For other uses of the term in other fields, see Parity (disambiguation).

In biology and human medicine, gravidity and parity are two terms that refer to the number of times a female 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:

• Gravida indicates the number of times the woman has been pregnant, regardless of whether these pregnancies were carried to term. A current pregnancy, if any, is included in this count.
• Parity, or "para" indicates the number of >20-week births (including viable and non-viable; i.e., stillbirths) (>24 in UK). Pregnancies consisting of multiples, such as twins or triplets, count as one birth for the purpose of this notation.
• 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.