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Conference Summary
Malaria during Pregnancy:
Epidemiology, Current Prevention Strategies, and Future Directions1
Robert D. Newman,*
Magda Robalo,† and Isabella Quakyi‡
*Centers for Disease Control and Prevention, Atlanta, Georgia, USA; †World
Health Organization/AFRO, Harare, Zimbabwe; and ‡School of Public Health,
College of Health Sciences, University of Ghana, Legon, Ghana
Suggested
citation for this article
Malaria during pregnancy is a major pubic health problem in sub-Saharan
Africa and is associated with maternal anemia, low birth weight, and premature
delivery. Efficacious prevention measures exist, namely, insecticide treated
bednets and intermittent preventive treatment. Malaria remains a disease
of poverty; the fact that poor women are also less likely to reveive antenatal
care worsens the opportunities for intervention for the most vulnerable
women. Future research needs to focus on new drugs and drug combinations
for use in pregnancy, the impact of combined use of insecticide-treated
bednets and intermittent preventive treatment, and the further exploration
of a pregnancy-specific malaria vaccine.
Epidemiology
of Malaria during Pregnancy
Malaria during pregnancy poses substantial risk to the mother, her fetus,
and the neonate; the infection contributes to as much as 15% of maternal
anemia, 14% of low birth weight infants, 30% of preventable low birth
weight, 70% of intrauterine growth retardation, 36% of premature deliveries,
and 8% of infant mortality. In areas of stable transmission where adult
women have considerable acquired immunity, Plasmodium falciparum
infection during pregnancy typically does not cause symptomatic malaria
but may lead to maternal anemia and placental malaria, especially among
women having their first and second children. This placental malaria contributes
to low birth weight, the single greatest risk factor for neonatal death,
and a major contributor to infant deaths. In areas of unstable transmission,
women do not acquire substantial antimalarial immunity; infection with
P. falciparum can cause severe clinical illness and has also been
linked to poor birth outcomes, including stillbirth and premature delivery.
HIV infection diminishes a pregnant woman’s ability to control P. falciparum
parasitemia and may contribute to up to 25% of maternal malaria, as well
as contributing independently to maternal anemia, low birth weight infants,
and infant deaths. The role of placental malaria in the vertical transmission
of HIV remains unclear.
Prevention
of Malaria during Pregnancy and Its Adverse Consequences
Data from clinical trials and program evaluations in stable transmission
areas indicate that intermittent preventive treatment with two doses of
sulfadoxine-pyrimethamine is safe, efficacious, and effective in preventing
maternal anemia, placental parasitemia, and low birth weight. Data also
show that women using insecticide-treated bednets during pregnancy are
also less likely to suffer these same adverse outcomes of malaria during
pregnancy. The World Health Organization currently recommends that all
pregnant women in malaria-endemic areas sleep under an insecticide treated
bednet and receive at least two doses of intermittent preventive treatment
with an efficacious antimalarial in the second and third trimesters. Chemoprophylaxis
with chloroquine is no longer recommended. HIV-positive women need more
than two doses of intermittent preventive treatment to achieve the same
protective effect. Currently, the recommended drug for intermittent preventive
treatment is sulfadoxine-pyrimethamine, because it is safe, easily delivered,
and remains efficacious for women of reproductive age in most of sub-Saharan
Africa.
Future Directions
in the Prevention of Malaria During Pregnancy
Because resistance of P. falciparum to current drugs and resistance
of malaria vectors to available insecticides are both spreading, alternative
strategies for the prevention of malaria during pregnancy need to be explored.
The safety and efficacy of new antimalarial agents and antimalarial combinations
for use in pregnancy require urgent investigation. The efficacy of current
interventions in combination (i.e., insecticide-treated bednets together
with intermittent preventive treatment) also merits further study. In
addition, novel control mechanisms, such as a pregnancy-specific vaccine,
should also be investigated. Potentially, a vaccine could be developed
that could protect against placental sequestration and the associated
adverse effects. Until such a vaccine is developed, insecticide-treated
bednets and intermittent preventive therapy will remain the mainstay of
malaria control efforts during pregnancy.
1The following comments were made in presentations
by the above authors at the International Conference on Women and Infectious
Disease.
Suggested citation
for this article:
Newman RD, Robalo M,
Quakyi I. Malaria during pregnancy: epidemiology, current prevention strategies,
and future directions. Emerg Infect Dis [serial on the Internet]. 2004
November [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol10no11/04-0624_09.htm
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