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Published on: January 12, 2018
Impact of diabetes, obesity and hypertension on preterm birth: Population-based study
Howard Berger1, Nir Melamed2, Beth Murray Davis3
1Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
Insights
Pre-existing diabetes, obesity, and hypertension significantly increase preterm birth (PTB) risk. Combining these conditions, particularly hypertension and diabetes, dramatically magnifies PTB risk, especially when provider-initiated or associated with preeclampsia or altered fetal growth.
Area of Science:
- Obstetrics and Gynecology
- Perinatal Medicine
- Public Health
Background:
- Pre-pregnancy conditions like diabetes mellitus (D), obesity (O), and chronic hypertension (H) are significant risk factors for adverse pregnancy outcomes.
- Preterm birth (PTB) remains a leading cause of neonatal morbidity and mortality worldwide.
- Understanding the compounded impact of D, O, and H on PTB is crucial for targeted interventions.
Purpose of the Study:
- To investigate the individual and combined effects of pre-pregnancy diabetes mellitus, obesity, and chronic hypertension on the risk of preterm birth.
- To analyze the impact of these conditions on different subtypes of PTB, including spontaneous vs. provider-initiated and early vs. late PTB.
- To assess the association of these maternal conditions with PTB complicated by preeclampsia, large for gestational age (LGA), and small for gestational age (SGA) infants.
Main Methods:
- A retrospective population-based cohort study was conducted using data from Ontario, Canada (2012-2016).
- Included were women with singleton livebirths or stillbirths after 20 weeks gestation.
- Multivariable Poisson regression models were used to calculate adjusted relative risks (aRR) for PTB, adjusting for maternal age and parity. Population attributable fractions (PAF) were also computed.
Main Results:
- The study analyzed 506,483 pregnancies, with 6.0% experiencing PTB.
- Individually, pre-pregnancy diabetes (aRR 3.51) and hypertension (aRR 3.81) showed higher PTB risks than obesity (aRR 1.14).
- The combination of diabetes and hypertension (DH) significantly increased PTB risk (aRR 6.34 for PTB < 37 weeks; aRR 10.33 for PTB < 34 weeks).
- Hypertension was strongly linked to PTB with preeclampsia (aRR 45.42) and SGA (aRR 9.78), while diabetes was associated with PTB with LGA (aRR 28.85).
Conclusions:
- Combinations of pre-pregnancy diabetes, obesity, and hypertension significantly amplify the risk of preterm birth.
- The risk is particularly elevated for provider-initiated PTB and PTB associated with altered fetal growth (LGA/SGA) or preeclampsia.
- These findings underscore the importance of preconception counseling and management of chronic conditions in women of childbearing age to reduce PTB rates.
Objective:
To determine the impact of pre-pregnancy diabetes mellitus (D), obesity (O) and chronic hypertension (H) on preterm birth (PTB).
Methods:
Retrospective population-based cohort study in Ontario, Canada between 2012-2016. Women who had a singleton livebirth or stillbirth at > 20 weeks gestation were included in the cohort. Exposures of interest were D, O and H, individually, and in various combinations. The primary outcome was PTB at 241/7 to 366/7 weeks. PTB was further analyzed by spontaneous or provider-initiated, early (< 34 weeks) or late (34-37 weeks), and the co-presence of preeclampsia, large for gestational age (LGA), and small for gestational age (SGA). Multivariable Poisson regression models with robust error variance were used to generate relative risks (RR), further adjusted for maternal age and parity (aRR). Population attributable fractions (PAF) were calculated for each of the outcomes by exposure state.
Results:
506,483 women were eligible for analysis. 30,139 pregnancies (6.0%) were complicated by PTB < 37 weeks, of which 7375 (24.5%) had D or O or H. Relative to women without D or O or H, the aRR for PTB < 37 weeks was higher for D (3.51; 95% CI 3.26-3.78) and H (3.81; 95% CI 3.55-4.10) than O (1.14; 95% CI 1.10-1.17). The combined state of DH was associated with a significantly higher aRR of PTB < 37 weeks (6.34; 95% CI 5.14-7.80) and < 34 weeks (aRR 10.33, 95% CI 6.96-15.33) than D alone. The risk of provider initiated PTB was generally higher than that for spontaneous PTB. Pre-pregnancy hypertension was associated with the highest risk for PTB with preeclampsia (aRR 45.42, 95% CI 39.69-51.99) and PTB with SGA (aRR 9.78, 95% CI 7.81-12.26) while pre-pregnancy diabetes was associated with increased risk for PTB with LGA (aRR 28.85, 95% CI 24.65-33.76).
Conclusion:
Combinations of DOH significantly magnify the risk of PTB, especially provider initiated PTB, and PTB with altered fetal growth or preeclampsia.
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