Stretch marks basically occur when the skin loses its elasticity and resilience due to over stretching. There are various reasons why your skin could undergo overstretching at various stages in life. The most important amongst them include excessive weight gain or loss and pregnancy.
As the repeated research studies have shown, stretch marks can never be fully cured once they have occurred. The cracks that have occurred in the elastic fibers below the skin can never be repaired. Hence the main aim of treatment of stretch marks is to lighten the stretch marks. There are various specialized creams which you can apply before as well as after your delivery for this purpose.
Another important step to be taken is to follow preventive care in pregnancy and at the time you are gaining or losing excess weight. There are special pre-bath creams and stretch mark creams that can be used for this.