Monsoon rainfall causes unique environmental and public health consequences. Sporadic seasonal febrile illnesses affect the general population and should be treated adequately, but for pregnant women, infections during monsoons pose increased health risks. Increased maternal vulnerability during pregnancy results from evolved immune adaptations aimed at tolerating a semi-allogeneic fetus, which may also contribute to some compromised maternal immune responses. Therefore, pregnancy is a state of increased susceptibility for women who are prone to serious complications of vector-borne, waterborne and respiratory infections. This article aims to review the main monsoon infections during pregnancy, the medical causes and risks to both mother and baby, as well as preventive clinical management.
Diseases transmitted by vectors during pregnancy
With the abundance of stagnant water during monsoons, which acts as a favorable breeding ground for Aedes, Anopheles and Culex mosquitoes, the incidence of common monsoon infections and vector-borne diseases increases dramatically.
Dengue fever
Dengue virus (DENV) is an RNA virus of the positive single-stranded variety that has four serotypes (DENV-1 to DENV-4). The Aedes aegypti mosquito is the main vector responsible for the transmission of the dengue virus. A pregnant woman with altered physiology, such as increased intravascular volume and initial capillary permeability, tends to mask the initial warnings of severe dengue plasma leakage.
Maternal risks
Acute monsoon infections such as DENV increase the risk of severe maternal morbidity, ranging from dengue hemorrhagic fever to dengue shock syndrome. Severe thrombocytopenia is a significant risk of severe obstetric bleeding at the time of vaginal or cesarean delivery.
Fetal risks
Multiple studies show that maternal DENV infection is associated with a statistically increased incidence of preterm delivery, low birth weight (LBW), failed abortion, and intrauterine fetal loss (IUFD). Dengue virus NS1 protein can also be detected in the placenta, umbilical cord tissue and cord blood.
Malaria
Malaria is one of the major diseases that occurs in endemic areas during the monsoons. Female Anopheles mosquitoes transmit Plasmodium parasites to humans. Physiologically susceptible pregnant women are susceptible to infection with malaria through their altered immunity and through changes in their placenta. Parasitized red blood cells from the infected maternal reservoir in the intervillous space of the placenta when they adhere to CSA (chondroitin sulfate A), a virulent binding site for malaria-infected red blood cells, through expression of the parasite surface antigen VAR2CSA. This accumulation traps the organisms in the microenvironment and, separate from the general maternal circulation, leads to replication within the placenta.
Clinical Implications
Placental malaria interferes with nutrient and oxygen exchanges between mother and fetus and can cause maternal anemia, IUGR (Intrauterine Growth Restriction), low birth weight, and perinatal mortality.
Emerging arboviruses (Chikungunya and Zika) are other seasonal vector-borne infections. Chikungunya, transmitted by Aedes mosquitoes, can cause severe joint pain in the mother and may carry risks of transmission after delivery. Zika virus can cause congenital Zika syndrome (CZS), which is characterized by structural and functional birth defects, including abnormal facial features, visual abnormalities, and severe neurological deficits
Gastrointestinal infection transmitted by water and food
Aqueous gastroenteritis and hepatotropic viral infections during monsoon usually increases as municipal water supply can be affected by sewage overflow
Hepatitis E virus (HEV) and Hepatitis A virus (HAV)
Hepatitis E is a waterborne disease. If pregnant women become infected in the second or third trimester, they develop acute liver failure, fulminant hepatitis, and hepatic encephalopathy more frequently than in the general population, in which it tends to resolve spontaneously.
Maternal Mortality and Obstetric Problems
The mortality rate among third-trimester pregnant women infected with HEV has been observed to be as high as 20-25%. High rates of PROM (Premature Rupture of Membranes), premature birth, vertical transmission to the fetus and neonatal hepatitis have been reported.
Enteric fevers and gastroenteritis
Incidents of typhoid and paratyphoid fever, cholera and various strains of E. Coli are common bacterial infections during the rainy season. Severe maternal gastroenteritis causes significant electrolyte loss and dehydration, which can reduce uterine blood flow and reduce uterine perfusion. This is then believed to cause uterine contractions and subsequent spontaneous abortion and/or premature labor.
Prevention Protocols
Integrated strategies including environmental modification, hygiene practices and clinical immunization are essential to prevent monsoon infections during pregnancy.
Carrier Control and Personal Protection Measures:
Environmental Hygiene
Standing water in pots, coolers or open containers in the immediate surrounding residential area should be avoided. These are breeding grounds for Aedes and Anopheles mosquitoes.
Physical Obstacles
The use of insecticide-treated bed nets (ITNs) at night and during the day and how to stay protected during the monsoon. The Aedes mosquito has biting and feeding patterns mainly during the day and screen should be used for all doors and windows.
Insect repellents
Use chemical repellants containing DEET (N,N-diethyltoluamide), Picaridin, or IR3535, as studies have found them safe and non-teratogenic when used appropriately. These help prevent monsoon disease during all quarters when applied strictly as per the manufacturer’s instructions.
Water and Nutrition Protocols
Cleaning
Purify all drinking water using safe methods such as boiling or a reliable reverse osmosis (RO) filtration system. Avoid consuming ice from unknown sources.
Healthy Diet
Unpeeled raw fruits and vegetables, street food and raw or undercooked seafood should be avoided during monsoon. Cook vegetables and meat thoroughly and always use fresh ingredients to reduce the risk of intestinal monsoons during pregnancy.
Personal Hygiene
Soap and water or alcohol-based sanitizers maintain strict hand hygiene and help prevent infections before cooking, before and after meals, and after returning from public places.
Conclusion
Monsoon brings a wide variety of infections that can be fatal to both mother and baby. Following monsoon immunity advice, proper vector control, good nutritional hygiene and vaccination when appropriate can limit clinical consequences for expectant mothers.
