Johanna H Kattenberg; Eleanor A Ochodo; Kimberly R Boer; Henk DFH Schallig; Petra F Mens; Mariska MG Leeflang

“ One of the other studies describes that submicroscopic infection was predictive of low birth weight in HIV positive, but not HIV negative women [ [73] . More comparisons with histology might shed more light on this issue and show that a significant proportion of the peripheral submicroscopic infections, are in fact placental infections. As mentioned before, pregnant women often have low parasite densities, and tests should have good sensitivity at these low densities; PCR techniques often have better sensitivities at low parasite densities than RDTs and microscopy. ”

“ Infants born after a pregnancy affected by malaria often suffer from anaemia and have an increased risk of contracting malaria themselves [ [2] . Furthermore, P. falciparum infection during pregnancy increases the risk of stillbirth [2] . The severe effects of P. falciparum and P. vivax malaria on pregnant women and their (unborn) infants make early detection and subsequent treatment of great importance. ”

“ IPTp greatly reduces prevalence of malaria and severe consequences, but women are not protected throughout the entire pregnancy and can still become infected between doses or after the final dose, especially when other protective measures such as ITNs are not being used, or parasites are resistant to sulphadoxine-pyrimethamine. IPTp is mostly applied in areas where there is high malaria transmission, where women have acquired immunity and infection during the pregnancy is often asymptomatic, but not without consequences. ”

“ To further investigate the sources of heterogeneity, subgroup analyses was performed rather than including covariates in the meta-regression models, because metandi is not capable of including covariates in the analyses. The type of antigen (HRP2 or pLDH or Aldolase or in combination) detected by the RDT was investigated as a source of heterogeneity. For other supposed sources that might affect the accuracy of the RDTs, such as malaria species, gravidity, anti-malarial treatment and RDT brand, insufficient data was reported to determine if these issues affected accuracy. ”

“ In high transmission areas, women have acquired immunity during their life, and although they might have substantial placental sequestration (especially in primi- and secundigravidae) , they can have a lower amount of parasites in the circulation by clearance of infected red blood cells by the immune system. ”

“ The proportion microscopy negatives with a negative RDT, however, is lower for HRP2 RDTs compared to pLDH RDTs. This pattern is similar to the results of a meta-analysis of RDTs for uncomplicated malaria, and the sensitivity of HRP2-based RDTs for pregnant women (94% [91-96 CI] ) is very similar to that for uncomplicated malaria (95% [93-96 CI] ) [17] . The specificity compared to peripheral microscopy for HRP2-based RDTs for pregnant women (81% [71-88 CI] ) , however, is much lower than for uncomplicated malaria (95% [93-99 CI] ) . ”

“ Slides are made from placental blood from the inter-villous space of the placenta, which can be collected in many different ways, for example, by aspiration with a syringe or as impression smear of placental tissue. ”

“ MiP: malaria in pregnancy; NCC: Nederlandse centrale catalogues (Dutch central catalogue) ; PCR: polymerase chain reaction; pLDH: Plasmodium lactate hydrogenase; PM: placental malaria; RDTs: rapid diagnostic tests; ROC: receiver operating characteristic; SROC plot: summary receiver operating characteristic plot; TDR: UNICEF/UNDP/World Bank/WHO Special Programme for research and Training in Tropical Diseases; WOS: Web of Science; QUADAS: Quality Assessment of Diagnostic Accuracy Studies.
Competing interests
The authors declare that they have no competing interests. ”

“ Maleta, K; Kulmala, T; Ashorn, P; et al. (2010) , Comparison of real-time PCR and microscopy for malaria parasite detection in Malawian pregnant women, vol. 9, p. 269, 10.1186/1475-2875-9-26920925928, pmid:20925928, DOI 10.1186/1475-2875-9-269
This work is released under the Creative Commons Attribution 2.0 license, which allows free use, distribution, and creation of derivatives, so long as the license is unchanged and clearly noted, and the original author is attributed. ”

“ Perez, O & Miyar, R (1993) , Materno-fetal transmission of pregnancy malaria: an immunoparasitological study on 202 parturients in Maputo, vol. 35, pp. 103–107, 10.1159/0002926758449440, pmid:8449440, DOI 10.1159/000292675 1 2 Desowitz, RS & Alpers, MP (1992) , Placental Plasmodium falciparum parasitaemia in East Sepik (Papua New Guinea) women of different parity: the apparent absence of acute effects on mother and foetus, vol. ”