Nulliparity

In biology and human medicine, gravidity and parity are the number of times a female is or has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These terms are usually coupled, sometimes with additional terms, to indicate more details of the woman's obstetric history. When using these terms:

In human 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.

Terms such as "gravida 0", referring to a nulligravida, "gravida 1" for a primigravida, and so on, can also be used. The term "elderly primigravida" has also been used to refer to a woman in her first pregnancy, who is at least 35 years old.

In biology, the term "gravid" (Latin: gravidus "burdened, heavy") 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.

Parity is the number of pregnancies carried to viable gestational age.

A woman who has never carried a pregnancy beyond 20 weeks is nulliparous, and is called a nullipara or para 0. A woman who has given birth once before is primiparous, and is referred to as a primipara or primip; moreover, a woman who has given birth two or more times is multiparous and is called a multip. Finally, grand multipara describes the condition of having given birth three or more times.

Like gravidity, parity may also be counted. A woman who has given birth one or more times can also be referred to as para 1, para 2, para 3 and so on.

Viable gestational age varies from region to region.

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". Those that have given birth twice may also be described as "secondiparous", in which case "pluriparous" is applied to those that have given birth three times or more.

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