Wu LX, Jin M, Yang J. Status, outcome, and related factors of postpartum hypertension in the Shanghai community. World J Clin Cases 2024; 12(21): 4632-4641 [DOI: 10.12998/wjcc.v12.i21.4632]
Corresponding Author of This Article
Ling-Xia Wu, MM, Attending Doctor, Department Women's Health, Xuhui District Maternal and Child Health Hospital, No. 118 Liuzhou Road, Xuhui District, Shanghai 200235, China. hopdolphin@163.com
Research Domain of This Article
Obstetrics & Gynecology
Article-Type of This Article
Observational Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Author contributions: Wu LX designed and performed the research and wrote the manuscript; Jin M collected the data and contributed to the analysis; Yang J provided clinical advice and supervised the study.
Institutional review board statement: The study was reviewed and approved by the Ethics Committee of Xuhui District Maternal and Child Health Hospital.
Informed consent statement: All study participants or their legal guardians provided written informed consent prior to study enrollment.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: Not supporting third-party data acquisition.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ling-Xia Wu, MM, Attending Doctor, Department Women's Health, Xuhui District Maternal and Child Health Hospital, No. 118 Liuzhou Road, Xuhui District, Shanghai 200235, China. hopdolphin@163.com
Received: April 24, 2024 Revised: May 23, 2024 Accepted: June 11, 2024 Published online: July 26, 2024 Processing time: 66 Days and 15.9 Hours
Abstract
BACKGROUND
Postpartum hypertension poses a considerable health risk. Despite research on gestational hypertension, comprehensive studies focusing on postpartum hy-pertension in communities are limited. Understanding its prevalence and associated risk factors is crucial for effective prevention and management.
AIM
To provide insights for postpartum hypertension’s prevention and management.
METHODS
In total, 3297 women who gave birth between June 2021 and December 2022 in Xuhui District, Shanghai were selected. Blood pressure was measured thrice within one month post-delivery during home visits. Eighty-six women with hypertension were followed up for four months to analyze hypertension per-sistence and its related risk factors. A predictive model for persistent postpartum hypertension was established and verified using the Nomo diagram model.
RESULTS
Hypertension prevalence 1 month post-delivery was 2.61% (86/3297). Among the 86 pregnant women, 32 (37.21 %) had persistent hypertension at four months post-delivery. Multivariate logistic regression analysis revealed that older age [odds ratio (OR) = 1.212; 95% confidence interval (CI): 1.065–1.380] and higher pre-pregnancy body mass index (BMI) (OR = 1.188; 95%CI: 1.006–1.404) were associated with hypertension (OR = 10.781; 95%CI: 1.006–1.404) during pregnancy. A 95%CI of 1.243–93.480 is a risk factor for persistent postpartum hypertension. The Nomograph model accurately predicted the risk of persistent postpartum hypertension, demonstrating high precision.
CONCLUSION
In Xuhui, older age, higher pre-pregnancy BMI, and gestational hypertension are risk factors for persistent postpartum hypertension. Our prediction model can identify high-risk individuals, thereby improving patient quality of life.
Core Tip: Postpartum hypertension is a critical health concern that affects a substantial proportion of women. Our study, conducted in Shanghai's community, identified advanced maternal age, high pre-pregnancy body mass index, and gestational hypertension as considerable risk factors for persistent postpartum hypertension. The early identification of at-risk individuals and tailored interventions are essential for mitigating long-term cardiovascular risks.
Citation: Wu LX, Jin M, Yang J. Status, outcome, and related factors of postpartum hypertension in the Shanghai community. World J Clin Cases 2024; 12(21): 4632-4641
The incidence of hypertensive diseases continues to increase during pregnancy. The Centers for Disease Control and Prevention in the United States conducted cross-sectional analyses revealing an increase in the incidence of new hypertensive diseases during pregnancy[1-3]. In addition, increasing evidence suggests that hypertensive diseases during pregnancy may extend beyond gestation, serving as an independent risk factor for future cardiovascular and cerebrovascular adverse events in women and their offspring[4-6]. Hypertension substantially contributes to the global cardiovascular disease epidemic, surpassing other cardiovascular risk factors in mortality[7]. Maternal hypertension poses a considerable public health challenge in both developed and developing countries[8]. Current studies primarily focus on hypertension outcomes during the prenatal stage and pregnancy[9,10], including the risk factors, pathogenesis, prevention, and management of the disease during pregnancy. However, a notable gap exists concerning morbidity across the entire maternal population and postpartum outcome management, treatment, and prevention[11]. Currently, in most areas of China, standard maternal health care services do not prioritize postpartum outcomes of pregnancy-induced hypertension or establish a continuous service path for postpartum hypertension, representing a deficiency in lifelong healthcare efforts. Owing to the current maternal healthcare service process concluding 42 days postpartum, understanding postpartum outcomes of hypertensive diseases in pregnancy, and providing morbidity information on postpartum hypertension remains limited. Amid the implementation of universal two-and three-child policies, safeguarding postpartum health is necessary for promoting fertility intentions[12]. Therefore, this study investigated the prevalence of postpartum hypertension 1 month post-delivery, followed up on the population for 4 months post-delivery to understand the incidence of persistent hypertension, and analyzed its influencing factors to provide reasonable suggestions for the prevention and monitoring of postpartum hypertension.
MATERIALS AND METHODS
Study participants
The study was conducted in 13 community health service centers in Xuhui District, Shanghai. In total, 3297 women who gave birth between June 2021 and February 2022 and between September 2022 and December 2022 in Xuhui District were selected as study participants. Eighty-six women were identified with systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg (1 mmHg = 0.133 kpa) within 1 month post-delivery. Their blood pressure was measured thrice on different days. Among them, some women received post-delivery antihypertensive medication effectively controlling their blood pressure below 140/90 mmHg. Eighty-six participants with systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg were followed up for 4 months postpartum, undergoing three blood pressure measurements on separate days. Among them, 32 patients received antihypertensive medication, achieving blood pressure control below 140/90 mmHg. Participants were divided into a case group (n = 54) and a control group (n = 32) based on the presence of postpartum hypertension at 4 months postpartum. Inclusion criteria included all pregnant women between 18 and 45 years old in Xuhui District, whereas the exclusion criteria included twin pregnancies and residing outside the Xuhui District postpartum.
Data collection
In the Xuhui District of Shanghai, all 3297 women who gave birth between June 2021 and December 2022 were selected for the study. Postpartum visits were conducted by medical personnel from 13 community health service centers, during which three blood pressure measurements were taken within 1 month post-delivery. Eighty-six parturient women diagnosed with hypertension were surveyed using a questionnaire and followed up for 4 months post-delivery to determine whether hypertension persisted and analyze related risk factors. Figure 1 presents the research flowchart. Blood pressure measurements were conducted after the mother rested in seated position for 5 min, using an electronic sphygmomanometer (J760, Omro, Japan) on the right arm. This procedure was repeated three times on separate days at the community hospital. All investigators underwent uniform training and used standardized blood pressure diagnostic criteria. The questionnaire gathered general maternal information [age, education level, family income, health insurance, smoking, family history of hypertension, family history of diabetes, pre-pregnancy body mass index (BMI), pre-delivery BMI, parity, method of conception, and gestational week] and disease history (gestational diabetes mellitus, hypertensive disorders during pregnancy, gestational hypertension, preeclampsia, eclampsia, chronic hypertension with preeclampsia, and chronic hypertension with pregnancy). Weight gain during pregnancy was calculated as pre-delivery weight minus pre-pregnancy weight, according to the Institute of the National Academy of Sciences guidelines (2009)[13]. For pregnant women with normal pre-pregnancy weight (BMI: 18.5–24.9 kg/m²), the recommended weight gain during pregnancy is approximately 11.5–16.0 kg. For pregnant women with low pre-pregnancy weight (BMI < 18.5 kg/m²), the recommended weight gain during pregnancy is approximately 12.5–18.0 kg. For pregnant women with overweight (BMI: 25–29.9 kg/m²), the recommended weight gain during pregnancy is approximately 7.0–11.5 kg. For pregnant women with obese (BMI ≥ 30 kg/m²), the recommended weight gain during pregnancy is approximately 5.0–9.0 kg. Weight gain within these ranges is considered appropriate, while gains above or below these ranges are classified as excessive or insufficient, respectively.
Hypertension and pregnancy-induced hypertension diagnoses followed the 2018 Revision of Chinese Guidelines for the Prevention and Treatment of Hypertension[14]. Diagnosis of hypertensive diseases during pregnancy adhered to the 9th edition of Obstetrics and Gynecology diagnostic criteria[15].
Statistical analyses
SPSS 26.0 analyzed statistical data expressed as [n (%)], with χ2 or Fisher’s exact probability tests used. The measurement data corresponded to a normal distribution via the S-W test and are represented as (mean ± SD). Independent t-tests were used for intergroup comparisons. The Mann–Whitney U test compared data groups that did not conform to the normal distribution, presenting median and percentiles (P25, P75). A multivariate logistic regression model analyzed factors affecting postpartum hypertension outcomes. A nomogram prediction model was constructed using R 4.3.1, and the training and validation sets were divided in a 6:4 ratio. P < 0.05 was considered statistically significant.
RESULTS
Univariate analysis of postpartum hypertension outcomes
According to the diagnostic criteria for hypertension, 86 patients (2.60%, 86/3297) had hypertension in the first month following delivery. The maternal age was 21–42 years old with an average age of (33.50 ± 4.91) years. The pre-pregnancy BMI was 17.88–34.10 kg/m2. The average BMI was (24.18 ± 3.49) kg/m2, with 70.93% (61/86) having college or university education. Among 86 women with hypertension followed up for 4 months postpartum, 32 (37.21%, 32/86) had persistent hypertension, with ages in the range of 28–42 years (average age: 35.91 ± 3.91 years) and primarily college or university educated (78.13%, 25/32). Among the 86 parturient who met the diagnostic criteria for hypertension 1 month post-delivery, 52 had pregnancy-induced hypertension, 19 had chronic hypertension combined with pregnancy, and 15 had newly diagnosed hypertension. According to the results of single factor analysis, there were significant differences between the two groups in age, pre-pregnancy BMI, and the presence of hypertension during pregnancy (P < 0.05), as shown in Figure 2. Comparisons of other data showed no statistical significance (P > 0.05), as shown in Table 1.
Figure 2 The two groups of the univariate analysis.
A: Age comparison between the two groups; B: Violin chart of body mass index comparison between the two groups; C: Proportion of hypertensive diseases in pregnancy between the two groups. bP < 0.001. BMI: Body mass index.
Table 1 Univariate analysis on relative factors of persistent postpartum hypertension [X ± S, n (%)].
Multivariate logistic regression analysis of factors associated with persistent postpartum hypertension
With the occurrence of hypertension at the fourth month postpartum as the dependent variable, indicators with statistically significant differences in univariate analysis were selected. A multivariate logistic regression model was subsequently constructed and evaluated using the receiver operating characteristic (ROC) curve. Logistic regression results showed that older maternal age, higher pre-pregnancy BMI, and hypertension during pregnancy were influential factors for persistent postpartum hypertension, and the differences were statistically significant (P < 0.05), as presented in Table 2. The ROC curve analysis revealed good predictive performance for age [area under curve (AUC) = 0.749], BMI (AUC = 0.707), and hypertensive diseases during pregnancy (AUC = 0.614), as shown in Figure 3.
Model establishment: According to the results of multivariate logistic regression analysis, age, BMI, and hypertension during pregnancy were used as predictors to construct a Nomo chart model for predicting persistent postpartum hypertension (Figure 4).
Figure 4 Nomo chart prediction model affecting persistent postpartum hypertension.aP < 0.05; bP < 0.001. BMI: Body mass index.
Evaluation and verification of the prediction effect of the Nomo diagram model: The average absolute errors of the calibration curves for the training and verification sets were 0.003 and 0.009, respectively. The threshold probabilities of the risk prediction model in the training and validation sets were 0%–90% and 0%–55%, respectively. The net benefit to patients was higher than that of the other two extreme curves, indicating that the model was clinically effective within this range (Figure 5).
Figure 5 Internal validation of the model's prediction of persistent postpartum hypertension.
A: Training set calibration curve; B: Verification set calibration curve; C: Training set decision curve; D: Verification set decision curve.
DISCUSSION
Currently, most studies on postpartum hypertension are based on cohort studies of pregnant women with gestational hypertension, whereas few studies are based on the entire population of pregnant women. In this study, 3297 pregnant women were investigated within the entire region in the first month post-delivery, revealing a hypertension prevalence rate of 2.61%. The rate of persistent hypertension in the fourth month postpartum population was 37.21%. Owing to China’s large population base, the number of patients cannot be overlooked. Numerous studies have confirmed the short-term and long-term adverse effects of hypertension on health, emphasizing the need to strengthen postpartum management of hypertensive diseases during pregnancy[16]. In this study, we observed that hypertensive disease during pregnancy, overweight BMI before pregnancy, and older age are high-risk factors for persistent postpartum hypertension, aiding in identifying high-risk groups.
Data from the Shanghai Weitun report indicates an annual increase in the incidence of hypertensive diseases during pregnancy in Xuhui District, consistent with a cross-sectional analysis conducted by the Centers for Disease Control and Prevention in the United States[17]. Previous study[18] excluded pregnant women with chronic hypertension, severe pregnancy-induced hypertension, and preeclampsia, and followed up pregnant women with pregnancy-induced hypertension for 2 years, finding that the incidence of postpartum secondary chronic hypertension was 12.3%. In a survey conducted by Hwang et al[19] in Korea, the incidence of postpartum chronic hypertension was 6.83% in pregnant women with pregnancy-induced hypertension who were followed up for 6 months postpartum after excluding pregnant women with renal, cardiac, vascular, or diabetic diseases during pregnancy. In a survey conducted in the United States by Giorgione et al[20] , 70 (33.2%) of 211 women with hypertensive disorders during pregnancy were still hypertensive at 124 days postpartum, which was significantly higher than in Korea. These studies suggest the importance of not overlooking the risk of pregnancy induced-hypertension secondary to chronic postpartum hypertension. Similarly, research in economically developed countries[21,22] also shows that women with pregnancy-induced hypertension have a long-term risks of chronic hypertension, diabetes, and cardiovascular disease.
This study exhibited a strong correlation between postpartum hypertension and hypertensive diseases during pregnancy, consistent with the findings of a large-sample survey conducted in Taiwan[23]. Compared to pre-pregnancy factors, factors during pregnancy have a greater impact on postpartum hypertension. With the gradual liberalization of fertility policies, the risk of cardiovascular events in pregnant women with hypertensive diseases is increasing[8]. Hypertension during pregnancy has an impact on postpartum arteriosclerosis in women, especially in those who are non-diabetic, < 50 years old, and < 10 years old post-delivery[24,25]. Regarding hypertension disease outcomes, postpartum hypertension primarily arises from pregnancy-induced hypertension. Early and systematic management should be advocated to reduce the long-term harm caused by hypertensive diseases during pregnancy. However, systematic measures for the prevention and management of hypertension in pregnant women with pregnancy-induced hypertension are currently insufficient, with recommendations limited to dietary control and self-monitoring of blood pressure. Therefore, identifying risk factors during pregnancy and the early postpartum period is essential for developing a systematic management model.
Improvements in living standards and changes in dietary structure have led to the emergence of overweight and obesity as considerable public health issues. Pre-pregnancy overweight and obesity are risk factors for hypertensive diseases during pregnancy. BMI is a composite index derived from the combination of height and body mass and can directly reflect body fat content and skinfold thickness. A high pre-conception BMI significantly increases the risk of gestational diabetes, gestational hypertension, and preeclampsia[26]. A linear relationship was found between pre-pregnancy BMI and systolic and diastolic blood pressure during pregnancy[27]. This study found that a high pre-pregnancy BMI was an independent risk factor for persistent postpartum hypertension, similar to the results obtained in a large sample study[23]. Therefore, controlling pre-pregnancy weight within the appropriate range will help maintain normal blood pressure levels to further reduce the risk of hypertensive diseases during pregnancy, improve long-term prognosis of the disease, and effectively promote maternal and child health.
In contrast to previous studies[27], this study could not confirm whether weight gain during pregnancy is a risk factor for persistent postpartum hypertension. This discrepancy could be related to Shanghai’s systematic management standards for pregnant women, which mandate close monitoring for those with pre-pregnancy BMI ≥ 24 to ensure appropriate weight gain. This interpretation is consistent with the results of a study in the Asia-Pacific region[28], which showed that weight gain during pregnancy is beneficial for maternal and infant health, whereas excessive weight gain can significantly increase the risk of pregnancy complications and adverse pregnancy outcomes.
With socio-economic development, evolving fertility concepts, and the full implementation of the multi-child policy, the number of older pregnant women (aged ≥ 35 years) is increasing annually. Old age, an immutable factor, presents new challenges in the management of pregnant women. With an increase in female age, damage to vascular endothelial cells gradually increases. Eventually, the balance of vasoactive substances becomes imbalanced, the secretion of substances that dilate blood vessels is reduced, and the synthesis of substances that constrict blood vessels is increased. This results in increased vascular smooth muscle tension and contraction, thus leading to hypertension. Studies have shown that older women have an increased probability of pregnancy-related complications and higher risks of pregnancy[29]. Under these new circumstances, it is advisable to strengthen pre-pregnancy health education, intensify prenatal screening and supervision, detect issues early, intervene promptly, and implement targeted prenatal care to mitigate inherent risks.
Therefore, older individuals with higher pre-pregnancy BMIs, should undergo comprehensive health assessments and receive tailored pre-pregnancy intervention plans. Regular blood pressure monitoring is crucial for high-risk groups during pregnancy and postpartum, especially within the first month, aiding early hypertension detection and timely intervention. Lifestyle interventions, including weight control, healthy diet, moderate exercise, and stress management should be emphasized.
This study had some limitations, primarily due to the reduced sample size, which could not identify potentially influential risk factors. Given the resource-intensive nature of repeated blood pressure measurements at the fourth month postpartum, only pregnant women identified with hypertension in the first month postpartum were included. Moreover, participants were selected from a district in Shanghai, limiting the extrapolation of the study results. Expanding the sample size to follow up all parturient women for prevalence data and conducting a multicenter study are recommended.
CONCLUSION
In summary, this study identified the prevalence of hypertension in the first month post-delivery and identified risk factors for persistent postpartum hypertension. In addition, postpartum chronic hypertension usually takes a longer time to develop, and postpartum visits at this point provide a window for early screening of cardiovascular disease risk. Identifying independent risk factors during pregnancy and early postpartum and establishing a systematic management model linking maternal and childcare with community family medicine and chronic disease management is highly significant.
Footnotes
Provenance and peer review: Unsolicited article; Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Medicine, research and experimental
Country of origin: China
Peer-review report’s classification
Scientific Quality: Grade C
Novelty: Grade B
Creativity or Innovation: Grade C
Scientific Significance: Grade B
P-Reviewer: Cengiz E, Türkiye S-Editor: Fan M L-Editor: A P-Editor: Chen YX
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