Birth: What happens in your body
How your body prepares and functions during labor
Understanding the physiology of childbirth not only gives you more control over what’s to come, but also helps build trust in your body’s ability.
Every woman can give birth – your body knows what to do. That sounds reassuring, but also a bit vague. Childbirth is not something that just happens to you. It’s an intense collaboration between hormones, muscles, emotions, and your breath – and you play the leading role.
What actually happens in your body?
A quick overview:
- Childbirth is a natural process driven by your brain, hormones, and muscles.
- Oxytocin triggers contractions and connection – it’s known as the “love hormone.”
- Endorphins relieve pain and help you enter a kind of “flow.”
- Your cervix softens, thins out, and gradually opens.
- Your breathing, heart rate, and muscles adapt to support the contractions.
Hormones: Your Secret Allies
During labor, three key hormones are at work:
1. Oxytocin – the driving hormone
Oxytocin is the hormone responsible for contractions. It’s also called the “cuddle hormone” because it’s released during sex, cuddling, and breastfeeding. During labor, it causes your uterus to contract rhythmically. These contractions help push your baby downward.
Oxytocin flows best in calm, safe, loving environments – not with stress or bright lights. That’s why creating a peaceful birthing space matters.
2. Endorphins – your natural painkillers
The more intense your contractions, the more endorphins your body releases. These reduce pain and help you enter a focused state – often described as a “labor bubble” or natural high. They allow you to cope with intense contractions.
3. Adrenaline – friend or foe
A small boost of adrenaline can help you when you need energy – for example, during the final phase of labor. But too much adrenaline from fear or panic can slow down labor. Your body then switches to “fight or flight” instead of “release and open.” That’s why relaxation is key.
Changes in the Cervix and Uterus
Throughout pregnancy, your cervix is firm and closed. As labor begins, it changes:
- Effacement: the cervix softens and becomes thinner.
- Dilation: the cervix gradually opens to about 10 centimeters.
- Descent and rotation: your baby drops into the pelvis and turns to find the way out.
The uterus is a powerful muscle, made up of different layers. During a contraction, the top of the uterus contracts while the bottom part relaxes, helping to push the baby downward.
What You’ll Notice in Your Body
Your body works hard – together with your hormones and your baby. You may notice:
- Muscle contractions (contractions): at first light and irregular, then stronger and more rhythmic.
- Faster breathing: a normal response to effort. Conscious breathing helps you relax and get oxygen to your baby.
- Increased heart rate: to supply your body with extra energy and oxygen.
- Warmth, trembling, sweating: all normal reactions to exertion and hormonal shifts.
You might also experience emotional shifts – like moments of doubt, sudden calm, or a burst of strength. These are part of the process. Many recognise labor phases not just by physical signs, but by emotional changes.
Your body is literally built to give birth. The collaboration between your brain, hormones, muscles, and breath is extraordinary. Understanding what’s happening helps you move with it – giving you peace and confidence.