Patient education: When your baby is overdue (The Basics)

How does my doctor or nurse figure out my due date? — To figure out your due date, your doctor or nurse counts 40 weeks from the first day of your last menstrual period.

If your periods are not regular (you don't normally get a period every month), counting won't give a correct due date. In that case, your doctor or nurse will do an imaging test called an ultrasound to figure out your due date. An ultrasound creates pictures of the baby inside of your body. Your doctor can use these pictures to measure your baby's size and figure out your due date.

When is a baby overdue? — Doctors begin to worry when a pregnancy lasts longer than 41 weeks, or 1 week after the due date.

A baby is "overdue" if it has not been born by 42 weeks, or 2 weeks after the due date. A pregnancy that lasts longer than 42 weeks is also called a "postterm pregnancy" or "postdates pregnancy."

What causes a baby to be overdue? — Doctors don't usually know. But you have a higher chance of having your baby after the due date if:

●It's your first pregnancy.

●You have already had a baby that was born after its due date.

Why is it a problem for babies to be born after 41 or 42 weeks? — Babies born after 41 or 42 weeks have a higher chance of having problems, such as:

●Being too big (heavier than 10 pounds or 4.5 kg) – A big baby can get hurt if they cannot easily fit through the birth canal. A big baby can also damage the mother's body when they come out through the birth canal. Sometimes, surgery is needed to get the baby out. This is called "cesarean birth."

●Having a bowel movement in the amniotic fluid before birth – Amniotic fluid is the fluid that surrounds the baby in the uterus. Babies who breathe in fluid with bowel movement in it can have breathing problems after they are born.

Other problems that can happen are:

●The placenta might not work as well as it did earlier in the pregnancy – The placenta is the organ that brings the baby nutrients and oxygen and carries away waste.

●There can be too little amniotic fluid surrounding the baby in the uterus – If there is not enough amniotic fluid, the umbilical cord can get squeezed. If the umbilical cord is squeezed, the baby might not get enough oxygen and nutrients from the placenta.

What happens if I am still pregnant after my due date? — If you are still pregnant after your due date, your doctor or nurse will talk to you about what to do next.

Many experts recommend using medicines to start or "induce" labor if it has not already started by 41 weeks.

The other option is to let your pregnancy continue until your body is ready to give birth, or until you reach 42 weeks. If this is what your doctor or nurse recommends, they will do regular tests to check your baby's health. The tests can check:

●Your baby's heartbeat

●Your baby's breathing and body movements

●The amount of amniotic fluid surrounding the baby in your uterus

What will happen if my doctor or nurse recommends inducing labor? — If your body isn't ready to give birth, your doctor can give you medicines to help start your labor. This is called "inducing labor" or "labor induction." These medicines often work.

Your doctor can also do surgery to get your baby out. You might have a cesarean birth if:

●Medicines to induce labor don't work.

●Your baby is too big to safely fit through the birth canal.

●There are problems during labor, and the baby needs to be born quickly.

Will my baby be healthy if it is born after the due date? — Most babies born after their due date are healthy. But babies born after their due date can look a little different at birth. They might have:

●Long and thin arms or legs

●Dry or peeling skin

●Long hair and nails

More on this topic

Patient education: Cesarean birth (The Basics)
Patient education: Shoulder dystocia (The Basics)

Patient education: Postterm pregnancy (Beyond the Basics)
Patient education: C-section (cesarean delivery) (Beyond the Basics)