Introduction

Pregnancy is a unique natural physiological process that may have serious pathological implications not only in the presence of underlying conditions, but also without them (1). In many developing countries, pregnancy and childbirth complications are among the leading causes of maternal mortality (2). Based on the reports on maternal health, approximately 800,000 women die from preventable pregnancy- and childbirth-related causes per day, and 99% of these deaths occur in developing countries (3).

According to the World Health Organization, the most prevalent complications of high-risk pregnancies are hemorrhage, preeclampsia, infection, preterm birth, maternal medical problems, and abortion, which are among the leading causes of the admission of pregnant women to specialized care units. These complications are the most important causes of maternal mortality all over the world and account for half of all postpartum deaths in developing countries (4).

Blood pressure disorders are among the most important complications of pregnancy and as stated before, among the top three causes of mortality in pregnant women (along withhemorrhage and infection). The prevalence of these disorders has been estimated as 5-7% (5). These disorders are classified into four groups, including gestationalhypertension, chronic hypertension with superimposed preeclampsia, preeclampsia/eclampsia syndrome, and chronic hypertension (3). It should be noted that all chronic hypertensive disorders, regardless
of their etiologies, are susceptible to preeclampsia/eclampsia superimposition (6).

The prevalence of preeclampsia and eclampsia among women has been investigated in several studies. In this regard, in a meta-analysis research conducted by Kharaghani et al. (2016) on 36 studies, the mean prevalence rate of preeclampsia was reported as 0.05%. According to the mentioned study, the prevalence of hypertension increased from 0.04% in 1996-2005 to 0.07% in 2010-2013 (7). Furthermore, in a retrospective study performed in China during 2002-2011, the prevalence of mild and severe preeclampsia was estimated as 1.42% and 0.49%, respectively (8). In the aforementioned studies, the risk factors for the development of gestationalhypertension were reported as age, multigravidity, multiple pregnancy, and medical complications. They also underscored the necessity of reviewing the current diagnostic protocols for this condition.

Although the etiology of gestationalhypertension is still unknown, its initial signs emerge early in pregnancy. These signs are associated with uncertain pathophysiologic changes that persist during pregnancy and ultimately become clinically apparent. In some cases, these changes may lead to multi-organ involvement and clinical features ranging
from hardly noticeable manifestations to pathophysiological disturbances that are dangerous to both mother and fetus (9). As repeatedly evidenced, gestational hypertensive disorders can cause HELLP syndrome-induced disseminated intravascular coagulation, intracerebral hemorrhage, hepatic rupture-induced hemorrhage, and early placental abruption, which may result in maternal mortality (3).

The most effective solutions to reduce the incidence of gestational hypertensive disorders and their implications for fetus and mother are to predict and prevent these conditions in susceptible patients. This condition can be managed effectively if diagnosed timely. Diagnosis of this condition is important not only in the prevention of this complication, but also in the assessment of the potential factors endangering the mother and neonate and identification of an appropriate treatment for risk mitigation.

With this background in mind, the present study aimed to investigate the prevalence of various types of gestational hypertensive disorders and its related factors in the mothers referring to the secondary and tertiary care hospitals affiliated to Isfahan University of Medical Sciences, Isfahan, Iran. Since this is the first study investigating this complication in referral hospitals, the results may assist the associated health providers and officials in the decision making processes related to this important condition.

Materials and Methods

This descriptive-analytic study was conducted on the pregnant women referring to the secondary and tertiary care hospitals affiliated to Isfahan University of Medical Sciences from July to October 2016. The sampling was performed using the census method since the goal was to investigate all patients with a gestational hypertensive disorder within the specified period.

After investigating the cause of referral in all 2,477 patients referring to the mentioned hospitals, 148 cases were found to be suffering from various types of gestational hypertensive disorders. The demographic, clinical, and therapeutic data of these mothers were collected using researcher-made forms and checklists. To study the factors associated with hypertensive disorders, 200 mothers who had no pregnancy complication were also randomly selected from the 2,477 referral cases. For these mothers, only the demographic and clinical data were collected.

In order to collect the data of the 348 included mothers (i.e., 200 healthy cases and 148 hypertensive cases), the researchers made daily visits to the maternity and obstetric wards and high-risk pregnancy care units of the hospitals under investigation to interview the mothers, and also physicians and personnel, when necessary. These interviews covered such data as patient’s biography, delivery report, paraclinical findings, and final diagnosis documented in the summary sheet of the medical records.

The hospitals sampled in this study were Isa-Ibn-Maryam and Shahid Beheshti recognized as secondary hospitals and Al-Zahra and Amin as tertiary care hospitals. All participants were living in Isfahan province and were enrolled in the study with informed consent. The data were analyzed in SPSS software (version 18) using the descriptive and inferential (e.g., Chi-square test and independent t-test) statistical methods.

The data collection instruments included a demographic form and a researcher-made form developed for collecting the medical and therapeutic data. The content and face validities of the instruments were confirmed by the members of the Faculty of Obstetrics and Gynecology of Isfahan University of Medical Sciences. This validation process involved an initial review of the instruments by the faculty members, followed by a second review after making the suggested modifications.

Results

In this study, the prevalence of gestational hypertensive disorders was estimated as 6%. In this regard, 1.2%, 4.2%, 0.1%, 0.3%, and 0.2% of the cases were related to chronic hypertension, preeclampsia, eclampsia, chronic hypertension with superimposed preeclampsia, and transient hypertension, respectively. The most prevalent type of gestational hypertensive disorder was preeclampsia (4.2%).

The findings showed no significant relationship between the frequency of preconception and prenatal care visits and hypertensive disorders (P>0.05). However, prenatal care (mean number of visits to care providers) was significantly higher (P<0.05) in the hypertensive group, compared to that in the healthy group. There was also a significant difference (P<0.05) between the two groups in terms of the frequency distribution of the type of care provider delivering preconception and prenatal care (tables 1 and 2).

The results also showed that the hypertensive group had a significantly higher prevalence of underlying diseases (i.e., diabetes and autoimmune, cardiovascular, and renal diseases) than the healthy group (P<0.05; Table 2). Another notable disease diagnosed in this study was hypothyroidism.

No significant difference was found between the two groups in terms of the mean age, occupation status, or education level (P<0.05). However, the hypertensive group had a significantly higher mean prevalence of previous abortions, compared to the healthy group (P<0.05; Table 1).

Discussion