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linea nigra

Linea nigra

Linea nigra also known as linea gravidarum, is the medical term for the dark vertical line that appears on a pregnant woman’s belly during pregnancy and it can be one of the earliest indicators of pregnancy 1. Linea nigra is also known as the ‘pregnancy line’. It can reappear with subsequent pregnancies 2. Linea nigra is darker in color than the surrounding skin, and it extends from the top of the belly down to the pubic hair, running through the belly button, but can run all the way up to the chest and usually disappears a few months after delivery. This is often accompanied by the displacement of the umbilicus to the right, known as the “ligamentum teres sign” 3. It is hypothesized that folic acid reduces the formation of linea nigra seen in foods such as leafy green vegetables, oranges, and whole wheat bread 1.

Linea nigra can occur in anyone of any race, but tends to be more obvious in women of color. In a population-based study of Nigerians, linea nigra was found to be present in both males and females. For males, incidence peaked at 40% in the 11- to 15-year-old age group, whereas in females, incidence was highest in the 16- to 30-year-old group, in which 85% were affected. Pregnant women were 60 times more likely than nonpregnant women to have linea nigra.

The reason for the development of the dark line during pregnancy is probably related to hormonal changes; after pregnancy, the linea nigra usually disappears after delivery. The darker your original skin color, the longer this will take, so it may take a year for the linea nigra to go away in some women. Sometimes babies, who share their mother’s hormones before birth, will be born with a similar line that also fades over time.

No treatment is needed for linea nigra. The line on your belly during pregnancy should slowly fade after your baby is born. No medical care is needed to treat linea nigra. Continue to take your prenatal vitamins and otherwise follow routine prenatal care guidelines. However, sun exposure can cause it to become darker or take longer to go away, so use a sunblock (at least SPF 30+) or keep your belly covered.

Linea nigra cause

Linea nigra is a physiological form of hyperpigmentation commonly seen on the abdomen in pregnant women and noticed in the second or third trimester 1. Linea nigra appears to be a consequence of increased production of melanin secondary to increased estrogen. In 90% of pregnant women, hyperpigmentation of some type is seen, including darkening of the areolae, ephelides, scars, or melasma. Fair-skinned women develop hyperpigmentation less often than women with darker pigmentation. After birth, the line fades over time, but it may never disappear entirely.

Linea nigra signs and symptoms

The line of linea nigra is darker than the surrounding skin and approximately a centimeter in width. It can be quite dark or fairly light in color. Women can be reassured that linea nigra has no adverse effect on pregnancy outcomes, and medical treatment is not required 4.

Linea nigra treatment

No treatment is needed for linea nigra. The line should slowly fade after your baby is born. No medical care is needed to treat linea nigra. Continue to take your prenatal vitamins and otherwise follow routine prenatal care guidelines. However, sun exposure can cause it to become darker or take longer to go away, so use a sunblock (at least SPF 30+) or keep your belly covered.

It has been suggested that folic acid reduces the formation of linea nigra. Folic acid can be found in foods such as leafy green vegetables, oranges and whole wheat bread 1. Bleaching has been used in some cases, with unsatisfactory results 5.

References
  1. Vora RV, Gupta R, Mehta MJ, Chaudhari AH, Pilani AP, Patel N. Pregnancy and skin. J Family Med Prim Care. 2014;3(4):318–324. doi:10.4103/2249-4863.148099 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311336
  2. Bieber AK, Martires KJ, Stein JA, Grant-Kels JM, Driscoll MS, Pomeranz MK. Pigmentation and pregnancy: knowing what is normal. Obstet Gynecol 2017; 129: 168–73. DOI: 10.1097/AOG.0000000000001806
  3. Kar S, Krishnan A, Shivkumar PV. Pregnancy and skin. J Obstet Gynecol India. 2012;62:268–75.
  4. Massinde A, Ntubika S, Magoma M. Extensive hyperpigmentation during pregnancy: a case report. J Med Case Rep 2011; 5: 464. DOI: 10.1186/1752-1947-5-464.
  5. Hyperpigmentation and melasma. In: Ingber A. Obstetric dermatology: a practical guide. Berlin/Heidelberg: Springer-Verlag, 2009: 7–18.
Health Jade Team

The author Health Jade Team

Health Jade