“…[18,21,28,44,45] Twenty-two of the selected studies were hospital based cohort studies, [18-21, 25-28, 31-34, 36-41, 44, 46, 51, 52] while twelve of the selected studies were population based cohort studies. [17,22,29,30,35,42,43,45,[47][48][49][50] Fourteen studies provided data on exclusively IVF procedures, [17, 19-21, 27-29, 32, 35, 39, 43, 44, 46, 47] and six studies on ICSI procedures. [17,18,27,35,44,47] Five studies reported data on fresh embryo transfer and frozen embryo transfer.…”