Lack of efficacy of pyrimethamine prophylaxis in pregnant Nigerian women

High prevalence of dihydrofolate reductase gene mutations in Plasmodium falciparum parasites among pregnant women in Nigeria after reported use of sulfadoxine-pyrimethamine

This study assesses the prevalence of asymptomatic Plasmodium falciparum parasitemia positivity and P. falciparum dihydrofolate reductase (pfdhfr) mutations in parasite isolates among pregnant women in Southwest Nigeria. Plasmodium falciparum parasitemia was confirmed by microscopy and nested PCR in 200 pregnant women attending antenatal care. The prevalence of pfdhfr polymorphisms was determined by direct sequencing of the gene fragments containing the C50R, N51I, C59R, S108N, and I164L mutations. Information on the use of antimalarial drugs and methods applied to prevent malaria were obtained by a questionnaire. The prevalence of asymptomatic P. falciparum infection was 30% (60/200). The frequency of the pfdhfr triple-mutant alleles (N51I, C59R, and S108N) was 63% (38/60); none of the isolates carried the I164L mutation. Among the investigated pregnant women, 40% used un-prescribed antimalarials such as dihydroartemisinin (18%), chloroquine (14%) or pyrimethamine (9%), while only 20.5% used sulfadoxine-pyrimethamine for prevention and 39.5% did not use any drug. The prevalence of P. falciparum parasitemia (37%) was higher among pregnant women who had not taken any antimalarial drugs. A significant difference in the prevalence of the pfdhfr triple-mutant alleles was observed among women who took SP (90%) compared to those who did not take any drug (82%) and women who took dihydroartemisinin (67%) p = 0.007). Poor adherence to the World Health Organisation (WHO) strategies for malaria prevention among pregnant women was observed in addition to high prevalence of pfdhfr mutations. These findings underline the need to improve control of malaria among pregnant women in the study area.

Drugs for preventing malaria in pregnant women in endemic areas: any drug regimen versus placebo or no treatment

BACKGROUND

Pregnancy increases the risk of malaria and this is associated with poor health outcomes for both the mother and the infant, especially during the first or second pregnancy. To reduce these effects, the World Health Organization recommends that pregnant women living in malaria endemic areas sleep under insecticide-treated bednets, are treated for malaria illness and anaemia, and receive chemoprevention with an effective antimalarial drug during the second and third trimesters.

OBJECTIVES

To assess the effects of malaria chemoprevention given to pregnant women living in malaria endemic areas on substantive maternal and infant health outcomes. We also summarised the effects of intermittent preventive treatment with sulfadoxine-pyrimethamine (SP) alone, and preventive regimens for Plasmodium vivax.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, EMBASE, LILACS, and reference lists up to 1 June 2014.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs of any antimalarial drug regimen for preventing malaria in pregnant women living in malaria-endemic areas compared to placebo or no intervention. In the mother, we sought outcomes that included mortality, severe anaemia, and severe malaria; anaemia, haemoglobin values, and malaria episodes; indicators of malaria infection, and adverse events. In the baby, we sought foetal loss, perinatal, neonatal and infant mortality; preterm birth and birthweight measures; and indicators of malaria infection. We included regimens that were known to be effective against the malaria parasite at the time but may no longer be used because of parasite drug resistance.

DATA COLLECTION AND ANALYSIS

Two review authors applied inclusion criteria, assessed risk of bias and extracted data. Dichotomous outcomes were compared using risk ratios (RR), and continuous outcomes using mean differences (MD); both are presented with 95% confidence intervals (CI). We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

Seventeen trials enrolling 14,481 pregnant women met our inclusion criteria. These trials were conducted between 1957 and 2008, in Nigeria (three trials), The Gambia (three trials), Kenya (three trials), Mozambique (two trials), Uganda (two trials), Cameroon (one trial), Burkina Faso (one trial), and Thailand (two trials). Six different antimalarials were evaluated against placebo or no intervention; chloroquine (given weekly), pyrimethamine (weekly or monthly), proguanil (daily), pyrimethamine-dapsone (weekly or fortnightly), and mefloquine (weekly), or intermittent preventive therapy with SP (given twice, three times or monthly). Trials recruited women in their first or second pregnancy (eight trials); only multigravid women (one trial); or all women (eight trials). Only six trials had adequate allocation concealment.For women in their first or second pregnancy, malaria chemoprevention reduces the risk of moderate to severe anaemia by around 40% (RR 0.60, 95% CI 0.47 to 0.75; three trials, 2503 participants, high quality evidence), and the risk of any anaemia by around 17% (RR 0.83, 95% CI 0.74 to 0.93; five trials,, 3662 participants, high quality evidence). Malaria chemoprevention reduces the risk of antenatal parasitaemia by around 61% (RR 0.39, 95% CI 0.26 to 0.58; seven trials, 3663 participants, high quality evidence), and two trials reported a reduction in febrile illness (low quality evidence). There were only 16 maternal deaths and these trials were underpowered to detect an effect on maternal mortality (very low quality evidence).For infants of women in their first and second pregnancies, malaria chemoprevention probably increases mean birthweight by around 93 g (MD 92.72 g, 95% CI 62.05 to 123.39; nine trials, 3936 participants, moderate quality evidence), reduces low birthweight by around 27% (RR 0.73, 95% CI 0.61 to 0.87; eight trials, 3619 participants, moderate quality evidence), and reduces placental parasitaemia by around 46% (RR 0.54, 95% CI 0.43 to 0.69; seven trials, 2830 participants, high quality evidence). Fewer trials evaluated spontaneous abortions, still births, perinatal deaths, or neonatal deaths, and these analyses were underpowered to detect clinically important differences.In multigravid women, chemoprevention has similar effects on antenatal parasitaemia (RR 0.38, 95% CI 0.28 to 0.50; three trials, 977 participants, high quality evidence)but there are too few trials to evaluate effects on other outcomes.In trials giving chemoprevention to all pregnant women irrespective of parity, the average effects of chemoprevention measured in all women indicated it may prevent severe anaemia (defined by authors, but at least < 8 g/L: RR 0.19, 95% CI 0.05 to 0.75; two trials, 1327 participants, low quality evidence), but consistent benefits have not been shown for other outcomes.In an analysis confined only to intermittent preventive therapy with SP, the estimates of effect and the quality of the evidence were similar.A summary of a single trial in Thailand of prophylaxis against P. vivax showed chloroquine prevented vivax infection (RR 0.01, 95% CI 0.00 to 0.20; one trial, 942 participants).

AUTHORS' CONCLUSIONS

Routine chemoprevention to prevent malaria and its consequences has been extensively tested in RCTs, with clinically important benefits on anaemia and parasitaemia in the mother, and on birthweight in infants.

Effects of pyrimethamine versus proguanil in malarial chemoprophylaxis in children with sickle cell disease: a randomized, placebo-controlled, open-label study

BACKGROUND

Malarial chemoprophylaxis is essential for patients with homozygous sickle cell disease (SCD) who live in areas where malaria is endemic. Endemic regions include most sub-Saharan African countries and Southeast Asia.

OBJECTIVE

This study compared the efficacy and tolerability of pyrimethamine with that of proguanil and placebo in the prevention of malaria and the complications of Plasmodium falciparum infection (hepatomegaly, splenomegaly, bone pain crisis, hemolytic crisis) in children with SCD.

METHODS

In this single-center, open-label study conducted in Nigeria, children aged 1 to 16 years with SCD were randomly assigned to receive tablets of pyrimethamine (0.5 mg/kg·wk), proguanil (1.5 mg/kg·d), or placebo (vitamin C, 7 mg/kg·d) for 9 months as prophylaxis from February to December (which includes the rainy season), the period of greatest malarial transmission. The clinical and laboratory features of malaria (presence of parasitemia, parasite count and density, hepatomegaly and/or splenomegaly, symptomatic malarial infection [fever, rigors], bone pain crises, and hemolytic crises) were assessed.

RESULTS

A total of 97 patients completed the study (49 boys, 48 girls; mean [SD] age, 7.8 [4.3] years). The pyrimethamine group comprised 36 patients (mean [SD] age, 8.1 [4.3] years; range, 2-16 years); the proguanil group, 32 patients (mean [SD] age, 9.5 [3.7] years; range, 3-16 years); and the placebo group, 29 patients (mean age, 5.9 years; range, 1-14 years). The male:female ratio was 1.1:1 in the pyrimethamine group, 1:1.7 in the proguanil group, and 1.6:1 in the placebo group. Parasitemia was noted in 7 patients (19.4%) in the pyrimethamine group, 6 (18.8%) in the proguanil group, and 7 (24.1%) in the placebo group at the start of the study. P falciparum was the only isolate. The mean parasite density over the 9-month period was significantly lower with proguanil compared with pyrimethamine (P = 0.045) and placebo (P<0.05). The incidence of splenomegaly was least with pyrimethamine, but this group had the most patients clinically diagnosed with malaria. Hospitalizations and episodes of bone pain and hemolytic crisis occurred most frequently with placebo. One patient in the placebo group died of septicemia.

CONCLUSIONS

Proguanil and pyrimethamine both reduced parasitemia; however, proguanil significantly decreased mean parasite density more effectively than pyrimethamine. Pyrimethamine and proguanil may protect children with SCD from the complications of P falciparum infection despite persistent parasitemia. Proguanil may be more useful than pyrimethamine in the prevention of bone pain crises among patients with SCD.

Scaling up of intermittent preventive treatment of malaria in pregnancy using sulphadoxine-pyrimethamine: prospects and challenges

Intermittent preventive treatment of malaria during pregnancy with sulphadoxine-pyrimethamine (IPTpSP) is one of the major strategies of malaria control in most African countries where malaria is endemic. The use of sulphadoxine-pyrimethamine (SP) for intermittent preventive treatment of malaria during pregnancy was adopted when proof of its superiority to weekly prophylactic dosing with either chloroquine or pyrimethamine became evident from studies in different malaria endemic countries. The administration of 2 and 3 treatment doses of SP for HIV-negative and HIV-positive pregnant women respectively, given after quickening and at an interval not less than 4 weeks was recommended. The prospects of this control strategy lies on the efficacy of SP, convenient treatment dose and high compliance rate. However, the implementation of this strategy and the efficacy of SP are faced with challenges such as: timing of SP administration, rising levels of parasite resistance to SP in the general population, effect of folate supplementation, adequacy of the recommended doses with regards to malaria endemicity and HIV status, interactions between SP and antiretroviral drugs and low coverage in the bid to scale-up its use. This review highlights the prospects and challenges of scaling up IPTp-SP.

Utilisation of malaria preventive measures during pregnancy and birth outcomes in Ibadan, Nigeria

Background

Malaria remains a major public health problem in sub Saharan Africa and the extent of utilisation of malaria preventive measures may impact on the burden of malaria in pregnancy. This study sought to determine the association between malaria preventive measures utilized during pregnancy and the birth outcomes of birth weight and preterm delivery.

Methods

This cross sectional survey involved 800 mothers who delivered at the University College Hospital, and Adeoyo Maternity Hospital, Ibadan. Data obtained included obstetric information, gestational age, birth weight and self reported use of malaria prevention strategies in index pregnancy.

Results

Most (95.6%) mothers used one or more malaria control measures. The most commonly used vector control measures were window net (84.0%), insecticide spray (71.5%) and insecticide treated bed nets (20.1%), while chemoprophylactic agents were pyrimethamine (23.5%), Intermittent Preventive Treatments with Sulphadoxine-Pyrimethamine (IPTsp) (18.5%) and intermittent chloroquine (9.5%) and 21.7% used herbal medications. The mean ± SD birthweight and gestational age of the babies were 3.02 kg ± 0.56 and 37.9 weeks ± 2.5 respectively. Preterm delivery rate was 19.4% and 9% had low birth weight.

Comparing babies whose mothers had IPTsp with those who did not, mean birth weight was 3.13 kg ± 0.52 versus 3.0 kg ± 0.56 (p = 0.016) and mean gestational age was 38.5 weeks ± 2.1 versus 37.8 weeks ± 2.5 (p = 0.002).

The non-use of IPTsp was associated with increased risk of having low birth weight babies (AOR: 2.27, 95% CI: 0.98; 5.28) and preterm birth (AOR: 1.93, 95% CI: 1.08, 3.44). The non use of herbal preparations (AOR: 0.55, 95% CI: 0.36, 0.85) was associated with reduced risk of preterm birth. The mean ± SD birth weight and gestational ages of babies born to mothers who slept under ITNs were not significantly different from those who did not (p = 0.07 and 0.09 respectively).

Conclusions

There is a need for improved utilisation of IPTsp as well as discouraging the use of herbal medications in pregnancy in order to reduce pregnancy outcome measures of low birth weight and preterm deliveries in this environment.

Malaria in pregnancy: the difficulties in measuring birthweight

Recommendations for interventions to control malaria in pregnancy are often based on studies using birthweight as the primary endpoint. Differences in birthweight may be attributable partly to methodological difficulties. We performed a structured search of the literature using ‘malaria’, ‘pregnancy’ and ‘birth weight’ as search terms. Of the clinical trials reporting birthweight, only 33% (14/43) gave information about the timing of the measurement and details on the scales used. Seventy seven per cent explained how gestational age was estimated. We propose a standardised method for the measurement and reporting of birthweight in future studies.

Efficacy of intermittent preventive treatment versus chloroquine prophylaxis to prevent malaria during pregnancy in Benin

BACKGROUND

In West Africa, treatment for the prevention of malaria during pregnancy has recently changed from chloroquine (CQ) prophylaxis to intermittent preventive treatment (IPTp). We assessed the benefits of IPTp with respect to those of CQ, using a before-after study.

METHODS

CQ efficacy was evaluated during a cross-sectional survey conducted in Benin between April 2004 and April 2005. IPTp efficacy was assessed using data from an ongoing clinical trial to compare sulfadoxine-pyrimethamine with mefloquine that began in the same maternity clinics during July 2005; the present analysis is limited to women who delivered between November 2005 and November 2006. Treatment assignments were not unblinded. We compared the efficacy of the 2 strategies against low birth weight and placental infection by performing multiple logistic regressions.

RESULTS

A total of 1699 women (1090 in the CQ group and 609 in the IPTp group) who delivered live singletons were analyzed. Characteristics of women in the CQ group were similar to those of women in the IPTp group. We showed that women in the IPTp group had a significantly decreased risk of delivering an infant with a low birth weight (adjusted odds ratio [aOR], 0.54; 95% confidence interval [CI], 0.38-0.78) and placental infection (aOR, 0.15; 95% CI, 0.09-0.24).

CONCLUSION

We clearly evidenced that IPTp is substantially more beneficial than CQ for the prevention of malaria during pregnancy.

Safety and toxicity of sulfadoxine/pyrimethamine: implications for malaria prevention in pregnancy using intermittent preventive treatment

Plasmodium falciparum infection during pregnancy is strongly associated with maternal anaemia and low birth weight, contributing to substantial morbidity and mortality in sub-Saharan Africa. Intermittent preventive treatment in pregnancy with sulfadoxine/pyrimethamine (IPTp-SP) has been one of the most effective approaches to reduce the burden of malaria during pregnancy in Africa. IPTp-SP is based on administering >or=2 treatment doses of sulfadoxine/pyrimethamine to pregnant women at predefined intervals after quickening (around 18-20 weeks). Randomised, controlled trials have demonstrated decreased rates of maternal anaemia and low birth weight with this approach. The WHO currently recommends IPTp-SP in malaria-endemic areas of sub-Saharan Africa. However, implementation has been suboptimal in part because of concerns of potential drug toxicities. This review evaluates the toxicity data of sulfadoxine/pyrimethamine, including severe cutaneous adverse reactions, teratogenicity and alterations in bilirubin metabolism. Weekly sulfadoxine/pyrimethamine prophylaxis is associated with rare but potentially fatal cutaneous reactions. Fortunately, sulfadoxine/pyrimethamine use in IPTp programmes in Africa, with 2-4 treatment doses over 6 months, has been well tolerated in multiple IPTp trials. However, sulfadoxine/pyrimethamine should not be administered concurrently with cotrimoxazole given their redundant mechanisms of action and synergistic worsening of adverse drug reactions. Therefore, HIV-infected pregnant women in malaria endemic areas who are already receiving cotrimoxazole prophylaxis should not also receive IPTp-SP. Although folate antagonist use in the first trimester is associated with neural tube defects, large case-control studies have demonstrated that sulfadoxine/pyrimethamine administered as IPTp (exclusively in the second and third trimesters and after organogenesis) does not result in an increased risk of teratogenesis. Folic acid supplementation is recommended for all pregnant women to reduce the rate of congenital anomalies but high doses of folic acid (5 mg/day) may interfere with the antimalarial efficacy of sulfadoxine/pyrimethamine. However, the recommended standard dose of folic acid supplementation (0.4 mg/day) does not affect antimalarial efficacy and may provide the optimal balance to prevent neural tube defects and maintain the effectiveness of IPTp-SP. No clinical association between sulfadoxine/pyrimethamine use and kernicterus has been reported despite the extensive use of sulfadoxine/pyrimethamine and related compounds to treat maternal malaria and congenital toxoplasmosis in near-term pregnant women and newborns. Although few drugs in pregnancy can be considered completely safe, sulfadoxine/pyrimethamine - when delivered as IPTp - has a favourable safety profile. Improved pharmacovigilance programmes throughout Africa are now needed to confirm its safety as access to IPTp-SP increases. Given the documented benefits of IPTp-SP in malaria endemic areas of Africa, access to this treatment for pregnant women should continue to expand.

Intermittent preventive treatment with sulphadoxine-pyrimethamine is effective in preventing maternal and placental malaria in Ibadan, south-western Nigeria

BACKGROUND

Intermittent preventive treatment with sulphadoxine-pyrimethamine (IPT-SP) is currently the recommended regimen for prevention of malaria in pregnancy in endemic areas. This study sets out to evaluate the effectiveness of IPT-SP in the prevention of maternal and placental malaria in parturient mothers in Ibadan, Nigeria, where the risk of malaria is present all year round.

METHOD

During a larger study evaluating the epidemiology of congenital malaria, the effect of malaria prophylaxis was examined in 983 parturient mothers. Five hundred and ninety eight mothers (60.8%) received IPT-SP, 214 (21.8%) received pyrimethamine (PYR) and 171 (17.4%) did not take any chemoprophylactic agent (NC).

RESULTS

The prevalence of maternal parasitaemia in the IPT-SP, PYR and NC groups was 10.4%, 15.9% and 17% respectively (p = 0.021). The prevalence of placental parasitaemia was 10.5% in the IPT-SP, 16.8% PYR and 17% NC groups, respectively (p = 0.015). The prevalence of maternal anaemia (haematocrit <30%) was 5.7% vs. 8.9% vs. 13.4% among the IPT-SP, PYR and NC groups respectively (p < 0.0001) while that of pre-term delivery (GA <37 weeks) was 10.5%, 19.2% and 25.3% among IPT-SP, PYR and NC groups respectively (p < 0.0001). Babies born to mothers in the IPT-SP, PYR and NC groups had mean birth weights of 3204 +/- 487.16, 3075 +/- 513.24 and 3074 +/- 505.92 respectively (rho < 0.0001). There was a trend towards a lower proportion of low birth weight babies in the IPT-SP group (p = 0.095).

CONCLUSION

IPT-SP is effective in preventing maternal and placental malaria as well as improving pregnancy outcomes among parturient women in Ibadan, Nigeria. The implementation of the recently adopted IPT-SP strategy should be pursued with vigour as it holds great promise for reducing the burden of malaria in pregnancy in Nigeria.

Drugs for preventing malaria in pregnant women

BACKGROUND

Malaria contributes to maternal illness and anaemia in pregnancy, especially in first-time mothers, and can harm the mother and the baby. Drugs given routinely to prevent or mitigate the effects of malaria during pregnancy are often recommended.

OBJECTIVES

To assess drugs given to prevent malaria infection and its consequences in pregnant women living in malarial areas. This includes prophylaxis and intermittent preventive treatment (IPT).

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (March 2006), CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE (1966 to March 2006), EMBASE (1974 to March 2006), LILACS (1982 to March 2006), and reference lists. We also contacted researchers working in the field.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing antimalarial drugs given regularly with no antimalarial drugs for preventing malaria in pregnant women living in malaria-endemic areas.

DATA COLLECTION AND ANALYSIS

Both authors extracted data and assessed methodological quality. Dichotomous variables were combined using relative risks (RR) and weighted mean differences (WMD) for mean values, both with 95% confidence intervals (CI).

MAIN RESULTS

Sixteen trials (12,638 participants) met the inclusion criteria; two used adequate methods to conceal allocation. Antimalarials reduced antenatal parasitaemia when given to all pregnant women (RR 0.53, 95% CI 0.33 to 0.86; 328 participants, 2 trials), placental malaria (RR 0.34, 95% CI 0.26 to 0.45; 1236 participants, 3 trials), but no effect was detected with perinatal deaths (2890 participants, 4 trials). In women in their first or second pregnancy, antimalarial drugs reduced severe antenatal anaemia (RR 0.62, 95% CI 0.50 to 0.78; 2809 participants, 1 prophylaxis and 2 IPT trials), antenatal parasitaemia (RR 0.27, 95% CI 0.17 to 0.44, random-effects model; 2906 participants, 6 trials), and perinatal deaths (RR 0.73, 95% CI 0.53 to 0.99; 1986 participants, 2 prophylaxis and 1 IPT trial; mean birthweight was higher (WMD 126.70 g, 95% CI 88.64 to 164.75 g; 2648 participants, 8 trials), and low birthweight less frequent (RR 0.57, 95% CI 0.46 to 0.72; 2350 participants, 6 trials). Proguanil performed better than chloroquine in one trial of women of all parities in relation to maternal fever episodes. Sulfadoxine-pyrimethamine performed better than chloroquine in two trials of low-parity women.

AUTHORS' CONCLUSIONS

Chemoprophylaxis or IPT reduces antenatal parasite prevalence and placental malaria when given to women in all parity groups. They also have positive effects on birthweight and possibly on perinatal death in low-parity women.

Congenital malaria among inborn babies at a tertiary centre in Lagos, Nigeria

Congenital malaria is increasingly reported among babies born to mothers continually residing in endemic areas. Given the high morbidity and mortality associated with malaria it is pertinent to determine its current status among newborns in Lagos, Nigeria. The aim was to determine the incidence of congenital malaria in newborn babies delivered at the Lagos University Teaching Hospital and also to determine the frequency of parasitaemia in their mothers and placentae. A cross-sectional study of mothers attending the antenatal clinic of the Lagos University Teaching Hospital was done. The Sociodemographic and clinical characteristics of mothers were documented. Samples of maternal, placental, cord and neonatal blood were taken and stained with Giemsa and examined for malaria parasites. Neonatal samples were examined at birth, on days 3, 7, 14 and 28. One hundred mothers and their placentae, as well as 104 babies and their cord blood were studied. The incidence of congenital malaria was 16/104 (15.3%) and parasite counts ranged from 47 to 1019/mul. Plasmodium falciparum was the predominant species. There was a strong association between placental, maternal, cord and neonatal parasitaemia. All the babies with congenital malaria had infected mothers, placentae and cords (p < 0.0001). In conclusion congenital malaria is not uncommon in Lagos nowadays, and there are relatively high rates of maternal, placental and cord blood parasitaemia. It is, therefore, recommended that babies born to mothers with malaria should be screened for congenital malaria.

Drugs for preventing malaria-related illness in pregnant women and death in the newborn

BACKGROUND

Malaria contributes to maternal illness and anaemia in pregnancy, especially in first-time mothers, and could harm the mother and the baby. Interventions to prevent or mitigate the effects of malaria during pregnancy are often recommended.

OBJECTIVES

To assess drugs given to prevent malaria infection and its consequences in pregnant women living in malarial areas.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register (July 2002); the Cochrane Controlled Trials Register (Issue 3, 2002); MEDLINE (1966-July 2002); EMBASE (1974-July 2002); and LILACS (accessed July 2002). We contacted researchers in the field.

SELECTION CRITERIA

Randomised and quasi-randomised trials in pregnant women of drugs given regularly that aim to mitigate the effects of malaria in pregnancy.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed. Data extraction was done by two reviewers using standard criteria.

MAIN RESULTS

14 trials included (n=3454); only 2 were adequately concealed. For women of all parity groups, the meta-analysis (n=2890) showed lower parasitaemia and placental malaria in the intervention arm. For women having the first or second baby, there were 9 studies (n=3454). Severe antenatal anaemia was less common (RR 0.62, 95%CI 0.50 to 0.78, 4 studies), perinatal mortality appeared lower (RR 0.73, 95% CI 0.73 to 0.99, 3 studies). Maternal parasitaemia was lower with the intervention (RR 0.24, 95%CI 0.14 to 0.42, random effects model, 6 studies), and mean birthweight higher (WMD 122 g, 95%I 81 to 164 g, 8 studies), and low birthweight was less common (RR 0.49, 95%CI 0.36 to 0.65, 6 studies).

REVIEWER'S CONCLUSIONS

Drugs given routinely for malaria during pregnancy reduce severe antenatal anaemia in the mother, and are associated with higher birthweight and probably reduced perinatal mortality. This effect appears to be limited to low parity women.

Management of HIV-infected pregnant patients in malaria-endemic areas: therapeutic and safety considerations in concomitant use of antiretroviral and antimalarial agents

Chemotherapy in pregnancy is an intricate process requiring prudent use of pharmacologic agents. Malarial infection during pregnancy is often fatal, and prophylaxis against the causative parasite necessitates rational therapeutic intervention. Various agents have been used for prophylaxis against malaria during pregnancy, including chloroquine, mefloquine, proguanil, pyrimethamine, and pyrimethamine-sulfadoxine. Use of these agents has been based on a risk-benefit criterion, without appropriate toxicologic or teratologic evaluation. Some of the aforementioned prophylactic agents have been shown to alter glutathione levels and may exacerbate the oxidation-reduction imbalance attendant on HIV infection. HIV-infected patients traveling to or residing in malaria-endemic areas require protection from malarial infection to avoid placing themselves in double jeopardy. Zidovudine (AZT) is recommended for the prevention of vertical transmission of HIV-1 from mother to child. Other agents, such as lamivudine alone or in combination with AZT, nevirapine, or the HIV-1 protease inhibitors, are either being considered or are currently undergoing trials for use in preventing vertical transmission of HIV-1 or managing HIV infection in infants and children. Although the potential for antimalarial agents to cause congenital malformations is low when they are used alone, their ability to cause problems when combined with antiretroviral drugs needs to be evaluated. In developing countries that have high birth rates, a high endemicity of malaria, and alarming rates of new cases of HIV, prophylaxis against both diseases with combination agents during pregnancy is a challenge.

Lack of association between levels of transplacentally acquired Plasmodium falciparum-specific antibodies and age of onset of clinical malaria in infants in a malaria endemic area of Nigeria

A cohort of 117 newborns was followed longitudinally for 12 months to determine the age of onset of clinical malaria and the subsequent episodes of malaria, and to investigate the possible existence of a correlation between level of transplacentally acquired Plasmodium falciparum-specific antibodies and age of onset of malaria in the infant. The mean age of onset of malaria in 49 infants was 4.48 +/- 1.54 months. Mean (+/- S.D.) age of onset of clinical malaria in haemoglobin AA infants (4.38 +/- 1.14) was significantly (P < 0.05) lower compared with haemoglobin AS (5.58 +/- 2.43) infants. No correlation was obtained between the age of onset of malaria and the level of cord serum total IgG, IgM and antibodies to P. falciparum antigens. Cord blood seropositivity for antibodies to the blood stage antigen Pf155/RESA and its C-terminal repeat sequence (EENV)6 or to the (NANP)6 peptide representing repeats of the circumsporozoite protein (CSP) did not influence the age of onset of clinical malaria. However, infants with haemoglobin AS whose cord blood was seropositive for antibodies to the (EENV)6 or (NANP)6 peptide showed delayed onset (P < 0.001) of malaria compared with AA seropositive infants. Although our results indicate that transplacentally acquired antibodies to the studied antigens alone offer no significant protection against malaria during the first few months of life, antibodies in concert with other factors such as haemoglobin genotype may contribute to the protection of the newborn.

Malaria in pregnancy: efficacy of a low dose of mefloquine in an area holoendemic for multi-drug resistant Plasmodium falciparum

Thirty-three pregnant women with pure P. falciparum parasitaemias (> or = 10(3) parasites/microliters blood), were each treated with a single, oral dose (12.5 mg/kg body weight) of mefloquine base (MQ), at Ahmadu Bello University Teaching Hospital, Zaria urban area, Nigeria. All 33 women were aparasitaemic by day 6 post-treatment and none became parasitaemic during the remaining 21 days of observation. Minimal side-effects were reported by the patients. The mean (S.D.) fever- and parasite-clearance times were 48 (17) and 50 (26) h, respectively. In standard microtests in vitro, schizont maturation was inhibited with MQ at 16 pmol/well (3.2 pmol/microliters). These findings indicate that, at least in the study area, semi-immune, pregnant women have high tolerability to relatively low doses of MQ and that such doses are fully effective against the local P. falciparum isolates.

The safety of antimalarial drugs in pregnancy

Alternative drugs to chloroquine are required to prevent the deleterious effects of malaria in pregnancy. Fear of potential toxicity has limited antimalarial drug use in pregnancy. Animal toxicity studies have documented teratogenicity when antimalarials are administered at high dosages. Excepting the tetracyclines, there is no evidence to suggest that, at standard dosages, any of the antimalarial drugs are teratogenic. Primaquine is not recommended because of the potential risk of haemolytic effects in the fetus. Rates of spontaneous abortion and birth defects were comparable in pregnant women taking mefloquine, compared with chloroquine-proguanil, or pyrimethamine-sulfadoxine prophylaxis, in the first trimester of pregnancy. Standard doses of quinine do not increase the risk of abortion or preterm delivery. Therapeutic mefloquine does not provoke hypoglycaemia. There is no evidence in the literature to support the hypothetical risk of kernicterus in the newborn, following exposure to antimalarial drugs containing sulphonamides or sulphones prior to delivery. Documentation of the safety of doxycycline, halofantrine, and the artemisinin derivatives in the treatment of malaria in pregnant women is currently limited.

Sensitivity of Plasmodium falciparum to reduced dose of mefloquine in pregnant women in Nigeria

Mefloquine base, (12.5 mg/kg body weight), was administered as a single oral dose to 34 pregnant women with Plasmodium falciparum parasitaemia. They were followed up in vivo using the modified 28-day WHO extended field test. The sensitivity of P. falciparum isolates obtained from these women to mefloquine (MQ) was evaluated in vitro. All women were parasite negative by day 4 and remained aparasitaemic throughout the 28-day period of observation. Parasitological and clinical responses were well correlated in all the patients. Minimal side effects, after drug intake, were reported by these women, but they all resolved spontaneously. The determined Mean Parasite Clearance Time (MPCT) was 57.7 +/- 14 hours. Seventeen parasite isolates were cultured in vitro; 9 (53%) grew satisfactorily. Schizont growth inhibitions was obtained at mefloquine concentration of 32 pmol/well (6.4 pmol/mu L). The effective drug concentration that gave 99% parasite growth inhibition (EC99) was 25.6 pmol/well (5.1 pmol/mu L); which indicates high parasite susceptibility to the drug in vitro. However, low dose of MQ may be ineffective in clearing parasitaemia in areas with mefloquine resistant parasite strains.

Congenital malaria in a hyperendemic area: a preliminary study

The prevalence of Plasmodium falciparum parasitaemia was evaluated in 59 neonates admitted to the University College Hospital, Ibadan in South-western Nigeria between August and December 1991--a period spanning part of both wet and dry seasons. Peripheral parasitaemia was present in 14 (23.7%) neonates; of these, four were preterm (4/26, 15%) and ten were term babies (10/33, 30.3%). The difference in the prevalence of P. falciparum parasitaemia in the two groups was not statistically significant (chi 2 = 1.78; p = 0.10). Parasite densities in all neonates were uniformly low (< 2000 asexual forms/microliters blood), and only four of the neonates had fever within 48 hrs of birth. Infected neonates weighed 200 g more than non-infected neonates, but the difference was not statistically significant. Maternal weekly pyrimethamine prophylaxis did not appear to be effective in preventing infection as six (21.4%) of the 28 neonates whose mothers had regular prophylaxis had parasitaemia compared with seven (26.9%) of the 26 neonates whose mothers had no prophylaxis (chi 2 = 0.22; p > 0.05). These data indicate that congenital malaria is not as uncommon as was previously thought and that the recent increase in reported cases may be due to an interplay of several factors.

Malaria parasitaemia in neonates with predisposing risk factors for neonatal sepsis: report of six cases

In a study of neonatal malaria at the University of Benin Teaching Hospital, we documented the features of six neonates in an effort to highlight that the manifestations of malaria in the newborn cannot be readily distinguished from those of neonatal sepsis. Maternal peripartum fever, an important identifiable risk factor for neonatal sepsis, also featured prominently in the mothers of these babies. These mothers ingested pyrimethamine weekly in the course of their pregnancy. All six neonates were critically ill. Their cultures of blood, CSF and urine for bacterial pathogens yielded no growth and they were unresponsive to conventional antibiotics. The diagnosis of malaria should be considered, in spite of regular maternal ingestion of antimalarial prophylaxis with pyrimethamine, in critically ill neonates in malarious areas. All six neonates responded satisfactorily to oral doses of chloroquine. We therefore suggest that a blood film for malaria parasites be included in screening for neonatal sepsis as part of the initial work-up.