Fetal macrosomia is when a newborn is significantly larger than average. These babies usually weigh more than  8 pounds, 13 ounces (4,000 grams) regardless of their gestational age. However babies weighing more than  9 pounds 15 ounces (4,500 grams) are at high risk of complications associated with fetal macrosomia. This condition may complicate vaginal delivery and increase the baby’s risk of birth injuries. It also puts the baby at risk of health problems after birth.

Fetal macrosomia is usually caused by genetic factors as well as maternal conditions such as diabetes  and obesity. You are also likely to have a large baby if :

• you gain a lot of week during pregnancy
• you are 35 years  or older
• go more than two weeks past your due date
• gained a lot of weight between pregnancies  and has not lost weight from previous pregnancy

Boys are also usually bigger than girls. You are likely to have a big baby if you had one in the past.

How  is fetal macrosomia detected ?

It may be difficult to detect or diagnose this condition . However  signs include

• large fundal height – a fundal height that measures  larger than normal can be an indication of macrosomia.
• excessive amniotic fluid – amniotic fluid reflects a baby urine output. A larger baby produces more urine.

How will fetal macrosomia affect delivery ?

It is possible to have vaginal delivery. However it can be difficult.  You may have a prolonged labor and may need assistance during delivery.  You also stand a greater risk of heavy blood loss after birth and  a severe perineal tear.

It  increases your risk for uterine rapture if you’ve had a previous c section  or a major uterine surgery.

The bigger your baby , the greater the risk of experiencing shoulder dystocia.

Inducing labor isn’t generally recommended because it increases your risk of a c-section.  Your  health care provider may however recommend a cesarean delivery if

• you have diabetes
•  you don’t have a history of maternal diabetes but your baby  weighs 11 pounds or more

If your doctor recommends an elective cesarean section, be sure to discuss the benefits and risks.

What health challenges do my baby face ?

Most babies do just fine. If your baby has shoulder dystocia during delivery, he may have some nerve damage in his shoulder and arms. If your baby has any nerve damage, he will recover fully. If there are any broken collar bones during birth, this should heal without any complications.

The baby may also be at risk of childhood obesity  and insulin resistance. He should be monitored for these conditions during  future checkups.

Can fetal macrosomia be prevented ?

You may not be able to prevent  it but you can take steps towards a healthy pregnancy which may reduce your risk. These include :

• going for regular and frequent prenatal appointment
• maintain a healthy weight during pregnancy
• keep diabetes under control
• stay active