Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor
It is biologically plausible that risk of autism spectrum disorder (ASD) is elevated by both short and long interpregnancy intervals (IPI). We conducted a retrospective cohort study of singleton, non-nulliparous live births, 1998–2007 in Denmark, Finland, and Sweden (N = 925,523 births). Optimal IPI...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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WILEY
2021
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| Online Access: | http://purl.org/au-research/grants/nhmrc/1099655 http://hdl.handle.net/20.500.11937/93719 |
| _version_ | 1848765772942278656 |
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| author | Pereira, Gavin Francis, R.W. Gissler, M. Hansen, S.N. Kodesh, A. Leonard, H. Levine, S.Z. Mitter, V.R. Parner, E.T. Regan, Annette Reichenberg, A. Sandin, S. Suominen, A. Schendel, D. |
| author_facet | Pereira, Gavin Francis, R.W. Gissler, M. Hansen, S.N. Kodesh, A. Leonard, H. Levine, S.Z. Mitter, V.R. Parner, E.T. Regan, Annette Reichenberg, A. Sandin, S. Suominen, A. Schendel, D. |
| author_sort | Pereira, Gavin |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | It is biologically plausible that risk of autism spectrum disorder (ASD) is elevated by both short and long interpregnancy intervals (IPI). We conducted a retrospective cohort study of singleton, non-nulliparous live births, 1998–2007 in Denmark, Finland, and Sweden (N = 925,523 births). Optimal IPI was defined as the IPI at which minimum risk was observed. Generalized additive models were used to estimate relative risks (RR) of ASD and 95% Confidence Intervals (CI). Population impact fractions (PIF) for ASD were estimated under scenarios for shifts in the IPI distribution. We observed that the association between ASD (N = 9302) and IPI was U-shaped for all countries. ASD risk was lowest (optimal IPI) at 35 months for all countries combined, and at 30, 33, and 39 months in Denmark, Finland, and Sweden, respectively. Fully adjusted RRs at IPIs of 6, 12, and 60 months were 1.41 (95% CI: 1.08, 1.85), 1.26 (95% CI: 1.02, 1.56), and 1.24 (95% CI: 0.98, 1.58) compared to an IPI of 35 months. Under the most conservative scenario PIFs ranged from 5% (95% CI: 1%–8%) in Denmark to 9% (95% CI: 6%–12%) in Sweden. The minimum ASD risk followed IPIs of 30–39 months across three countries. These results reflect both direct IPI effects and other, closely related social and biological pathways. If our results reflect biologically causal effects, increasing optimal IPIs and reducing their indications, such as unintended pregnancy and delayed age at first pregnancy has the potential to prevent a salient proportion of ASD cases. Lay Summary: Waiting 35 months to conceive again after giving birth resulted in the least risk of autism. Shorter and longer intervals resulted in risks that were up to 50% and 85% higher, respectively. About 5% to 9% of autism cases might be avoided by optimizing birth spacing. |
| first_indexed | 2025-11-14T11:40:34Z |
| format | Journal Article |
| id | curtin-20.500.11937-93719 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:40:34Z |
| publishDate | 2021 |
| publisher | WILEY |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-937192023-11-27T01:43:49Z Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor Pereira, Gavin Francis, R.W. Gissler, M. Hansen, S.N. Kodesh, A. Leonard, H. Levine, S.Z. Mitter, V.R. Parner, E.T. Regan, Annette Reichenberg, A. Sandin, S. Suominen, A. Schendel, D. Science & Technology Social Sciences Life Sciences & Biomedicine Behavioral Sciences Psychology, Developmental Psychology autism spectrum disorder birth intervals family planning services longitudinal studies PREGNANCY HEALTH autism spectrum disorder birth intervals family planning services longitudinal studies Autism Spectrum Disorder Birth Intervals Female Finland Humans Pregnancy Retrospective Studies Risk Factors Humans Risk Factors Retrospective Studies Pregnancy Birth Intervals Finland Female Autism Spectrum Disorder It is biologically plausible that risk of autism spectrum disorder (ASD) is elevated by both short and long interpregnancy intervals (IPI). We conducted a retrospective cohort study of singleton, non-nulliparous live births, 1998–2007 in Denmark, Finland, and Sweden (N = 925,523 births). Optimal IPI was defined as the IPI at which minimum risk was observed. Generalized additive models were used to estimate relative risks (RR) of ASD and 95% Confidence Intervals (CI). Population impact fractions (PIF) for ASD were estimated under scenarios for shifts in the IPI distribution. We observed that the association between ASD (N = 9302) and IPI was U-shaped for all countries. ASD risk was lowest (optimal IPI) at 35 months for all countries combined, and at 30, 33, and 39 months in Denmark, Finland, and Sweden, respectively. Fully adjusted RRs at IPIs of 6, 12, and 60 months were 1.41 (95% CI: 1.08, 1.85), 1.26 (95% CI: 1.02, 1.56), and 1.24 (95% CI: 0.98, 1.58) compared to an IPI of 35 months. Under the most conservative scenario PIFs ranged from 5% (95% CI: 1%–8%) in Denmark to 9% (95% CI: 6%–12%) in Sweden. The minimum ASD risk followed IPIs of 30–39 months across three countries. These results reflect both direct IPI effects and other, closely related social and biological pathways. If our results reflect biologically causal effects, increasing optimal IPIs and reducing their indications, such as unintended pregnancy and delayed age at first pregnancy has the potential to prevent a salient proportion of ASD cases. Lay Summary: Waiting 35 months to conceive again after giving birth resulted in the least risk of autism. Shorter and longer intervals resulted in risks that were up to 50% and 85% higher, respectively. About 5% to 9% of autism cases might be avoided by optimizing birth spacing. 2021 Journal Article http://hdl.handle.net/20.500.11937/93719 10.1002/aur.2599 English http://purl.org/au-research/grants/nhmrc/1099655 http://purl.org/au-research/grants/nhmrc/1117105 http://purl.org/au-research/grants/nhmrc/1173991 WILEY fulltext |
| spellingShingle | Science & Technology Social Sciences Life Sciences & Biomedicine Behavioral Sciences Psychology, Developmental Psychology autism spectrum disorder birth intervals family planning services longitudinal studies PREGNANCY HEALTH autism spectrum disorder birth intervals family planning services longitudinal studies Autism Spectrum Disorder Birth Intervals Female Finland Humans Pregnancy Retrospective Studies Risk Factors Humans Risk Factors Retrospective Studies Pregnancy Birth Intervals Finland Female Autism Spectrum Disorder Pereira, Gavin Francis, R.W. Gissler, M. Hansen, S.N. Kodesh, A. Leonard, H. Levine, S.Z. Mitter, V.R. Parner, E.T. Regan, Annette Reichenberg, A. Sandin, S. Suominen, A. Schendel, D. Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor |
| title | Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor |
| title_full | Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor |
| title_fullStr | Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor |
| title_full_unstemmed | Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor |
| title_short | Optimal interpregnancy interval in autism spectrum disorder: A multi-national study of a modifiable risk factor |
| title_sort | optimal interpregnancy interval in autism spectrum disorder: a multi-national study of a modifiable risk factor |
| topic | Science & Technology Social Sciences Life Sciences & Biomedicine Behavioral Sciences Psychology, Developmental Psychology autism spectrum disorder birth intervals family planning services longitudinal studies PREGNANCY HEALTH autism spectrum disorder birth intervals family planning services longitudinal studies Autism Spectrum Disorder Birth Intervals Female Finland Humans Pregnancy Retrospective Studies Risk Factors Humans Risk Factors Retrospective Studies Pregnancy Birth Intervals Finland Female Autism Spectrum Disorder |
| 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/20.500.11937/93719 |