The majority of research articles were obtained by online computer search using the CINAHL and MEDLINE database.
The following key words were used: pregnancy, smoking, behavioral modification, interventions, cessation and program.
In addition to computer searches, the ancestry approach was utilized to conduct a more extensive literature search. The
ancestry approach is the process of gathering information from related publications by reviewing bibliographies of related
studies [13]. A critical appraisal was conducted to assess the quality of studies that met the inclusion criteria. The criteria
used for evaluating methodological quality was based on the (a) level of research significance, (b) characteristics of the
study sample, and (c) statistical importance of the results.