The pregnancy test was positive, and your bump has been growing ever since. You can’t wait until the big day arrives and you finally get to meet your baby — but you’re also wondering what it’ll be like to go into labor.
Every birth experience is remarkable and life-changing, but what exactly is going on as you bring your new bundle of joy into the world?
Welcome to the miracle of your body in labor.
How your body prepares for birth
Before the first whisper of a contraction, your body is already preparing for the big event.
About two to four weeks before you deliver, you may notice your bump looks a little bit lower than it used to. That’s because, near the end of pregnancy, your baby “drops,” moving into a head-down (vertex) position deeper into the pelvis to prepare for the grand exit.
Around this time, your body may also release a blob of clear or pink discharge, sometimes referred to by the charming name “bloody show.” This is your mucous plug, a jellylike barrier that seals off your uterus during pregnancy to protect your baby from pesky bacteria that are trying to get in.
As your body prepares for birth, your cervix — the muscular ring between your uterus and vagina — begins to soften, dislodging the mucous plug.
The exact chain of events that trigger your body to prepare for and begin labor, however, is still a mystery.
“For all that we know about the human body, we still don’t know what starts labor,” explains Margaret Bolton, a certified nurse midwife at Meridian Women’s Health at UW Medicine. “We suspect that it has something to do with the baby and the placenta.”
The early signs of labor
Although experts don’t quite understand how labor starts, there are some telltale signs that labor is imminent.
One is your water breaking. This isn’t actually water but is rather amniotic fluid, which is released when the amniotic sac around your baby ruptures. It may feel like a trickle or small gush. Either way, you can tell the difference between this and urine — no judgement, leaking is common — because amniotic fluid is pale and odorless. If your water breaks, contractions are usually only a few hours away.
Not all women have their waters break, though. Only about 1 in 10 moms-to-be experience this before they go into labor. For the other 90%, your water may not break until you’re already laboring or when your OB-GYN or midwife does it manually.
“Rarely, the baby is born ‘in the caul,’ which means that the baby is born with the bag of water intact,” Bolton says.
Amniotic sac rupture or not, once labor does start, your brain releases a hormone called oxytocin to trigger contractions. This hormone travels through your uterine artery and lands on receptors in the uterus, signaling to your uterine cells that it’s time to wake up and start contracting.
“You’ll feel a cramping, tightening sensation in the lower abdomen and sometimes in the back as well,” Bolton notes. “The sensation builds and then releases as the contraction passes.”
The first stage of labor
Labor is typically divided into three stages. The first stage — marked by contractions and cervical dilation — is further divided into three distinct phases: early, active and transitional labor.
During early labor, your cervix will open to around 3 centimeters. Your uterine cells start out sporadically, with short contractions and long stretches between each one. This can go on for a few hours or a few days, with contractions becoming more regular and intense as time goes on.
Right around the end of early labor, when contractions start lasting longer and occurring with more frequency, is when many pregnant women leave for the hospital. Usually your OB-GYN or midwife will tell you to wait until you’re experiencing at least an hour of contractions that last one minute, with five minutes between each one.
Contractions pick up even more during active labor, dilating your cervix to about 7 centimeters. At this point, contractions feel like a tightening or cramping in your midsection and are coming every four or five minutes. The pain can radiate to your back and other areas of your body as your adrenaline wears off from the initial excitement of going into labor.