Substantial decrease in preeclampsia prevalence and risk over two decades: A population-based study of 1,153,227 deliveries in Norway

Hypertensive disorders of pregnancy among women with cardiovascular disease in Norway: A historical cohort study

INTRODUCTION

Women with cardiovascular disease may be at increased risk of hypertensive disorders of pregnancy (HDP). We aimed to: (1) Investigate the occurrence of HDP in a cohort of pregnant women with cardiovascular disease and compare it with the occurrence in the general population. (2) Assess the association between maternal cardiovascular risk and risk of HDP.

MATERIAL AND METHODS

We reviewed clinical data on a cohort of 901 pregnancies among 708 women with cardiovascular disease who were followed at the National Unit for Pregnancy and Heart Disease and gave birth at Oslo University Hospital between 2003 and 2018. The exposure under study was maternal cardiovascular risk, classified as low, moderate, or high based on a modified classification by the World Health Organization. The main outcome of interest was HDP, which included pre-eclampsia and gestational hypertension. The proportion of HDP cases in the general population in the same period was extracted from the Medical Birth Registry of Norway. We used logistic regression to estimate crude and adjusted odds ratios (OR) of HDP, with associated 95% confidence intervals (CIs), for women with moderate- and high cardiovascular risk compared to women with low risk.

RESULTS

The occurrence of HDP in the study cohort was 12.1% (95% CI: 10.0%-14.4%) and varied between 8.7% (95% CI: 6.5%-11.3%) in the low-risk group, 15.7% (95% CI: 11.1%-21.4%) in the moderate-risk group, and 22.2% (95% CI: 15.1%-30.8%) in the high-risk group. By contrast, the nationwide occurrence of HDP was 5.1% (95% CI: 5.1%-5.2%). In the study cohort, the proportions of pregnancies with gestational hypertension and pre-eclampsia were similar (6.3% and 5.8%, respectively). Compared to pregnancies with low cardiovascular risk, the adjusted OR of HDP was 2.04 (95% CI: 1.21-3.44) in the moderate-risk group and 2.99 (95% CI: 1.73-5.18) in the high-risk group.

CONCLUSIONS

The occurrence of hypertensive disease of pregnancy in the study cohort was more than doubled compared to the general population in Norway. The risk of HDP increased with maternal cardiovascular risk group. We recommend taking into account maternal cardiovascular risk group when assessing risk and prophylaxis of HDP.

Time trends in preeclampsia and gestational diabetes in Denmark and Alberta, Canada, 2005-2018-A population-based cohort study

INTRODUCTION

Preeclampsia and gestational diabetes mellitus share risk factors such as obesity and increased maternal age, which have become more prevalent in recent decades. We examined changes in the prevalence of preeclampsia and gestational diabetes between 2005 and 2018 in Denmark and Alberta, Canada, and investigated whether the observed trends can be explained by changes in maternal age, parity, multiple pregnancy, comorbidity, and body mass index (BMI) over time.

MATERIAL AND METHODS

This study was a register-based cohort study conducted using data from the Danish National Health Registers and the provincial health registers of Alberta, Canada. We included in the study cohort all pregnancies in 2005-2018 resulting in live-born infants and used binomial regression to estimate mean annual increases in the prevalence of preeclampsia and gestational diabetes in the two populations across the study period, adjusted for maternal characteristics.

RESULTS

The study cohorts included 846 127 (Denmark) and 706 728 (Alberta) pregnancies. The prevalence of preeclampsia increased over the study period in Denmark (2.5% to 2.9%) and Alberta (1.7% to 2.5%), with mean annual increases of 0.03 (95% confidence interval [CI] 0.02-0.04) and 0.06 (95% CI 0.05-0.07) percentage points, respectively. The prevalence of gestational diabetes also increased in Denmark (1.9% to 4.6%) and Alberta (3.9% to 9.2%), with average annual increases of 0.20 (95% CI 0.19-0.21) and 0.44 (95% CI 0.42-0.45) percentage points. Changes in the distributions of maternal age and BMI contributed to increases in the prevalence of both conditions but could not explain them entirely.

CONCLUSIONS

The prevalence of both preeclampsia and gestational diabetes increased significantly from 2005 to 2018, which portends future increases in chronic disease rates among affected women. Increasing demand for long-term follow up and care will amplify the existing pressure on healthcare systems.

Treatable traits in asthma during pregnancy: a call for a shift towards a precision-based management approach

Asthma is the most common chronic medical condition in pregnancy. Asthma exacerbations in pregnancy are unpredictable, and are associated with adverse maternal and fetal perinatal outcomes such as preterm birth and low birthweight. Goals of asthma management in pregnancy are to establish effective asthma control and prevent exacerbations. Optimising the management of asthma in pregnancy is an important goal of practice and future research.Treatable traits is a precision medicine paradigm proposed for the management of airways diseases, which holistically addresses the complexity and heterogeneity of airways disease. It is an individualised treatment approach that aims to improve outcomes. This makes treatable traits well suited for pregnant women with asthma, who have a high prevalence of obesity, mental health conditions, poor symptom perception and suboptimal asthma management skills including low treatment adherence. These traits are measurable and treatable. In this review, we explore current knowledge on the burden of asthma, maternal and perinatal consequences of asthma during pregnancy, the treatable traits paradigm, the prevalence of treatable traits in pregnant women with asthma, and consider how the treatable traits paradigm can be integrated into the management of asthma in pregnancy.

Postpartum Lifestyle Behaviors among Women with Hypertensive Disorders of Pregnancy: Data from the HUNT Study

Hypertensive disorders of pregnancy (HDP) are associated with an increased risk of cardiovascular disease later in life. Clinical guidelines for postpartum follow-up after HDP often recommend lifestyle counseling to reduce this risk. However, knowledge about lifestyle behaviors and perceptions among women with a history of HDP is limited. We linked data from the fourth survey of the population-based Trøndelag Health Study (HUNT4) with data from the Medical Birth Registry of Norway. The associations between HDP and postpartum lifestyle behaviors and perceptions were examined using multivariable logistic regression. In a secondary analysis, HUNT4 participants with a recent history of pre-eclampsia were compared with women with a recent history of pre-eclampsia participating in a postpartum pilot intervention study. Lifestyle behaviors and perceptions were self-reported and included diet (intake frequency of fruits, vegetables, meat, fish, and sugar-sweetened beverages), alcohol intake, physical activity, sleep, smoking, lifestyle satisfaction, and the importance of a healthy lifestyle. Among 7551 parous HUNT4 participants, 610 had a history of HDP. We found no differences in lifestyle behaviors between women with and without a history of HDP. However, women with HDP had higher odds of being unsatisfied with their lifestyle. Women with pre-eclampsia participating in a postpartum lifestyle intervention study tended to have a healthier lifestyle at baseline than women participating in HUNT4. Future studies should explore how lifestyle intervention programs could be adapted to the needs of women who have experienced HDP or other pregnancy complications that are associated with an increased risk of CVD.

Trends in Term Intrapartum Stillbirth in Norway

Importance

Fetal death during labor at term is a complication that is rarely studied in high-income countries. There is a need for large population-based studies to examine the rate of term intrapartum stillbirth in high-income countries and the factors associated with its occurrence.

Objective

To evaluate trends in term intrapartum stillbirth over time and to investigate the association between the trends and term intrapartum stillbirth risk factors from 1999 to 2018 in Norway.

Design, Setting, and Participants

This cohort study used data from the Medical Birth Registry of Norway from 1999 to 2018 to examine rates of term intrapartum stillbirth and risk factors associated with this event. A population of 1 021 268 term singleton pregnancies without congenital anomalies or antepartum stillbirths was included in analyses, which were performed from September 2022 to February 2023.

Exposure

The main exposure variable was time, which was divided into four 5-year periods: 1999 to 2003, 2004 to 2008, 2009 to 2013, and 2014 to 2018.

Main Outcomes and Measures

The primary study outcome was term intrapartum stillbirth. Risk ratios were calculated, and multivariable logistic regression analyses were conducted to identify factors associated with secular trends of term intrapartum stillbirth.

Results

The study population consisted of 1 021 268 term singleton births (maternal mean [SD] age, 29.72 [5.01] years; mean [SD] gestational age, 39.69 [1.27] weeks). During the study period, there were 95 term intrapartum stillbirths (0.09 per 1000 births). Maternal age, the proportion of individuals born in a country other than Norway, and the prevalence of gestational diabetes, labor induction, operative vaginal delivery, and previous cesarean delivery increased over the course of the study period. Conversely, the prevalence of infants large for gestational age, hypertensive disorder in pregnancy, and spontaneous vaginal delivery and the proportion of individuals who smoked decreased. The term intrapartum stillbirth rate decreased by 87% (95% CI, 68%-95%) from 0.15 per 1000 births in 1999 to 2008 to 0.02 per 1000 births in 2014 to 2018. Three in 4 term intrapartum stillbirths (70 of 95) occurred during intrapartum operative deliveries. The increased prevalence of older maternal age and obstetric risk factors were not associated with the variation in intrapartum stillbirth rates among the time periods. The prevalence of term intrapartum stillbirth was higher for individuals who gave birth in maternity units with fewer than 3000 annual births (adjusted odds ratio, 1.67; 95% CI, 1.07-2.61) than for those who gave birth in units with 3000 or more annual births.

Conclusions and Relevance

Findings of this study suggest that, despite increases in maternal and obstetric risk factors, term intrapartum stillbirth rates substantially decreased during the study period. Reasons for this decrease may be due to improvements in intrapartum care.

Differential trend of mild and severe preeclampsia among nulliparous women: a population-based study of South Korea

We explored the annual risks of mild and severe preeclampsia (PE) among nulliparous women. Using the National Health Information Database of South Korea, 1,317,944 nulliparous women who gave live births were identified. Mild PE increased from 0.9% in 2010 to 1.4% in 2019 (P for trend=0.006), while severe PE decreased from 0.4% in 2010 to 0.3% in 2019 (P=0.049). The incidence of all types of PE (mild and severe) showed no linear change (P=0.514). Adjusted odds ratio (OR) of severe PE decreased in 2013 (0.68; 95% confidence interval [CI]: 0.60, 0.77) and beyond compared to that in 2010, while the OR of mild PE increased in 2017 (1.14; 95% CI: 1.06, 1.22) and beyond. Mild PE was found to be less likely to progress to the severe form since 2010; however, the overall risk of PE among women did not change.

High prevalence of pre-eclampsia in women with coarctation of the aorta

Aims

The aim was to study pregnancy outcomes in women with coarctation of the aorta (CoA) and associations to hypertensive disorders of pregnancy. Maternal morbidity and mortality are higher in women with heart disease and pre-eclampsia. Chronic hypertension, frequently encountered in CoA, is a risk factor for pre-eclampsia.

Methods and results

Clinical data from the National Unit for Pregnancy and Heart Disease database was reviewed for pregnant women with CoA from 2008 to 2021. The primary outcome was hypertensive pregnancy disorders. The secondary outcomes were other cardiovascular, obstetric, and foetal complications. Seventy-six patients were included, with a total of 87 pregnancies. Seventeen (20%) patients were treated for chronic hypertension before pregnancy. Fifteen (20%) patients developed pre-eclampsia, and 5 (7%) had pregnancy-induced hypertension. Major adverse cardiac events developed in four (5%) patients, with no maternal or foetal mortality. Maternal age at first pregnancy [odds ratio (OR) 1.37], body mass index before first pregnancy (OR 1.77), and using acetylsalicylic acid from the first trimester (OR 0.22) were statistically significantly associated with pre-eclampsia. At follow-up (median) 8 years after pregnancy, 29 (38%) patients had anti-hypertensive treatment, an increase of 16% compared to pre-pregnancy. Five (7%) patients had progression of aorta ascendens dilatation to >40 mm, seven (9%) had an upper to lower systolic blood pressure gradient >20 mmHg, and six (8%) had received CoA re-intervention.

Conclusion

Pre-eclampsia occurred in 20% of women with CoA in their first pregnancy. All pre-eclamptic patients received adequate anti-hypertensive treatment. All CoA patients were provided multi-disciplinary management, including cardiologic follow-up, to optimize maternal-foetal outcomes.

Metabolic profiling of pregnancies complicated by preeclampsia: A longitudinal study

INTRODUCTION

Preeclampsia is associated with maternal metabolic disturbances, but longitudinal studies with comprehensive metabolic profiling are lacking. We aimed to determine metabolic profiles across gestation in women who developed preeclampsia compared with women with healthy pregnancies. We also explored the respective effects of body mass index (BMI) and preeclampsia on various metabolic measures.

MATERIAL AND METHODS

We measured 91 metabolites by high-throughput nuclear magnetic resonance spectroscopy at four time points (visits) during pregnancy (weeks 14-16, 22-24, 30-32 and 36-38). Samples were taken from a Norwegian pregnancy cohort. We fitted a linear regression model for each metabolic measure to compare women who developed preeclampsia (n = 38) and healthy controls (n = 70).

RESULTS

Among women who developed preeclampsia, 92% gave birth after 34 weeks of gestation. Compared to women with healthy pregnancies, women who developed preeclampsia had higher levels of several lipid-related metabolites at visit 1, whereas fewer differences were observed at visit 2. At visit 3, the pattern from visit 1 reappeared. At visit 4 the differences were larger in most subgroups of very-low-density lipoprotein particles, the smallest high-density lipoprotein, total lipids and triglycerides. Total fatty acids were also increased, of which monounsaturated fatty acids and saturated fatty acids showed more pronounced differences. Concentration of glycine tended to be lower in pregnancies with preeclampsia until visit 3, although this was not significant after correction for multiple testing. After adjustment for age, BMI, parity and gestational weight gain, all significant differences were attenuated at visits 1 and 2. The estimates were less affected by adjustment at visits 3 and 4.

CONCLUSIONS

In early pregnancy, the metabolic differences between preeclamptic and healthy pregnancies were primarily driven by maternal BMI, probably representing the women's pre-pregnancy metabolic status. In early third trimester, several weeks before clinical manifestation, the differences were less influenced by BMI, indicating preeclampsia-specific changes. Near term, women with preeclampsia developed an atherogenic metabolic profile, including elevated total lipids, very-low-density lipoprotein, triglycerides, and total fatty acids.

Is the increasing prevalence of labor induction accompanied by changes in pregnancy outcomes? An observational study of all singleton births at gestational weeks 37-42 in Norway during 1999-2019

INTRODUCTION

Induction of labor is often performed to prevent adverse perinatal and maternal outcomes, and has become increasingly common. We studied whether changes in prevalence of labor induction in gestational weeks 37-42 weeks were accompanied by changes in adverse pregnancy outcomes or mode of delivery.

MATERIAL AND METHODS

We used data from the Medical Birth Registry of Norway, and included all singleton births in gestational weeks 37-42 in Norway, 1999-2019 (n = 1 127 945). We calculated the prevalence of labor induction and outcome measures according to year of birth. We repeated these calculations for each gestational week at birth.

RESULTS

The prevalence of labor induction increased from 9.7% to 25.9%, and the increase was particularly high in gestational week 41. A modest decline in fetal deaths was observed in all gestational weeks, except gestational week 41. The overall decline was from 0.18% in 1999-2004 to 0.13% during 2015-2019. There were no overall changes in other perinatal outcomes. The prevalence of postpartum hemorrhage ≥500 ml increased from 11.4% in 1999 to 30.1% in 2019, and operative deliveries increased slightly. The prevalence of acute cesarean section increased from 6.5% to 9.3%, whereas vacuum and/or forceps assisted deliveries increased from 7.8% to 10.4%.

CONCLUSIONS

A high increase in labor inductions was accompanied by a modest decline in fetal deaths, but no decline in other adverse perinatal outcomes. In settings where the prevalence of adverse perinatal outcomes is low, the beneficial effect of increased use of labor induction may not outweigh the side effects or the costs.