Many different study designs are used in epidemiological research. State which study design is being used in each of the scenarios described below. Your choices are as follows:

EXPERIMENTAL STUDY

RETROSPECTIVE COHORT STUDY

PROSPECTIVE COHORT STUDY

CASE-CONTROL STUDY

CROSS-SECTIONAL STUDY

ECOLOGICAL STUDY

a. A hospital-based study of antidepressant medication use during pregnancy and the risk of cleft lip in the offspring. Investigators are currently enrolling two groups of women: those who just delivered an infant with a cleft lip and a sample of women who just delivered an infant without any birth defects. The presence or absence of birth defects is based on the newborn physical exam. All mothers are being interviewed to determine their use of antidepressant medications during the pregnancy that just ended.

The study design that better fits is the "Retrospective Cohort Study", consisting of a comparison between 2 groups, one exposed to certain circumstance and the other one excempted from it, to detemine the rate, occurrence or impact of such circumstance on a disease;

RCS aka"Historic Cohort Study", involves repeated observations of certain elements or factors by sampling groups that share common traits, and applied at intervals over time.

Explanation: