layer contracts during childbirth, it keeps the cervix closed and can therefore stop or slow down the function of the uterus. This usually will only happen if the mother feels threatened or unsafe in any way.