Review
Malaria prevention in the pregnant traveller: A review

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Summary

Malaria is still a major threat to health in tropical regions. Particular attention should be directed to malaria prevention in infants and pregnant women as they are at high risk for plasmodial infection and complicated malaria. In this review, we summarize and discuss current evidence on malaria prevention in pregnant travellers.

As neither anti-mosquito measures nor anti-malarial drugs have been proven to be unequivocally safe or toxic in pregnant women, the individual risk assessment should take into account the risk of transmission at the destination, the benefit of travelling despite being pregnant as well as the individual risk perception. All three factors may differ in various groups of travellers like tourist travellers, expatriate travellers as well as those visiting friends and relatives.

For pregnant women, mefloquine appears to be the drug of choice for prophylaxis and stand by-therapy if no contraindications exist – despite recent renewed warnings related to prolonged side effects. In areas with high resistance against mefloquine or in women with contraindications to mefloquine, atovaquone–proguanil or artemether–lumefantrine should be considered as an option for stand-by emergency therapy. Nevertheless, evidence on the safety of anti-malarials especially during the first trimester is still insufficient.

Introduction

In 2011 more than 100 million tourists travelled to malaria-endemic countries [1]. Pregnant women travelling to malaria-endemic areas usually fall into one of the following categories: Women seeking pre-travel advise for tourist travel, sometimes explicitly planning to get pregnant at the tropical destination (tourist traveller), women with their entire family destined to stay in malarious areas on longer term contracts/for professional purposes, already pregnant or planning pregnancy during a long-term stay (expatriate traveller) as well as migrant women needing to visit friends and relatives in their country of origin in order to attend important reunions/festivities with their family despite being pregnant (visiting friends and relatives, VFR traveller). Thus, health experts involved in travel medicine are frequently confronted with questions around malaria prevention during pregnancy.

Section snippets

Malaria and pregnancy

Malaria infection during pregnancy poses a serious risk for the mother and the unborn child [2], [3]. The interaction of malaria and pregnancy is complex and not yet fully understood [4], [5]. Malaria parasites adhere in the vascular system of the placenta which leads to impairment of the (micro) circulation and eventually placental insufficiency [4]. A relationship between concurrent malaria infection and abnormal uterine blood flow has been demonstrated [4].

Semi-immunity to malaria is of

Anti-mosquito measures

In Sub-Saharan Africa and in particular during the rainy season, the average transmission risk exceeds one infectious mosquito bite per person per day. Anti-mosquito measures aim to reduce infectious mosquito bites. Interestingly, it has been shown in rural Gambia that pregnant women attract twice as many Anopheles gambiae complex mosquitoes as their non-pregnant counterparts, probably due to physiological and behavioural changes [8]. This finding underlines the importance of protective

Mefloquine

Plasmodium species causing malaria are sensitive to mefloquine but resistance to mefloquine exists especially in Thailand and borders to neighbouring countries [18].

Next to chloroquine (see below) and compared to other commonly used anti-malarials in travellers, mefloquine is certainly the drug with most data available on safety in pregnancy. Regarding embryotoxicity, animal studies only proved a teratogenic effect of mefloquine if the dose several fold exceeded the dose recommended for

International recommendations

First, it should be emphasised that the German Society for Tropical Medicine and International Health (DTG), the National Travel Health Network and Centre (NaTHNaC), the Centers for disease Control and Prevention (CDC) and the World Health Organisation (WHO) strongly recommend pregnant women to avoid travelling to malaria endemic regions [30], [31], [32]. If travelling to malaria-endemic areas cannot be avoided or postponed, consequent malaria prophylaxis including avoidance of mosquito bites

Risk assessment and recommendations

Travel medicine guidelines in general do not recommend travelling to malarious areas while being pregnant (see previous paragraph). Yet, the likelihood of acquiring malaria (=risk), the motivation for travelling (benefit) as well as the risk perception related to both, malaria disease and safety/tolerability aspects related to prophylactic (both chemoprophylaxis as well as repellents) may vary among the different groups of pregnant women travellers i) tourist traveller, ii) expatriate and iii)

Conclusion

Risk assessment taking into account risks, benefits as well as individual risk perception should be based on the reason/motivation for travelling to malaria-endemic areas which will be different in tourist-, expatriate- or VFR-travellers. If possible, pregnant women should be advised to avoid or postpone travelling to regions were malaria is endemic. If travelling is inevitable for the pregnant woman for whatever reason, effective malaria prevention measures should be used consequently.

There

Conflict of interest

Jakob P. Cramer participates as investigator in the pregnancy registry initiated by Sigma Tau.

Louise Roggelin has no conflict of interest to declare.

Funding

None.

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