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Malaria and Miscarriage Risk
Malaria occurs in more than 100 countries and territories, and malaria risk areas include large areas of Central and South America, Hispaniola (the Caribbean island that is divided between Haiti and the Dominican Republic), Africa, the Indian subcontinent, Southeast Asia, the Middle East and Oceania. Economic development and public health efforts have eliminated malaria from the southern United States, southern Europe, Taiwan, Singapore and all of the Caribbean islands (except Hispaniola). About 1,500 cases of malaria are diagnosed in the United States annually, mostly in returned travelers, according to the Centers for Disease Control and Prevention. Worldwide, malaria kill around 1 million people each year, and just one episode of malaria during a first trimester pregnancy is linked to a three times greater risk of miscarriage.
A study by the Shokio Malaria Research Unit (SMRU) in Thailand and funded by the Wellcome Trust is the largest study to assess the effects of malaria and its treatment in the first trimester of pregnancy. The study, published the journal Lancet Infectious Diseases, found that while the disease significantly increases the risk of miscarriage, treating it with antimalarial drugs is relatively safe and reduces this risk.
"Malaria is a potentially deadly disease and is particularly dangerous during pregnancy, both to the health of the mother and to the health of her unborn child," says Dr. Rose McGready from SMRU. "Understanding the risks is essential for weighing up the treatment options. Our work has highlighted the particular risk factors with malaria infection during pregnancy. Particularly worrying is the risk of miscarriage even when the disease is asymptomatic. However, whilst the dangers of miscarriage are considerable, our study offers some good news, that the most common drugs reduce this risk significantly."
What Is Malaria
Malaria in pregnancy can cause severe anemia and parasitic infection in the fetus. It is a major cause of maternal mortality and can cause low birth weight and premature birth, which predisposes to neonatal mortality. Malaria is caused by infection with the malaria parasite, which is transmitted into the bloodstream through the bite of infected mosquitoes. The parasites enter the liver where they multiply before leaving and infecting red blood cells.
The most effective drug for treating malaria is artemisinin. Artemisinin combination therapies (ACT) are recommended by the World Health Organization for the treatment of malaria except in the first trimester. This is because animal studies have indicated that the drugs can be toxic to embryos.
SMRU researchers examined the records of all women attending antenatal clinics of SMRU. Of these, 16,668 had no malaria during pregnancy, while 945 had only a single episode during their first trimester and no episodes later in pregnancy. The found:
- Around one in five pregnancies resulted in miscarriage when malaria was not a factor.
- Symptomatic malaria increased the risk of miscarriage to one in two pregnancies.
- For asymptomatic malaria, the risk of miscarriage was one in three pregnancies.
- In women with malaria, the more the severe disease, the higher levels of parasites in the blood and the infection at an earlier stage of pregnancy increased the risk of miscarriage further.
- The risks associated with miscarriage were similar for both strains of malaria — P. falciparum and P. vivax infections.
P. falciparum infections were treated with quinine or artesunate (part of the artemisinin group of drugs that treat malaria), or inadvertently with ACT (Artemisinin-based Combination Therapy), and P. vivax infections were treated with chloroquine. Of the women treated:
- 26 percent miscarried following chloroquine
- 27 percent miscarried following quinine
- 31 percent miscarried following artesunate
- After inadvertent treatment with an ACT, the miscarriage rate was 24 percent, comparable to the rate associated with other treatments.
"This is a very important observational study on the risks of treating malaria in women in early pregnancy, a key high-risk group for this infection," says Dr. Jimmy Whitworth, Head of International Activities at the Wellcome Trust. "These results, which come from the research group that has done the majority of studies of malaria in pregnancy anywhere in the world, show that antimalarial treatment with standard first-line drugs reduces the risk of miscarriage in the first trimester. These findings are likely to change practice guidelines worldwide and to save the lives of many women and unborn children."
Protect Yourself from Malaria if Traveling
According to the CDC, an individual risk assessment should be conducted for every traveler, which takes into account the destination country; the detailed itinerary, including specific cities; types of accommodations; the season; and the style of travel; conditions such as pregnancy; and the presence of antimalarial drug resistance at the destination.
Specific malaria prevention interventions should be based on the risk assessment. These interventions include avoiding mosquito bites through the use of repellents or insecticide treated bed nets, and specific medicines to prevent malaria. The CDC provides information on choosing a drug to prevent malaria, many of which cannot be used by pregnant women.
Most importantly, know the symptoms of malaria. According to the CDC, travelers who become ill with a fever or flu-like illness either while traveling in a malaria-risk area or after returning home (for up to 1 year) should seek immediate medical attention and should tell the physician their travel history.