Fetal Macrosomia

Fetal macrosomia is an obstetric condition that describes a newborn with a higher than normal birth weight. Macrosomia is associated with potentially life-threatening complications for the baby and increases the baby’s risk of birth injury and birth complications.

According to the American College of Obstetrics and Gynecology (ACOG), babies with a birth weight equal to or greater than the 90th percentile for their gestational age are described as “large for gestational age” (LGA).

Note: “90th percentile” means the baby’s birth weight is higher than 90% of the babies of that age.

The ACOG goes on to define “macrosomia” as growth of the baby beyond a specified absolute birth weight. In general, 4,000 g (8 lb, 13 oz) to 4,500 g (9 lb, 15 oz) of absolute birth weight is recognized as macrosomia, irrespective of the baby’s gestational age. Importantly though, there is no universally accepted absolute birth weight figure that defines macrosomia.

The 2017 National Vital Statistics Report showed that about 7.8% of the babies born in the US had a birth weight in excess of 4,000 g, indicating macrosomia.

There are serious birth complications that can occur if a baby with macrosomia is delivered vaginally. The baby may be too large to fit down the birth canal causing prolonged or arrested labor that can cause fetal distress or complications right at birth including shoulder dystocia that increases the risk of use of vacuum extractors and forceps that can cause birth complications.

During pregnancy, an ultrasound scan or fundal height measurement (measuring the distance between the top of the uterus to the pubic bone) can effectively diagnose fetal macrosomia. This is the primary method and tool used by doctors to determine if a baby suffers from the birth complication of macrosomia.

Polyhydramnios (the presence of excessive amniotic fluid) may also indicate a larger than average size of the baby. The principle behind this indicator is that the volume of amniotic fluid is correlated to the baby’s urine output. A baby with macrosomia is likely to produce increased urine output, contributing to excessive amniotic fluid.

Obstetricians should also note other risk factors that increase the suspicion of macrosomia. These may include a prior history of macrosomia in earlier pregnancies, gestational diabetes, maternal obesity, post term pregnancy (over 40 weeks), maternal age over 35 years, and multiple previous pregnancies. When a combination of some of these risk factors exists, the medical providers should suspect macrosomia and determine whether vaginal delivery will increase the risk of birth injury.

Close medical observation and monitoring during pregnancy is important in a high-risk pregnancy when fetal macrosomia is suspected.

Medical History is important to diagnose Macrosomia

The obstetrician or maternal fetal medicine specialists (and their nurses) should obtain a detailed medical history of the expectant mother during the initial and subsequent prenatal visits. The key elements of the history must include:

• First day of the LMP (last menstrual period)
• Gestational age
• Pre-pregnancy weight
• History of immunization
• Gravidity – the number of previous pregnancies
• Parity – the number of times the patient carried pregnancies to a viable gestational age
• Mode of past deliveries and past birth complications
• History of macrosomic babies
• Baby’s gender
• Past or current medical conditions, such as obesity, type 2 diabetes, Polyhydramnios, and rhesus factor (RH) incompatibility (the blood of the baby and the mother are incompatible)

Physical Examination

A comprehensive physical examination of the expectant mother should include body weight monitoring at each visit during pregnancy. The weight measurements should be compared with the standard IOM (the US Institute of Medicine) guidelines as follows:

• When the expectant mother’s body mass index (BMI) is below 18 – the standard range of weight gain is 28 to 40 pounds
• When the BMI ranges from 18 to 24.9 – the standard range of weight gain is 25 to 35 pounds
• When the BMI ranges from 25 to 29.9 – the standard range of weight gain is 15 to 25 pounds
• When the BMI is higher than 30 – the standard range of weight gain is 11 to 20 pounds

At the time of body weight measurement, if any deviations from this standard range are found, the medical provider should recommend a repeat abdominal ultrasound exam along with fundal height measurement and its correlation with the gestational age. This should be followed by the medical provider’s performance of the Leopold maneuver to determine the fetal position and manually assess/predict term fetal weight.

The Leopold maneuvers are used to palpate the gravid uterus systematically. This method of abdominal palpation is of low cost, easy to perform, and non-invasive. It is used to determine the position, presentation, and engagement of the fetus in utero.

While an ultrasound exam, fundal height measurement, or the Leopold maneuver in isolation may not help diagnose the condition, when they are reviewed in combination as well as in the context of other risk factors, it may be possible to effectively diagnose fetal macrosomia.

Maternal Evaluation

Maternal hyperglycemia (high blood sugar) has been identified as one of the important causes of macrosomia. The expectant mother should be screened for this condition with the following tests:

1-hour 50 g glucose challenge test should be performed between 24 and 28 weeks of pregnancy. Values greater than 190 mg/dL will confirm a diagnosis of gestational diabetes. Values between 140 and 190 mg/dL are also considered abnormal and will lead to a 3-hour 100 g glucose tolerance test for the confirmation of gestational diabetes.

Other maternal evaluations must include complete blood count (CBC), blood pressure monitoring, kidney and liver function tests (KFT and LFT), lipid profile, and urinalysis, apart from routine abdominal ultrasound exams.

Fetal Evaluation

A baby with suspected macrosomia is at a risk of serious metabolic disorders, including hypoglycemia (low blood sugar) and fetal acidosis. If left undiagnosed or untreated, these conditions may sometimes contribute to hypoxic-ischemic encephalopathy (HIE) and eventually result in cerebral palsy. In-utero babies with the risk of macrosomia should be closely monitored with fetal heart rate monitoring devices.

Immediately after the baby’s delivery, laboratory tests must be performed to check the following parameters:

• Glucose levels: A baby born to a diabetic mother may develop hypoglycemia following sudden removal from the in-utero glucose-rich environment.
• Bilirubin levels: High levels of bilirubin in the baby’s blood can cause brain damage known as kernicterus (newborn jaundice), which can lead to cerebral palsy.
• Magnesium and Calcium levels: Hypomagnesemia (low levels of magnesium in the blood) in newborns can cause neonatal seizures, while hypocalcemia (low levels of calcium in the blood) can cause lethargy and tremors.

Clinical evaluation for respiratory distress syndrome (RDS) after birth is also necessary because the risk of transient tachypnea of the newborn (respiratory disorder) and fetal distress related to meconium aspiration syndrome (MAS) is up to three times higher in babies with macrosomia.

Improved glycemic control (blood sugar control) in expectant mothers with gestational diabetes or pre-pregnancy diabetes with appropriate medical interventions can reduce the risk of birth complications related to fetal macrosomia.

Aerobic and muscle strength exercises should be encouraged during pregnancy (where exercise is not contra-indicated) to lower the risk of macrosomia. A registered dietitian should also be involved from an early stage in the care of an expectant mother with a suspected macrosomic pregnancy.

The ACOG recommends an elective cesarean section in the following conditions with a macrosomic baby:

• a. Baby’s estimated weight is at least 4,500 g and the expectant mother is diagnosed with gestational or pre-existing diabetes; or
• b. Baby’s estimated weight is at least 5,000 g and the expectant mother has no diabetes.

Assisted vaginal delivery with vacuum devices or forceps should be performed with abundant caution when fetal macrosomia is diagnosed or suspected. The medical team should be prepared to perform an emergency cesarean section if there is significant risk of birth injury with vaginal delivery.

Effective coordination and communication among the inter-professional team members, including obstetric providers, neonatologists, anesthesiologists, endocrinologists, pediatricians, mental health counselors, and registered dietitians is vital to the successful management of a macrosomic pregnancy.

Parents whose children suffer from macrosomia related birth injuries or birth complications want and deserve answers as to cause of their child’s injury and whether mistakes by the doctors and nurses contributed to the injury.

• Were there signs of macrosomia during the pregnancy, labor, and delivery process, or presence of risk factors, which were either not recognized or properly treated?
• Did the medical team fail to order a series of tests to diagnose macrosomia in a timely manner?
• Was the decision to perform a cesarean delivery delayed?
• During the labor and delivery, were there clear indications that their baby was suffering from fetal distress, but appropriate actions were not taken by the obstetrician or nurses?
• Did the neonatal resuscitation team delay in providing important breathing support after birth?
• Were serious neonatal conditions like hypoglycemia or jaundice missed or treated incorrectly?
• Should brain cooling (also called “hypothermia therapy”) have been offered to your baby, but the doctors and nurses failed to perform the appropriate tests or ignored the results of the tests?

The hard working Macrosomia birth injury lawyers at Miller Weisbrod Olesky, who have been through the legal minefields before, will help you determine if mistakes of the medical providers caused a birth injury to your child, including Hypoxic-Ischemic Encephalopathy (HIE) or cerebral palsy. Our profound and proven birth injury attorneys have represented families all over the United States in their time of need after a birth injury. We use our experience and expertise to obtain you and your child a medical malpractice settlement that will help provide specialized medical therapy to maximize the quality of life and independence of your child throughout their life.

Sometimes families are reluctant to contact a medical malpractice lawyer. It’s also not uncommon for parents to feel overwhelmed by the responsibilities they encounter in caring for their injured child and worried that they will not be able to help out in a lawsuit involving their child’s birth injury. Our birth injury attorneys and nursing staff will address these hesitations and concerns, so you can focus on your child and maximizing their care.

Most birth injury law firms will employ one or two nurses to assist the review of cases and medical research. But Miller Weisbrod Olesky offers an unmatched number of nurses and nurse-attorney employees support to both the birth injury attorneys and our clients.

Our team of registered nursing staff and nurse-attorneys bring a deep level of medical and personal insight to every client’s case. Our nursing team includes both an experienced labor and delivery nurse as well as an ICU nurse. Working closely with the rest of the team, they investigate the reasons behind a birth injury and how medical professionals breached their standard of care.

The only way to find out if you have a birth injury case is to talk to a lawyer experienced in birth injury lawsuits. It’s not uncommon that a birth related complication results in a preventable birth injury, including cerebral palsy, but it takes a detailed expert review by a birth injury attorney of the medical records from your child’s birth to determine if the birth injury was the result of medical malpractice.

At Miller Weisbrod Olesky, a team of committed lawyers, nurses and paralegals uses our detailed medical negligence case review process to assess your child’s potential birth injury case. We start by learning more about you and your child and the status of meeting/missing developmental milestones. Then we gather medical records to determine what happened before, during, and after your delivery. We call in skilled medical experts who review your records and let us know if they think medical errors could have caused your child’s injuries.

If we feel medical negligence caused or contributed to your child’s injuries, we meet with you to discuss how you can receive compensation from the medical professionals who made the errors. Our birth injury attorneys have recovered millions of dollars in settlements for families of children that have suffered a birth injury.

At no point in our legal intake process will we ask you to pay anything. The medical review of your case and the consultation are free. We only receive payment when you do.