Malaria control has been disrupted in recent years by several factors, including the emergence of Plasmodium resistance to antimalarial drugs, female Anopheles resistance to insecticides, the COVID-19 pandemic, and climate change. According to the World Health Organization (WHO), approximately 263 million people were affected by malaria across 83 malaria-endemic countries in 2023, an increase of 11 million cases compared to 2022 [1]. The WHO African Region is the most severely impacted, accounting for about 94% of malaria cases, or approximately 247 million cases [1]. While all individuals are at risk, the majority of victims are children under five years old and pregnant women. Every year, over 36 million women become pregnant, 12.4 million of whom (34%) contract malaria [1]. Moreover, around one-quarter of pregnant women in endemic regions, particularly primigravidae, present with placental infection [2]. Malaria has devastating effects on maternal and fetal health, as well as on newborns and pregnancy outcomes [1,2,3,4]. For the fetus, sequestration of infected red blood cells in the placenta leads to placental damage, reduced oxygen and nutrient transport, and, consequently, low birth weight, with reductions of up to 170 grams on average [5].

Additionally, malaria significantly increases the risk of maternal and fetal anemia, miscarriage, intrauterine growth restriction, preterm delivery, and maternal and neonatal mortality [3,4]. In Africa, 5.7% of maternal deaths are attributed to placental malaria infection [6,7]. In Côte d’Ivoire, malaria is endemic and remains a major public health issue. In 2020, approximately 469,943 cases of gestational malaria were reported [8].

To effectively combat this disease, particularly among pregnant women, the WHO recommends several promising strategies through the National Malaria Control Programs (NMCPs), especially in areas of high and moderate endemicity: (i) the use of long-lasting insecticide-treated nets (LLINs); (ii) monthly administration of a dose of Sulfadoxine–Pyrimethamine (SP) as an Intermittent Preventive Treatment (IPTp-SP) starting from the second trimester during antenatal visits; and (iii) rapid, adequate, and effective management of malaria cases [3]. IPTp-SP is a crucial component in combating malaria among pregnant women. One of the NMCP’s key objectives for malaria prevention in Côte d’Ivoire is to ensure that at least 80% of pregnant women receive at least three doses of IPTp-SP during antenatal care (ANC) [9]. Studies have shown that administering at least three doses of IPTp-SP significantly reduces the number of infants born with low birth weight and mitigates the adverse effects of malaria during pregnancy [1,2,10]. However, the emergence and spread of Plasmodium parasites resistant to Sulfadoxine–Pyrimethamine threaten the effectiveness of IPTp-SP during pregnancy [11]. Limited published data exist on the efficacy of IPTp-SP among pregnant women in Bouna, a recently designated sentinel site for antimalarial drug surveillance by the NMCP. Therefore, several years after the adoption of these guidelines, it is critical to assess the coverage and effectiveness of IPTp-SP among pregnant women in Bouna from 2021 to 2024. Enhanced and regular monitoring will enable the adaptation of guidelines to ensure sustained malaria control.

Studies evaluating the effectiveness of Intermittent Preventive Treatment with Sulfadoxine–Pyrimethamine (SP) have been conducted in Côte d’Ivoire since 2016 by the National Malaria Control Program (NMCP) [2,10]. However, limited data are available on the effectiveness of this strategy in Bouna. In fact, Bouna was designated as a sentinel site by the NMCP in 2017 to monitor the effectiveness of antimalarials. The first study on evaluating the effectiveness of Intermittent Preventive Treatment in pregnant women (IPTp-SP) started in 2021, followed by another in 2024. These studies not only verify whether the goals set by the NMCP are being achieved but also help to identify factors that could undermine the effectiveness of this control strategy, enabling corrective action.

In this study, adherence to the third dose of SP (SP3) increased from 59.6% in 2021 to 62.1% in 2024. These SP3 adherence rates are higher than those found by several authors in West Africa [10,13] and elsewhere [14]. However, other authors have reported higher rates than ours [15,16]. The low adherence rate in our series was associated with several factors including occupation, parity, antenatal care visits, age, education level, and use of insecticide-treated mosquito nets (ITNs), depending on the study year. Work constraints, low education levels, limited access to antenatal care, and a sense of security due to ITN use often lead women to underestimate the importance of IPTp-SP. Multiparous women or very young women may perceive a lower risk. This observation shows the interconnection of these factors. Therefore, a multifactorial approach is essential to improve adherence to IPTp-SP among pregnant women. These factors have also been observed by other authors [17,18]. Enhanced community awareness, increased accessibility to healthcare, and targeted training on malaria during pregnancy could help overcome these barriers.

It was observed that regardless of the study year, antenatal care (ANC) was associated with SP intake. In fact, ANC is a key opportunity for healthcare providers to assess a woman’s health status and the progress of her pregnancy. According to the WHO, a pregnant woman is considered to have had good ANC coverage if she has attended at least four visits [19]. The ANC coverage rate increased by 30% in 2024 according to this study. This increase reflects the effectiveness of the awareness campaigns conducted by the Ministry of Health, Public Hygiene, and Universal Health Coverage (MSHP-CMU) in raising awareness of the importance of ANC. Good ANC coverage can increase SP coverage. The link found in our study between the number of ANC visits and SP coverage over the two study years can be explained by the fact that for several years, SP has been administered to pregnant women at health centers through the DOT (Directly Observed Treatment) strategy during their ANC visits. These results suggest that, in addition to ANC, other opportunities to administer SP to women, such as involving community health workers, could further increase coverage and adherence to the Intermittent Preventive Treatment (IPTp-SP). However, this strategy could reduce the number of pregnant women visiting health centers. Moreover, raising community awareness about the risks of gestational and congenital malaria and involving and strengthening communication for behavior change among both populations and healthcare workers are essential strategies. Combating malaria in pregnant women is a strategy that will also help increase coverage of SP3 and other malaria control methods. Additionally, training healthcare workers [20] on malaria should be considered. Despite the numerous free campaigns distributing long-lasting insecticidal nets (LLINs), the usage rate of LLINs remains low in Bouna (60% in 2021 and 42.9% in 2023) compared to the NMCP’s target. These results highlight the need for the NMCP to strengthen awareness campaigns on the use of LLINs.

The majority of parturients in our study presented with anemia. This result was also observed by Tall et al. in 2023 [21,22]. Several factors could contribute to this, including malaria infection and, notably, pregnancy itself, which is the leading cause of anemia in pregnant women. Pregnant women are particularly vulnerable to malaria, thus requiring protective measures. Since 2008, Côte d’Ivoire has adopted Intermittent Preventive Treatment with Sulfadoxine–Pyrimethamine (IPTp-SP) to protect the mother–child couple from the detrimental effects of malaria. The effectiveness of this strategy is threatened by the spread of SP resistance in Plasmodium falciparum. High prevalence rates of mutations in the resistance genes Pfdhfr and Pfdhps to SP have been reported in Côte d’Ivoire by several authors [23,24,25,26,27]. In this series, it was observed that venous, placental, and cord infestations were less prevalent among women who had taken at least three doses of SP. This finding has also been observed by other authors in Côte d’Ivoire and elsewhere [2,10]. Despite mutations in the Pfdhfr and Pfdhps resistance genes, SP remains effective and can still be used to prevent malaria in pregnant women in Côte d’Ivoire. However, regular monitoring must be conducted to inform timely decision-making. Women, especially those who are illiterate and multiparous, must be made aware of the benefits of using SP and long-lasting insecticidal nets (LLINs) during pregnancy. In this study, a low SP coverage rate was observed among illiterate and multiparous women. Although multiparous women naturally acquire resistance to Plasmodium falciparum during successive pregnancies by producing antibodies against parasitized red blood cells that bind to chondroitin sulfate A in the placenta [28], they must continue to adhere to malaria-preventive measures. In fact, parasite sequestration depends on the level of premunity, which in turn depends on the intensity of transmission [29].

In this study, a reduction in Plasmodium infection was observed at the venous, placental, and cord levels from 2021 to 2024. This further supports the effectiveness of IPTp-SP when properly administered. Additionally, the study revealed that with three or more doses of IPTp-SP, there was a significant reduction in low birth weight (p = 0.03). This finding has been corroborated by several other authors [2,10,18]. The study showed that the majority of women whose newborns had a birth weight below 2500g were the most infested. A statistically significant link was observed between placental (p = 0.018) and venous (p = 0.007) Plasmodium infection and birth weight in 2021. This link was not observed in 2024, likely due to the lower rate of placental and peripheral infestations. Placental malaria is responsible for maternal anemia, low birth weight, preterm birth, or in utero death. To prevent this, it is essential to implement preventive measures such as IPT-SP and long-lasting insecticidal nets (LLINs). Other factors such as parity, gravidity, IPT-SP administration, presence of anomalies, and prenatal care were significantly associated with low birth weight.

This study evaluated the effectiveness of IPTp-SP and compared adherence over two years to assess its evolution and the impact of public health interventions. However, it can have certain limitations, particularly from confounding factors.

The results of this study show that despite high levels of SP resistance markers, IPTp-SP remains effective and can therefore be maintained. However, regular monitoring of its effectiveness and the search for new strategies to combat malaria during pregnancy are recommended. It would also be valuable to extend this study to multiple sites and investigate markers of resistance to Sulfadoxine–Pyrimethamine.