Introduction: Amniotic band syndrome (ABS) includes limb deficiencies accompanied by fibrous strands originating from the amniotic lining. Terminal transverse limb deficiencies (TTLD) appear to be similar but lack fibrous strands. Both are hypothesized to result from vascular disruption. For ABS, limb deficiencies are considered secondary to amnion rupture. We explored an alternative possibility-that TTLD is the primary defect and ABS is secondary.
Methods: Using data from the National Birth Defects Prevention Study, we expanded on a previous study. We examined smoking, alcohol, and medications categorized by indicated vasoactivity as markers of vascular disruption. Logistic regression models with Firth's penalized likelihood were used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).
Results: Use of bronchodilators and aspirin appeared to increase the risk of ABS, while decongestants and nonaspirin NSAIDs increased the risk of TTLD. The risk of ABS was markedly increased in cases reporting combinations of vasoactive exposures, particularly alcohol and aspirin (aOR 3.7, 95% CI 1.6, 7.8), and alcohol and bronchodilators (aOR 3.4, 95% CI 1.4, 7.5). Increased risk of TTLD due to combinations of vasoactive exposures was only observed for smoking and decongestants (aOR 2.3, 95% CI 1.4, 3.6).
Conclusions: Exposures associated with increased risk of ABS had no apparent association with TTLD, supporting previous evidence that these may be distinct phenotypes. ABS appears to be associated with combined exposures with vasodilation properties, such as alcohol and bronchodilators, while increased risk of TTLD may be associated with smoking and decongestants, both vasoconstrictive exposures.
Keywords: amniotic band syndrome; aspirin; bronchodilators; limb deformities; nasal decongestants; nonsteroidal anti-inflammatory agents.
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