Prenatal Pediatrics: Traditional Specialty Definitions No Longer Apply
Authors: Nichols Virginia G. , Bianchi Diana W. 
Published: December 2021

These four cases illustrate different aspects of the impact of prenatal sonography on the practice of newborn medicine. The themes illustrated by these cases are summarized below.

Diagnostic Sensitivity

Prenatal sonographic diagnosis is not a precise science. The technical and cognitive limitations of this developing technology demand an appreciation of the distinction between identification and diagnosis. Although the sensitivity of the technology for detecting fetal abnormalities is quite good in many settings, the "total picture" is not always apparent in utero. This is not to deny the clinical benefit of identifying a fetus likely to require specialized postnatal care even if a precise diagnosis cannot be made, but to emphasize the difficulty of counseling a woman contemplating pregnancy termination when the underlying syndromic diagnosis for an affected fetus is not technically possible before birth. Furthermore, the sensitivity of fetal ultrasound examination appears to vary by site and type of obstetric service. The Helsinki study demonstrated a far greater ascertainment rate for fetal abnormalities in an academic practice dedicated to the provision of high-risk services when compared with a community setting,9 and the multisite RADIUS study demonstrated a low detection rate for fetal abnormalities.10

Case 1 demonstrates that while the sensitivity of sonography for a specific anatomic abnormality may be great, the comprehensive diagnosis can still be missed. In this case, the antenatal detection of a cardiac malformation triggered a postnatal echocardiogram within the first hour after birth and prompted prostaglandin infusion. Work-up and treatment of the cardiac disease would not have been the first priority had the likelihood of a lethal chromosomal abnormality been appreciated by the admitting team, who were significantly influenced by the antenatal diagnosis of structural heart disease.

Case 2 demonstrates the confusion that can be generated when an anatomic sonographic finding becomes a diagnosis without full appreciation of important details. In this case, the subtle but important prognostic difference between a hypoplastic left ventricle and a single ventricle with left ventricular morphology made an enormous difference in the predicted outcome for the infant.

In both cases 1 and 4, neonatal demise occurred but autopsy permission was denied. The absence of autopsy limits the opportunity to correlate prenatal and postnatal findings. The importance of autopsy consent should be emphasized to all involved in the perinatal care of fetuses and infants with anomalies.

Postnatal Interpretation of Prenatal Findings

The interpretation of what appear to be fetal abnormalities is often not an entirely straightforward process. The technical capabilities of fetal sonography have resulted in the discovery of a new natural history for a number of conditions that may be variants of normal fetal development, or are of minor clinical significance in childhood. Examples include hydronephrosis and choroid plexus cysts. Pediatricians cians are left to sort out which of these conditions require postnatal confirmation, which require follow-up surveillance, and which can be ignored.

The antenatal detection of conditions that are normally detected later in infancy or childhood or remain undetected due to lack of clinical symptoms can also create serious therapeutic dilemmas. For example, adrenal masses consistent with neuroblastoma can now be detected prenatally. In one study, 11 patients with prenatally diagnosed neuroblastoma had surgical resection of the tumor. In 7 of these cases, histologic studies were consistent with neuroblastoma in situ.11 The natural history of neuroblastoma in situ includes spontaneous regression. Thus, one might question whether surgical resection is truly warranted. Yet, how many parents, knowing that their fetus has an adrenal tumor, are comfortable with conservative care when surgical removal is an option at birth?

Case 3 demonstrates that prenatal diagnosis can be a double-edged sword, in that infants who are clinically well at birth can undergo extensive diagnostic testing in an attempt to elucidate prenatal findings that may no longer be relevant clinically. For example, one of the infants in Case 3 was labeled as "abnormal," and normal newborn management, including feeding, was delayed. The other twin underwent a cardiac work-up in the setting of a normal physical examination with no heart murmur. The adverse psychological effects of this "labeling" for parents and subsequent care of the child or children are unexplored. The implications of such labeling for insurance purposes have also not been addressed.

Coordination of Multidisciplinary Services: Prenatal and Postnatal Care

Optimal management of prenatal patients requires clinicians who are able to cross traditional subspecialty definitions to work as a multidisciplinary team.12-16 Unless specific mechanisms for the transfer of prenatal records are devised, perinatologists, neonatologists and pediatricians can be unaware of important information, as they were in Case 4. Even within the same institution, breaches of communication can occur both between and within specialties, particularly when prenatal records are not centralized and available to all clinicians taking care of both the mother and the infant. Although neonatologists are more likely to have opportunities for face to face communication with obstetricians and perinatologists, general pediatricians must often rely on thirdhand information transcribed into the perinatal summaries in newborn charts to ascertain prenatal findings that may have implications for postnatal management.

Prenatal diagnosis does not conclude with delivery or pregnancy termination. All these cases demonstrate the importance of coordinating prenatal and postnatal care. The logistical difficulty of this endeavor should not be underestimated. In a regionalized system of prenatal care, whereby pregnant women with suspected fetal abnormalities are referred from community sites into tertiary centers for diagnosis and delivery, then sent back to their primary care sites for follow-up, the window of opportunity for postnatal counseling can be very short. Karyotype results obtained at delivery or at pregnancy termination are rarely available before the mother leaves the tertiary center.

The postnatal management of all cases described was complicated by transfer of both mothers and infants. In Cases 1 and 4, the infants died and the mothers' care was transferred back to the referring health care sites before chromosome results were available. The twins in Case 3 were transferred to a Level II nursery before assumption of care by their pediatrician, and the infant in Case 2 was transferred from the tertiary pennatal center to an adjacent children's hospital before discharge to the care of his pediatrician. Given the expected patient movement between tertiary site and referral center, mechanisms need to be created for improved communication between health care providers. In some cases, patients may need to return to tertiary centers for appropriate postnatal counseling and work-up if these cannot be provided at the referring health care site.

Clinical Outcomes Research: The New Natural History of Malformations and Genetic Diseases

The clinical outcomes for children with specific prenatal diagnoses have not been gathered into a comprehensive shared resource suitable for use by obstetricians, pediatricians, genetic counselors, pediatric subspecialists, and pediatric surgeons. In large part, this has resulted because data on functional outcomes in children with many of these conditions have not been collected systematically. In some important areas, pediatric surgical and medical therapies have advanced so rapidly that prognostic information is quickly outdated. For example, the prognosis for surgical repair of patients with hypoplastic left heart syndrome has dramatically improved, yet this information may not be readily available to all obstetricians performing sonography and counseling parents. In other diseases our understanding of the relationship between genotype and phenotype (information that can be a major factor in decisions regarding pregnancy termination) changes so quickly that prenatal counseling demands a sophisticated and cautious appreciation of the dynamic state of this field.

Further complexity is introduced by the fact that prenatal diagnosis may in fact alter expected outcomes by permitting pediatricians to initiate therapy before symptoms appear. Infants whose duct-dependent cardiac malformations have been detected prenatally can be treated before they present with cyanosis and acidosis. Infants with unsuspected disease might be expected to present later as outpatients with more severe symptoms. In a similar fashion, infants with significant hydronephrosis detected prenatally can be treated with prophylactic antibiotics and urinary decompression, if necessary, while their undetected counterparts will be diagnosed only when they present as outpatients with urinary tract infections and diminution of renal function.