Over the last decade a number of reviews have firmly established the burden of malaria in pregnancy as a priority public health issue 1234. One intervention widely promoted to tackle this burden in malaria endemic areas in sub-Saharan Africa is intermittent preventive treatment for pregnant women (IPTp) 56.

With few exceptions, the implementation of IPTp has been integrated within the existing antenatal care structure as part of the WHO recommended focused antenatal care schedule 7. The regime consists of the administration of two or three complete curative doses of an anti-malarial medicine, the first after quickening – early in the second trimester – and subsequent doses at monthly intervals 8. There is increasing awareness of the importance of administering at least two doses for a protective effect 9101112. Currently, sulphadoxine-pyrimethamine (SP) is the recommended IPTp drug in several African countries although, in light of increasing malaria parasite resistance to SP, alternative drugs are under investigation 1314.

It is estimated that 80% of women across sub-Saharan Africa access antenatal clinic at least once during pregnancy, and 74% at least twice 15. SP is a relatively cheap drug, has been widely available, and is amenable to directly observed therapy requiring only a single dose for each treatment. In theory, therefore, IPTp coverage using SP should be high. However, as reported from many settings 161718192021 second dose coverage has been disappointing, with one exception 22, and there is concern that the effectiveness of IPTp under programme conditions may be much reduced 23. There is an urgent need to understand how the potential of this strategy can be realized.

Using national level linked household and facility data in Tanzania collected annually over the period 2005–2007, trends in IPTp coverage at a national scale are investigated, and the influence of individual, facility and policy level indicators on second dose IPTp coverage countrywide explored.

Across mainland Tanzania in 2007, 65% of women who had a pregnancy in the previous year reported receiving first dose of IPTp and 30% second dose. This national level analysis of individual, facility and policy influences on coverage has revealed that throughout the period 2005–2007 delivery of second dose was negatively influenced by facility level factors, and probably policy related factors in Tanzania, but not by the individual characteristics of women beyond living in an urban area.

A lack of association between uptake of two doses of IPTp and individual factors in Tanzania has been reported previously, right from the beginning of IPTp implementation. The Demographic and Health Survey conducted in 2004 – soon after nationwide IPTp implementation – found no individual level association with IPTp second dose, nor did a small-scale exploration during the same time-period 2428. Our finding of 65% first dose and 30% second dose coverage shows some improvement on the 2005 Demographic and Health Survey estimates, 53% and 22% respectively, but remains far from the target of 80%.

This analysis uses responses following the lead question "When you went to the clinic were you given the medicine to prevent malaria?" Restricting the data to only those women who could state the type of drug administered considerably restricts the number of valid responses as women frequently cannot state the drug used. However, the only drug administered as IPTp during the study period was SP. Observations from the facility survey suggest that stock outs of SP had a dramatic effect on coverage of the intervention. Previously the delivery of IPTp benefited from using the same drug as the first-line anti-malarial treatment drug, SP, and needed no separate delivery system. It would appear that since the change over to co-artemether lumifantrine in 2006, the mechanisms for maintaining stocks of SP for IPTp require urgent attention, particularly in non-urban settings. It is worth mentioning here that facility user data is prone to responder bias as participants tend to give more positive responses than in population level household surveys and therefore levels of coverage observed may not be comparable between the two sources. However, the finding that coverage was at least 100% higher for women who attended a clinic with SP in stock than women who attended a clinic with no SP is likely a true reflection of the problem.

Less than half of health education sessions observed delivered malaria prevention messages. Such observations are sometimes associated with a Hawthorne effect – that workers observed for a short period of time tend to improve performance – and so the reality may be lower. The finding is surprising in Tanzania where there is clear commitment to reducing the burden of malaria and a number of initiatives have been designed to raise the profile of malaria nationally. It is worthwhile to investigate why these training and support initiatives are not translating into measurable delivery of clear malaria prevention messages to clinic users.

The delivery of IPTp at outreach clinics was reported to have declined during the period of the surveys. Again, this finding is contrary to the strong national commitment to control malaria. It is possible that this has arisen because of drug shortages – with rationing of SP for clinic based services taking place. Certainly barriers to delivery of IPTp at outreach where the most remote and vulnerable women are targeted should be addressed.

The schedule for delivery of IPTp has been scrutinized over the last year in a number of settings 9293031. The Tanzanian antenatal policy of giving IPTp first dose at the second antenatal visit and second dose at the third antenatal visit was developed in part for its simplicity, and to minimize the burden placed on health staff from the increasing number of interventions being channelled through antenatal clinics. However, for high coverage to be realized, this policy demands simultaneous behaviour change from the pregnant woman population – to first attend clinic earlier than the current median of 20 weeks gestation – and from the facility worker – to implement the schedule. A previous small scale study in Tanzania found that facility workers do aim to stay within the recommendation for IPTp delivery, and reported missed opportunities for protecting pregnant women with two doses 16. The Tanzanian antenatal guideline is critically different from the current WHO recommendation to distribute SP to all pregnant women at the first visit after quickening 8. This is also designed to be an easily operationalized policy which stays within safety limits of SP in pregnancy, and importantly is not dependent on individual timing preferences for first attendance to antenatal clinic. It may be that the Tanzanian IPTp antenatal schedule should be revised accordingly while there is no evidence of behaviour change for earlier first attendance to clinic.

Results from investigations on a smaller-scale in sub-Saharan Africa have indicated a combination of lack of awareness, health worker behaviour, stock-outs and policy as possible explanations for low recorded coverage of IPTp 1618192032. Our national level analysis indicates that, in Tanzania, successful delivery of at least two doses of IPTp relies on facility and policy level factors that could potentially be resolved. Following a trial of IPTp implementation in the community compared to routine clinics, Mbonye and others 33 found that the community approach resulted in higher – and earlier – two-dose coverage than the routine approach. However, they caution that it would be important to support access to routine care where all other access to antenatal services was focussed. In Zambia, where high coverage of IPTp second dose has been achieved and sustained within existing systems, an analysis of enabling factors highlights co-ordinated support to the routine clinic system and training to antenatal care workers as key enabling factors 22.

Acting upon the observed rural stock outs and unintentionally restrictive antenatal guidelines in Tanzania is the most direct and sustainable option for optimising delivery of IPTp with SP. The challenge posed to IPTp with SP by increasing drug resistance of the Plasmodium falciparum parasite is beyond the operational control of the health system. Should a new drug for IPTp be recommended, the obstacles to high coverage will undoubtedly persist. It is essential that lessons are learned on how to maximize the existing regime in order to avoid any backward step on the road to 80% access.

The authors declare that they have no competing interests.

TM and KH participated in design and implementation of the study, data analysis and interpretation. RN and HM participated in design and implementation. CJ contributed to design of the study and interpretation of the findings. JB participated in design and data analysis. YS contributed to implementation of the study and interpretation of data. HS and JS supported activities at each stage. TM wrote the first draft of this manuscript. All authors contributed to, and approved, the manuscript for publication.