Why do I get a dark vertical line on my stomach even though I am definitely not pregnant?
1. Introduction The dark vertical line on the stomach, known clinically as linea nigra, occurs due to a localized increase in melanin production stimulated by fluctuating hormone levels, specifically estrogen and melanocyte-stimulating hormone. While commonly associated with pregnancy, this hyperpigmentation can be triggered in non-pregnant individuals by hormonal contraceptives, polycystic ovary syndrome, or natural endocrine … Read more