Association of maternal home blood pressure trajectory during pregnancy with infant birth weight: the BOSHI study

Development and evaluation of machine learning models for predicting large-for-gestational-age newborns in women exposed to radiation prior to pregnancy

INTRODUCTION

The correlation between radiation exposure before pregnancy and abnormal birth weight has been previously proven. However, for large-for-gestational-age (LGA) babies in women exposed to radiation before becoming pregnant, there is no prediction model yet.

MATERIAL AND METHODS

The data were collected from the National Free Preconception Health Examination Project in China. A sum of 455 neonates (42 SGA births and 423 non-LGA births) were included. A training set (n = 319) and a test set (n = 136) were created from the dataset at random. To develop prediction models for LGA neonates, conventional logistic regression (LR) method and six machine learning methods were used in this study. Recursive feature elimination approach was performed by choosing 10 features which made a big contribution to the prediction models. And the Shapley Additive Explanation model was applied to interpret the most important characteristics that affected forecast outputs.

RESULTS

The random forest (RF) model had the highest average area under the receiver-operating-characteristic curve (AUC) for predicting LGA in the test set (0.843, 95% confidence interval [CI]: 0.714-0.974). Except for the logistic regression model (AUC: 0.603, 95%CI: 0.440-0.767), other models' AUCs displayed well. Thereinto, the RF algorithm's final prediction model using 10 characteristics achieved an average AUC of 0.821 (95% CI: 0.693-0.949).

CONCLUSION

The prediction model based on machine learning might be a promising tool for the prenatal prediction of LGA births in women with radiation exposure before pregnancy.

Associations of prenatal blood pressure trajectory and variability with child neurodevelopment at 2 years old

BACKGROUND

The patterns of blood pressure (BP) change throughout the pregnancy were related to adverse birth outcomes. However, little is known about the long-term effect of BP change patterns on child neurodevelopment. This study aimed to explore the relationship between the BP trajectory and BP variability during pregnancy and early childhood neurodevelopment.

METHOD

A total of 2797 mother-newborn pairs were derived from the Wuhan Healthy Baby Cohort Study. BP was measured during each antenatal visit, and Mental and Psychomotor Development Indexes (MDI and PDI) were assessed using the Bayley Scales of Infant Development (BSID) when the children were 2 years old. Delayed neurodevelopment was defined as scores of PDI or MDI less than - 1SD relative to the mean score of the study population. A group-based multi-trajectory model was adopted to identify multi-trajectories of systolic blood pressure (SBP) and diastolic blood pressure (DBP). Visit-to-visit BP variability was assessed by the coefficient of variation (CV), standard deviation (SD), and average real variability (ARV). Generalized linear models and multivariate logistic regressions were used to assess the associations of BP trajectories and variability with BSID scores and delayed neurodevelopment, respectively.

RESULTS

Five distinct trajectories for SBP and DBP were identified, namely, "Low-increasing," "Low-stable," "Moderate-decreasing," "Moderate-increasing," and "High-stable" groups. Compared with the "Low-stable" group, the children whose mothers' BP fell into the other four groups had lower PDI scores, and mothers in the "Low-increasing," "Moderate-increasing," and "Moderate-decreasing" groups had 43% (OR: 1.43, 95% CI: 1.01, 2.03), 48% (OR: 1.48, 95% CI: 1.05, 2.08) and 45% (OR:1.45, 95% CI: 1.03, 2.04) higher risk of having offspring with delayed psychomotor neurodevelopment, respectively. High DBP variability was associated with lower BSID scores, and delayed psychomotor neurodevelopment (OR = 1.46, 95% CI: 1.10, 1.92 for DBP-SD; OR = 1.53, 95% CI: 1.16, 2.02 for DBP-CV).

CONCLUSION

Our findings suggest that BP change patterns assessed by multi-trajectory and visit-to-visit variability were associated with lower BSID scores and delayed neurodevelopment. Health professionals should be aware of the influence of BP level and its oscillations during pregnancy on the risk of delayed neurodevelopment.

Association Between Smoking and Hypertension in Pregnancy Among Japanese Women: A Meta-analysis of Birth Cohort Studies in the Japan Birth Cohort Consortium (JBiCC) and JECS

BACKGROUND

Recent literature suggest the effect of maternal smoking on risk of hypertensive disorders in pregnancy (HDP) and preeclampsia may differ by ethnicity; however, studies on Asians are limited.

METHODS

We investigated the association of maternal smoking with HDP and preeclampsia using a common analysis protocol to analyze the association in six birth cohorts participating in a Japanese consortium of birth cohorts (JBiCC). Results were compared with-published results from cohorts not included in this consortium, and, where possible, we produced a meta-analysis including these studies.

RESULTS

Meta-analysis of four cohort studies including 28,219 participants produced an odds ratio (OR) of 1.24 (95% confidence interval [CI], 0.88-1.87) for the effect of smoking beyond early pregnancy compared to women who did not smoke during pregnancy. These results combined with those from the Japan Environment and Children's Study (JECS) yielded an OR of 1.19 (95% CI, 1.00-1.43, P = 0.056). Meta-analysis results for categories of smoking volume were insignificant, but when combined with JECS yielded an OR of 0.86 (95% CI, 0.65-1.12) for smoking 1-4 cigarettes, 1.25 (95% CI, 0.98-1.60) for smoking 5-9 cigarettes, and 1.27 (95% CI, 1.04-1.54) for smoking 10 or more cigarettes per day. All effects were insignificant for preeclampsia.

CONCLUSION

Our results suggest that the protective effects of smoking longer and smoking more on HDP and preeclampsia repeatedly observed among Europeans and North Americans likely do not hold for the Japanese.

A personal history of research on hypertension From an encounter with hypertension to the development of hypertension practice based on out-of-clinic blood pressure measurements

In the 1970s, many people had severe hypertension and related cardiovascular and cerebrovascular diseases; however, antihypertensive treatments were not available at the time. The author encountered such conditions during the initial exposure to medicine. The author subsequently entered the field of hypertension medicine to prevent such conditions and engaged in hypertension research for more than 50 years. The author's central interest was the physiological and clinical aspects of blood pressure (BP) variability. Out-of-clinic BP measurements were the focus of clinical research. It was anticipated that self-measurement of BP at home (HBP) would improve medical practice surrounding hypertension. To establish evidence-based hypertension medicine, the Ohasama study (an epidemiology based on HBP) was conducted. The study provided firm evidence of the clinical significance of HBP and diagnostic criteria for hypertension and normotension. To establish target HBP levels for antihypertensive therapy, the Hypertension Objective treatment based on Measurement by Electrical Devices of Blood Pressure (HOMED-BP) study (a prospective intervention study) was also conducted. Application of HBP measurements expanded to obstetric, clinical pharmacology, pathophysiology, and genetic studies. During these studies, crucial information on the clinical significance of BP variability (such as circadian and day-by-day variation of BP, nocturnal BP, white-coat hypertension, and masked hypertension) was established. Finally, the author described the priority of HBP over clinic-measured BP for the diagnosis of hypertension in the 2014 Japanese Society of Hypertension Guidelines. In this article, the author's history of hypertension research, from the first encounter with hypertension to the construction of guidelines on hypertension, is reviewed.

Hypertensive disorders of pregnancy: definition, management, and out-of-office blood pressure measurement

Hypertensive disorders of pregnancy increase the risk of adverse maternal and fetal outcomes. In 2018, the Japanese classification of hypertensive disorders of pregnancy was standardized with those of other countries, and a hypertensive disorder of pregnancy was considered to be present if hypertension existed during pregnancy and up to 12 weeks after delivery. Strategies for the prevention of hypertensive disorders of pregnancy have become much clearer, but further research is needed on appropriate subjects and methods of administration, and these have not been clarified in Japan. Although guidelines for the use of antihypertensive drugs are also being studied and standardized with those of other countries, the use of calcium antagonists before 20 weeks of gestation is still contraindicated in Japan because of the safety concerns that were raised regarding possible fetal anomalies associated with their use at the time of their market launch. Chronic hypertension is now included in the definition of hypertensive disorders of pregnancy, and blood pressure measurement is a fundamental component of the diagnosis of hypertensive disorders of pregnancy. Out-of-office blood pressure measurements, including ambulatory and home blood pressure measurements, are important for pregnant and nonpregnant women. Although conditions such as white-coat hypertension and masked hypertension have been reported, determining their occurrence in pregnancy is complicated by the gestational week. This narrative review focused on recent reports on hypertensive disorders of pregnancy, including those related to blood pressure measurement and classification.

Annual reports on hypertension research 2020

In 2020, 199 papers were published in Hypertension Research. Many excellent papers have contributed to progress in research on hypertension. Here, our editorial members have summarized eleven topics from published work and discussed current topics in depth. We hope you enjoy our special feature, Annual Reports on Hypertension Research.

Associations Between Trajectory of Different Blood Pressure Components in Pregnancy and Risk of Adverse Birth Outcomes - A Real World Study

Background

High blood pressure during pregnancy has been suggested to be associated with adverse birth outcomes (ABO), but it is unclear how different blood pressure changes and the extent of the effect. Therefore, we aimed to investigate the association between blood pressure trajectories (systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP)) of pregnant women and ABO in a real-world study.

Material and Methods

Leveraging 28,679 pregnant women and their fetuses from a register-based cohort from January 1, 2010, to December 31, 2019. Blood pressure trajectories were estimated by package “traj” in R software using real-world blood pressure data of routine antenatal care examinations. Logistic regression models were applied to examine the association between trajectories of different blood pressure components (SBP, DBP, MAP, and PP) during pregnancy and the risk of ABO.

Results

Trajectories of all blood pressure components were identically labeled as low-stable, moderate-increasing, moderate-decreasing and high-stable. After adjusting for confounding factors, compared with pregnant women with the low-stable pattern, pregnant women with a high-stable or moderate-increasing pattern had a significantly increased risk of developing adverse birth outcomes. Pregnant women with a moderate-decreasing pattern had no significant increased risk of ABO but had a lower risk of adverse birth outcomes than those with a moderate-increasing pattern. The trajectories crossed at 17–20 weeks of gestation for all blood pressure components.

Conclusion

Our study results indicated that reduction and maintenance of blood pressure to a low level of less than 110 mmHg for SBP and 65 mmHg for DBP after 20 weeks of gestation would benefit prevention of adverse birth outcomes, regardless of the level of blood pressure at early pregnancy.

Exposure to heavy metals and trace minerals in first trimester and maternal blood pressure change over gestation

BACKGROUND

While several heavy metals and trace minerals have been linked with hypertensive disorders during pregnancy (HDP) in women, no studies have estimated the relationship of exposure to these chemicals, both independently and as a mixture, with systolic blood pressure (SBP) or diastolic blood pressure (DBP) over gestation.

OBJECTIVES

We examined individual and joint effects of 1^st trimester chemicals with SBP and DBP over gestation, and whether those chemicals were associated with HDP.

METHODS

We used data from 1832 non-obese pregnant women with low-risk antenatal profiles from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies - Singleton cohort (2009-2013). In plasma collected from women at 8-13 weeks' gestation (baseline enrollment), we measured heavy metals, barium (Ba), cesium (Cs), antimony (Sb), as well as trace minerals, cobalt (Co), copper (Cu), molybdenum (Mo), selenium (Se), and zinc (Zn). We obtained BP at baseline and throughout gestation until delivery and diagnosis of HDP from medical records. We used Bayesian Kernel Machine Regression (BKMR) as well as traditional linear and logistic regressions to examine the cross-sectional associations of chemicals with baseline BP and HDP. We used linear mixed effect regression to examine longitudinal associations between chemicals and rate of weekly change in BP in each trimester. We adjusted for sociodemographic and lifestyle factors and pre-pregnancy body mass index in all models.

RESULTS

BKMR revealed that comparing the entire chemical mixture at the 90^th percentile vs. the 50^th percentile was associated with a 1.61 mmHg (95% CI: 0.41, 2.81) higher SBP and a 1.09 mmHg (0.10, 2.09) higher DBP. No interactions were observed between chemicals. Accounting for chemical co-exposure in BKMR, each interquartile range (IQR) increment in Cu was associated with a 0.67 mmHg (0.02, 1.32) higher SBP and a 0.60 mmHg (0.08, 1.12) higher DBP at baseline; each IQR increment in Se was associated with a 0.67 mmHg (0.05, 1.29) higher SBP but not DBP. In longitudinal analyses, women with higher (i.e., above median concentration) baseline Cu had a 0.09 mmHg (0.01, 0.17) and 0.06 mmHg (0.001, 0.12) larger weekly decrease in SBP and DBP in 2^nd trimester, respectively. Women with higher baseline Ba had a 0.12 mmHg (0.04, 0.20) larger weekly increase in SBP in 2^nd trimester, while women with higher Cs had a 0.05 mmHg (0.01, 0.10) larger weekly increase in DBP in 3^rd trimester. None of the chemicals examined were significantly associated with HDP.

CONCLUSIONS

In this multi-ethnic cohort of women with low antenatal risk, plasma metals and trace minerals in early pregnancy, both individually and as a mixture, were statistically significantly associated with BP during gestation in small magnitude and in different directions, but not with HDP. The implications of these findings for women's postpartum BP and future cardiovascular health remains to be investigated.

Gestational systolic blood pressure trajectories and risk of adverse maternal and perinatal outcomes in Chinese women

Background

Associations between trajectories of systolic blood pressure (SBP) during pregnancy and pregnant outcomes remain unclear and disparate.

Methods

Data of 20,353 mothers without chronic hypertension and who delivered live singletons between January, 2014 and November, 2019, was extracted from Taicang register-based cohort. Based on SBP measured during 10 to 40 weeks of gestation, SBP trajectories were explored using latent class growth mixture model, and their associations with maternal and neonatal outcomes were assessed by logistic regression analyses.

Results

Six heterogeneous SBP trajectories were identified: low delayed-increasing (7.47%), low reverse-increasing (21.88%), low-stable (19.13%), medium-stable (21.64%), medium reverse-increasing (16.47%), and high stable (13.41%) trajectories. The high-stable trajectory had SBP around 125 mmHg in the 10th gestational week, and increased slightly onwards. When compared with the low-stable trajectory, the high-stable trajectory had maximally adjusted odds ratio (95% confidence interval) of 5.28 (2.76–10.10), 1.30 (1.13–1.50), 1.53 (1.12–2.08), 1.32 (1.06–1.65) and 1.64 (1.08–2.48) for gestational hypertension (GH), early-term delivery (ETD), preterm delivery (PTD), small for gestational age and low birth weight (LBW), respectively. Besides, the medium reverse-increasing trajectory showed significantly increased risk of GH and ETD, while the medium-stable trajectory had significantly elevated risk of ETD and PTD. Notably, SBP trajectories slightly but significantly improved risk discrimination of GH, ETD and LBW, over traditional risk factors.

Conclusion

Women with different SBP trajectories were at varied risk of adverse maternal and fetal outcomes. Meanwhile, our study suggested that BP monitoring during pregnancy is necessary, especially for women with high SBP in early pregnancy or upward trajectory.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03599-7.

Epidemiological studies regarding hypertensive disorders of pregnancy: A review

A hypertensive disorder of pregnancy (HDP) is defined as hypertension emerging after 20 weeks of gestation and resolving up to 12 weeks post-partum, and occurs in about 5% of all pregnancies. Complications associated with HDP have poor prognoses, and maternal deaths attributable to HDP are predicted to exceed 70 000 per year worldwide. Understanding the pathogenesis and risk factors of hypertensive disorders of pregnancy is important, and they are often investigated in observational studies. Given that therapeutic interventions cannot be controlled in observed studies, it is necessary to interpret which factors correspond to exposure and which factors correspond to confounding and intermediate factors in each study. From the Babies and their parents' longitudinal observation in the Suzuki Memorial Hospital on Intrauterine period study, blood pressure in early pregnancy was not only predictive of a child's birthweight, but the trajectory was also associated with the birthweight. From the larger-scale birth cohort studies currently conducted in Japan will provide the novel potential risk factors of hypertensive disorders of pregnancy and preventive strategies of them. In Japan, observational or intervention studies are just beginning to emerge. The continuation of both a distinctive cohort and a large cohort is needed, and the development of good quality intervention trials based on the results of observational studies is important.