The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study
Objective: To estimate the degree of confounding necessary to explain the associations between complications in a first pregnancy and the subsequent risk of preterm birth. Design: Population-based cohort study. Setting: Western Australia. Population: Women (n = 125 473) who gave birth to their first...
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| Format: | Journal Article |
| Language: | English |
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WILEY
2022
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| Online Access: | http://purl.org/au-research/grants/nhmrc/1099655 http://hdl.handle.net/20.500.11937/93727 |
| _version_ | 1848765775372877824 |
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| author | Dunne, Jennifer Tessema, Gizachew Pereira, Gavin |
| author_facet | Dunne, Jennifer Tessema, Gizachew Pereira, Gavin |
| author_sort | Dunne, Jennifer |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Objective: To estimate the degree of confounding necessary to explain the associations between complications in a first pregnancy and the subsequent risk of preterm birth. Design: Population-based cohort study. Setting: Western Australia. Population: Women (n = 125 473) who gave birth to their first and second singleton children between 1998 and 2015. Main outcome measures: Relative risk (RR) of a subsequent preterm birth (<37 weeks of gestation) with complications of pre-eclampsia, placental abruption, small-for-gestational age and perinatal death (stillbirth and neonatal death within 28 days of birth). We derived e-values to determine the minimum strength of association for an unmeasured confounding factor to explain away an observed association. Results: Complications in a first pregnancy were associated with an increased risk of a subsequent preterm birth. Relative risks were significantly higher when the complication was recurrent, with the exception of first-term perinatal death. The association with subsequent preterm birth was strongest when pre-eclampsia was recurrent. The risk of subsequent preterm birth with pre-eclampsia was 11.87 (95% CI 9.52–14.79) times higher after a first term birth with pre-eclampsia, and 64.04 (95% CI 53.58–76.55) times higher after a preterm first birth with pre-eclampsia, than an uncomplicated term birth. The e-values were 23.22 and 127.58, respectively. Conclusions: The strong associations between recurrent pre-eclampsia, placental abruption and small-for-gestational age with preterm birth supports the hypothesis of shared underlying causes that persist from pregnancy to pregnancy. High e-values suggest that recurrent confounding is unlikely, as any such unmeasured confounding factor would have to be uncharacteristically large. Tweetable abstract: First pregnancy complications are associated with a higher risk of subsequent preterm birth, with evidence strongest for pregnancies complicated by pre-eclampsia. |
| first_indexed | 2025-11-14T11:40:36Z |
| format | Journal Article |
| id | curtin-20.500.11937-93727 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:40:36Z |
| publishDate | 2022 |
| publisher | WILEY |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-937272023-11-27T08:02:46Z The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study Dunne, Jennifer Tessema, Gizachew Pereira, Gavin Science & Technology Life Sciences & Biomedicine Obstetrics & Gynecology Confounding e-values placental abruption pre-eclampsia preterm birth small-for-gestational age ISCHEMIC PLACENTAL DISEASE RISK EPIDEMIOLOGY PREECLAMPSIA RECURRENCE ABRUPTION TERM DELIVERY Confounding e-values placental abruption pre-eclampsia preterm birth small-for-gestational age Abruptio Placentae Child Cohort Studies Female Humans Infant, Newborn Infant, Newborn, Diseases Perinatal Death Placenta Pre-Eclampsia Pregnancy Pregnancy Complications Premature Birth Placenta Humans Pregnancy Complications Pre-Eclampsia Abruptio Placentae Premature Birth Infant, Newborn, Diseases Cohort Studies Pregnancy Child Infant, Newborn Female Perinatal Death Objective: To estimate the degree of confounding necessary to explain the associations between complications in a first pregnancy and the subsequent risk of preterm birth. Design: Population-based cohort study. Setting: Western Australia. Population: Women (n = 125 473) who gave birth to their first and second singleton children between 1998 and 2015. Main outcome measures: Relative risk (RR) of a subsequent preterm birth (<37 weeks of gestation) with complications of pre-eclampsia, placental abruption, small-for-gestational age and perinatal death (stillbirth and neonatal death within 28 days of birth). We derived e-values to determine the minimum strength of association for an unmeasured confounding factor to explain away an observed association. Results: Complications in a first pregnancy were associated with an increased risk of a subsequent preterm birth. Relative risks were significantly higher when the complication was recurrent, with the exception of first-term perinatal death. The association with subsequent preterm birth was strongest when pre-eclampsia was recurrent. The risk of subsequent preterm birth with pre-eclampsia was 11.87 (95% CI 9.52–14.79) times higher after a first term birth with pre-eclampsia, and 64.04 (95% CI 53.58–76.55) times higher after a preterm first birth with pre-eclampsia, than an uncomplicated term birth. The e-values were 23.22 and 127.58, respectively. Conclusions: The strong associations between recurrent pre-eclampsia, placental abruption and small-for-gestational age with preterm birth supports the hypothesis of shared underlying causes that persist from pregnancy to pregnancy. High e-values suggest that recurrent confounding is unlikely, as any such unmeasured confounding factor would have to be uncharacteristically large. Tweetable abstract: First pregnancy complications are associated with a higher risk of subsequent preterm birth, with evidence strongest for pregnancies complicated by pre-eclampsia. 2022 Journal Article http://hdl.handle.net/20.500.11937/93727 10.1111/1471-0528.17007 English http://purl.org/au-research/grants/nhmrc/1099655 http://purl.org/au-research/grants/nhmrc/1173991 http://purl.org/au-research/grants/nhmrc/1195716 WILEY restricted |
| spellingShingle | Science & Technology Life Sciences & Biomedicine Obstetrics & Gynecology Confounding e-values placental abruption pre-eclampsia preterm birth small-for-gestational age ISCHEMIC PLACENTAL DISEASE RISK EPIDEMIOLOGY PREECLAMPSIA RECURRENCE ABRUPTION TERM DELIVERY Confounding e-values placental abruption pre-eclampsia preterm birth small-for-gestational age Abruptio Placentae Child Cohort Studies Female Humans Infant, Newborn Infant, Newborn, Diseases Perinatal Death Placenta Pre-Eclampsia Pregnancy Pregnancy Complications Premature Birth Placenta Humans Pregnancy Complications Pre-Eclampsia Abruptio Placentae Premature Birth Infant, Newborn, Diseases Cohort Studies Pregnancy Child Infant, Newborn Female Perinatal Death Dunne, Jennifer Tessema, Gizachew Pereira, Gavin The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| title | The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| title_full | The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| title_fullStr | The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| title_full_unstemmed | The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| title_short | The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| title_sort | role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study |
| topic | Science & Technology Life Sciences & Biomedicine Obstetrics & Gynecology Confounding e-values placental abruption pre-eclampsia preterm birth small-for-gestational age ISCHEMIC PLACENTAL DISEASE RISK EPIDEMIOLOGY PREECLAMPSIA RECURRENCE ABRUPTION TERM DELIVERY Confounding e-values placental abruption pre-eclampsia preterm birth small-for-gestational age Abruptio Placentae Child Cohort Studies Female Humans Infant, Newborn Infant, Newborn, Diseases Perinatal Death Placenta Pre-Eclampsia Pregnancy Pregnancy Complications Premature Birth Placenta Humans Pregnancy Complications Pre-Eclampsia Abruptio Placentae Premature Birth Infant, Newborn, Diseases Cohort Studies Pregnancy Child Infant, Newborn Female Perinatal Death |
| url | http://purl.org/au-research/grants/nhmrc/1099655 http://purl.org/au-research/grants/nhmrc/1099655 http://purl.org/au-research/grants/nhmrc/1099655 http://hdl.handle.net/20.500.11937/93727 |