Parity (biology)

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For other uses of the term in other fields, see parity.

In biology, parity is a technical term that refers to the number of times a female has given birth.[1]

It can lead to some ambiguity for events occurring between 20 and 24 weeks,[2] and for multiple pregnancies.[3]

Terminology[edit]

In biology, the term gravid (from Latin gravid-us,-a, burdened, heavy[4]) is used to describe the condition of an animal (most commonly fish or reptiles) when carrying eggs internally. For example, Astatotilapia burtoni females can transform between reproductive states, one of which is gravid, and the other non-gravid. In entomology it describes a mated female insect.

In agriculture, parity is a factor in productivity in domestic animals kept for milk production. Animals that have given birth once are described as primiparous; those that have given birth more than once are described as pluriparous.[5][6]

In human medicine, gravidity refers to the number of times a woman has been pregnant,[1] regardless of whether the pregnancies were interrupted or resulted in a live birth.

  • A gravida is a pregnant woman.
  • A nulligravida or gravida 0 is a woman who has never been pregnant.
  • A primigravida or gravida 1 is a woman who is pregnant for the first time or has been pregnant one time.
  • A multigravida or more specifically a gravida 2 (also secundigravida), gravida 3, and so on, is a woman who has been pregnant more than one time.
  • An elderly primigravida is a woman in her first pregnancy, who is at least 35 years old. This term is becoming less common as it may be considered offensive.[7]

The term gravida is generally coupled with para (and occasionally additional terms) to indicate more details of the woman's obstetric history.[2]

Enumeration[edit]

A woman's obstetrical history is recorded as: number of pregnancies, known as gravida and number of pregnancies carried to viable gestational age , known as parity. Viable gestational age varies from region to region, for example in the UK it is considered to be 24 weeks whilst in the USA 23 weeks is considered viable.

  • A woman who has never completed a pregnancy beyond 20 weeks is also referred to as being nulliparous, a nullipara or para 0.[8]
  • A woman who has given birth one or more times is referred to as para 1, para 2, para 3 and so on.
  • A woman who has given birth once before is primiparous, and is referred to as a primipara or primip.
  • A woman who has given birth two or more times is multiparous and is called a multip.
  • Grand multipara refers to a (grand multiparous) woman who has given birth five or more times.

Gravida/para/abortus[edit]

Gravida/para/abortus (GPA), or sometimes just gravida/para (GP), is a shorthand notation for a woman's obstetric history.[citation needed]

  • Gravida indicates the number of times the mother has been pregnant, regardless of whether these pregnancies were carried to term. A current pregnancy, if any, is included in this count.[citation needed]
  • Para indicates the number of >20-week births (including viable and non-viable; i.e., stillbirths). Pregnancies consisting of multiples, such as twins or triplets, count as one birth for the purpose of this notation.[citation needed]
  • Abortus is the number of pregnancies that were lost for any reason, including induced abortions or miscarriages. The abortus term is sometimes dropped when no pregnancies have been lost. Stillbirths are not included.[citation needed]

Therefore, the history of a woman who has had two pregnancies (both of which resulted in live births) would be noted as G2P2. The obstetrical history of a woman who has had four pregnancies, one of which was a miscarriage before 20 weeks, would be noted as G4P3A1 (in the UK this is written as G4P3+1). That of a woman who has had one pregnancy of twins with successful outcomes would be noted as G1P1.[9]

Contrast with TPAL[edit]

Though similar, GPA should not be confused with the TPAL system, which may be used to provide information about the number of miscarriages, preterm births, and live births by dropping the "A" and including four separate numbers after the "P", as in G5P3114. This indicates 5 pregnancies, with 3 term births, 1 preterm birth, 1 induced abortion or miscarriage, and 4 living children.[10]

TPAL[edit]

TPAL is one of the methods to provide a quick overview of a female's obstetric history.[11] Two other methods often used are gravida/para and GPA.

In TPAL, the T refers to term births (after 37 weeks gestation), the P refers to premature births, the A refers to abortions, and the L refers to living children.[12] The TPAL is described by numbers separated by hyphens. Multiple births (twins, triplets and higher multiples) count as one birth, but each living child is counted separately.

For example, a pregnant woman who carried one pregnancy to term with a surviving infant; carried one pregnancy to 35 weeks with surviving twins; carried one pregnancy to 9 weeks as an ectopic (tubal) pregnancy; and has 3 living children would have a TPAL annotation of T1, P1, A1, L3. This could also be written as 1-1-1-3.

Note, the "abortions" number refers to the total number of induced abortions and miscarriages or ectopic pregnancies prior to 20 wks. If a fetus is aborted after 20 wks, spontaneously or electively, then it is counted as a premature birth and P will increase but L will not.

GTPAL[edit]

The term "GTPAL" is used when the TPAL is prefixed with gravidity, and "GTPALM" when GTPAL is followed by number of multiple pregnancies.[12]

For example, Gravida and parity are noted here using GTPAL. A woman who has given birth at term once and has had one miscarriage at 12 weeks would be recorded as G2 T1 P1 A1 L1. This notation is not standardized and can lead to misinterpretations.[8]

Nulliparity[edit]

A nulliparous (or nullipara or para 0) woman may have a higher risk for some complications during birth including experiencing more frequently interventions due to slow labour progress and a higher likelihood of experiencing a pregnancy that goes post dates. However, primips and multips may have increased risks related to their previous birth and pregnancy histories.

Prolonged nulliparity is a risk factor for breast cancer. For instance, a meta-analysis of 8 population-based studies in the Nordic countries found that nulliparity was associated with a 30% increase in risk of breast cancer compared with parous women, and for every 2 births, the risk was reduced by about 16%. Women having their first birth after the age of 35 years had a 40% increased risk compared to those with a first birth before the age of 20 years.[13] However risks related to pregnancy, such as maternal mortality are much larger than the increased risk of breast cancer for a nulliparous woman.[citation needed]

References[edit]

  1. ^ a b Borton, Chloe (November 12, 2009). "Gravidity and Parity Definitions (and their Implications in Risk Assessment)". Patient.co.uk. Retrieved June 26, 2013. 
  2. ^ a b Creinin MD, Simhan HN (March 2009). "Can we communicate gravidity and parity better?". Obstet Gynecol 113 (3): 709–11. doi:10.1097/AOG.0b013e3181988f8f (inactive June 26, 2013). PMID 19300338. 
  3. ^ Opara EI, Zaidi J (October 2007). "The interpretation and clinical application of the word 'parity': a survey". BJOG 114 (10): 1295–7. doi:10.1111/j.1471-0528.2007.01435.x. PMID 17877683. 
  4. ^ Oxford English Dictionary[page needed]
  5. ^ Mehrzad J, Duchateau L, Pyörälä S, Burvenich C. (2002). Blood and milk neutrophil chemiluminescence and viability in primiparous and pluriparous dairy cows during late pregnancy, around parturition and early lactation. Journal of Dairy Science 85 (12): 3268-76.
  6. ^ D. Vecchio, G. Neglia, M. Rendina, M. Marchiello, A. Balestrieri, R. Di Palo (2007). Dietary influence on primiparous and pluriparous buffalo fertility. Italian Journal of Animal Science 6 (Suppl. 1): 512–514.
  7. ^ Brassil MJ, Turner MJ, Egan DM, MacDonald DW (June 1987). "Obstetric outcome in first-time mothers aged 40 years and over". European Journal of Obstetrics & Gynecology and Reproductive Biology 25 (2): 115–20. doi:10.1016/0028-2243(87)90114-6. PMID 3609426. 
  8. ^ a b F. Gary Cunningham, 2005. Williams Obstetrics, 22nd Edition, McGraw-Hill Companies.
  9. ^ Hatfield, Nancy; N. Jayne Klossner (2006). Introductory maternity & pediatric nursing. Hagerstown, MD: Lippincott Williams & Wilkins. p. 142. ISBN 0-7817-3690-0. 
  10. ^ Bardsley CR (2011). "Normal Pregnancy". In Tintinalli JE, Kelen GD, Stapczynski JS. Tintinalli's Emergency Medicine: A Comprehensive Study Guide (7th ed.). New York: McGraw-Hill. Retrieved December 19, 2011. 
  11. ^ http://www.meddean.luc.edu/lumen/MedEd/obgyne/tools.pdf[full citation needed]
  12. ^ a b Lippincott Manual of Nursing Practice Series: Assessment. Lippincott Manual of Nursing Practice. Hagerstwon, MD: Lippincott Williams & Wilkins. 2006. p. 385. ISBN 1-58255-939-2. 
  13. ^ Ewertz M, Duffy SW, Adami HO, et al (1990). "Age at first birth, parity and risk of breast cancer: A meta-analysis of 8 studies from the Nordic countries". International Journal of Cancer 46 (4): 597–603. PMID 2145231.