Intestinal parasitic infections and adverse outcomes for pregnant women and their newborns in Sao Tome &amp; Principe: a hospital-based cross-sectional study
Authors: Vasconcelos Alexandra , Sousa Swasilanne , Bandeira Nelson , Alves Marta , Papoila Ana Luisa , Pereira Filomena , Machado Maria Ceu 
Published: May 2023

Background
Up to 70% of pregnant women in Africa have an intestinal parasitic infection (IPI), but the associated adverse birth outcomes (ABOs) remain unclear, with gaps to be addressed. IPI prevalence among pregnant women in Sao Tome & Principe (STP) was found to be up to 60%, mainly due to Ascaris lumbricoides. Schistosoma intercalatum and Entamoeba histolytica IPIs were also identified. Despite this high-IPI prevalence, the impact of IPIs on maternal and neonatal health is unknown and has never been studied in STP. Therefore, this study sought to identify whether there were ABOs, including maternal anaemia (haemoglobin <11 g/dL), preterm birth (PTB) for gestational age <37 weeks, low birth weight (LBW) <2500 g and stillbirths associated with pregnant women with an IPI compared to their noninfected counterpart.
Methods
A hospital-based cross-sectional study was conducted among pregnant women admitted for delivery at the only maternity hospital in STP. Only women with an antenatal care (ANC) copro-parasitological screening were included. Pregnant women with HIV, sickle cell, malaria and STHs who were adequately treated were excluded. Data were abstracted from ANC pregnancy cards, newborns’ medical records, and a structured face-to-face interviewer-administered questionnaire. Pregnant women with an IPI (n=210) were compared to noninfected women (n=151). Subgroup analyses were conducted comparing ABOs in noninfected (no-IPI group) with ABOs in i) monoparasitic-IPI (n=145), ii) polyparastic-IPI (n=25), iii) STHs (n=162), iv) S intercalatum (n=11), and v) E histolytica (n=7). Data analysis was performed using SPSS version 25.0. Chi-square and Fisher´s exact tests were used to identify associations between ABOs and IPI in pregnant women at p value <0.05.
Results
A total of 361 women with a mean age of 26.96 (SD: 7.00) were included, 43.6% (156) practiced open defecation, 15.8% (57) had no access to improved water, and 53.6% (192) lived in a rural area. The ABOs identified were 127 (39.6%) maternal anaemia, 26 (8.1%) PTB, 48 (14.9%) LBW and 8 (2.5%) stillbirths. ABOs in the monoparasitic-IPI and no-IPI groups were 46.7% vs 38.7% maternal anaemia, 6.2% vs 10.6% PTB, 11% vs 19.2% LBW and 3.4% vs 1.3% stillbirth, respectively. No statistically significant difference (p 0.182, p0.175, p 0.07, p 0.275) was found between the two groups. ABOs for S. intercalatum were anaemia 4 (36.4%) and LBW 1 (9.1%). A statistically significant difference was not found between ABOs in the no-IPI group compared to S. intercalatum or to other IPI-subgroups (polyparasitic-IPI, STHs, and E. histolytica).
Conclusion
Maternal anaemia was found in almost half of pregnant women, but an association with IPI was not established. ABOs-related to IPIs are linked to the type of parasite, pathogenesis, intensity, and timing of the infection. Thus, the predominant parasite type –Ascaris lumbricoides– a low pathogenicity parasite, can support this study´s lack of association between IPIs and ABOs. Therefore, it is very important to know the country specific-setting of IPI epidemiology. To achieve a schistosomiasis elimination status, women-of-reproductive age and pregnant women should be included in the country preventive chemotherapy programmes.