Researchers conducted a study in 2010 to examine the effects of methamphetamine use during pregnancy (exposure) on birth outcomes (outcome). They used medical records for pregnancies that occurred between the years of 1990 and 2009 to identify methamphetamine exposed and unexposed pregnancies. They then linked these records to infant medical records to identify preterm and low birth-weight infants based on ICD-10 codes. What type of study design was used