The observational study is one of the commonly used types of study designs to answer questions or evaluate relationships between variables. Depending on the outcome determination, the observational study can be case control, cross-sectional, or cohort study. In our research, we designed that study as a retrospective cohort study to evaluate whether incorporation of amniotic fluid analysis into clinical assessment may improve clinical outcomes in pregnancies suspected of clinical chorioamnionitis. This study could have been designed either as a retrospective or prospective cohort study. We present why we chose the retrospective cohort design to find an answer to our research question. Besides discussing advantages and red flags (like confounding and bias-related errors) of that study type, we explain how we conducted this study, including the type of analysis we used, while dealing with these challenges.