How to survive your O&G Placement: Gravidity & Parity

When on your Obstetrics and Gynaecology placement, taking an obstetric or gynaecological history can be challenging, especially due to a large amount of content to cover alongside the introduction of new concepts. One such concept in an Obstetric history is Gravidity and Parity.

Through this blog series, I hope to dispel some of the confusion related to O&G placement. I am starting firstly with the terms GRAVIDITY and PARITY!

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GRAVIDITY is defined as the number of times a woman is or has been pregnant.

Important rules for gravidity:

• Regardless of pregnancy outcome

• Current pregnancy is included

• Multiple pregnancies count as 1

Based on gravidity, the term ‘gravida’ is used to refer to a pregnant woman.

• Nulligravida (gravida 0) – a woman who has never been pregnant

• Primigravida (gravida 1) – a woman who is pregnant for the first time or has been pregnant once

• Multigravida – a woman who has been pregnant more than once

• Elderly primigravida – a term that may refer to a woman in their first pregnancy, who is at least 35 years old

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PARITY is defined as the number of times a woman has carried the pregnancies to a viable gestational age (24+0 in the UK).

Important rules for parity:

• Includes stillbirths

• Number of foetuses does not determine parity – twin pregnancy carried to 24+0 are counted as 1

A study published in 2007 has shown that only 20% of Midwives and Obstetricians recognise twin delivery as a single parous event so G1P1, highlighting the lack of standardisation as the majority use G1P2.

Based on parity, the term 'parous' is used to describe the number of times a woman has given birth.

• Nulliparous (nullipara) – a woman that has never carried a pregnancy beyond 24+0

• This includes women who have experienced spontaneous miscarriage and/or abortions

• Primiparous (primipara, para 1) – a woman who has given birth once before

• Multiparous – a woman who has given birth more than once

• Grand multiparous – a woman who has given birth more than five times

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ABORTUS is defined as the number of pregnancies that were lost for any reason (abortions or miscarriages).

The GPA (Gravidity, Parity and Abortus) system is not always included and often dropped if no pregnancies have been lost.

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Now we will go through some examples to consolidate this knowledge:

Obstetric history of a woman who has had two successful pregnancies → G2P2

Obstetric history of a woman who has had four pregnancies, one of which was a miscarriage before 24+0 weeks → G4P3A1 or G4P3+1,

Obstetric history of a woman who has had one successful pregnancy of twins → G1P1

Obstetric history of a primigravida woman who is currently 20 weeks pregnant → G1P0

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References:

Opara, E. and Zaidi, J. (2007), The interpretation and clinical application of the word ‘parity’: a survey. BJOG: An International Journal of Obstetrics & Gynaecology, 114: 1295-1297. DOI:10.1111/j.1471-0528.2007.01435.x

Creinin MD, Simhan HN. Can we communicate gravidity and parity better?. Obstet Gynecol. 2009;113(3):709-711. doi:10.1097/AOG.0b013e3181988f8f

TeachMeObGyn. 2020. The Obstetric History - OSCE - Gravidity - Parity - Teachmeobgyn. [online] Available at: <https://teachmeobgyn.com/history-taking-examinations/history-taking/obstetric/> [Accessed 4 September 2020].