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. Recording systems A number of systems are incorporated into a woman's obstetric history to record the number of past pregnancies and pregnancies carried to viable age. These include: The gravida/para/abortus (GPA) system, or sometimes just gravida/para (GP), is one such shorthand. For example, the obstetric history of a woman who has had two pregnancies (both of which resulted in live births) would be noted as G2P2. The obstetric history of a woman who has had four pregnancies, one of which was a miscarriage before 20 weeks, would be noted in the GPA system as G4P3A1 and in the GP system as G4P3. The obstetric history of a woman who has had one pregnancy of twins with successful outcomes would be noted as G1P1+1. TPAL is one of the methods to provide a quick overview of a person's obstetric history. In TPAL, the T refers to term births (after 37 weeks' gestation), the P refers to premature births, the A refers to abortions, and the L refers to living children. When reported, the "abortions" number refers to the total number of spontaneous or induced abortions and miscarriages, including ectopic pregnancies, prior to 20 weeks. If a fetus is aborted after 20 weeks, spontaneously or electively, then it is counted as a premature birth and P will increase but L will not. The TPAL is described by numbers separated by hyphens. Multiple births (twins, triplets and higher multiples) count as one pregnancy (gravidity) and as one birth. For example, a pregnant woman who carried one pregnancy to term with a surviving infant; carried one pregnancy to 35 weeks with surviving twins; carried one pregnancy to 9 weeks as an ectopic (tubal) pregnancy; and has three living children would have a TPAL annotation of T1, P1, A1, L3. This could also be written as 1-1-1-3. The term GTPAL is used when the TPAL is prefixed with gravidity, and GTPALM when GTPAL is followed by number of multiple pregnancies. For example, the gravidity and parity of a woman who has given birth