Anatomy of pregnancy and birth - pelvis
5-minute read
Key facts
- Your pelvis is the part of your body that contains your uterus and bladder.
- The female pelvis is wider than the male pelvis, as it’s designed for pregnancy and childbirth.
- The pregnancy hormone relaxin helps your pelvic joints and ligaments to relax during pregnancy. This helps to support your growing baby and makes childbirth easier.
- Most babies naturally get into the 'head down' position in the uterus in time for labour and birth. This position helps your baby travel through your pelvis and birth canal.
What is the pelvis?
Your pelvis is found below your abdomen (tummy) and above your thighs.
In females, it is made up of the:
- bony pelvis — which includes your hip bones
- pelvic cavity — which houses your uterus and bladder
- pelvic floor
- perineum — the area between the opening of your vagina and your anus
The bones around your pelvis are attached by several ligaments, comprised of tough and flexible tissue. These help your pelvis to function.
What does my pelvis do?
Your pelvis has many roles, including holding your body upright so you can stand, walk and run.
The female pelvis is wider than the male pelvis. This is because it’s designed for pregnancy and childbirth.
How does my pelvis change during pregnancy?
Your pelvis changes throughout pregnancy. The pregnancy hormone relaxin helps your pelvic joints and ligaments to relax. This means that your pelvis can adjust to:
- support and accommodate your growing baby during pregnancy
- make childbirth easier for both you and your baby
What causes pelvic pain in pregnancy?
While the changes to your pelvis help your pregnancy and birth, they can also cause discomfort. When the joints of your pelvis relax and become more mobile, a you may feel:
- discomfort in your pelvis (pelvic girdle pain)
- lower back pain
Pelvic girdle pain is related to joint instability as well as the effects of:
- your growing uterus (womb)
- changes in your posture
- reduced muscle strength
What can help my pelvic pain in pregnancy?
Pelvic girdle pain can be relieved by:
- applying a heat pack to the painful areas
- wearing low-heeled, supportive shoes
- avoiding standing on one leg (sit down to get dressed, climb stairs one at a time)
- seeing a physiotherapist to get exercise and posture advice
- avoiding standing or walking for long periods of time
- being careful about movements that stretch your hip, such as getting in and out of cars, sitting on low stools and squatting
Although rare, there are other conditions that can affect your pelvis during pregnancy and childbirth. See your doctor if you have ongoing pelvic pain or back pain during pregnancy.
What happens in my pelvis during childbirth?
For birth, your baby is likely to be positioned with their head down and facing your back. This position helps your baby descend through your pelvis and birth canal.
Most babies naturally get into the 'head down' position in time for labour and birth.
Baby in breech position
A baby who lies bottom or feet down in your pelvis during late pregnancy is said to be in a ‘breech’ position. Breech presentations may increase the chance of a complicated vaginal birth.
Your obstetrician can perform techniques such as an external cephalic version (ECV), to help your baby turn. This may be done late in pregnancy if your baby is still in the breech position.
Talk to your doctor or midwife about your options if your baby is in the breech position. If it is not possible to turn your baby, your doctor may recommend a caesarean section.
Speak to a maternal child health nurse
Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.