WUNRN
MALARIA OF PREGNANT WOMEN STUNTS
EARLY FETAL GROWTH - RESEARCH
BANGKOK, 6 March 2012 (IRIN) - Malaria infection during the
earliest months of pregnancy stunts foetal growth even when the mothers do not
have any malarial symptoms, according to a large-scale study conducted along the Thai-Burmese
border.
"Malaria needs to be taken into account from the beginning of the
pregnancy and not only in the last months before the birth," François
Nosten, director of the Mae Sot-based Shoklo Malaria Research Unit (SMRU), which tracked 3,779
women's pregnancies from 2001-2010, told IRIN.
SMRU is attached to the Mahidol University-Oxford University Tropical Medicine
Research Programme in Bangkok, which is supported by the UK-based health
programmes donor, Wellcome Trust.
Pregnant women are among the most vulnerable to malaria infections as pregnancy
reduces a woman's immunity, making her more susceptible to malaria infection
and increasing the risk of illness, severe anaemia and death, according to the
World Health Organization (WHO).
And while the impact of malaria on later stages of pregnancy and birth weight
are well documented (increased risk of spontaneous abortion, stillbirth,
premature delivery and low birth weight), the SMRU study is among the first to
show a direct impact of malaria on early foetal growth, even in areas where
malaria infections have plummeted.
Hidden parasite reservoir
People who have been repeatedly struck by malaria can develop partial immunity
and may not have symptoms, despite harbouring the parasite.
And in communities where malaria infections have dropped (mainly due to prevention
and treatment), the parasite level can also be so low as to not show up in
tests, noted David Bell, head of malaria diagnostics at the Geneva-based
research organization, Foundation
for Innovative New Diagnostics (FIND).
Evidence that this hidden parasite reservoir can harm foetuses boosts the need
for prevention even in areas that have already slashed infections, noted Andrea
Bosman with the WHO Global Malaria Programme.
During pregnancy, the parasite hides in the placenta, rendering finger-prick
blood tests inaccurate, Bell added. And while DNA analyses are more accurate,
the technology is more expensive and less widely available.
Throughout most of sub-Saharan Africa, the WHO recommends giving anti-malarial
drugs to pregnant women at intervals in case such a "hidden" malaria
infection is present, but preventative treatment does not currently begin until
after the first three months of pregnancy.
New evidence
On average, at the mid-pregnancy ultrasound scan in the SMRU study, the
diameter of the foetus's head - an indication of foetal growth - was 2 percent
smaller when the woman was infected by malaria than if not.
The foetuses of close to 57 percent of the mothers infected with malaria had a
smaller head than those who were not. Researchers said disrupted foetal growth
can heighten the risk of pregnancy complications.
"The mother may not have any symptom of malaria and the reduction of the
growth of the foetus is relative, not easily detected by ultrasound for
individual cases [versus a large-scale study where the trend is more apparent].
The malaria infection nevertheless increases the risk of miscarriage, affects foetal growth
and may hinder the child's development later in his life," said Nosten.
Detected early enough, it is possible to prevent the worst impacts of malaria,
said Heidi Hopkins, a medical officer at FIND in Uganda.
"We can't necessarily 'reverse' the damage, but the earlier we diagnose
and treat, the less time the foetus and mother are exposed to the infection, so
the less impact it has."
With timely detection, "perhaps the growth of the foetus can catch up to
compensate", added Nosten.
The challenge with early detection, noted Hopkins, is many women do not know
they are pregnant until several weeks into the pregnancy.
FIND and the multi-agency Special Programme for Research and Training in
Tropical Diseases (TDR) are testing new rapid diagnostic tests on pregnant
women in Uganda and Burkina Faso, where malaria is more prevalent than in most
parts of Southeast Asia, to learn whether earlier and affordable detection is
possible during pregnancy.
"A preventive and safe medication to women from the beginning
of their pregnancy should be evaluated where malaria is endemic,"
concluded Nosten.
Due to limited safety data, the WHO does not recommend the anti-malarial
medication artemisinin during the first three months of pregnancy unless the
"treatment is considered lifesaving for the mother and other treatments
are considered unsuitable".
More than 50 million pregnancies occur in malaria-endemic areas annually,
mostly in sub-Saharan Africa, according to the WHO.
An estimated 10,000 of these women and 200,000 of their infants die as a result
of malaria infection during pregnancy, and severe malarial anaemia contributes
to more than half of these deaths.