The 5 Ps of Labour: What You Need To Know About Birth

While most labouring women solely focus on dilation, there is so much more to the story of birth. Five key factors must all work together for a safe and successful vaginal delivery. These are called the 5 Ps of Labour. Knowing these elements can help parents feel more confident and informed about the birth process. Healthcare providers can also make recommendations for progress, informed decisions regarding operative vaginal birth and cesarean birth options and provide added support.

Power

The first P stands for Power. Powers are the physical forces that move your baby through the pelvis during labour.

The primary powers focus on the strength and coordination of the uterine contractions. Contractions become regular and build up over time, putting pressure on the cervix to open (dilation) and thin out (effacement), allowing the baby to move down the birth canal (station) (Cunningham et al., 2022). Contractions are measured by their duration (how long each one lasts), intensity (how strong they feel), and frequency (how often they occur).

The secondary powers begin once the cervix is fully effaced and dilated and involve the mother's pushing efforts. Pushing can be affected by her strength, energy, position, use of pain relief like an epidural, and how the baby is positioned inside the pelvis. If contractions are not strong or frequent enough, labour may slow down or stop altogether. This is known as dystocia.

Passageway

The second P is the Passageway. This refers to the mother’s pelvis, cervix, birth canal, and the surrounding soft tissues. Every woman’s pelvis has a slightly different shape. Some shapes give more room for the baby to move down. Pelvis shapes include gynecoid, android, anthropoid, and platypelloid, but none of these shapes alone guarantees an easy or difficult labour (Cunningham et al., 2022).

The four female parent pelvic shapes. The inlet, mid-pelvis, and outlet of an individual mother's pelvis can be a combination of all these pelvic types or consistent throughout.

The pelvic floor muscles also play a big role. These muscles help support the uterus during pregnancy and stretch so the baby can move through. If the pelvic floor is too tight or too loose, it can make it harder for the baby to descend. Previous injuries or multiple births can also affect the pelvic floor.

Hormones also help by softening and relaxing the surrounding tissues, but if your pelvis doesn’t open easily, labour may be slow or need extra help.

Passenger

The third P is the Passenger—the baby. How the baby is lying in the uterus (fetal lie), what part is coming first (presentation), and which way the baby is facing (position) are all important during birth (Simkin et al., 2020).

Ideally, the baby is in a head-down position with the chin tucked in. This makes the head smaller and easier to pass through the pelvis. This is called a vertex presentation. Babies who are bottom-first (breech) or sideways (transverse) may need help turning or require a cesarean birth. During labour, your midwife, physician, or nurse may use tools like Leopold’s maneuvers, vaginal exams, or ultrasound to check the baby’s position.

Position

The fourth P stands for Position. This refers to how the mother moves during labour. Changing positions often helps labour progress by encouraging the baby to move through the pelvis and rotate into the best position for birth (Declercq et al., 2021). Being upright, walking, squatting, or using a birth ball can help labour move along. Even with an epidural, changing positions regularly helps avoid injuries and keeps labour progressing.

Forward-leaning position using doula support during labour.

Psyche

The fifth P is Psyche. This refers to the mother’s emotional and mental state. Feeling safe, supported, and calm can help labour progress more effectively.  On the other hand, when the mother feels fear and stress, the contractions slow, pain increases, and labour becomes longer (Lothian, 2004).

Midwives, nurses, doulas, and birth partners can create a positive birth environment by offering reassurance, quiet surroundings, music, comfort items, and gentle touch. Prenatal education classes also help prepare women and their partners for what to expect during childbirth.

Why the 5 Ps of Labour Matter

The 5 Ps of labour are all connected and explain what’s happening with the baby, the mother's body, the mother's mental state, and how the forces of birth are coordinating. If even one of them is out of balance, such as weak contractions, a baby in a difficult position, or a mother who feels anxious, labour may slow down or become more challenging. Nurses, midwives, doulas, and doctors use this model to help troubleshoot labour challenges and support a healthy and safe birth for both mom and baby.

Birth involves not just the physical process but also mental strength, movement, teamwork, and knowledge. Whether you are planning a natural birth, an epidural, or a cesarean, knowing what affects labour helps you take control and make informed choices.

Parent Resources

Amanda breaks down the 5 P's of Labour.

References

Cunningham, F. G., Leveno, K. J., Bloom, S. L., Dashe, J. S., Hoffman, B. L., Casey, B. M., & Sheffield, J. S. (2022). Williams Obstetrics (26th ed.). McGraw Hill.

Declercq, E., Sakala, C., Corry, M. P., Applebaum, S., & Herrlich, A. (2021). Listening to mothers in California: A population-based survey of women's childbearing experiences. National Partnership for Women & Families. https://www.chcf.org/wp-content/uploads/2018/09/ListeningMothersCAFullSurveyReport2018.pdf

Lothian, J. A. (2004). Birth plans: The good, the bad, and the future. The Journal of Perinatal Education, 13(3), 4–8. https://www.sciencedirect.com/science/article/abs/pii/S0884217515343513

Simkin, P., Klein, M. C., & Dixon, L. (2020). Pregnancy, Childbirth, and the Newborn: The Complete Guide (5th ed.). Harvard Common Press.