Dataset Information

The effects of smoking and hypertensive disorders on fetal growth.

ABSTRACT:

Background

It is well known that smoking and pregnancy induced hypertension (PIH) are associated with decreased fetal growth. It has been reported that in preeclampsia the fetal growth deficit attributable to smoking is higher, which has been contradicted in other studies. We therefore evaluated the effects on fetal growth of early- and late onset PIH and chronic hypertension and how cigarette smoking modify these effects. We also quantified the proportion of small for gestational age (SGA) cases attributable to PIH, chronic hypertension, and smoking.

Methods

Population-based study based on record of 215598 singleton pregnancies from the Medical Birth Registry of Norway.

Results

In severe preeclampsia, mild preeclampsia, transient hypertension, and normotension in term birth, odds ratios (ORs) of SGA in smokers compared with non-smokers were 1.4 (95% confidence interval 0.9, 2.2), 1.6 (1.3, 1.9), 2.3 (1.8, 3.1), and 2.0 (1.9, 2.1), respectively. For preterm births, corresponding ORs were 1.3 (0.9, 2.0), 1.8 (1.1, 3.0), 4.1 (1.9, 9.0), and 1.7 (1.4, 2.0), respectively. The effect of early onset PIH was stronger than that in term births, while the effect of smoking was equal in preterm and term newborns. Only in non-smokers who delivered at term, the rates of SGA significantly increased with the severity of PIH (ORs = 1.3 (1.1, 1.5), 1.8 (1.7, 2.0), and 2.5 (2.2, 3.0) for transient hypertension, mild-, and severe preeclampsia, respectively). The combined effects of smoking and hypertension were generally not synergistic. The effect of smoking was not stronger in women who had chronic hypertension. Nor were the effects of chronic hypertension stronger in smokers. PIH explained 21.9 and 2.5% of preterm and term cases of SGA, respectively, while smoking explained 12% of SGA cases.

Conclusion

The effects of hypertensive disorder and smoking were generally not synergistic, which suggest that they may exert their main actions on separate sites or work through separate mechanisms within or outside the placenta. If smoking were eliminated in pregnant women, the number of SGA cases would be reduced by 12%.

SUBMITTER: Rasmussen S

PROVIDER: S-EPMC1463005 | biostudies-literature | 2006 Apr

REPOSITORIES: biostudies-literature

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The effects of smoking and hypertensive disorders on fetal growth.

Rasmussen Svein S Irgens Lorentz M LM

BMC pregnancy and childbirth 20060421

<h4>Background</h4>It is well known that smoking and pregnancy induced hypertension (PIH) are associated with decreased fetal growth. It has been reported that in preeclampsia the fetal growth deficit attributable to smoking is higher, which has been contradicted in other studies. We therefore evaluated the effects on fetal growth of early- and late onset PIH and chronic hypertension and how cigarette smoking modify these effects. We also quantified the proportion of small for gestational age (S ...[more]

PMID: 16630351

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Project description:BACKGROUND:Fetal growth patterns in pregnancy-associated hypertensive disorders is poorly understood because prospective longitudinal data are lacking. OBJECTIVE:The objective of the study was to compare longitudinal fetal growth trajectories between normotensive women and those with pregnancy-associated hypertensive disorders. STUDY DESIGN:This is a study based on data from a prospective longitudinal cohort study of fetal growth performed at 12 US sites (2009-2013). Project gestational age was confirmed by ultrasound between 8 weeks 0 days and 13 weels 6 days, and up to 6 ultrasounds were performed across gestation. Hypertensive disorders were diagnosed based on 2002 American College of Obstetricians and Gynecologists guidelines and grouped hierarchically as severe preeclampsia (including eclampsia or HELLP [hemolysis, elevated liver enzymes, and low platelet count] syndrome), mild preeclampsia, severe gestational hypertension, mild gestational hypertension, or unspecified hypertension. Women without any hypertensive disorder constituted the normotensive group. Growth curves for estimated fetal weight and individual biometric parameters including biparietal diameter, head circumference, abdominal circumference, and femur and humerus length were calculated for each group using linear mixed models with cubic splines. Global and weekly pairwise comparisons were performed between women with a hypertensive disorder compared with normotensive women to analyze differences while adjusting for confounding variables. Delivery gestational age and birthweights were compared among groups. RESULTS:Of 2462 women analyzed, 2296 (93.3%) were normotensive, 63 (2.6%) had mild gestational hypertension, 54 (2.2%) mild preeclampsia, 32 (1.3%) severe preeclampsia, and 17 (0.7%) unspecified hypertension. Compared with normotensive women, those with severe preeclampsia had estimated fetal weights that were reduced between 22 and 38 weeks (all weekly pairwise values of P < .008). Women with severe preeclampsia compared with those without hypertension also had significantly smaller fetal abdominal circumference between 23-31 and 33-37 weeks' gestation (weekly pairwise values of P < .04). Scattered weekly growth differences were noted on other biometric parameters between these 2 groups. The consistent differences in estimated fetal weight and abdominal circumference were not observed between women with other hypertensive disorders and those who were normotensive. Women with severe preeclampsia delivered significantly earlier (mean gestational age 35.9 ± 3.2 weeks) than the other groups (global P < .0001). Birthweights in the severe preeclampsia group were also significantly lower (mean -949.5 g [95% confidence interval, -1117.7 to -781.2 g]; P < .0001) than in the normotensive group. CONCLUSION:Among women with pregnancy-associated hypertensive disorders, only those destined to develop severe preeclampsia demonstrated a significant and consistent difference in fetal growth (ie, smaller estimated fetal weight and abdominal circumference) when compared with normotensive women.

Project description:Aims:Current antihypertensive therapies cannot cure hypertension and a life-long medication is necessary. Maternal treatment may represent a promising strategy for hypertension treatment. We have previously shown that maternal treatment of spontaneously hypertensive rats (SHR) with pentaerythritol tetranitrate (PETN) leads to a persistent blood pressure reduction in the female offspring. The underlying mechanisms include improved endothelial function resulting from long-lasting epigenetic changes. In the present study, we address the renal effects of maternal PETN treatment. Methods and Results:F0 parental SHR were fed with either normal chow or PETN-containing (1 g/kg) chow ad libitum from the time point of mating to the end of lactation period. The F1 offspring received normal chow without PETN from the time point of weaning (at the age of 3 weeks). At the age of 16 weeks, female PETN offspring showed lower blood pressure than the control. No difference was observed in male offspring. All following experiments were performed with kidneys from 16-week-old female offspring. Maternal PETN treatment reduced the mRNA and protein expression of angiotensin-converting enzyme (ACE) and basic fibroblast growth factor (FGF2), resulting from epigenetic modifications found at the proximal promoter regions. The expression levels of mineralocorticoid receptor (MR) and factors in the MR signalling pathway (Rac1 and Sgk1) were also reduced by PETN. Major profibrotic cytokines, including Wnt4, TNF-alpha, TGF-beta, and MMP9, were downregulated by PETN, which was associated with reduced collagen deposition and glomerulus sclerosis in the kidney of PETN offspring. In addition, PETN treatment also decreased the markers of inflammation and immune cell infiltration in the kidneys. Conclusions:PETN maternal treatment leads to epigenetic changes in the kidney of female SHR offspring. The reduced renal inflammation, alleviated kidney fibrosis, and decreased MR signalling are potential mechanisms contributing to the observed blood pressure-lowering effect.

Dataset Information

The effects of smoking and hypertensive disorders on fetal growth.

Background

Methods

Results

Conclusion

Publications

The effects of smoking and hypertensive disorders on fetal growth.

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