30/07/2026
Malaria in Pregnancy Lecture Notes
1. Introduction
Malaria in pregnancy is an important cause of illness and death for both the mother and the baby, especially in endemic regions. Pregnancy reduces a woman’s immunity to malaria, making her more vulnerable not only to infection, but also to severe disease and its complications. This increased susceptibility does not end immediately after delivery; it may continue for up to 60–70 days postpartum.
The consequences of malaria in pregnancy can be serious. For the mother, it may lead to maternal mortality, maternal anemia, and severe systemic illness. For the fetus and newborn, malaria can result in spontaneous abortion, preterm delivery, intrauterine growth restriction (IUGR), low birth weight (LBW), stillbirth, and neonatal mortality.
In short, malaria in pregnancy is not just an infection — it is a major obstetric and public health problem.
2. Epidemiology
Malaria in pregnancy occurs mainly in tropical and subtropical regions, with the greatest burden seen in Sub-Saharan Africa, where malaria transmission is high and continuous in many areas. In such high-transmission settings, the median prevalence of maternal malaria has been estimated at around 28%.
Although prevalence is generally lower in parts of Asia and Latin America, malaria in pregnancy remains clinically important there as well. Even in lower-transmission areas, infection may cause significant maternal and fetal complications.
Certain groups of pregnant women are at especially high risk. These include:
- Primigravidae and secundigravidae, because immunity to placental malaria develops gradually over successive pregnancies
- Younger pregnant women
- Women living with HIV
- Women in the first and second trimesters
- Nonimmune travelers visiting endemic areas
Thus, both biological and epidemiological factors influence the level of risk.
3. Etiology and Malaria Species
Human malaria is caused by five main Plasmodium species:
- Plasmodium falciparum
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
- Plasmodium knowlesi
Among these, Plasmodium falciparum is by far the most important in pregnancy because it is associated with high parasitemia, placental sequestration, and the most severe maternal and fetal outcomes.
P. vivax usually causes less severe disease in pregnancy because it does not sequester in the placenta to the same extent as falciparum malaria. However, it can still contribute to anemia and poor pregnancy outcomes.
P. knowlesi is relatively uncommon but may cause severe malaria.
P. ovale and P. malariae are generally associated with milder disease in pregnancy.
So, while all malaria infections deserve attention, P. falciparum is the species of greatest obstetric concern.
4. Pathophysiology
Placental Malaria: the Central Mechanism
The hallmark of malaria in pregnancy, especially falciparum malaria, is placental sequestration. In this process, infected red blood cells adhere to the syncytiotrophoblast within the intervillous space of the placenta. This adhesion is mediated by parasite surface antigens, especially VAR2CSA.
This placental accumulation sets off a chain of harmful events:
- Monocyte infiltration
- Release of inflammatory cytokines, such as TNF-α
- Impaired placental blood flow
- Reduced oxygen and nutrient transfer to the fetus
- Fetal growth restriction
- Preterm labor
A key clinical point is that a woman may have placental malaria even when the peripheral blood smear is negative. This means that absence of parasites in peripheral blood does not always exclude clinically important infection.
On placental histology, the characteristic findings include:
- Infected erythrocytes
- Hemozoin pigment deposition
- Inflammatory cell infiltrates
- Syncytial damage
This explains why malaria in pregnancy can be so dangerous even when maternal symptoms are mild or laboratory findings seem limited.
5. Clinical Manifestations
Maternal Features
The symptoms of malaria in pregnancy may resemble those seen in nonpregnant adults, but the disease is often more severe. Common maternal features include:
- Fever
- Chills
- Headache
- Myalgia
- Anemia
- Hypoglycemia
Pregnant women are more likely to develop severe malaria, which may present with:
- Cerebral malaria
- Severe anemia
- Acute pulmonary edema
- Acute kidney injury
- Metabolic acidosis
Because pregnancy alters immunity and physiology, clinical deterioration may be rapid, so prompt recognition is essential.
Fetal and Neonatal Complications
The fetus is also at significant risk. Malaria in pregnancy may lead to:
- Miscarriage
- Preterm birth
- Intrauterine growth restriction
- Low birth weight
- Stillbirth
- Conge***al malaria
- Neonatal death
These complications are largely related to placental dysfunction, maternal anemia, and severe maternal illness.
6. Diagnosis
The diagnosis of malaria in pregnancy relies mainly on laboratory confirmation. The standard methods are:
- Peripheral blood smear using thick and thin films
- Rapid diagnostic tests (RDTs)
- PCR, mainly in research or reference settings
The blood smear remains important because it can identify the parasite species and estimate parasitemia.
However, an important limitation must be remembered: placental infection may occur without detectable parasites in peripheral blood. Therefore, a negative smear does not completely rule out malaria-related placental disease.
Clinical suspicion remains important, especially in symptomatic pregnant women from endemic areas or with relevant travel history.
7. Prevention
Prevention is one of the most important aspects of managing malaria in pregnancy. It includes vector avoidance, chemoprophylaxis for travelers, and intermittent preventive treatment in pregnancy (IPTp) in appropriate settings.
A. Mosquito Avoidance
All pregnant women in endemic areas should be advised to reduce mosquito exposure. Effective preventive measures include:
- Insecticide-treated bed nets (ITNs)
- Indoor residual spraying
- Long sleeves and protective clothing
- DEET-based repellents, which are considered safe in pregnancy
- Screened housing
Among these, ITNs are especially important, as they have been shown to reduce:
- Placental malaria
- Low birth weight
- Stillbirth
- Maternal anemia
These simple measures can produce major maternal and neonatal benefits.
B. Chemoprophylaxis for Travelers
Pregnant women should ideally avoid travel to malaria-endemic regions whenever possible.
If travel cannot be avoided, preventive medication may be necessary:
- Chloroquine can be used in areas with chloroquine-sensitive malaria
- Mefloquine is used in chloroquine-resistant regions
The dosing is generally the same as for nonpregnant adults, but regional guidelines should always be checked, since resistance patterns vary.
C. Intermittent Preventive Treatment in Pregnancy (IPTp)
In moderate-to-high transmission areas in Africa, IPTp is recommended for HIV-negative pregnant women.
The standard drug is sulfadoxine-pyrimethamine (SP).
- Dose: 1500 mg sulfadoxine + 75 mg pyrimethamine
- This is given as 3 tablets
- It should start in the early second trimester
- A minimum of 3 doses is recommended
- Each dose should be given at least 4 weeks apart
- Directly observed therapy is preferred
The benefits of IPTp-SP include reduced:
- Low birth weight
- Placental malaria
- Moderate-to-severe maternal anemia
However, its effectiveness is reduced in areas where SP resistance is high. For that reason, local and national protocols should always be followed.
8. Treatment of Malaria in Pregnancy
Treatment depends on several factors:
- Trimester
- Plasmodium species
- Severity of disease
- Local drug resistance patterns
A. Uncomplicated Malaria
In the first trimester, the traditional preferred treatment has been:
- Quinine plus clindamycin
However, some artemisinin-based combination therapies (ACTs) are increasingly considered safe, though treatment should still follow local or national guidance.
In the second and third trimesters, the usual treatment for uncomplicated malaria is:
- Artemisinin-based combination therapy (ACT)
B. Severe Malaria
Severe malaria in pregnancy is a medical emergency and requires urgent treatment.
The preferred treatment in any trimester is:
- Intravenous artesunate
Once the patient improves and can take oral treatment, this should be followed by a full course of ACT.
Supportive management is equally important and may include:
- Glucose monitoring, because hypoglycemia is common
- Careful fluid balance
- Blood transfusion for severe anemia
- Treatment of complications such as renal failure, pulmonary edema, or acidosis
Management must always be aligned with current national malaria treatment guidelines.
9. Special Considerations
HIV Coinfection
Pregnant women with HIV infection are at even greater risk of malaria. They tend to have:
- Higher parasite densities
- More frequent infection
- Greater risk of adverse maternal and fetal outcomes
HIV may also affect the effectiveness of prevention strategies, so management in these patients requires special attention.
Postpartum Period
The increased susceptibility to malaria does not stop immediately after childbirth. The risk may remain elevated for around 2 months postpartum. This is an important clinical point, especially in endemic settings or when evaluating postpartum fever.
10. Public Health Importance
Malaria in pregnancy remains a major public health challenge, particularly in low-resource endemic areas. Effective prevention and treatment are often limited by:
- Poor access to antenatal care
- Drug resistance
- Inadequate distribution of insecticide-treated bed nets
- Weak health systems
Because of these barriers, malaria control in pregnancy must be integrated into routine antenatal care. Early booking, prevention, screening, treatment, and follow-up all play a crucial role in improving outcomes
