Congenital malformations in twins: epidemiologic survey

Area of Science:

• Reproductive Medicine
• Genetics
• Developmental Biology

Background:

• Congenital malformations represent a significant public health concern.
• Twin pregnancies present unique risks and outcomes compared to singleton pregnancies.
• Understanding the etiology and patterns of malformations in twins is crucial for improved prenatal care and counseling.

Purpose of the Study:

• To investigate the frequency and types of congenital malformations in twins compared to singletons.
• To explore differences in malformation rates between monozygotic (MZ) and dizygotic (DZ) twins.
• To examine the influence of zygosity, sex, and amnionicity on congenital malformation occurrence in twins.

Main Methods:

• Analysis of data from the Collaborative Perinatal Project, including 1195 twin pairs.
• Comparison of malformation rates between twins and singletons from the same population.
• Assessment of malformation concordance rates between MZ and DZ twins.

Main Results:

• Twins exhibited a higher frequency of malformations (18.33%) than singletons, primarily driven by MZ twins.
• Increased prevalence of cardiovascular and alimentary tract malformations was observed in twins.
• Monoamniotic twins showed higher mortality and significantly more congenital malformations than diamniotic twins.
• Concordance rates for malformations were significantly higher in MZ twins compared to DZ twins, especially for musculoskeletal defects.

Conclusions:

• Zygosity is a key factor influencing congenital malformation risk in twins.
• Specific malformations, including cardiovascular and alimentary tract anomalies, are disproportionately common in twin gestations.
• Monoamniotic twins face increased risks for complications and malformations, highlighting the importance of careful monitoring.