Epidemiology of eclampsia

Effect of indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005-2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39,657 women aged 15-49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26-3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings.

Is teenage pregnancy an obstetric risk in a welfare society? A population-based study in Finland, from 2006 to 2011

OBJECTIVE

To assess obstetric outcomes in teenage pregnancies in a country with a low teenage delivery rate and comprehensive high-quality prenatal care.

DESIGN

Retrospective population-based register study.

SETTING

Finland.

PARTICIPANTS

All nulliparous teenagers (13-15 years (n=84), 16-17 years (n=1234), 18-19 years (n=5987)) and controls (25-year-old to 29-year-old women (n=51 142)) with singleton deliveries in 2006-2011.

MAIN OUTCOME MEASURES

Risk of adverse obstetric outcomes adjusted for demographic factors and clinically relevant pregnancy complications, with main focus on maternal pregnancy complications.

RESULTS

Teenage mothers were more likely than controls to live in rural areas (16% (n=1168) vs 11.8% (n=6035)), smoke (36.4% (n=2661) vs 7% (n=3580)) and misuse alcohol or drugs (1.1% (n=82) vs 0.2% (n=96); p<0.001 for all). Teenagers made a good mean number of antenatal clinic visits (16.4 vs 16.5), but were more likely to have attended fewer than half of the recommended visits (3% (n=210) vs 1.4% (n=716)). Teenagers faced increased risks of several obstetric complications, for example, anaemia (adjusted OR 1.8, 95% CI 1.6 to 2.1), proteinuria (1.8, 1.2 to 2.6), urinary tract infection (UTI; 2.9, 1.8 to 4.8), pyelonephritis (6.3, 3.8 to 10.4) and eclampsia (3.2, 1.4 to 7.3), the risks increasing with descending age for most outcomes. Elevated risks of pre-eclampsia (3.7, 1.5 to 9.0) and preterm delivery (2.5, 1.2 to 5.3) were also found among 13-year-olds to 15-year-olds. However, teenage mothers were more likely to have vaginal delivery (1.9, 1.7 to 2.0) without complications. Inadequate prenatal care among teenagers was a risk factor of eclampsia (12.6, 2.6 to 62.6), UTI (5.8, 1.7 to 19.7) and adverse neonatal outcomes.

CONCLUSIONS

Pregnant teenagers tended to be socioeconomically disadvantaged versus controls and faced higher risks of various pregnancy complications. Special attention should be paid to enrolling teenagers into adequate prenatal care in early pregnancy.

Risk factors for eclampsia: a population-based study in Washington State, 1987-2007

OBJECTIVE

We sought to investigate whether previously identified risk factors are associated with eclampsia in a contemporary, heterogeneous cohort of women.

STUDY DESIGN

Data were collected from birth certificate and hospital discharge records and used to conduct a population-based case-control study among women giving birth to singletons in Washington State from 1987 through 2007. We used multivariable logistic regression to estimate odds ratios and 95% confidence intervals. Multiple imputation procedures were used to address missing data.

RESULTS

Risk of eclampsia was greater in nulliparous compared to parous women. Being a young mother (< 20 years) or an older mother (≥ 35 years) were each associated with elevated eclampsia risk. Longer birth interval, low socioeconomic status, gestational diabetes, prepregnancy obesity, and weight gain during pregnancy above or below recommended guidelines were positively associated with eclampsia. Multiparity and smoking were inversely associated with eclampsia risk.

CONCLUSION

Exposures identified more than a decade ago continue to be associated with eclampsia in contemporary birth cohorts.

A randomized comparative trial of the efficacy and safety of exercise during pregnancy: Design and methods

Use of an exercise intervention for high-risk and vulnerable populations, such as pregnant women at risk for gestational hypertension or preeclampsia, requires special consideration. A comparative trial testing the effects of two types of physical exercises - stretching (a comparator) and walking (a testing intervention) - for sedentary pregnant women at risk for preeclampsia - is presented in this paper. The study was designed to reduce post-randomization bias and dropout rates from both groups, and closely to monitor safety of subjects. The strengths of the study design and methods include use of a run-in phase; use of a stretching exercise as a comparator; multiple ways to measure daily physical activities and the exercise intervention; and tailored support to remove barriers to exercise for subjects. The intervention consists of 40 min of walking at moderate intensity (i.e., 55-69% of maximum heart rate and rating of perceived exhaustion 12-13) five times a week from 18 weeks gestation until birth. The comparator exercise consists of 40 min of stretching exercise without increasing heart rate to more than 10% of resting heart rate, five times a week from 18 weeks gestation until birth. The primary outcome is the incidence of preeclampsia. Secondary outcomes include the physiologic effects of the intervention and birth outcomes.

Maternal cigarette smoking and the risk of pregnancy-induced hypertension and eclampsia

BACKGROUND

Although previous studies have found that maternal smoking decreases the risk of pregnancy-induced hypertension (PIH), the difference of this effect between primiparous and multiparous women has not been well studied and the results of the exposure-response relationships between maternal smoking and PIH are inconsistent. No previous study has specifically examined the relationship between maternal smoking and eclampsia.

METHODS

We analysed data from a population-based retrospective cohort study of 3 153 944 singleton pregnancies in the US. The data were derived from the national linked birth/infant mortality database for 1998. Multiple logistic regressions were used to describe the relationship between cigarette smoking and PIH and eclampsia.

RESULTS

The adjusted odds ratios (ORs) [95% confidence intervals (95% CIs)] for PIH were 0.80 (0.77-0.83) for primiparous women and 0.81 (0.78-0.83) for multiparous women among smokers compared with non-smokers. The corresponding adjusted ORs (95% CIs) for eclampsia were 0.74 (0.66-0.82) and 0.75 (0.68-0.83), respectively. For PIH, the adjusted OR (95% CI) for smokers vs non-smokers were 0.82 (0.79-0.86), 0.81 (0.78-0.83), 0.80 (0.77-0.83), and 0.88 (0.79-0.98), respectively, for 1-5, 6-10, 11-20, and >20 cigarettes per day (test for trend: P = 0.86). The corresponding figures for eclampsia were 0.85 (0.75-0.95), 0.74 (0.66-0.82), 0.68 (0.58-0.78), and 0.73 (0.49-1.04), respectively (test for trend: P = 0.02).

CONCLUSION

Maternal cigarette smoking decreases the risk of PIH and eclampsia, with a significant inverse exposure-response relationship apparent for eclampsia.

Incidence of severe pre-eclampsia, postpartum haemorrhage and sepsis as a surrogate marker for severe maternal morbidity in a European population-based study: the MOMS-B survey

OBJECTIVE

To describe the incidence of three conditions of acute severe maternal morbidity in selected regions in nine European countries.

DESIGN

A population-based questionnaire survey.

SETTING

Eleven regions in nine countries of Europe.

POPULATION

All the pregnant women in each region who had delivered during the period covered by the study.

METHODS

Standard definitions of three severe obstetric conditions, pre-eclampsia, postpartum haemorrhage and sepsis were established by a steering committee. A common questionnaire was used in each participating country. The incidence of the three obstetric conditions and characteristics of the study women were compared.

MAIN OUTCOME MEASURES

Incidence of three severe obstetric conditions: pre-eclampsia, postpartum haemorrhage and sepsis.

RESULTS

The study identified 1734 women with at least one of the three conditions, with 847 experiencing severe haemorrhage, 793 experiencing severe pre-eclampsia and 142 experiencing severe sepsis. There were wide variations in incidence of three conditions combined, ranging from 14.7 per thousand deliveries in Brussels, Belgium to 6.0 per thousand deliveries in Upper Austria.

CONCLUSIONS

This study sets a simple and straightforward approach to the definition of three severe obstetric conditions and allows population-based comparisons between developed countries in Europe, even though difficulties may have been present with applying the definition across countries. The reported incidence of these severe obstetric conditions in general and severe haemorrhage varied significantly between countries. Overall, severe haemorrhage in particular was the most common of the three conditions, followed closely by severe pre-eclampsia.

Stress-related preeclampsia: an evolutionary maladaptation in exaggerated stress during pregnancy?

The authors hypothesize that preeclampsia is a stress-related disease and an evolutionary maladaptation of exaggerated stress during human pregnancy. Epidemiologic studies show that relative risk for preeclampsia is increased in many stressful situations. Many risk factors for preeclampsia are stress-related. Low-stress situations, on the contrary, are protective. Stress in pregnancy corroborates all physiopathologic theories for preeclampsia; it does not contradict them. Animals exposed to intense stress show many characteristics of preeclampsia, and some animal models for human preeclampsia have been proposed. The stress-alarm reaction is protective for survival in animals. But the evolutionary maladaptation of this intense stress could lead to preeclampsia in humans.

Preeclampsia. Part 1: clinical and pathophysiologic considerations

Preeclampsia-eclampsia is still one of the leading causes of maternal and fetal morbidity and mortality. Despite active research for many years, the etiology of this disorder exclusive to human pregnancy is an enigma. Recent evidence suggests there may be several underlying causes or predispositions leading to the signs of hypertension, proteinuria, and edema, findings that allow us to make the diagnosis of the "syndrome" of preeclampsia. Despite improved prenatal care, severe preeclampsia and eclampsia still occur. Although understanding of the pathophysiology of these disorders has improved, treatment has not changed significantly in over 50 years. Although postponement of delivery in selected women with severe preeclampsia improves fetal outcome to a degree, this is not done without risk to the mother. In the United States, magnesium sulfate and hydralazine are the most commonly used medications for seizure prophylaxis and hypertension in the intrapartum period. The search for the underlying cause of this disorder and for a clinical marker to predict those women who will develop preeclampsia-eclampsia is ongoing, with its prevention the ultimate goal. This review begins with the clinical and pathophysiologic aspects of preeclampsia-eclampsia (Part 1). In Part 2, the experimental observations, the search for predictive factors, and the genetics of this disorder will be reviewed.

Possible beneficial effect of exercise, by reducing oxidative stress, on the incidence of preeclampsia

We hypothesize that regular exercise enhances antioxidative enzymes in pregnant women, which reduce oxidative stress and, thus, the incidence of preeclampsia. Oxidative stress with enhanced lipid peroxide formation could lead to endothelial dysfunction in preeclampsia. Other conditions, such as increased transferrin saturation and decreased iron-binding capacity, directly and indirectly promote the process of oxidative stress and subsequent endothelial dysfunction. Exercise increases oxidative metabolism and produces a prooxidant environment. This acidic environment during exercise (at or beyond anaerobic threshold) promotes oxygen release from hemoglobin and increases in PO(2) in tissues, as well as releases iron from transferrin. When exercise is repeated regularly, the body promptly adjusts so that oxidative stress is eliminated or reduced. The body's adaptations to a regular exercise habit seem to have an antioxidant effect. In humans, training effects have been identified with an enhanced activity of antioxidative enzymes. Another concerted adaptation that regular exercise brings to women's bodies is resistance against production of prooxidants by increasing the number of mitochondria. Equally important is a training effect that decreases susceptibility to lipid peroxidation. Evidence suggests that physically active women are less likely to develop preeclampsia. In theory, intracellular and extracellular conditions resulting from regular exercise should counteract the enhancement of oxidative stress, thus interfering with the process leading to endothelial dysfunction. This position paper describes a hypothesis and includes a brief review of exercise physiology and biochemical research in preeclampsia. Unlike other preventive treatments, such as aspirin or calcium supplements, a regular exercise habit leads to a positive and healthy lifestyle without concern of side effects.

Cigarette smoking during pregnancy and risk of preeclampsia: a systematic review

In this systematic review of the existing evidence regarding the relationship between cigarette smoking during pregnancy and preeclampsia, studies were found through searches of MEDLINE (1966-October 31, 1998), Embase, Popline, CINAHL, Lilacs, bibliographies of identified studies, and proceedings of meetings on preeclampsia, and also through contact with relevant researchers. No language restrictions were imposed. Only cohort and case-control studies dealing with the relationship between cigarette smoking and preeclampsia were considered. Assessment of methodologic quality and data extraction of each study were carried out by 2 authors working independently. Typical relative risks and odds ratios with 95% confidence intervals were calculated for cohort and case-control studies, respectively, with both fixed and random effects models. Twenty-eight cohort studies and 7 case-control studies including a total of 833,714 women were included. All cohort studies reported an inverse association between cigarette smoking during pregnancy and incidence of preeclampsia (typical relative risk, 0.68; 95% confidence interval, 0.67-0.69). The findings were similar for case-control studies (typical odds ratio, 0.68; 95% confidence interval, 0.57-0.81). An inverse dose-response relationship was also found. Pooled data from cohort and case-control studies showed a lower risk of preeclampsia associated with cigarette smoking during pregnancy.

Epidemiology of eclampsia in Colombia

OBJECTIVE

To measure the incidence of eclampsia, its maternal and perinatal outcomes and patterns of presentation of this disease in our environment.

METHOD

Retrospective descriptive study of 164 cases of eclampsia managed at the Hospital Universitario del Valle, Cali, Colombia from September 1993 to August 1995. Information was collected from reviews of hospital case-notes.

RESULTS

The incidence of eclampsia was 8.1/1000 deliveries. Maternal mortality was 6.1%. Fifty-seven percent of seizures occurred antepartum, 22% during labor, and 21% after delivery. Sixty-nine cases (42%) presented preterm. Ninety-eight women (60%) were nulliparous. Approximately one quarter of the women did not have hypertension or significant proteinuria at the time of seizures. Twenty percent of all women had at least one major complication. Perinatal mortality was 12.8%. Antepartum and postpartum cases were more severe than intrapartum cases.

CONCLUSION

Eclampsia occurs in one in 124 deliveries in Cali, Colombia and is associated with high maternal and perinatal morbidity and mortality.