Overweight Baby – Does Fetal Macrosomia Causes Injuries To The Mother?

Overweight Baby – Does Fetal Macrosomia Causes Injuries To The Mother?

Do you know 1 in 200 babies in India is born with weight of 4kgs or more? Excess of baby weight can cause serious complications to the mother during delivery. Let’s discuss why millions of babies come into this world with extra fat and muscle mass.


Macrosomia or fetal macrosomia is a term used for a newborn baby who is significantly larger in weight than his or her gestational age. The gestational age here refers to the number of weeks the baby spent in the womb.

How much weight is called larger than gestational age?

On an average, a normal baby weighs between 2.5kg to 4kg. But baby diagnosed with macrosomia has a birth weight of more than 4kgs. Fetal macrosomia can complicate the process of vaginal delivery, especially when the weight is over 4.5kgs.

Do macrosomic babies face health problems later in life?

Larger than average babies not only causes delivery complications to the mothers but they also face health problems later in life. They have greater chances of having:

  • Lower blood sugar level than normal. In some cases, blood sugar levels can be high.
  • Childhood obesity
  • Metabolic syndrome which include health problems such as high blood pressure, abnormal cholesterol levels and diabetes

Also Read

Delayed Growth of Baby During Pregnancy – How Intrauterine Growth Restriction Is TreatedLow baby weight during pregnancy – How Intrauterine Growth Retardation is Treated

What causes macrosomia? Possible risk factors

Although many cases of fetal macrosomia remain unclear, there are various reasons why babies can buildup extra weight during pregnancy. These include:

  • Diabetes in the mother or gestational diabetes
  • Genetics
  • Obesity in the mother
  • Certain medical condition in the baby that speeds up fetal growth

Many factors might increase the likelihood of fetal macrosomia. Some of these you can control, but some others are out of your bounds.

  • Poorly controlled diabetes
  • History of fetal macrosomia
  • Gaining too much weight during pregnancy
  • Having a male baby
  • Overdue pregnancy (more than 2 weeks past the due date)
  • Advanced maternal age (35 years or above)

Are there any early signs and symptoms of fetal macrosomia?

Though fetal macrosomia is hard to detect during the pregnancy phase, yet there are some possible signs which indicate large baby in your belly. These include:

  1. Large fundal height – During the regular checkup, the doctor would be checking your fundal height. This measures the distance from the top of the uterus to your pubic bone. If the fundal height is larger than normal, then it could indicate fetal macrosomia.
  2. Too much amniotic fluid – The amount of amniotic fluid in the womb indicates the urine output of the baby. And a large baby would produce more urine.

How is fetal macrosomia diagnosed?

On meeting with your doctor, you would be asked questions about your medical history as well as earlier pregnancies. The gynecologist may also measure the size of the baby, however, accuracy is questionable. Besides measuring the fundal height and amniotic fluid, the doctor might perform the following testing.

Glucose tolerance test – A good way to rule out the possibility of gestational diabetes is to perform a glucose tolerance test around 24-28 weeks of pregnancy. If the blood sugar levels are high, working up further and preventing complications might be easy.

Ultrasound – The ultrasound scan would be done at the end of the third trimester or around 32 weeks. This is to measure the body parts of the baby such as head, abdomen, and femur (thigh bone).

Antenatal testing – If the doctor suspect of macrosomia, antenatal test such as fetal biophysical profile and non-stress test can be conducted. A non-stress test checks heart rate of the baby in response to his/her movements. While, the fetal biophysical profile combines both non-stress test and ultrasound to analyze baby’s movement, breathing, tone as well as the amount of amniotic fluid.

You might also want to consult a pediatrician before your baby is born to know more about the condition.

Complications – How large baby affects labor and delivery?

Besides complications of the baby discussed above, the mother too is vulnerable to several complications. The possible complications include:

  1. Labor difficulties – A larger than normal baby may get stuck in the birth canal during the delivery. This might require the help of assistive deliveries techniques including forceps and vacuum extractor. In some cases, cesarean delivery might be the last resort.
  2. Excessive bleeding – Fetal macrosomia increases the chances of uterine atony. This means the uterine muscles don’t contract properly after the birth. This can result in severe post-birth bleeding.
  3. Genital tract injuries and lacerations – The excessive force during the delivery might injure the vaginal tissue and the birth canal in case the baby is large.
  4. Uterine rupture – Woman with history of fetal macrosomia might experience uterine rupture. Although it occurs rarely, if that happens, emergency c-section will be conducted in order to avert life-threatening complications.

The labour process might also take longer time which may create fetal distress and bring forth other complications.

Health effects of macrosomia on babies

In case of obstructed labor and babies delivered normally with or without using forceps and vacuum, the baby might sustain birth-time injuries. This includes shoulder dystocia, a condition in which shoulder get stuck after the head of the baby during the delivery.

There are chances of neurological complications as a result of head injury during the delivery.

Also Read

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Treatment – How the problem is solved?

The solution for fetal macrosomia will depend on case to case. The doctor can recommend following things.

Vaginal delivery

Diagnosing fetal macrosomia doesn’t mean vaginal delivery is ruled out. However, you need to undergo careful monitoring in case forceps or vacuum extractor and c-section is needed.


The doctor might suggest cesarean delivery:

  • If you have diabetes and doctor estimates baby’s weight is 4.5kgs or more
  • If your baby’s weight is 5kgs or without having diabetes or gestational diabetes
  • If you have the history of delivering a baby with shoulder dystocia

Make sure you discuss the advantages and disadvantages of both the treatment with your doctor.

Prevention and outlook

You might not be able to completely prevent macrosomia, as certain risk factors and causes are out of your bounds. However, timely medical consultation, maintaining healthy weight during pregnancy and eating a well-balanced diet might cut the chances of developing the condition.

In fact, maintaining proper weight prior getting pregnant is a wise decision. Remember, if you are not alert, you might be predisposing your baby to chronic complications which he or she might develop later in life. If despite all the effort you have been diagnosed by macrosomia, make sure you discuss every minute detail of the condition with your gynecologist.


1. Gibson E, et al. (2015). Large-for-gestational-age(LGA) Infant read more
2. Mohammadbeigi A, et al. (2013). Fetal macrosomia: Risk factors, maternal, and perinatal outcome read more
3. Chatfield A(2001). Guidelines on Fetal Macrosomia read more