Parity in pregnancy refers to the number of times a woman has been pregnant and carried the pregnancies to a viable gestational age. In human medicine, parity is the number of pregnancies carried by a female for at least 20 weeks. The duration of 20 weeks varies from region to region, depending upon the age of viability. If a female carries the fetus to a viable age, even if ultimately the fetus is born deceased, this still counts as an instance of parity, as parity is based on the time of gestation prior to a birth, and not the status of the offspring once born.

Parity is an important factor in assessing the risk of pregnancy outcomes46017-6/abstract). Increased parity is often associated with increasing maternal age, lower socio-economic and educational status, and poorer prenatal care. It is also associated with an increased risk of levator ani dysfunction.

Gravidity, on the other hand, refers to the total number of pregnancies, regardless of outcome. It is important to distinguish between gravidity and parity, as they are often used together to assess the risk of pregnancy outcomes.

In summary, parity in pregnancy refers to the number of times a woman has been pregnant and carried the pregnancies to a viable gestational age, while gravidity refers to the total number of pregnancies, regardless of outcome. Parity is an important factor in assessing the risk of pregnancy outcomes.