The response to iron supplementation of pregnant women with the haemoglobin genotype AA or AS.

The influence of haemoglobin genotype on the response to iron supplementation was studied in a randomized, double blind, placebo-controlled trial involving 497 multigravid pregnant women from a rural area of The Gambia. Women were randomly allocated to receive either oral iron (60mg elemental iron per day) or placebo. At 36 weeks of pregnancy, women who had received oral iron during pregnancy had higher mean haemoglobin, packed cell volume, plasma iron and ferritin levels than did women who received placebo. Iron supplementation of pregnant women with the AA haemoglobin genotype also resulted in increases in the packed cell volume (PCV) and haemoglobin level measured after delivery, and in the birth weight of the infant. However, in AS women PCV and haemoglobin level at delivery were lower in the supplemented group and supplementation was also associated with reduced birth weights. In malaria endemic areas, pregnant women with the haemoglobin genotype AS may not benefit from iron supplementation during pregnancy.

Can malaria chemoprophylaxis be restricted to first pregnancies?

The harmful effects of malaria are most pronounced during first pregnancies and chemoprophylaxis is most effective when given at this time. However, restriction of chemoprophylaxis to first pregnancies might lead to enhanced susceptibility to malaria during second pregnancies. We have investigated this possibility by studying the outcome of second pregnancies in 165 Gambian women who had received either malaria chemoprophylaxis with Maloprim or placebo during their first pregnancy. Many of these primigravidae did not present until the third trimester of pregnancy so that some are likely to have experienced a malaria infection before they started medication. The prevalence of malaria infection of the blood and of the placenta during second pregnancies was similar in women who had received chemoprophylaxis during their first pregnancy and in those who had not, and the mean birth weights of babies born to women in each group were almost identical. Thus, in areas where the epidemiology of malaria is similar to that of The Gambia and where most women present relatively late in pregnancy, it may be possible to restrict malaria chemoprophylaxis to first pregnancies with consequent savings in cost and a reduction in drug pressure on Plasmodium falciparum.

The effects of iron supplementation during pregnancy, given by traditional birth attendants, on the prevalence of anaemia and malaria.

A randomized, double-blind, placebo-controlled community-based trial of oral iron supplementation (200 mg ferrous sulphate daily) administered to multigravid pregnant women by traditional birth attendants (TBAs) was carried out in a rural area of The Gambia. Iron supplementation led to a significant reduction in the prevalence of anaemia and of iron deficiency. Iron supplementation was not accompanied by increased susceptibility to malaria infection; there was no difference in the prevalence and severity of peripheral blood or placental malaria infection between the 2 groups of women. The birth weight of children born to women who received iron prophylaxis was increased by an average of 56 g. It is concluded that oral iron prophylaxis can be successfully delivered through TBAs integrated into a primary health care programme. This simple intervention can produce significant beneficial effects on the health of the mother without inducing increased susceptibility to malaria and has the potential for reducing perinatal mortality by increasing birth weight.

The contribution of Gambian traditional birth attendants to field research.

One thousand, one hundred and forty-seven pregnant women from a rural area of The Gambia were followed throughout pregnancy. In order to determine the incidence of malaria infection of the placenta, traditional birth attendants (TBAs) from 18 villages were trained to collect placental biopsies and to prepare thick smears of placental blood at delivery. Nine hundred and eighty-eight of 1112 term deliveries (89%) occurred at home. Eight hundred and fifty-nine (87%) of these home deliveries were assisted by a TBA. TBAs collected 829 placental biopsies and 800 thick blood smears from the 859 women whom they assisted. Seven hundred and forty-seven thick blood films (93%) and 807 placental samples (97%) were satisfactory. TBAs are an important resource for clinical research; in this case they made a major contribution to a community study of the impact of malaria on pregnancy.

Factors influencing vaccination compliance in peri-urban Gambian children.

The vaccination status of 251 children aged 12-18 months in two peri-urban Gambian communities was determined from their health cards. Two subgroups were identified: children who were fully vaccinated, and those who had received less than half their vaccinations. The social and environmental circumstances of these children were investigated to detect factors which were associated with poor vaccination compliance. Mothers of well vaccinated children were more inclined to bring them for non-curative services. Mothers of poorly vaccinated children had a poorer knowledge of the diseases against which their children should be vaccinated and they also had a more superstitious view of disease causation. Those children who showed poor compliance came from larger families. In the poorly vaccinated group both parents were less well educated and there was a trend towards poorer literacy.

Trial of an attenuated bovine rotavirus vaccine (RIT 4237) in Gambian infants.

A randomised, controlled trial of bovine rotavirus vaccine was undertaken in Gambian infants. Three doses were administered, from the age of ten weeks, concurrently with oral or killed polio vaccine. Prevaccination rotavirus neutralising antibody levels were high. 84/185 infants (45%) showed an increase in neutralising antibody titre after receiving rotavirus vaccine, compared with 20/91 (22%) unvaccinated infants. Clinical rotavirus infection was detected in 24/78 (31%) children in the rotavirus/oral polio group, 34/83 (41%) children in the placebo/oral polio group, and 23/92 (25%) children in the rotavirus/killed polio group, giving an overall vaccine efficacy of 33% (95% CI 4-53%). RIT 4237 did not appear to reduce the severity of clinical infections. Most cases (92%) were caused by rotaviruses with short RNA electropherotypes. Serological responses to rotavirus vaccination appeared unaffected by the concurrent administration of oral polio vaccine. Lower types 1 and 3 polio antibody levels were found in children who received oral polio and rotavirus vaccines but the differences were not statistically significant.