Malaria continues to be a serious public health concern with 229 million cases and 409,000 deaths reported in the year 2019. Nearly 6.3 million cases were reported from Southeast Asia region out of which majority were present in India¹. In the last two decades, there has been a sustained and focussed effort to reduce malaria infection by health agencies with some degree of success, even so areas of high burden among the vulnerable populations continues to be a problem (1).

Pregnant women are one such group which shows increased risk of malaria in endemic areas with potentially life-threatening consequences for mother, fetus, and the neonate. Malarial infection during pregnancy is associated with high risk of anemia, miscarriages, preterm deliveries, low birth weight, congenital malaria, and deaths of infants (2). Several studies have been carried out that have estimated the burden of malaria in pregnant women from sub-Saharan Africa (3–6). However, there is lack of comprehensive data from India, regarding pregnancy associated malaria and adverse pregnancy outcomes.

Though there is distinct lack of statistical data published for malaria in pregnancy from India, yet there are several studies that analyse its implications. A study published from Gujarat, West India, from the period of 1987–1988, showed that pregnant women are more prone to malaria infection than non-pregnant women (7). In another study from Odisha, east India, it was found that neonates are more prone to infection and parasitaemic infection are more common in primigravidae than multigravida women (8). Prevalence of malaria in pregnancy in health care centers from Madhya Pradesh was found to range between 6.4 and 55% approximately (9).

Even a cursory analysis of the prevalence of malaria in pregnant women indicates that in endemic regions pregnant women are more prone to malaria infection as compared to non-pregnant women, resulting in severe consequences for the health and wellbeing of the mother, fetus and infant.

Many individual studies from India are available looking at sub-national estimates of malaria in different parts of the country. A comprehensive analysis of the burden of malaria during pregnancy from India is urgently required. Such studies have the potential to guide targeted public health efforts toward the affected population. The present study is a systematic review and meta-analysis of published literature to estimate the proportion of malaria in pregnant women and pregnancy outcomes associated with malaria infection from India.

Our initial systematic search of PubMed and Web of Science resulted in 774 research articles pertaining to malaria in pregnancy reported during years 2000–2020 from India. After removal of duplicates, 270 unique articles were identified and they were reviewed for title and abstract. Out of these 130 were considered for full text review (Figure 1).

Finally, twenty articles were ultimately found to fulfill the eligibility criteria and were included in the final systematic review (11–30). Among these 20 articles, 11 were cross sectional studies, three were retrospective analysis, 5 were hospital based observational studies and the remaining one was a case series (Table 1).

These studies were carried out in pregnant females within the age group ranging from 18 to 45 years. Many of the studies were reported primarily from the states of Madhya Pradesh, Chhattisgarh, and Jharkhand. Quality analysis using JBI criteria resulted in 16 studies scoring ≥ 5. Among these 16 studies, 11 studies reported malaria in asymptomatic pregnant women and five studies reported malaria in symptomatic women. The symptom commonly associated with malaria was fever. These 16 studies were finally included in the pooled prevalence analysis.

Out of 20 publications covered in this nationwide systematic review of malaria in pregnancy, there were 16 high quality studies that reported prevalence in asymptomatic or symptomatic pregnant women. Some of the highest prevalence were reported from the state of Madhya Pradesh which is one of the most endemic regions for malaria in India (11–13). Other states reported much lower prevalence. This wide range in prevalence can be due to several reasons. The primary reason, being the endemicity of malaria. Earlier studies have reported that five states, Jharkhand, Madhya Pradesh, Odisha, Uttar Pradesh, and Gujarat are responsible for 65% malaria cases reported from India (31). The population living in this area is at a much greater risk for developing the disease as compared to other northern, western and southern states of India. Other reasons are variable seasons in India, especially monsoon season which provide the suitable condition for mosquito breeding, poor medical infrastructure, lack of awareness among maternal and caregiver population about malaria and possibly poor immunity among them, might contribute toward high mortality and morbidity among pregnant women and their neonates (32–34).

Also, majority of the publications reported higher prevalence of P. falciparum than P. vivax, with only few publications showing higher prevalence of P. vivax (14, 18, 21, 23, 28) with almost no severe maternal or perinatal mortality and morbidity which could be proved by the fact that P. vivax is less dangerous for pregnant women as it does not attach to the epithelium of placenta causing lesser risk (35). Also, there were cases of extreme perinatal, neonatal and infant mortality and morbidity among population with higher P. falciparum infections. Other adverse outcomes were low birth weight, preterm births, abortions and still births. Other than this, overall, there were not many cases in which severe maternal outcomes were reported which could be due to moderate immunity among pregnant women in area of low transmission (36).

Apart from cross sectional studies, an analysis of hospital based observational studies, retrospective analysis and case series indicated malaria prevalence in symptomatic pregnant women. A study carried out by Nayak et al. (30) in the district of Bikaner reported 25 pregnant women, positive for P. vivax with extreme maternal effects such as severe anemia in 15 cases with 14 cases of preeclampsia and extreme perinatal outcome including eight preterm live birth, two intrauterine death, two still birth, two abortions, and 20 cases with low birth weight. Among all the cross-sectional studies reported in this review, only one publication by Guin et al. (23) reported in district of Jabalpur of Madhya Pradesh estimated maternal mortality with severe anemia and preeclampsia. This could be due to the socioeconomic status of Bhil's which is the largest tribal group of India condensed in Madhya Pradesh and the subject of this study. Delayed detection of disease among pregnant women resulting from poor accessibility to basic health infrastructure and poor awareness about prevention strategies and literacy rate might also contributes toward higher malaria prevalence.

Despite comprehensive search and analysis, several regions of India remained underrepresented in our systematic review either due to lack of comprehensive studies or due to lack of malaria prevalence, as India has a “National Framework for Malaria Elimination (NFME) in India 2016–2030,” that prioritizes malaria elimination by the year 2030. Many of these studies were carried out during different time frames which could lead to disparity in results. Most of the studies included women that choose to deliver in hospital and at least visited antenatal clinic during their pregnancy and by this it can be estimated that most of these women must have received preventive measures during their pregnancy such as chemoprophylaxis, which could further reduce the risk of extreme perinatal outcomes such as still births. We also observed publication bias based on the funnel plot. All 16 studies included in the final meta-analysis were not uniform in their study design as some were cross sectional studies while others were hospital based observational studies or retrospective analysis and may add to outcome variability. More in depth studies covering all aspects of malaria in pregnancy from other parts of India including northern, north-west region and south of India would have given a better understanding about prevalence of malaria in pregnancy. The health policy makers must include stringent preventive measures and improved access to malaria prevention, care and treatment to reduce the morbidity of malaria in pregnancy.

Globally the burden of malaria in pregnancy is substantial with severe outcomes for maternal and neonatal health. Also, in endemic countries like India, it remains a major public health problem and contributes toward obstetric mortality, thus its prevention and control are a humanitarian priority. Assessment of its prevalence in India is crucial for targeting the at-risk population. Our systematic review estimates prevalence of pregnancy associated malaria and identifies geographical regions of high prevalence and associated adverse maternal and pregnancy outcomes. This information can be used by health agencies for targeted control program toward vulnerable and affected population. Our study also indicates that there is insufficient data for malaria in pregnancy from India, and more thorough and comprehensive analysis is required given the size and diversity of the country which will pave the way for improved maternal and neonatal health.

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author/s.

NS conceived the work. KJ and NS did the searches, extracted the data, and wrote the manuscript. PG, AB, and FD reviewed the extracted data. All authors reviewed and discussed the manuscript. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.