Prevention and control of malaria in pregnancy - new threats, new opportunities?

Associations of maternal iron deficiency with malaria infection in a cohort of pregnant Papua New Guinean women

BACKGROUND

Iron deficiency (ID) is common in malaria-endemic settings. Intermittent preventative treatment of malaria in pregnancy (IPTp) and iron supplementation are core components of antenatal care in endemic regions to prevent adverse pregnancy outcomes. ID has been associated with reduced risk of malaria infection, and correspondingly, iron supplementation with increased risk of malaria infection, in some studies.

METHODS

A secondary analysis was conducted amongst 1888 pregnant women enrolled in a malaria prevention trial in Papua New Guinea. Maternal ID was defined as inflammation-corrected plasma ferritin levels < 15 μg/L at antenatal enrolment. Malaria burden (Plasmodium falciparum, Plasmodium vivax) was determined by light microscopy, polymerase chain reaction, and placental histology. Multiple logistic and linear regression analyses explored the relationship of ID or ferritin levels with indicators of malaria infection. Models were fitted with interaction terms to assess for modification of iron-malaria relationships by gravidity or treatment arm.

RESULTS

Two-thirds (n = 1226) and 13.7% (n = 258) of women had ID and peripheral parasitaemia, respectively, at antenatal enrolment (median gestational age: 22 weeks), and 18.7% (120/1,356) had evidence of malaria infection on placental histology. Overall, ID was associated with reduced odds of peripheral parasitaemia at enrolment (adjusted odds ratio [aOR] 0.50; 95% confidence interval [95% CI] 0.38, 0.66, P < 0.001); peripheral parasitaemia at delivery (aOR 0.68, 95% CI 0.46, 1.00; P = 0.050); and past placental infection (aOR 0.35, 95% CI 0.24, 0.50; P < 0.001). Corresponding increases in the odds of infection were observed with two-fold increases in ferritin levels. There was effect modification of iron-malaria relationships by gravidity. At delivery, ID was associated with reduced odds of peripheral parasitaemia amongst primigravid (AOR 0.44, 95% CI 0.25, 0.76; P = 0.003), but not multigravid women (AOR 1.12, 95% CI 0.61, 2.05; P = 0.720). A two-fold increase in ferritin associated with increased odds of placental blood infection (1.44, 95% CI 1.06, 1.96; P = 0.019) and active placental infection on histology amongst primigravid women only (1.24, 95% CI 1.00, 1.54; P = 0.052).

CONCLUSIONS

Low maternal ferritin at first antenatal visit was associated with a lower risk of malaria infection during pregnancy, most notably in primigravid women. The mechanisms by which maternal iron stores influence susceptibility to infection with Plasmodium species require further investigation.

TRIAL REGISTRATION

Assessment of the Teratogenic Effect of Sulfadoxine-Pyrimethamine on the Chicken Embryo

Background

The sulfadoxine-pyrimethamine combination is a product used in the intermittent preventive treatment (IPT) of malaria in pregnant women in our country. To date, there is very little data on the teratogenic effect of this product. This study proposed to evaluate the teratogenic effect of sulfadoxine-pyrimethamine on chicken embryos.

Methods

The teratogenic effect of the product was evaluated on chicken embryos at a dose of 1.3 mg/g sulfadoxine and 0.06 mg/g pyrimethamine. The product was injected before the start of incubation and on days 12, 14, 16, and 18 of incubation. One batch received a double injection of the product on days 16 and 18 of incubation. The quality of the hatched chicks was evaluated by the Tona Score followed by the determination of hematological and biochemical parameters.

Results

From the aforementioned, it appears that the eggs treated with sulfadoxine-pyrimethamine significantly decreased the hatchability rate of the eggs. The chicks obtained were all of very good quality. Apart from a significant decrease in the weight of the chicks of the batch that received the injection twice and a significant increase in the weight of the yolk sac of the chicks of the batch that received the injection on day 16 compared to the control, no variation was obtained. A significant increase in the white blood cell count of the chicks compared to the control was reported in the chicks of the batch injected before incubation and on day 12, as well as a significant increase in the platelet count of the chicks of the batch injected twice. For biochemical parameters, no significant difference was reported in ALT and AST.

Conclusion

Sulfadoxine-pyrimethamine decreased egg hatch and caused an increase in embryo and chick mortality as well as a loss in relative chick weight and an increase in relative yolk sac weight. More in-depth studies would be needed on sulfadoxine-pyrimethamine teratogenicity and the benefit/risk ratio of this drug during pregnancy.

Safety and efficacy of intermittent presumptive treatment with sulfadoxine-pyrimethamine using rapid diagnostic test screening and treatment with dihydroartemisinin-piperaquine at the first antenatal care visit (IPTp-SP+): study protocol for a randomized controlled trial

Background

Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended by the World Health Organization for the prevention of malaria in pregnancy (MIP)-associated adverse outcomes in high burden areas. However, the efficacy of IPTp-SP has decreased in step with increasing parasite drug resistance. Suitable alternative strategies are needed.

Methods

This is a protocol for a phase IIIb open-label, two-armed randomized controlled superiority trial to assess the safety and efficacy of a hybrid approach to IPTp combining screening and treatment with dihydroartemisinin-piperaquine (DP) to the current IPTp-SP regimen at the first antenatal care clinic visit. Pregnant women without HIV infection and without signs or symptoms of malaria will be randomized to either standard IPTp-SP or hybrid IPTp-SP plus screening and treatment (IPTp-SP+). In the IPTp-SP+ arm, participants who screen positive by rapid diagnostic test for P. falciparum will be treated with DP at the first antenatal visit while those who screen negative will receive SP per current guidelines. All participants will be administered SP on days 35 and 63 and will be actively followed biweekly up to day 63 and then monthly until delivery. Infants will be followed until 1 year after delivery. The primary endpoint is incident PCR-confirmed MIP at day 42. Secondary endpoints include incident MIP at other time points, placental malaria, congenital malaria, hemoglobin trends, birth outcomes, and incidence of adverse events in infants up to the first birthday.

Discussion

A hybrid approach to IPTp that combines screening and treatment with an artemisinin-based combination therapy at the first visit with standard IPTp-SP is hypothesized to confer added benefit over IPTp-SP alone in a high malaria transmission area with prevalent SP resistant parasites.

Trial registration

Pan African Clinical Trials Registry 201905721140808. Registered retrospectively on 11 May 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05745-0.

Diagnosis & management of imported malaria in pregnant women in non-endemic countries

Malaria in pregnancy is an important cause of maternal and foetal morbidity and is a potentially life-threatening infection. With ever-growing global exchanges, imported malaria in pregnancy is becoming an issue of concern in non-endemic countries where women, because of low immunity, have higher risk of severe diseases and death. Malaria in pregnancy is a dangerous condition which can be associated with important consequences for both mother and child such as stillbirth, low birth weight, maternal anaemia. In non-endemic-countries it is more frequent in its severe form which can lead to maternal death if not treated adequately. Specific anti-malarial interventions such as the use of repellents and insecticide treated bed nets in addition to chemoprophylaxis should be used by pregnant women if they are travelling to endemic areas. In cases of confirmed infection, specific treatment regimens vary according to gestational age and the presence of complications. Malaria should be considered a global health problem, increasingly involving western countries. Clinicians all over the world need to be prepared for this emerging disease both in terms of prevention and therapy.

Counter-Selection of Antimalarial Resistance Polymorphisms by Intermittent Preventive Treatment in Pregnancy

BACKGROUND

Innovative approaches are needed to limit antimalarial resistance evolution. Understanding the role of intermittent preventive treatment in pregnancy (IPTp) on the selection for resistance and the impact such selection has on pregnancy outcomes can guide future interventions.

METHODS

Plasmodium falciparum isolates (n = 914) from 2 randomized clinical trials were screened for pfmdr1 copy number variation and pfcrt, pfmdr1, pfdhfr, and pfdhps resistance markers. The trials were conducted between 2010 and 2013 in Benin, Gabon, Kenya, and Mozambique to establish the efficacy of IPTp-mefloquine (MQ) compared with IPTp-sulphadoxine-pyrimethamine (SP) in human immunodeficiency virus (HIV)-uninfected and to IPTp-placebo in HIV-infected women.

RESULTS

In HIV-uninfected women, the prevalence of pfcrt mutants, pfdhfr/pfdhps quintuple mutants, and pfmdr1 copy number was similar between women receiving IPT-SP and IPTp-MQ. However, prevalence of pfmdr1 polymorphism 86Y was lower in the IPTp-MQ group than in the IPTp-SP group, and within the IPTp-MQ group it was lower at delivery compared with recruitment. No effect of IPTp-MQ on resistance markers was observed among HIV-infected women. The carriage of resistance markers was not associated with pregnancy outcomes.

CONCLUSIONS

Selection of wild-type pfmdr1 polymorphism N86 by IPTp-MQ highlights the strong selective pressure IPTp can exert and the opportunity for using negative cross-resistance in drug choice for clinical treatment and IPTp.

Updated pharmacokinetic considerations for the use of antimalarial drugs in pregnant women

INTRODUCTION

The association between pregnancy and altered drug pharmacokinetic (PK) properties is acknowledged, as is its impact on drug plasma concentrations and thus therapeutic efficacy. However, there have been few robust PK studies of antimalarial use in pregnancy. Given that inadequate dosing for prevention or treatment of malaria in pregnancy can result in negative maternal/infant outcomes, along with the potential to select for parasite drug resistance, it is imperative that reliable pregnancy-specific dosing recommendations are established.

AREAS COVERED

PK studies of antimalarial drugs in pregnancy. The present review summarizes the efficacy and PK properties of WHO-recommended therapies used in pregnancy, with a focus on PK studies published since 2014.

EXPERT OPINION

Changes in antimalarial drug disposition in pregnancy are well described, yet pregnant women continue to receive treatment regimens optimized for non-pregnant adults. Contemporary in silico modeling has recently identified a series of alternative dosing regimens that are predicted to provide optimal therapeutic efficacy for pregnant women.

Coverage of intermittent preventive treatment of malaria in pregnancy (IPTp) influences delivery outcomes among women with obstetric referrals at the district level in Ghana

Background

The aim of the study was to determine the coverage of intermittent preventive treatment of malaria in pregnancy (IPTp) and its relationship with delivery outcomes among obstetric referral cases at the district level of healthcare.

Methods

An implementation research within three districts of the Greater Accra region was conducted from May 2017 to February 2018, to assess the role of an enhanced inter-facility communication system on processes and outcomes of obstetric referrals. A cross-sectional analysis of the data on IPTp coverage as well as delivery outcomes for the period of study was conducted, for all the referrals ending up in deliveries. Primary outcomes were maternal and neonatal complications at delivery. IPTp coverage was determined as percentages and classified as adequate or inadequate. Associated factors were determined using Chi square. Odds ratios (OR, 95% CI) were estimated for predictors of adequate IPTp dose coverage for associations with delivery outcomes, with statistical significance set at p = 0.05.

Results

From a total of 460 obstetric referrals from 16 lower level facilities who delivered at the three district hospitals, only 223 (48.5%) received adequate (at least 3) doses of IPTp. The district, type of facility where ANC is attended, insurance status, marital status and number of antenatal clinic visits significantly affected IPTp doses received. Adjusted ORs show that adequate IPTp coverage was significantly associated with new-born complication [0.80 (0.65–0.98); p = 0.03], low birth weight [0.51 (0.38–0.68); p < 0.01], preterm delivery [0.71 (0.55–0.90); p = 0.01] and malaria as indication for referral [0.70 (0.56–0.87); p < 0.01]. Positive association with maternal complication at delivery was seen but was not significant.

Conclusion

IPTp coverage remains low in the study setting and is affected by type of health facility that ANC is received at, access to health insurance and number of times a woman attends ANC during pregnancy. This study also confirmed earlier findings that, as an intervention IPTp prevents bad outcomes of pregnancy, even among women with obstetric referrals. It is important to facilitate IPTp service delivery to pregnant women across the country, improve coverage of required doses and maximize the benefits to both mothers and newborns.

[Sulfadoxine-pyrimethamine-based intermittent preventive treatment in pregnant women and its effect on birth weight: application of 3-dosing regimen in the urban area of South Benin in 2017]

Introduction

Le paludisme est un problème de santé publique majeur, responsable de nombreuses complications durant la grossesse parmi lesquelles le retard de croissance intra utérin et les hypotrophies. L'objectif de ce travail était de déterminer l'effet du respect des 3 doses du traitement préventif intermittent (TPI) à la sulfadoxine-pyrimétamine (SP) sur le poids de naissance des nouveau-nés de la zone sanitaire Cotonou II et III.

Méthodes

Il s'agit d'une étude transversale qui a porté sur 630 femmes en période post partum résidant dans la zone sanitaire Cotonou II-III et sélectionnées par une technique de sondage à deux degrés. Les données ont été recueillies par un questionnaire et une fiche de dépouillement. Pour l'analyse, les données ont été pondérées et nous avons utilisé l'analyse de variance pour la comparaison des moyennes et une comparaison de proportions avec le test de chi² assorti d'une estimation de la force de l'association par l'odds ratio (OR) et son intervalle de confiance à 95%.

Résultats

Le respect des 3 doses du TPI à la SP était de 34,08% (IC95%: [24,84% - 43,30%]). On note un gain significatif de poids de naissance de 264,5g (p < 0,001) chez les mères qui avaient reçu plus de 3 doses de SP et la probabilité d'avoir un bébé ayant un faible poids de naissance était plus faible (OR = 0,45; p = 0,001) chez ces mères comparativement à celles qui avaient reçu moins de 3 doses de sulfadoxine-pyriméthamine.

Conclusion

Cette étude révèle une faible observance de la nouvelle politique à 3 doses du traitement préventif intermittent à la sulfadoxine-pyriméthamine dans la zone sanitaire de Cotonou II et III, mais elle témoigne de son potentiel de contribution à la réduction du risque de faible poids de naissance. Des stratégies doivent donc être mises en œuvre pour renforcer son application en vue de la prévention du paludisme et de ses conséquences pour les cibles vulnérables.

A Randomized Open-Label Evaluation of the Antimalarial Prophylactic Efficacy of Azithromycin-Piperaquine versus Sulfadoxine-Pyrimethamine in Pregnant Papua New Guinean Women

Emerging malaria parasite sulfadoxine-pyrimethamine (SP) resistance has prompted assessment of alternatives for intermittent preventive treatment in pregnancy (IPTp). The objective was to evaluate the tolerability and prophylactic efficacy of azithromycin (AZ) plus piperaquine (PQ) in pregnant women in Papua New Guinea. The study was an open-label, randomized, parallel-group trial. A total of 122 women (median gestation, 26 weeks [range, 14 to 32 weeks]) were randomized 1:1 to three daily doses of 1 g AZ plus 960 mg PQ tetraphosphate or single-dose SP (4,500 mg sulfadoxine plus 225 mg pyrimethamine), based on computer-generated block randomization. Tolerability was assessed to day 7, and efficacy was assessed to day 42 (when participants were returned to usual care) and at delivery. Data for 119 participants (AZ-PQ, n = 61; SP, n = 58) were analyzed. Both regimens were well tolerated, but AZ-PQ was associated with more gastrointestinal side effects (31%) and dizziness (21%). Eight women (6.7%) were parasitemic at recruitment but all were aparasitemic by 72 h. There were no differences in blood smear positivity rates between AZ-PQ and SP up to day 42 (0% versus 5.2%; relative risk [RR], 0.14 [95% confidence interval [CI], 0.01 to 2.58] [P = 0.18]; absolute risk reduction [ARR], 5.2% [95% CI, -1.3 to 11.6%]) and at the time of delivery (0% versus 8.7%; RR, 0.11 [95% CI, 0.01 to 2.01] [P = 0.14]; ARR, 8.7% [95% CI, -0.2 to 17.6%]). Of 92 women who were monitored to parturition, 89 (97%) delivered healthy babies; there were 3 stillbirths (SP, n = 1; AZ-PQ, n = 2 [twins]). There was a higher live birth weight (mean ± standard deviation) in the AZ-PQ group (3.13 ± 0.42 versus 2.88 ± 0.55 kg [P = 0.016]; mean difference, 0.25 kg [95% CI, 0.02 to 0.48 kg]). AZ-PQ is a promising candidate for IPTp.

Sulphadoxine-pyrimethamine plus azithromycin may improve birth outcomes through impacts on inflammation and placental angiogenesis independent of malarial infection

Intermittent preventive treatment with sulphadoxine-pyrimethamine (SP) and SP plus azithromycin (SPAZ) reduces low birthweight (<2,500 g) in women without malarial and reproductive tract infections. This study investigates the impact of SPAZ on associations between plasma biomarkers of inflammation and angiogenesis and adverse pregnancy outcomes in 2,012 Papua New Guinean women. Concentrations of C-reactive protein (CRP), α-1-acid glycoprotein (AGP), soluble endoglin (sEng), soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) were measured at enrolment and delivery in a trial comparing SPAZ to SP plus chloroquine (SPCQ). At antenatal enrolment higher CRP (adjusted odds ratio 1.52; 95% confidence interval [CI] 1.03–2.25), sEng (4.35; 1.77, 10.7) and sFlt1 (2.21; 1.09, 4.48) were associated with preterm birth, and higher sEng with low birthweight (1.39; 1.11,3.37), in SPCQ recipients only. Increased enrolment sFlt1:PlGF ratios associated with LBW in all women (1.46; 1.11, 1.90). At delivery, higher AGP levels were strongly associated with low birthweight, preterm birth and small-for-gestational age babies in the SPCQ arm only. Restricting analyses to women without malaria infection did not materially alter these relationships. Women receiving SPAZ had lower delivery AGP and CRP levels (p < 0.001). SPAZ may protect against adverse pregnancy outcomes by reducing inflammation and preventing its deleterious consequences, including dysregulation of placental angiogenesis, in women with and without malarial infection.

Pharmacotherapy for the prevention of malaria in pregnant women: currently available drugs and challenges

INTRODUCTION

Malaria in pregnancy continues to be a significant public health burden globally, with over 100 million women at risk each year. Sulfadoxine-pyrimethamine (SP) is the only antimalarial recommended for intermittent preventive therapy in pregnancy (IPTp) but increasing parasite resistance threatens its viability. There are few other available antimalarial therapies that currently have sufficient evidence of tolerability, safety, and efficacy to replace SP.

AREAS COVERED

Novel antimalarial combinations are under investigation for potential use as chemoprophylaxis and in IPTp regimens. The present review summarizes currently available therapies, emerging candidate combination therapies, and the potential challenges to integrating these into mainstream policy.

EXPERT OPINION

Alternative drugs or combination therapies to SP for IPTp are desperately required. Dihydroartemisinin-piperaquine and azithromycin-based combinations are showing great promise as potential candidates for IPTp but pharmacokinetic data suggest that dose modification may be required to ensure adequate prophylactic efficacy. If a suitable candidate regimen is not identified in the near future, the success of chemopreventive strategies such as IPTp may be in jeopardy.

Management of malaria in pregnancy

Pregnant women are especially susceptible to malaria infection. Without existing immunity, severe malaria can develop requiring emergency treatment, and pregnancy loss is common. In semi-immune women, consequences of malaria for the mother include anaemia while stillbirth, premature delivery and foetal growth restriction affect the developing foetus. Preventive measures include insecticide-treated nets and (in some African settings) intermittent preventive treatment. Prompt management of maternal infection is key, using parenteral artemisinins for severe malaria, and artemisinin combination treatments (ACTs) in the second and third trimesters of pregnancy. ACTs may soon also be recommended as an alternative to quinine as a treatment in the first trimester of pregnancy. Monitoring the safety of antimalarials and understanding their pharmacokinetics is particularly important in pregnancy with the altered maternal physiology and the risks to the developing foetus. As increasing numbers of countries embrace malaria elimination as a goal, the special needs of the vulnerable group of pregnant women and their infants should not be overlooked.

'Researchers have love for life': opportunities and barriers to engage pregnant women in malaria research in post-Ebola Liberia

BACKGROUND

Adoption of prevention and therapeutic innovations to ensure that National Malaria Control Programmes meet their incidence reduction targets is highly dependent on the conduct of rigorous clinical trials. In Liberia, malaria control virtually halted during the recent Ebola epidemic, and could enormously benefit from innovations to protect its most vulnerable populations, including pregnant women, against malaria. Health policy-planners could feel more inclined to adopt novel interventions with demonstrated safety and efficacy when trialled among their women population. However, pregnant women are especially vulnerable when targeted as research participants. Whilst some studies in the region attempted to understand the ethical issues around the conduct of clinical research, there is need of such information from Liberia to inform future malaria research.

METHODS

This is a grounded theory study that aims to understand the barriers and opportunities for pregnant women to consent to participate in malaria research in Liberia. The study was conducted between November 2016 and May 2017 at the St Joseph's Catholic Hospital, Monrovia. In-depth interviews and focus group discussions were held with hospital staff, traditional community representatives, and pregnant women.

RESULTS

According to the participants, useful strategies to motivate pregnant women to consent to participate in malaria research could be providing evidence-based education on malaria and research to the general population and encouraging engagement of traditional leaders in research design and community mobilization. Fears and suspicions towards research and researchers, which were amplified during the conduct of Ebola vaccine and drug clinical trials, may influence women's acceptance and willingness to engage in malaria research. Population's mistrust in the public healthcare system might hinder their acceptance of research, undermining the probability of their benefiting from any improved malaria control intervention.

CONCLUSION

Benchmarking for acceptable practices from previous public health interventions; building community discussion and dissemination platforms; and mapping communication and information errors from how previous research interventions were explained to the Liberian population, are strategies that might help ensure a safe and fully informed participation of pregnant women in malaria research. Inequity issues impeding access and use of biomedical care for women must be tackled urgently.