I used this cream when I was pregnant with my daughter and did not get one stretch mark HOWEVER I already had stretch marks on my hips just from losing and gaining weight (the same 10 - 20 pounds

) before I was pregnant. I have noticed that those marks (hips) are not as obvious but they are still there despite heavy use of Trilastin.
When I was pregnant I used Trilastin mainly & Pure Vitamin E Oil -- I slathered this on twice a day and even used some other brands (Magia Bella, Mustela, Mother's Special Blend) of stretch mark cream/lotion/oils in between the twice daily regimen. I was determined not to have stretch marks as it runs in our family in a major way.
Who knows what was the actually "trick" was but I would buy it again.