Linea nigra
A brownish midline abdominal streak linked to hormonal changes.
Linea nigra is a dark line that appears on the abdomen during pregnancy, typically running from the pubic area to the bellybutton.[1][2] It is usually about 0.25 to 0.5 inches wide and darkens as pregnancy advances.[2] Following childbirth, the linea nigra typically disappears over a period of a few months.[3][2]
Quick Facts
- Width
- approximately 1 cm (0.4 in)
- Typical extent
- from pubis to umbilicus, variably to upper abdomen
- Prevalence peak age
- 11 to 15 years
- Common associated conditions
- melasma, darkened nipples
Facts from the source article.
Key facts and history
The term "linea nigra" is Latin for "black line"[1] It is colloquially known as the pregnancy line.[1] The line is a brownish streak about one centimeter wide.[1] This hormone increase also causes melasma and darkened nipples.[4]
The pre-existing white line on all humans is called linea alba.[2] People with darker skin pigmentation experience linea nigra more frequently.[3][2] This brownish line, about one centimeter wide, runs vertically from the pubic bone up to the navel.[1] In some cases, the line can continue upward from the pubis into the upper abdomen.[1]
The placenta's increased output of melanocyte-stimulating hormone triggers the development of this condition.[4][5]
What the research sources say
The Pregmed 2014 article states that linea nigra appears in the second and third trimesters due to rising hormone levels.[2] The same source notes that belonging to a dark-skinned ethnic group increases the chance of hyperpigmentation symptoms like linea nigra.[2]
References
- Wikipedia, "Linea nigra" (CC BY-SA 4.0), which cites: She Knows Network: "What's that line? All about linea nigra" (original not read by us) en.wikipedia.org
- "Linea nigra and pregnancy", Pregmed, 2014-11-15. facts only, no text reused. pregmed.org
- Wikipedia, "Linea nigra" (CC BY-SA 4.0), which cites: "Linea nigra and pregnancy", Pregmed, 2014-11-15 (we also read that source) en.wikipedia.org
- Wikipedia, "Linea nigra" (CC BY-SA 4.0), which cites: Heffner, "The Reproductive System at a Glance", Wiley-Blackwell, 2010, p. 51 (we also read that source) en.wikipedia.org
- Open Library record, ISBN 9781405194525 ("The reproductive system at a glance"). CC0 (metadata); book content not read. openlibrary.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Linea nigra (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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