Parity (biology)

Parity (biology)
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 fetus.[1]

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

Contents

Enumeration

A woman who has given birth a particular number of times is referred to as para 0, para 1, para 2, para 3 and so on.

  • A woman who has never completed a pregnancy beyond 20 weeks is referred to as being nulliparous, a nullipara or para 0.[4]
  • A woman in her first pregnancy can also be referred to as being primipara which can be shortened to primip.
  • Biparous or bipara are sometimes used as synonyms for para 2.
  • A woman who has given birth two or more times is referred to as multiparous or just as a multip. The term multiparous can also describe a birth of more than one offspring at once, in contrast to a uniparous birth of one offspring.
  • Grand multipara refers to a (grand multiparous) woman who has given birth five or more times.

TPAL

Parity is recorded in the format, T-P-A-L:

is the number of term births (twins and other multiple births count as 1). Term births are those occurring at 37 weeks or beyond.
is the number preterm births (twins and other multiple births count as 1). Preterm births are those that occur before 37 weeks.
is the number of abortions (spontaneous or induced).
is the number of living children.

For example, parity of a woman who has given birth at term once and has had one miscarriage would be recorded as P 1-0-1-1. This notation is not standardized and can lead to misinterpretations.[4]

Nulliparity

A nulliparous (or nullipara or para 0) woman has a higher risk during pregnancy. It is a factor in calculating Bishop score, increasing the risk that induction of labour will be required. Nulliparity is a risk factor for a poor outcome in twin pregnancies achieved by assisted reproductive technology and is associated with an increased risk for severe preterm birth and possibly late abortions.[5]

Prolonged nulliparity is a risk factor for breast cancer. For instance, having the first live birth after age 30 doubles the risk compared to having first live birth at age less than 25. Never having children triples the risk.[6]

References

  1. ^ "Gravidity and Parity Definitions (and their Implications in Risk Assessment) | Doctor | Patient UK". http://www.patient.co.uk/doctor/Gravidity-and-Parity-Definitions.htm. Retrieved 2010-01-16. 
  2. ^ 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. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0029-7844&volume=113&issue=3&spage=709. 
  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. ^ a b F. Gary Cunningham, 2005. Williams Obstetrics, 22nd Edition, McGraw-Hill Companies.
  5. ^ Berkovitz A, Hershko-Klement A, Fejgin M (April 2010). "Nulliparity, fertility treatments and twins: a time for rethinking". Fertil. Steril. 93 (6): 1957–60. doi:10.1016/j.fertnstert.2008.12.035. PMID 19249760. 
  6. ^ Chapter 19 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson. Robbins Basic Pathology. Philadelphia: Saunders. ISBN 1-4160-2973-7. 8th edition

See also