Macrosomia is the medical term for a fetus whose estimated weight exceeds 4,000 to 4,500 grams, depending on the clinical definition used, at or near term. A large baby creates specific delivery risks that are well-understood by the obstetric community and that require specific management decisions by the clinical team. When those management decisions are not made, or when they are made incorrectly, the result can be shoulder dystocia, one of the most dangerous obstetric emergencies, and the catastrophic injuries to the infant and mother that this complication can produce when it is not handled according to established protocols.
A macrosomia birth injury malpractice claim examines whether the clinical team identified the risk of fetal macrosomia, whether they communicated that risk to the mother, whether the delivery plan accounted for the size-related risks, and whether the team’s response when complications arose met the standard of care for managing those specific complications. The answers to these questions live in the prenatal record, the delivery record, and the documentation of any discussions about delivery planning that occurred before and during labor.
How Macrosomia Creates Foreseeable Delivery Risk
A large baby creates risk at the moment of delivery when the widest part of the baby’s body, typically the shoulders, must pass through the maternal pelvis. When the baby’s shoulders are too wide to pass through the pelvis without difficulty, shoulder dystocia occurs. The baby’s anterior shoulder becomes impacted behind the maternal pubic symphysis, and the normal traction used to complete delivery cannot free the shoulder without risking serious injury to the brachial plexus nerves that run through the baby’s shoulder and neck.
Shoulder dystocia is a recognized obstetric emergency with documented associations with fetal macrosomia, maternal diabetes, prior shoulder dystocia, and certain labor patterns. Its occurrence rate increases substantially as estimated fetal weight increases. Healthcare providers who deliver babies in high-risk categories are trained in the specific maneuvers, including McRoberts maneuver, suprapubic pressure, and rotational maneuvers, designed to free the impacted shoulder without applying the downward traction that causes brachial plexus injury.
What the Standard of Care Requires When Macrosomia Is Identified
The standard of care when macrosomia is identified through prenatal ultrasound or clinical examination includes several specific obligations:
- Counseling about delivery options: When estimated fetal weight indicates significant macrosomia, particularly in the presence of additional risk factors such as maternal diabetes or prior shoulder dystocia, the standard of care requires that the provider discuss the risks of attempted vaginal delivery and offer elective cesarean section as an alternative. This discussion must occur in enough time before delivery for the mother to make an informed choice
- Intrapartum monitoring for labor dystocia: A prolonged or dysfunctional labor pattern in a macrosomic baby is an indication that cephalopelvic disproportion may exist, meaning the baby is too large for the pelvis. Continuing to allow labor to progress in the presence of significant dystocia without reassessing the delivery plan may fall below the standard
- Appropriate response to shoulder dystocia: When shoulder dystocia occurs, the response must be immediate, coordinated, and follow the established sequence of maneuvers that are most effective at freeing the impacted shoulder without causing injury. Applying fundal pressure, a maneuver that is specifically contraindicated in shoulder dystocia because it worsens the impaction, is a clear departure from the standard that is associated with some of the worst brachial plexus injuries
The Injuries That Macrosomia Mismanagement Produces
The most common serious injuries resulting from macrosomia mismanagement and shoulder dystocia include:
- Brachial plexus injury and Erb’s palsy: Stretching or tearing of the brachial plexus nerve bundle produces weakness or paralysis of the affected arm, ranging from temporary neuropraxia that resolves with therapy to complete avulsion injuries requiring microsurgical repair. Erb’s palsy, which involves injury to the upper brachial plexus, is the most common pattern and produces the characteristic arm position with the elbow extended, forearm pronated, and wrist flexed
- Hypoxic brain injury from prolonged impaction: When shoulder dystocia is not resolved promptly, the baby’s cord may be compressed and oxygen delivery interrupted. Prolonged impaction that exceeds five minutes significantly increases the risk of fetal asphyxia and the brain injury that follows
- Clavicle and humerus fractures: Fractures of the clavicle and humerus can occur during the maneuvers to resolve shoulder dystocia. Some fractures may be unavoidable in the process of resolving the emergency, but fractures associated with excessive traction in the wrong direction are associated with departures from the standard
Building a macrosomia malpractice case requires obstetric experts who can review the prenatal record to establish what the clinical team knew about the baby’s size and when they knew it, examine the delivery record for the specific maneuvers used and their sequence, and assess whether the outcomes were the result of appropriate emergency management or of departures from the standard that caused preventable injury. Working with an experienced macrosomia birth injury lawyer gives families access to that expert analysis and to the legal representation that translates it into a viable claim for the injuries the mismanagement produced.
