Prevalence of hypertensive disorders of pregnancy, associated factors and pregnancy complications in a primigravida population

1 Introduction

Hypertensive disorders of pregnancy (HDP) are among obstetrics' most intriguing and yet unsolved problem. HDP is blood pressure greater than or equal to 140/90 ​mmHg, with each measurement usually corroborating within 4 ​hours.¹ According to the World Health Organization (WHO), the lethal trifecta of pregnancy are haemorrhage, HDP, and infection, which contribute significantly to maternal mortality and morbidity and claim the lives of at least one woman every 7 ​min.² These complicate up to 5%∼10% of pregnancies worldwide.³ Globally, the incidence of HDP has increased from 16.30 million to 18.08 million from 1990 to 2019, a total increase of 10.9% over two decades.⁴ The High Blood Pressure Education Program (2000) has classified HDP as gestational hypertension, preeclampsia, eclampsia syndrome, and superimposed preeclampsia on chronic hypertension.⁵ Mehta et al.⁶ in his study found an incidence of HDP of 6.9% in the Indian population. The incidence of preeclampsia in hospital practice in India varies from 5% to 15%, and that of eclampsia is about 1.5%.⁷ In India, over the years, from 1976 to 2014, the risk of eclampsia ranges from 0.179 to 5%, with the average being 1.5%.⁸ Every year, over 5.2 million women die from pregnancy-related complications worldwide. ⁹ With an estimated 62,000–77,000 deaths each year, HDP account for approximately 18.1% of maternal mortality.^10–12 Pregnant women in third-world countries are at a higher risk of developing hypertension and its consequences for various reasons. If those at risk for HDP are detected early in the prenatal period, effective treatment can be given, and complications can be prevented.

Despite Kerala being a state of India that has a high literacy rate and health indicators, we see that HDP complications account for most maternal near-miss cases (an event in which a pregnant woman comes close to maternal death but does not die) and very few research has been conducted in Kerala to determine the relationship between risk factors and the development of HDP. This study aims to estimate the prevalence of HDP in primiparous women and compare the prevalence of associated risk factors and pregnancy complications in primiparous women with and without HDP in a tertiary care centre in South Kerala, India. The current research is necessary since it is a realistic, cost-effective, simple and convenient way to reduce the scarcity of information about this topic in our population.

2 Materials and methods

A retrospective analytical study was carried out at Pushpagiri Institute of Medical Sciences and Research Centre in Kerala, India, for 12 months, from December 2020 to December 2021. After taking permission from the institutional ethics committee, the study was ethically conducted as per the Declaration of Helsinki. Primigravidae of all ages who consented to the study and gave birth in the hospital during the study period were included. Women with multiple pregnancies, chronic hypertension, and missing clinical history (without proper antenatal records) were excluded from the study.

We have collected the prevalence, risk factors, pregnancy outcomes, and maternal and foetal outcomes from the patient's medical records. The variables analysed were the presence of hypertension, type of hypertension and potential risk factors: maternal age, educational status, income level, occupation, body mass index (BMI) at the first antenatal visit, family history of hypertension, history of smoking, in-vitro fertilisation (IVF) pregnancy, polycystic ovary syndrome (PCOS), and associated medical disorders (hyperglycaemia in pregnancy, renal disease, cardiac disease, collagen vascular disease, hypothyroidism). The pregnancy outcomes were evaluated by analysing the gestational age, mode of delivery and maternal and perinatal outcomes such as premature baby (a baby who delivers before 37 weeks).

The study utilised the SPSS 18.0 software package to analyse the data. The association between the risk factors and HDP in primigravida was measured in terms of the ODDS ratio with a 95% confidence interval and tested for significance using the Chi-square test. A p-value of less than 0.05 was considered statistically significant.

3 Results

A total of 807 primigravidae were included in the study, with 18.6% (150) having HDP. The mean age of participants was found to be 26.34 ​± ​3.84 years. Among the prevalent population, the study results showed that 79.3% (119) of women had gestational hypertension, 19.3% (29) had preeclampsia, and 1.3% (2) had eclampsia.

4 Discussion

HDP is one of the most common complications of pregnancy and it increases the risks for both mother and foetus. Hence, assessment of risk factors and proper follow-up help to predict HDP, thereby modifying maternal and perinatal outcomes. This study compared primigravidae with and without HDP, and HDP was found to be present in 18.6% of the study population, which is almost comparable to the study conducted by Magee LA et al., in 2019 which showed an incidence of 10.3% in India.¹³ This increase in the incidence of HDP in our population could be because the study represents a cross-section of high-risk pregnancies referred to this tertiary centre with anticipated complications for mother and foetus. Of the study population with HDP, the prevalence of gestational hypertension was 79.3%, preeclampsia was 19.3% and eclampsia was 1.3%. The prevalence of gestational hypertension and preeclampsia was higher in our study compared to a similar study done in 2020 in Odisha by Pradhan et al.,¹⁴ which was 60% and 12.8%. This may be due to the health-seeking behaviour of our population, which helps in regular antenatal visits and BP monitoring. It was also seen that the prevalence of eclampsia is less in our study than in the study mentioned above due to the early detection and prevention of adverse outcomes following gestational hypertension in our population.

Among the risk factors analysed in our study, age less than 18 years and more than 40 years were found to be statistically significant for predicting HDP, which is also reported in the studies done by Parmer et al.¹⁵ and Li et al.¹⁶ which proves that extremes of age are a non-modifiable risk factor. Our study corroborated with the study conducted by Bezzara et al.¹⁷ on family history and preeclampsia, which revealed that a family history of hypertension in pregnancy for a mother or sister is a risk factor that points toward worsening maternal outcomes, especially in developing eclampsia, HELLP and chronic hypertension.

In our study, BMI> 30 ​kg/m² was statistically significant, as similar was observed by Alba et al.¹⁸ in their retrospective cohort study about maternal overweight and obesity as a risk factor for hypertensive states of pregnancy. That is, BMI is a significant and independent risk factor for HDP. With the onset of artificial reproductive techniques, the number of IVF pregnancies has also increased. A study done by Toshimitsu¹⁹ et al. states that IVF is a risk factor for HDP, especially at extremes of age, which is similar to the results in our study. HDP was statistically significantly higher in pregnancies conceived via IVF technique. Among the medical disorders seen during pregnancy, hyperglycaemia was a statistically significant risk factor for HDP. The study by Lee W et al.²⁰ also reinstates that gestational hypertension and gestational diabetes mellitus (a component of hyperglycaemia of pregnancy) have a conjoint association, hence becoming predictors of each other. Another novel finding from our study was that our population had a significant association between PCOS and HDP. Similarly, a study by Zhous S et al.²¹ also stated the increased incidence of HDP among PCOS patients. This should alert the medical practitioner to identify PCOS in the medical history of expectant mothers to predict HDP as pregnancy advances.

From our study, 27% of mothers with HDP delivered preterm due to various complications following HDP, similar to results studied by Vats et al.²² in Delhi which states that preterm deliveries are one of the anticipated maternal outcomes. The need for preterm deliveries due to the progressive worsening of maternal conditions following HDP is reflected in the increase in demand for preterm operative deliveries among our study participants. In our study, 55.3% of primigravidae with HDP required preterm LSCS to reduce maternal and foetal morbidity and mortality. The study by Toshimitsu et al.¹⁹ states an increased risk of operative deliveries in patients with HDP. Similar results were observed in the study conducted by Hemapriya et al.²³ in 2001–2005 in Mysuru, India, where the rate of caesarean section was relatively high at 69%. From our study, out of the 28 who developed complications, the most common complication following HDP was postpartum haemorrhage (31%), followed by placental abruption (17%) and all maternal complications were statistically significant. Our study's most common perinatal outcomes were preterm birth resulting in prematurity (54%) and FGR (39%), which were clinically significant. This was comparable to the study by Un Nisa S et al.²⁴ at Sukkur in 2018, which stated that there is a higher incidence of iatrogenic prematurity, often resorted to as a method of reducing perinatal mortality following complications of HDP.

A limitation of our study was its retrospective design and that the study group was limited to primigravidae. Similarly, the majority of study participants lived in cities and were above the poverty line, resulting in better health seeking behaviour and a sampling bias. Also, this study was carried out as a single-centre study. Therefore, a large study including multiple centres is needed to generalise these results.

5 Conclusion

In summary, our study looked at the risk factors and pregnancy outcomes following HDP and found that the risk factors studied, like extremes of age, family history of HDP, increased BMI, IVF pregnancy, hyperglycaemia in pregnancy and PCOS, have a substantial correlation with HDP.

HDPs are on the rise in India, and they contribute to maternal and perinatal morbidity and mortality in a significant way. From this study, we emphasise the importance of knowledge and timely assessment of risk factors of HDP. Proper interventions with the right treatment can help reduce maternal and perinatal mortality and morbidity and their long-term effects. However, there are currently no well-established measures for predicting or preventing HDP. So, the study highlights the need for pre-conceptional counselling, which includes early detection, careful monitoring and treatment of HDP to prevent morbidity and mortality related to this disorder. It should be followed up even in the postpartum period.

Ethics approval

Local Institutional Review Board approval was obtained from Pushpagiri Institute of Medical Sciences and Research Centre Ethical Committee with PIMSRC/E1/388A/84/2021 registration number. This study was performed in accordance with ethical standards as settled down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Consent to participate

The patients gave informed consent and the patient anonymity preserved.

Consent to publish

All authors of the original manuscript have read and approved the manuscript. We confirm that the inclusion of each author in the authorship list is based only 1) On substantial contributions to a) concept and design or analysis, and interpretation of data and b) drafting the manuscript or revising it critically for important intellectual content and 2) Final approval by each author of the version of the manuscript.

Sources of funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Author contributions

RM made a substantial contribution to the concept of design of the article; BPD was responsible for the acquisition, analysis or interpretation of data for the article and drafted the article or revised it critically for important intellectual content. SM helped in the concept of design and drafted the article for important intellectual content. NSS approved the version to be published.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.