Women give birth through a process that unfolds in three distinct stages: the gradual opening of the cervix, the delivery of the baby, and the delivery of the placenta. The entire process is driven by hormones, involves a remarkable sequence of movements by the baby, and can take anywhere from a few hours to more than a day. Here’s what actually happens in the body before, during, and after birth.
What Triggers Labor to Start
Labor begins when a cascade of hormones shifts the body from maintaining pregnancy to actively ending it. Prostaglandins, produced naturally in the body, soften and thin the cervix so it can stretch open. They also stimulate the uterus to begin contracting. Oxytocin, often called the “love hormone,” ramps up uterine contractions during the later stages of labor and keeps them strong and regular as delivery approaches. A third hormone, relaxin, helps ripen the cervix in the weeks leading up to birth.
These hormones don’t switch on all at once. The body builds toward labor gradually, and several physical signs appear in the days or weeks beforehand.
Signs That Labor Is Approaching
Before contractions become regular, the body sends a series of signals that birth is getting closer. One of the most noticeable is “lightening,” when the baby’s head drops deep into the pelvis. This can happen anywhere from a few weeks to a few hours before labor and often changes the shape of the belly visibly.
The cervix also begins preparing well before active labor. It starts out about 3.5 to 4 centimeters long and needs to thin completely (a process called effacement) before a vaginal delivery is possible. Early on, the thick mucus plug that sealed the cervix during pregnancy may come loose, producing a clear, pink, or slightly bloody discharge. This can happen days before labor or right at the start.
Water breaking, when the fluid-filled sac surrounding the baby ruptures, is perhaps the most well-known sign. It can happen at the beginning of labor or well into it. For many women, contractions start first and the water breaks later.
First Stage: The Cervix Opens
The first stage of labor is the longest. It has two phases, and each feels distinctly different.
During early labor, the cervix dilates from closed to about 6 centimeters. Contractions are typically mild to moderate and may feel like strong menstrual cramps. They come and go at irregular intervals at first, then gradually become more rhythmic. This phase usually lasts 6 to 12 hours, though it can be shorter or significantly longer, especially for a first birth. Many women spend this phase at home, walking, resting, or timing contractions.
Active labor picks up where early labor leaves off, taking the cervix from 6 centimeters to a full 10 centimeters. Contractions are now intense, lasting longer, and coming closer together. This phase typically lasts 4 to 8 hours. It demands focused concentration, and this is when most women in a hospital setting choose pain relief if they want it.
Pain Relief During Labor
The two most common options for managing labor pain are epidurals and nitrous oxide, and they work very differently.
An epidural delivers numbing medication near the spinal cord through a thin catheter placed in the lower back. It blocks pain signals from the waist down and is widely considered the most effective form of labor pain relief. Most women who receive an epidural can still feel pressure and the urge to push but experience dramatically less pain.
Nitrous oxide (sometimes called “laughing gas”) works by triggering the body’s own pain-modulating pathways. You breathe it through a mask that you hold yourself, inhaling before and during each contraction. Its pain relief is more limited than an epidural, and some women report little benefit. However, satisfaction levels among women who use nitrous oxide are surprisingly similar to those who choose epidurals, and most say they would use it again. Nitrous oxide can be used throughout all stages of labor and even during postdelivery procedures like stitching a tear.
Other approaches include warm water immersion, movement and position changes, and IV or injected pain medications. Many women combine several methods over the course of labor.
How the Baby Moves Through the Birth Canal
Delivery isn’t simply the baby being pushed straight out. The baby performs a specific sequence of movements to navigate the narrow, curved passage of the pelvis. These are sometimes called the cardinal movements of labor, and they happen in order: engagement, flexion, descent, internal rotation, extension, external rotation, and finally expulsion.
In practical terms, the baby first tucks its chin to make its head as small as possible, then descends and rotates so the narrowest part of its skull lines up with the widest part of the pelvis. As the head emerges, it extends backward (face pointing up or down depending on position), then rotates one more time so the shoulders can fit through. The rest of the body follows quickly after the shoulders deliver. This entire sequence is driven by the force of contractions and the mother’s pushing effort working together against the shape of the pelvic bones.
Second Stage: Pushing and Delivery
Once the cervix is fully dilated, the second stage begins. This is when you actively push with each contraction to move the baby down and out. For first-time mothers, pushing can last anywhere from 20 minutes to a few hours. For women who have given birth before, it’s often much shorter.
The sensation of pushing is often described as an overwhelming urge, similar to bearing down during a bowel movement but far more intense. Women push in various positions: on their backs, on hands and knees, squatting, or lying on their sides. The baby’s head gradually becomes visible at the vaginal opening, and once the widest part of the head passes through (called crowning), the rest of the body typically delivers within one or two more contractions.
Third Stage: Delivering the Placenta
After the baby is born, the uterus continues to contract. These contractions create a shearing force between the elastic uterine wall and the more rigid placenta, causing the placenta to peel away from the uterine lining. Separation usually starts at one edge and spreads across until the entire organ detaches.
As the placenta moves downward, the uterus firms up and becomes more globe-shaped. A gush of blood typically accompanies the placenta’s descent. The whole process usually happens within 30 minutes of the baby’s birth. If it takes longer, the risk of heavy bleeding increases, and a healthcare provider may intervene to help remove it.
Cesarean Birth
Not all births happen vaginally. Globally, about 21% of babies are now delivered by cesarean section, up from 7% in 1990. Rates vary enormously by region: in sub-Saharan Africa, only about 5% of births are cesarean (often reflecting limited access to surgical care), while in Latin America and the Caribbean, the rate reaches 43%.
During a cesarean, a horizontal incision is made low on the abdomen, and the surgeon opens through several layers of tissue to reach the uterus. The time from the first cut to delivering the baby is remarkably fast, typically about 5 minutes for a first cesarean and 7 minutes for a repeat procedure. Extracting the baby itself takes less than a minute on average. Closing the incision afterward takes considerably longer, around 17 minutes, as the uterus and abdominal layers are sutured back together.
Cesareans may be planned in advance for reasons like the baby’s position (breech, for example) or a previous cesarean scar, or they may happen during labor if complications arise.
The First Hour After Birth
The first hour after delivery, often called the “golden hour,” is when the baby is placed belly-down directly on the mother’s bare chest. This skin-to-skin contact does more than just introduce parent and child. It helps stabilize the newborn’s heart rate, regulate breathing patterns, and prevent the baby’s body temperature from dropping. Research consistently shows that this early contact also supports breastfeeding initiation and encourages longer, more restful sleep cycles in the newborn.
For babies born early or at a low birth weight, skin-to-skin contact (sometimes called kangaroo care) has even more pronounced benefits, including supporting growth and lowering the risk of serious infection. This practice works after cesarean births too, though it may be initiated in the operating room or shortly after in the recovery area depending on the circumstances.