Definition

Macrosomia is a term for newborns who are larger than average. A baby is diagnosed with macrosomia if it weighs more than 4 kg, regardless of gestational age. The birth of a large baby can complicate delivery, increasing the risk of vaginal tears or difficulties in pushing the baby out. If the doctor assesses that the fetus is large or the mother has diabetes, a cesarean section may be recommended as the safest option.

Causes

Macrosomia is commonly caused by uncontrolled diabetes in the mother. This diabetes can occur only during pregnancy (gestational diabetes) or may have been present before pregnancy. High blood sugar levels in the mother can pass through the placenta and be converted into fat, causing the baby to grow larger.

You can read more about diabetes during pregnancy here: Gestational Diabetes - Understanding, Cause, Symptoms And Treatment.

Apart from diabetes, other causes of macrosomia include:

• Family history of large babies
• Excessive weight gain during pregnancy
• Twin pregnancies
• Post-term pregnancy, which lasts more than 40 weeks
• Mothers with above-average weight and height
• Male fetus

Risk Factor

Several factors can increase the risk of macrosomia.

Non-Modifiable Factors

• Diabetes during pregnancy
• The risk of macrosomia increases if you have diabetes before pregnancy or develop gestational diabetes. If diabetes is not controlled, your baby may have broad shoulders and a higher fat percentage than babies of non-diabetic mothers.
• Previous macrosomia
• If you had a large baby in a previous pregnancy, you are at risk of having another large baby.
• Carrying a male fetus
• Gestational age more 40 weeks
• Maternal age. Women over 35 years of age are at a higher risk of delivering a macrosomic baby.

Modifiable Factors

• Obesity during pregnancy: Obesity, whether before or during pregnancy, can be managed with a balanced diet and physical activities such as prenatal yoga.
• Excessive weight gain during pregnancy

Symptoms

Macrosomia can be difficult to detect and diagnose during pregnancy. Some of the symptoms include:

• Excessive fundal height: During routine check-ups, the doctor will measure the fundal height, which is the distance between the top of the uterus and the pubic bone. A large fundal height could be a sign of macrosomia.
• Excessive amniotic fluid: An excess amount of amniotic fluid may indicate that the fetus is larger than average.

Diagnosis

The doctor will inquire about your medical history and previous pregnancies. Although the baby's size is monitored during pregnancy, these measurements are not always accurate. The fetus’s size can be assessed through various methods, such as:

• Fundal height measurement
• Ultrasound examination: This uses sound waves to visualize the fetus inside the womb. Although it’s not 100% accurate in estimating birth weight, it can help estimate whether the fetus is large.
• Amniotic fluid measurement
• Non-stress test: This test measures the fetal heart rate.
• Biophysical profile: This combines a non-stress test with ultrasound to examine fetal movements and the amount of amniotic fluid.

Management

Management of macrosomia focuses on controlling the underlying health conditions of the mother, such as diabetes or obesity. The doctor and mother work together to control these conditions and other issues that could lead to pregnancy or delivery complications. In some cases, a healthy diet and sufficient exercise can help manage diabetes.

The doctor may discuss the risks of vaginal delivery and may recommend a cesarean section to reduce the chance of complications. It’s important to note that delivering the baby earlier does not always reduce complications, so scheduling early delivery before 39 weeks is not recommended unless there are other medical conditions beyond the baby’s size.

Cesarean Section

A cesarean section may be recommended if:

• The baby has shoulder dystocia, a condition where the baby’s shoulders get stuck behind the mother’s pelvic bone.
• The mother has diabetes, and the estimated fetal weight is more than 4 kg.
• The mother does not have diabetes, but the fetus is estimated to weigh more than 4.5 kg.

Post-Delivery

After birth, the baby will be examined for any birth injuries, low blood sugar levels (hypoglycemia), and an excess of red blood cells (polycythemia). The baby may also need neonatal resuscitation, which involves special care and attention at birth. It’s also important to monitor the baby for future risks, such as obesity and insulin resistance.

Complications

Macrosomia can lead to complications for both the mother and the baby.

Maternal Complications

• Vaginal tears: A large baby may tear the mother’s vagina or perineum, the area between the vagina and anus, during delivery.
• Postpartum hemorrhage: A large baby can prevent the uterus muscles from contracting properly during delivery, leading to excessive bleeding.
• Uterine rupture: If the mother has had a previous cesarean section or if the uterus tears during delivery, it can be life-threatening.

Fetal Complications

• Obesity
• Abnormal blood sugar levels
• Health problems in adulthood, including:
• Diabetes
• Hypertension
• Obesity
• Other metabolic disorders

Prevention

While you cannot prevent macrosomia, mothers can adopt a healthy lifestyle during pregnancy. Some studies suggest that exercise during pregnancy and a low-sugar diet can reduce the risk of macrosomia.

Tips to Prevent Macrosomia

Here are some tips to help prevent macrosomia:

• Schedule a consultation with your doctor
• If you plan to become pregnant, discuss it with your doctor. If you are obese, you may also be advised to consult a nutritionist to achieve a healthy weight before pregnancy.
• Monitor your weight
• During pregnancy, a normal weight gain is around 11–16 kg. Consult your doctor to monitor your weight.
• Control diabetes
• If you have diabetes before pregnancy or develop gestational diabetes, discuss with your doctor how to monitor and control your blood sugar levels. Managing your blood sugar is the best way to prevent diabetes-related complications during pregnancy, including macrosomia.
• Stay active: Discuss with your doctor the physical activities you can do during pregnancy. Prenatal yoga is generally recommended.

When to See a Doctor?

Macrosomia is usually detected during routine pregnancy check-ups, especially by monitoring the mother’s weight. Consult your doctor about lifestyle choices, including eating habits, exercise, and adequate rest, as well as planning for your baby’s delivery.

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