In antenatal care, it is important to capture illicit substance use by the expectant mother so that early interventions can be implemented to prevent damaging complications to the fetus and the baby - please see the following link from Medical Faculty of University of New South Wales for supporting rationale:
https://ndarc.med.unsw.edu.au/sites/default/files/ndarc/resources/Supporting%20Pregnant%20Women%20who%20use%20Alcohol%20or%20Other%20Drugs%20Resource.pdf

The MedicationStatement / MedicationUsage resource currently lack a structure to support capturing of such relevant clinical information.

This request is to add a proposed structure to MedicationStatement / MedicationUsage resource to support this clinical requirement:
MedicationStatemet.relatedClinicalInfo 0..* Reference(Observation | Condition)