Parity (biology)
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It has been suggested that TPAL (medicine), Gravida/para/abortus and Glossary of terms associated with gravidity be merged into this article. (Discuss) Proposed since August 2011. |
- 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 to a baby.[1]
It can lead to some ambiguity for events occurring between 20 and 24 weeks,[2] and for multiple pregnancies.[3]
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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 given birth is a nullipara, a nullip, or para 0.
- A woman who has never completed a pregnancy beyond 20 weeks is also referred to as being nulliparous, a nullipara or para 0.[4]
- 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 in her first pregnancy and who has therefore not yet given birth is a nullipara or nullip. After she gives birth she becomes a primip.
- A woman who has given birth once before is primiparous, and would be 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.
GTPAL [edit]
Gravida status is the number of pregnancies a woman has had. Parity is recorded in the format, T-P-A-L:
- T
- is the number of term births (twins and other multiple births count as 1). Term births are those occurring at 37 weeks or beyond.
- P
- is the number preterm births (twins and other multiple births count as 1). Preterm births are those that occur after 20 weeks and before 37 weeks.
- A
- is the number of abortions (spontaneous or induced) prior to 20 weeks.
- L
- is the number of living children.
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 P0 A1 L1. This notation is not standardized and can lead to misinterpretations.[4]
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.[5] However risks related to pregnancy, such as maternal mortality are much larger than the increased risk of breast cancer for a nulliparous woman.
References [edit]
- ^ "Gravidity and Parity Definitions (and their Implications in Risk Assessment) | Doctor | Patient UK". Retrieved 2010-01-16.
- ^ Creinin MD, Simhan HN (March 2009). "Can we communicate gravidity and parity better?". Obstet Gynecol 113 (3): 709–11. doi:10.1097/AOG.0b013e3181988f8f. PMID 19300338.
- ^ 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.
- ^ a b F. Gary Cunningham, 2005. Williams Obstetrics, 22nd Edition, McGraw-Hill Companies.
- ^ http://www.ncbi.nlm.nih.gov/pubmed/2145231
See also [edit]
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