Pregnant women wait for their turn to undergo a Cesarean section (c-section) procedure at the Santa Ana public maternity hospital in Caracas October 19, 2011. The world's population will reach seven billion on October 31, according to projections by the United Nations. Picture taken October 19, 2011. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: HEALTH SOCIETY TPX IMAGES OF THE DAY)