Stretch marks occur when the skin stretches rapidly due to sudden growth or weight gain. This can happen during puberty, pregnancy, rapid weight gain or loss, and muscle building. The stretching causes the middle layer of skin (dermis) to tear, allowing the deeper skin layers to show through, forming stretch marks. They initially appear as red, purple, pink, reddish-brown, or dark brown streaks, depending on your skin colour, and over time, they may fade to a lighter, more silvery shade.

Stretch marks during pregnancy typically appear during the second and third trimesters, as this is when the most significant skin stretching occurs due to the growing baby. For most women, this could start anywhere from the 6th month of pregnancy onwards. However, the timing can vary widely depending on the individual, their skin elasticity, and how quickly they gain weight during pregnancy.

The best time to start using stretch mark creams is as soon as you anticipate rapid stretching of the skin, such as early in pregnancy. For pregnancy, starting in the first or early second trimester is often recommended. The goal is to keep the skin well-hydrated and supple, potentially making it more elastic and able to stretch without tearing. However, it's important to note that genetics also play a significant role in whether you'll develop stretch marks, and no product can guarantee prevention.

Pregnancy stretch marks might not disappear completely, but they often become less noticeable over time. After pregnancy, the marks can fade to a lighter colour and become less pronounced. The extent to which they fade can depend on various factors, including skin tone, diet, hydration, and genetics. While some treatments and creams can help reduce their appearance, there's no universal cure for stretch marks.