Acne during pregnancy happens mainly because of big changes in hormones. These shifts make oil glands in the skin work harder, which clogs pores and leads to breakouts.[1][2][4]
Progesterone levels shoot up fast early in pregnancy to help the baby grow. This hormone tells the sebaceous glands, the ones that make oil, to produce more sebum. Extra oil mixes with dead skin cells and bacteria, trapping them inside hair follicles and causing pimples.[1][4]
The immune system also changes during pregnancy. It gets less strong in some ways to protect the baby, which lets bacteria grow easier and sparks more inflammation. This makes skin break out more on the face, back, chest, shoulders, neck, or even butt.[1]
Most acne shows up in the first trimester. That’s when hormones like human chorionic gonadotropin, or hCG, progesterone, and estrogen jump around a lot. Things often calm down by the third trimester as levels steady out and skin gets used to them.[1]
Other factors can make it worse. If you already had acne before, genetics play a role. Stress, bad sleep, or using products that clog pores add to the problem. Skin gets extra sensitive too, so even normal cleansers might irritate it.[2]
Not every pregnant woman gets acne the same way. About 42 percent do, but for some it gets better, while for others it flares up more.[1][3]
Sources
https://www.cosmopolitan.com/style-beauty/beauty/a69307596/pregnancy-acne/
https://www.hindustantimes.com/lifestyle/health/doctor-explains-why-acne-and-skin-changes-are-so-common-during-pregnancy-and-shares-tips-to-protect-your-skin-101765544008659.html
https://www.aol.com/articles/pregnancy-gave-cystic-acne-actually-122400849.html
https://www.drbatras.com/hormonal-acne-what-causes-it-and-how-to-treat-it
https://www.uvahealth.com/healthy-balance/skincare-in-pregnancy
