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Malaria and Pregnancy

Each year between 75,000 and 200,000 infant deaths are attributed to malaria infection in pregnancy globally, and between 200,000 and 500,000 pregnant women develop severe anaemia as a result of malaria in Sub-Saharan Africa. Pregnant compared to non-pregnant women are at an increased risk of malaria, and the severity of the clinical manifestations in the woman and her foetus depends on the level of pre-pregnancy immunity. In areas of low, stable malaria endemicity all pregnant women are equally susceptible to the consequences of malaria infection, as they are likely to have built up little previous immunity. In areas of high endemicity women are most susceptible during their first pregnancy (when levels of pre-pregnancy immunity are at their lowest) than later ones, but there is still significant susceptibility in multigravidae.

Malaria Transmission Status

Primigravidae Multigravidae
High endemicity, stable Higher risk for severe malaria and low birth weight (LBW) Often symptom-less, but can still suffer from anaemia and placental malaria infection
Unstable, epidemic High risk of fever, severe malaria, LBW, severe anaemia, and placental infection. High risk of fever, severe malaria, LBW, severe anaemia, and placental infection.
 

 

 

 

 

Pregnancies in women living in malaria epidemic-prone regions (ie with unstable transmission) are associated with a high frequency and density of P. falciparum parasitaemia, with occasional high rates of maternal morbidity including fever, severe anaemia, hypoglycaemia, cerebral malaria, puerperal sepsis, pulmonary oedema and death. However, many malaria infections remain sub-clinical and are not detected, as the parasite preferentially sequesters in the placenta. As pregnancies progress, maternal immunity to malaria increases, and parasites are even less likely to be detected by conventional microscopy. Long-term exposure of the foetus to parasites and concurrent maternal anaemia can lead to complications such as congenital infection, low birth weight, growth retardation and even abortion and stillbirth. Low birth weight (LBW) is the largest cause of neonatal mortality, and malaria has a big effect on this, being responsible for up to 60% of LBW. 

At the African Summit on Roll Back Malaria (RBM) in Abuja, Nigeria 2000, it was agreed there should be a substantial increase in the proportion of pregnant women at risk who receive protection from malaria's effects during pregnancy (desired proportion: at least 60%) over the following few years. RBM and WHO promote the use of insecticide-treated mosquito nets (ITNs) and intermittent preventive treatment (IPT) for malaria infection in pregnant women. The most appropriate control methods depend on the epidemiology of malaria transmission.

ITNs should be provided to pregnant women where possible, as they are proven to reduce the level of placental malaria, and levels of LBW and stillbirths in primigravidae and subsequent pregnancies. Effects on clinical malaria and anaemia are not as strong. Women should be encouraged to use the nets throughout the pregnancy as well as after giving birth to protect the new born.

Intermittent Preventive Treatment (IPT) has been recommended for all pregnant women living in areas of high malaria transmission, where SP resistance is not too high. This involves a curative dose of sulfadoxine/pyrimethamine, given regardless of infection status. IPT in women having their first or second baby is associated with fewer women having severe anaemia (particularly primigravidae) and reducing placental infection and preventing LBW. The size of the effect for severe anaemia is considerable, while the size of the effect with perinatal mortality is more modest. In areas of unstable epidemic malaria, with low endemicity, IPT is not normally indicated, as the cost effectiveness is outweighed by the dangers of accelerating development of drug resistance. It is important to increase accessibility and quality of antenatal care (ANC) services to ensure high IPT utilisation rates.

HIV infection exacerbates the severity of malaria infection in pregnant women. They are more likely to have symptomatic malaria, maternal anaemia and low birth weight offspring. The reason for this is likely to be the reduction in CD4 T cells by HIV infection, leading to loss of any acquired immunity to malaria in the mother. In terms of IPT, it is recommended that HIV infected pregnant women are given more frequent curative doses - at least three times during the pregnancy, if not monthly during the second and third trimester.

Special attention to effective case management is essential for pregnant woman presenting with fever in malaria endemic areas.

Programme Activities:

The Malaria Consortium, collaborating with the Ugandan Ministry of Health, distributed ITNs at the end of the first antenatal visit to pregnant women. As the net was handed over pregnant women were educated on key messages about the importance of the nets. Between February and October 2004 16,629 LLINs were delivered to pregnant women through ANC services covering 50-60% of the expected numbers of pregnant women in the two districts served during this period.

Comparisons of ANC attendance over the two years prior to the introduction of LLIN distribution and during the distribution period suggested that the availability of LLINs resulted in an increase in the number of women attending ANC. In the districts as a whole there was a 50% increase in the proportion of expected pregnant women attending ANC with some health facilities seeing double the number they would have previously seen.

Six months after the start of the LLIN distribution a net retention and use survey was carried out for evaluation purposes. This demonstrated remarkably successful retention with 86-93% of LLINs still in the possession of the women. The survey also asked who had used the net the night previously. 47% of the targeted women had used the net the night previously, this lower than expected figure could be due to misconceptions about use during pregnancy, the data available suggested that some women may have been waiting until they have delivered to use the net.

Delivering ITNs to pregnant women in Northern Uganda [Link]

 

References:

  1. * Mockenhaupt, F.P., Bedu-Addo, G., von Gaertner, C., Boye, R., Fricke, K., Hannibal, I., Karakaya, F., Schaller, M., Ulmen, U., Acquah, P.A., Dietz, E., Eggelte, T.A. and Bienzle, U. (2006) Detection and clinical manifestation of placental malaria in southern Ghana. Malaria Journal 13: 119-128.
  2. * Mockenhaupt, F.P., Rong, B. Till, H., Eggelte, T.A., Beck, S., Gyasi-Sarpong, C., Thompson, W.N.A. & Bienzle, U. (2000) Submicroscopic Plasmodium falciparum infections in pregnancy in Ghana. Tropical Medicine and International Health 5(3): 167-173.
  3. * Ter Kuile, F., Parise, M.E., Verhoeff, F.H., Udhayakumar, V., Newman, R.D. Van Eijk, A.M., Rogerson, S.J. & Steketee, R.W. (2004) The burden of co-infection with human immunodeficiency virus Type 1 and malaria in pregnant women in sub-Saharan Africa. American Journal of Tropical Medicine and Hygiene, 71(Suppl 2), 2004, pp. 41-54.
  4. Mavoungou, E. (2006) Interactions between natural killer cells, cortisol and prolactin in malaria during pregnancy. Clinical Medicine & Research 4(1): 33-41.
  5. Nosten, F., Rogerson, S.J., Beeson, J.G., McGready, R.,Mutabingwa T.K. & Brabin, B. (2004) Malaria in pregnancy and the endemicity spectrum. What can we learn? TRENDS in Parasitology 20(9) 425-432.
  6. * Van Geertruyden, J.P., Thomas, F., Erhart, A. & D'Alessandro, U. (2004) The contribution of malaria in pregnancy to perinatal mortality. American Journal of Tropical Medicine and Hygiene 71(2 Suppl): 35-40.
  7. Whitty, C, Edmonds, S. & Mutabingwa, T. K. (2005) Malaria in Pregnancy. British Journal of Obstetrics and Gynaecology 112: 1189-1195.
  8. * White NJ. (2005) Intermittent presumptive treatment for malaria. PLoS Medicine 2(1): e3-e9.
  9. * Kalanda, G.C, Hill, J., Verhoeff, F.H. & Brabin, B.J. (2006) Comparative efficacy of chloroquine and sulphadoxine-pyrimethamine in pregnant women and children: a meta-analysis . Tropical Medicine and International Health 11(5):569-577.
  10. * World Health Organization (2004) A strategic framework for malaria prevention and control during pregnancy in the Africa Region. Brazzaville, Regional Office for Africa AFR/MAL/04/01.
  11. * Global Health Technical Brief. Prevent and Treat Malaria during Pregnancy .
  12. K. Kolaczinski (2006) Delivering ITNs through ante-natal services to pregnant women in conflict-affected northern Uganda. Malaria Consortium Publication.
  13. * Greenwood, B. (2004) The use of anti-malarial drugs to prevent malaria in the population of malaria endemic areas. American Journal of Tropical Medicine and Hygiene 70(1): 1-7.
  14. * Miaffo, C., Some, F., Kouyate, B., Jahn, A. & Mueller, O. (2004) Malaria and anemia prevention in pregnant women of rural Burkina Faso . BMC Pregnancy and Childbirth 4:18-24.