The influence of maternal smoking and LBW incidence is studied. Detailed smoking history is taken at first antenatal visit and smoking history and bih weight were studied later. The type of study is -: (A) Retrospective coha study, (B) Cross sectional study, (C) Clinical trial, (D) Prospective coho study
Answer is D. Ans. is 'd' i.e. Prospective coho study