neck pigmentation in pregnancy

The neck pigmentation you’re observing is actually pretty common during pregnancy and usually not something serious. It sounds like what’s called “melasma” or “chloasma” which is sometimes known as the “mask of pregnancy.” This type of hyperpigmentation is triggered by hormonal changes during pregnancy, specifically an increase in estrogen and progesterone, which enhance melanin production in your skin. The fact it’s also showing under your arms and face is not unusual—these are areas where the skin is naturally more pigmented and can become even more so during pregnancy. Your OB is likely correct in pointing to melanin as the cause. Generally, this pigmentation is harmless and fades a few months after delivery. However, I understand it can be unsettling when it’s unexpected. You can keep an eye on the pigmentation and look for any unusual changes, like itchiness, rapid spreading, or development of new patches that seem different in color. If any symptoms like these occur, or if your comfort level about the changes reaches a concern, setting up a follow-up with your dermatologist or OB could be a good idea for peace of mind. For the time being, protect your skin by wearing broad-spectrum sunscreen daily, even if staying indoors, as UV exposure can accentuate pigmentation. There’s typically no need for medical treatment unless it’s a cosmetic concern for you after delivery. In that case, dermatological options like topical creams or procedures can be discussed after consulting your healthcare provider.