When it’s safe to do so, doctors often encourage waiting for labor to begin on its own. This is known as spontaneous labor, and it gives your baby time to finish important development so they’re truly ready to emerge.

Learn why a full-term pregnancy is often recommended and what to know if labor needs to be induced.

What Does a Full-Term Pregnancy Mean?

A typical full-term pregnancy lasts about 40 weeks, starting from the first day of your last period.

Pregnancies between 37 and 42 weeks are considered “term,” but this range is divided into categories:

• Babies born at 37 to 38 weeks are considered early term.
• Babies born at 39 to 40 weeks are considered term babies or full term.
• Babies born at 41 weeks are considered late term.
• Babies born at 42 weeks or later are considered post-term.

“Early term is used for babies born at 37 to 38 weeks because, while technically ‘term,’ these babies have higher risks of respiratory issues, admission to the neonatal intensive care unit (NICU) and other complications compared to those born at 40 weeks,” says Rakhi S. Shah, DO, an obstetrics and gynecology specialist at Northwestern Medicine.

Many early-term babies do well, especially if labor starts naturally. But studies show that when it’s safe to do so, babies do best when they are born at 39 weeks or later.

Why a Few Weeks Make a Big Difference

Those last few weeks of pregnancy are crucial for your baby’s development.

• At 37 weeks, the brain is only about two‑thirds developed. Also, babies gain about one-half pound per week in the last few weeks of pregnancy.
• At 38 weeks, organs are still maturing and being fine-tuned.
• By 39 to 40 weeks, the brain, lungs, liver and muscles are more fully developed.

Babies who arrive at full term have lower risks of several health problems after birth. They’re also better able to suck and swallow, which can make feeding easier and may lead to a shorter hospital stay.

Babies born before 37 weeks are considered preterm or premature babies. Early delivery can increase the chances of:

• Breathing issues
• Trouble feeding
• Difficulty keeping warm
• Jaundice (a condition that causes yellowing of the skin due to excess bilirubin in the blood)
• Low blood sugar

Reaching full term gives babies a stronger start and helps them adjust more easily to life outside the womb.

Waiting until labor begins naturally can also benefit you. Spontaneous labor often leads to fewer risks for you, including:

• Fewer medical interventions
• Lower risk of complications
• Shorter recovery time after birth

When Is Inducing Labor the Right Choice?

Labor induction is a medical approach used to help start labor using medications or specific techniques instead of waiting for labor to start on its own.

If you and your baby are healthy, the American College of Obstetricians and Gynecologists recommends that labor induction begin no earlier than 39 weeks, since babies born at or after 39 weeks have the best chance at healthy outcomes.

If your labor does not start on its own by 39 weeks and you and your baby are healthy, talk to your doctor about the pros and cons of inducing labor in your situation. While inducing labor can be the right choice in some cases, it may involve stronger contractions and a longer labor. 

Delivering before 39 weeks

Sometimes delivering before 39 weeks is the safest option. Your doctor may recommend induction before 39 weeks if there are concerns about your health or your baby’s health, such as:

• High blood pressure or preeclampsia (a serious condition that can occur after 20 weeks of pregnancy and can include high blood pressure, headaches, vision changes, swelling and abdominal pain)
• Gestational diabetes

• Slowed baby growth
• Low amniotic fluid
• Ruptured membranes (your water “broke” but contractions haven’t started)

• Signs of infection
• Problems with the placenta
  

In these situations, the benefits of early delivery may outweigh the risks of waiting for labor to start on its own.

Delivering after 41 weeks

If labor hasn’t started on its own by 41 weeks, your care team may recommend inducing labor. This is because pregnancy beyond 41 weeks can increase certain risks for both you and your baby.

“If delivering after 41 weeks, there is a higher risk of stillbirth, placental dysfunction, aspiration of meconium (the baby’s first stool) and higher rates of NICU admission and perinatal complications,” says Dr. Shah. “These risks rise more noticeably after 42 weeks. There is evidence that there is a clear increase in perinatal morbidity and mortality beyond 42 weeks.”

When you reach 41 weeks of pregnancy, your doctor may also suggest extra monitoring to check on your baby’s well‑being. This can include:

• Ultrasounds to check your baby’s movement, position and the amount of amniotic fluid
• Non-stress tests to monitor your baby’s heart rate and make sure they’re getting enough oxygen
• Regular check‑ins to discuss how you’re feeling and whether any new symptoms have developed

These steps help your care team decide whether it’s best to continue waiting for labor to start naturally or to move forward with an induction.

When To Call Your Doctor

• Fewer baby movements
• Heavy bleeding or fluid leakage
• Fever or signs of infection
• Severe headaches or vision changes
• Strong, frequent contractions that do not ease

Common Myths About Labor and Delivery

Myth: It’s always safe to go the full 40 weeks.
Fact: Some medical conditions, such as preeclampsia, may make earlier delivery safer. Your care team will carefully balance your health with your baby’s needs to choose the right timing.

Myth: Scheduling delivery early is easier, more convenient or safer.
Fact: When there’s no medical reason, inducing labor before 39 weeks can carry increased risks for your baby, especially problems with breathing, feeding and blood sugar. A simple rule is: Don’t rush unless your doctor recommends it for safety. However, if your water breaks, you have a higher risk of infection by waiting. Call your doctor and go to the hospital right away.

Myth: Labor always starts on or by the due date.
Fact: Only a small number of babies arrive on their due date. A due date is simply an estimate to help track the stages of pregnancy.

Myth: Walking, eating spicy food or doing certain exercises can start labor.
Fact: Although these may affect how your body feels, there is no evidence that they can reliably trigger labor.

Supporting the Full 40 Weeks of Pregnancy

Simple habits can help support a healthy pregnancy that goes the full 40 weeks:

• Eat balanced meals.
• Stay hydrated.
• Get regular, gentle movement.
• Prioritize sleep.
• Manage stress.
• Keep up with prenatal visits.
  

These healthy habits help reduce the increased risks that can lead to early delivery.

Coping With the Final Weeks of Pregnancy

The last stretch can feel long — physically and emotionally. Rest when you can, accept help and lean on your support system. Your partner and other loved ones can help by handling meals, errands and planning so you can focus on your well‑being.

The goal is always the same: a healthy parent and a healthy baby who arrives when they’re ready.