# Nulliparity Risk factor · id `maternal:nulliparity` · Maternal & Newborn Atlas · release `15708f235d73cd42` (public) > General information from published sources, not medical advice, and not reviewed by clinicians. Check the cited source before relying on anything here. The atlas's own text and curation may be reused under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0, https://creativecommons.org/licenses/by-nc/4.0/): credit the atlas, and do not use it commercially. See the atlas About page. Text quoted from a source stays under that source's own terms, given as the source's reuse\_basis. The atlas's reuse terms do not cover it. The downloads list each quotation with its source in third\_party\_quotations. Browse, life stage: Pregnancy ## In plain language NICE uses the term nulliparity without defining it. MeSH files it under parity, which MeSH defines as "The number of offspring a female has borne." NICE lists it as one of six moderate risk factors for pre-eclampsia. Having more than one of these factors is a reason NICE gives for advising low-dose aspirin. NICE does not say how much nulliparity raises the risk by itself. ## Technical summary A trait of the pregnant woman. The NICE NG133 page does not define nulliparity. In August 2022 NICE changed the wording of recommendation 1.1.3 from first pregnancy to nulliparity, so the two terms must not be treated as the same. MeSH defines parity as the number of offspring a female has borne, and files nulliparity under it with no definition of its own. WHO 2021 uses a different term, primiparity, in its own moderate-risk list, and this record does not treat primiparity and nulliparity as the same. ## Claims, with the population each applies to ## Context: Nulliparity as one moderate risk factor for pre-eclampsia (NICE NG133 recommendation 1.1.3) Recipient: Maternal; Population: Pregnant women with nulliparity, one of six factors that NICE lists as indicating moderate risk of pre-eclampsia. The NICE page does not define nulliparity.; Care setting: Not stated in the source.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.; Life stage: Pregnancy. The source gives no gestational age for the risk factor itself.; Gestational age: Not reported; Postnatal age: Not reported; Follow-up: Not applicable (risk factor context) ### NICE lists nulliparity as one of six factors that indicate moderate risk of pre-eclampsia, alongside age 40 years or older, a pregnancy interval of more than 10 years, a body mass index of 35 kg/m2 or more at the first visit, a family history of pre-eclampsia and a multi-fetal pregnancy. NICE advises aspirin for women who have more than one of these factors. - Category: Description - Evidence stage: Guidance - Certainty: Certainty not assessed - Applies to: Recipient: Maternal; Population: Pregnant women with nulliparity, one of six factors that NICE lists as indicating moderate risk of pre-eclampsia. The NICE page does not define nulliparity.; Care setting: Not stated in the source.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.; Life stage: Pregnancy. The source gives no gestational age for the risk factor itself.; Gestational age: Not reported; Postnatal age: Not reported; Follow-up: Not applicable (risk factor context) - Limitations: NICE does not say how much nulliparity raises the risk by itself, and the NICE page does not define the term, so no risk figure is recorded. In August 2022 NICE corrected the wording of recommendation 1.1.3 from first pregnancy to nulliparity, so the two terms must not be used as if they meant the same. WHO 2021 uses a different term, primiparity, in its own moderate-risk list. A list of risk factors is not an estimate of risk for any one woman. - Last checked: 2026-10-11 - Sources: 1. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, edition The version shown on 2026-10-11, with a page header that gives 17 April 2023 as the last update. The same bytes came back on a second fetch minutes later.) Locator: 1.1.3, moderate-risk list, items 1 to 3. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: NICE NG133, cited and linked only. Nulliparity is the first item of the list. 2. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, edition The version shown on 2026-10-11, with a page header that gives 17 April 2023 as the last update. The same bytes came back on a second fetch minutes later.) Locator: 1.1.3, moderate-risk list, items 4 to 6 and recommendation tag. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: The other three moderate risk factors. 3. Background: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Update information chapter (Guideline, edition The Update information chapter of NICE guideline NG133, as shown on 2026-10-11 with the page header Last updated: 17 April 2023. It lists what changed in June 2019, the minor changes after publication (August 2022, April 2023 and October 2023) and the guideline ISBN. The chapter has no identifier of its own because the Recommendations chapter source already holds the identifier NG133. Cluster B and cluster C fetched this page separately on 2026-10-11 and both returned the same bytes (sha256 248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58). The integration step kept this one source and snapshot and redirected the cluster C citations to them.) Locator: Minor changes since publication, August 2022. Retrieved 2026-10-11T19:16:21Z. Source state: Current. Snapshot hash: 248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58. How it applies: NICE's own correction of the term in recommendation 1.1.3. 4. Background: MeSH concept M0015959 (Parity) (Dataset, edition MeSH linked-data concept record as fetched on 2026-10-11. It holds the scope note and the list of narrower concepts, and states no date.) Locator: scopeNote.@value, sentence 1. Retrieved 2026-10-11T19:15:23Z. Source state: Current. Snapshot hash: aa475bcc0d87b166a854aa3561a27082f8367683a553c1373d3e85a550aeadf4. How it applies: MeSH definition of parity, the term that groups nulliparity. It is not a definition of nulliparity itself. ## Connected pages - NICE NG133 lists it as one of six moderate risk factors for pre-eclampsia; the guideline gives no risk figure: Pre-eclampsia (`maternal:preeclampsia`) [a claim, not a settled fact; see claim `maternal:claim-nice-ng133-1-1-3-nulliparity-risk-factor` and its context] ## Provenance Content hash: a508fe3aea2fd347e181c525e3b9c169d612509e9165023988c02a4e82758f2d Last substantive edit: 2026-10-12 Evidence last checked: 2026-10-12