Causal hypothesis for some congenital anomalies.

Area of Science:

• Perinatology
• Developmental Pediatrics
• Genetics

Background:

• Congenital anomalies are a leading cause of fetal/neonatal death and childhood morbidity.
• While some causes are known (genetics, teratogens), many congenital anomalies and cases of cerebral palsy have unknown etiologies.
• Monochorionic placentation in monozygotic twins presents unique risks.

Purpose of the Study:

• To propose a hypothesis linking a significant proportion of unexplained congenital anomalies and cerebral palsy to unrecognized vanishing twins in monochorionic pregnancies.
• To elucidate the pathological mechanism of hemodynamic instability and feto-fetal transfusion in such cases.
• To explain the variable clinical outcomes based on severity, affected organs, and gestational timing.

Main Methods:

• Hypothesis-driven theoretical framework.
• Review of pathological mechanisms in monochorionic twin pregnancies.
• Analysis of clinical presentations and outcomes of congenital anomalies and cerebral palsy.

Main Results:

• A proposed mechanism involving acute feto-fetal transfusion in early monochorionic monozygotic conceptions.
• Hemodynamic instability leading to ischemic organ impairment in one or both conceptuses.
• Variable clinical manifestations including fetal/infant death, congenital anomalies, or normal development.

Conclusions:

• Early, unrecognized loss of a co-twin in monochorionic monozygotic pregnancies is a potential cause of congenital anomalies and cerebral palsy.
• The severity, affected organs, and timing of feto-fetal transfusion influence the clinical outcome.
• This hypothesis offers a unifying explanation for a subset of previously unexplained neurodevelopmental and congenital disorders.