The medical terms Gravida (G) and Parity (P) form a standardized shorthand used globally by healthcare professionals, including doctors, nurses, and midwives. This notation provides a rapid, condensed summary of a patient’s entire obstetric history. By quickly reviewing these numbers, providers can gain an immediate understanding of previous pregnancies and their outcomes, which is foundational to planning current care.
Defining Gravida (G)
Gravida (G) is a count of the total number of times a woman has been pregnant. This number includes every confirmed pregnancy event, regardless of how long the pregnancy lasted or what the final outcome was. It encompasses live births, stillbirths, miscarriages, and ectopic pregnancies. The current pregnancy, if one is ongoing, is always included in the Gravida count.
A pregnancy resulting in multiples, such as twins or triplets, is counted as only one single Gravida event. For instance, a woman pregnant for the first time is designated as G1. If she has had two prior pregnancies and is currently pregnant, her Gravida count would be G3, reflecting three separate pregnancy events in total.
Defining Parity (P)
Parity (P) refers to the number of pregnancies that have progressed to the stage of viability, generally defined as a gestational age of 20 weeks or more. Parity is counted by the pregnancy event, not the number of infants born, and it is recorded regardless of whether the fetus was born alive or was a stillbirth.
For example, a woman who carried one pregnancy to 35 weeks, resulting in the birth of twins, would be counted as P1. If a woman is currently pregnant and has never delivered past 20 weeks, she would be designated as P0. The simple G/P notation, such as G3P2, tells a provider that the woman has been pregnant three times and has delivered past the 20-week mark twice.
Understanding the Detailed Parity Breakdown (TPAL)
The simple Parity (P) count is often broken down into a more detailed system known as TPAL, which provides a comprehensive picture of all prior pregnancy outcomes. The TPAL system uses four specific digits to replace the single Parity number, and it is usually preceded by the Gravida count, creating the full GTPAL notation. This expansion is necessary because the single P number does not distinguish between a full-term birth and a preterm birth, or account for pregnancy losses.
The T in TPAL stands for Term births, counting any delivery that occurred at 37 weeks of gestation or later. The first P stands for Preterm births, which includes any delivery between 20 weeks and 36 weeks and six days. These first two numbers, Term and Preterm, will always sum up to the total Parity count established by the simple P definition.
The A in the sequence represents Abortions, which is the number of pregnancies that ended before the 20-week threshold of viability. This category includes both spontaneous miscarriages and elective terminations. L stands for Living children, which is the total number of children currently alive. The Living count is the only number in the entire system that counts individual infants rather than pregnancy events.
Clinical Significance and Reading the Notation
The combined Gravida and TPAL notation (GTPAL) is a powerful tool for quickly assessing a patient’s obstetric risk profile. By reviewing this five-digit sequence, a care team can immediately identify factors that may impact the current pregnancy. For example, a history showing multiple preterm births suggests an increased possibility of a recurrent preterm delivery in the current pregnancy, requiring closer monitoring.
The notation is read aloud with the Gravida number first, followed by the four Parity components in order. A notation of G4P1112 translates to four total pregnancies, one Term birth, one Preterm birth, one Abortion/loss before 20 weeks, and two Living children.
If a patient is currently pregnant for the first time, their notation would be G1P0000, indicating one pregnancy and no prior outcomes in any category. A patient who had twins delivered at 35 weeks and is not currently pregnant would be G1P0102, reflecting one pregnancy, zero Term, one Preterm event, zero Abortions, and two Living children. The concise nature of the GTPAL system allows providers to tailor prenatal care and delivery planning based on the specific historical details revealed by these five numbers.