Fetal macrosomia refers to a health condition in which the fetus grows considerably more than average in the uterus of a mother. Normally, the average weight of newborns would be seven and a half pounds. When it comes to babies affected by fetal macrosomia, their weight would be more than 8 pounds and 13 ounces, irrespective of their gestational age. Note that many studies conducted in the field claim that more than 9% of newborns in the world suffer from fetal macrosomia disorder.

The risk related to this health issue tends to get higher with increase in the weight of the baby. The disorder can become life-threatening for both the mother and the baby if the newborn weighs more than nine pounds. Apart from that, vaginal delivery of babies with fetal macrosomia is likely to put them at higher risk of injuries, and the disorder can also result in many other health issues post childbirth.

The Symptoms

Unfortunately, it is really difficult to detect fetal macrosomia during the pregnancy period. However, there are certain symptoms which may indicate abnormal body weight gain by a fetus. Some of those possible signs are listed below.

Large Fundal Height

The Fundal height is the distance between the uterus and the pubic bone. During the prenatal checkup, doctors will usually measure this and if it is larger than usual, that could be a sign of fetal macrosomia.

Excessive Amniotic Fluid

In the uterus, babies would be secured by an amniotic sac which would be filled with amniotic fluid. This fluid surrounds and protects the child during pregnancy. If the amount of amniotic fluid is more than usual, it can be a symptom of underlying fetal macrosomia disorder. Note that the amount of amniotic fluid will be proportional to the urine output of the baby, and of course, the urine output of larger babies would be higher.


Sadly, the potential cause of fetal macrosomia has not yet been discovered. However, some of the main factors which can cause fetal macrosomia are genetic in nature, and some are also health conditions in the mother such as diabetes and obesity. It is extremely rare for the health issues of the baby to lead to increased fetal growth.

Risk Factors

There are many factors that can put your baby at higher risk of fetal macrosomia, some of which can be addressed by proper medication and lifestyle changes, whereas the others cannot be controlled. Some risk factors are as follows.

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    About the Author

    Dr. Ghassan M. Al-Jazayrly, MD

    A graduate of University of Aleppo Faculty of Medicine, Dr. Al-Jazayrly or, as he is colloquially known: Dr. AJ, is an oncologist and hematologist of a Complete Care Community Health Center (CCCHC) with more than 36 years of experience. In recent years, he’s been involved with a non profit organization known as Every Woman Counts (EWC) which provides free breast and cervical cancer screening and diagnostic services to California’s underserved populations in order to eliminate health disparities for low-income individuals.

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