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

Parity

Parity may refer to:* Parity , a symmetry property of physical quantities or processes under spatial inversion* Parity , indicates whether a number is even or odd...

.

In biology

Biology

Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

, parity is a technical term that refers to the number of times a female has given birth

Birth

Birth is the act or process of bearing or bringing forth offspring. The offspring is brought forth from the mother. The time of human birth is defined as the time at which the fetus comes out of the mother's womb into the world...

 to a fetus

Fetus

A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...

.

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

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.

• 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

TPAL (medicine)

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

:
T : is the number of term births (twins

TWINS

Two Wide-Angle Imaging Neutral-Atom Spectrometers are a pair of NASA instruments aboard two United States National Reconnaissance Office satellites in Molniya orbits. TWINS was designed to provide stereo images of the Earth's ring current. The first instrument, TWINS-1, was launched aboard USA-184...

 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 before 37 weeks.
A : is the number of abortions (spontaneous or induced).
L : 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.

Nulliparity

A nulliparous (or nullipara or para 0) woman has a higher risk during pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

. It is a factor in calculating Bishop score

Bishop score

Bishop score, also Bishop's score, is a pre-labour scoring system to assist in predicting whether induction of labour will be required. It has also been used to assess the odds of spontaneous preterm delivery.-Components:...

, increasing the risk that induction of labour

Induction (birth)

Labor induction is a method of artificially or prematurely stimulating childbirth in a woman.-Indications:Common suggested reasons for induction include:* Postterm pregnancy, i.e. if the pregnancy has gone past the 42 week mark....

 will be required. Nulliparity is a risk factor for a poor outcome in twin pregnancies achieved by assisted reproductive technology

Assisted reproductive technology

Assisted reproductive technology is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. It is reproductive technology used primarily in infertility treatments. Some forms of ART are also used in fertile couples for genetic reasons...

 and is associated with an increased risk for severe preterm birth and possibly late abortions.

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.

See also

• Gravida/para(/abortus)
  Gravida/para/abortus
  Gravida/para/abortus , or sometimes just gravida/para , is a shorthand notation for a woman's obstetric history.* 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...
  
  
• Gravidity
  Gravidity
  In medicine, gravidity refers to the number of times a woman has been pregnant, regardless of whether the pregnancies were interrupted or resulted in a live birth....
  
  
• Multigravida
• TPAL
  TPAL (medicine)
  TPAL is one of the methods to provide a quick overview of a female's obstetric history. Two other methods often used are gravida/para and GPA....