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Cited by 26Malaria Research and ControlPregnancy and preeclampsia studiesCOVID-19 Impact on Reproduction

Effects of Vivax Malaria Acquired Before 20 Weeks of Pregnancy on Subsequent Changes in Fetal Growth

Open access
Machado Filho, Amantino C., da Costa, Elenice P., da Costa, Emely P., Reis, Iracema S., Fernandes, Emanoela A. C., Paim, Bernardo V., Martinez-Espinosa, Flor E.·2014·The American Society of Tropical Medicine and Hygiene
DOI 10.4269/ajtmh.13-0285PMC PMC3919251
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Abstract

The resistance index (RI), pulsatility index (PI), fetal biometry, fetal heart rate (FHR), placental thickness, and hemoglobin levels were compared in 30 Plasmodium vivax-infected women between 14 and 20 weeks of pregnancy and a control group. Evaluations were performed at the moment of the malaria diagnosis and 26 weeks of pregnancy. The malaria group had lower levels of hemoglobin and greater placental thickness in both assessments, higher FHR in the first evaluation, and lower values on fetal biometry in the second assessment. There were no differences when comparing RI and PI on umbilical arteries between the two groups. Birth weight and height were lower in newborns in the malaria group than the control group. The results suggest that P. vivax infections at an earlier gestational age do not affect umbilical arteries blood flow but do affect fetal biometry in the second trimester of pregnancy and at birth.

AI snapshot

Written from the paper’s full text.

TL;DR

In this case-control study in Manaus, Brazil, *Plasmodium vivax* malaria acquired at 14–20 weeks of pregnancy was associated with lower hemoglobin, greater placental thickness, and lower fetal biometry at 26 weeks and at birth, but not with altered umbilical artery Doppler indices. The authors conclude that early *P. vivax* infection may affect fetal growth without affecting umbilical artery blood flow.

Key findings

  • Malaria-group women had lower hemoglobin than controls at both assessments (first: 10.8 ± 1.4 vs. 12.0 ± 0.8 g%, P = 0.001; second: 10.7 ± 0.7 vs. 11.3 ± 0.4 g%, P = 0.006), and anemia was present in 40% vs. 6.6% (P = 0.006).
  • Placental thickness above the upper limit of normality was more frequent in the malaria group at the first evaluation (40% vs. 10%, P = 0.015) and at 26 weeks (56.7% vs. 6.7%, P = 0.001).
  • At 26 weeks, all fetal biometry parameters were lower in the malaria group: BPD 61.2 ± 2.7 vs. 63.3 ± 3.1 mm (P = 0.005), HC 231.3 ± 8.9 vs. 237.2 ± 8.6 mm (P = 0.01), AC 204.0 ± 10.0 vs. 211.6 ± 7.2 mm (P = 0.001), FL 45.2 ± 2.3 vs. 46.5 ± 2.0 mm (P = 0.02), and EFW 754.7 ± 99.6 vs. 830.1 ± 69.4 g (P = 0.001).
  • Newborn weight and length were lower in the malaria group (2,948.2 ± 789.9 vs. 3,382.5 ± 289.5 g, P = 0.001; 46.1 ± 6.1 vs. 49.7 ± 1.3 cm, P = 0.001), while umbilical artery RI and PI did not differ significantly between groups.

Methods

  • Case-control study at Fundação de Medicina Tropical Dr. Heitor Vieira Dourado in Manaus, Western Brazilian Amazon, enrolling pregnant women with *P. vivax* infection diagnosed between 14 and 20 weeks of gestation and non-infected pregnant controls from the same area.
  • Participants were evaluated at malaria diagnosis and at 26 weeks of pregnancy for hemoglobin/hematocrit, placental thickness, fetal biometry, fetal heart rate, and umbilical artery Doppler velocimetry; 34 women per group were recruited, with 30 per group analyzed after exclusions.
  • Statistical comparisons used Student’s t and Mann-Whitney tests for continuous variables, χ² and Fisher’s exact tests for categorical variables, and odds ratios with 95% confidence intervals; significance was set at P ≤ 0.05.

Limitations

  • The authors state that the small sample size may explain the lack of association between anemia and low birth weight, and they call for future studies with a larger sample to confirm the association.
  • The authors note that findings may differ from studies in Southeast Asia because their population comes from an area of low malaria transmission and because *P. vivax* is highly prevalent in the Amazon region.
  • Evident from the text: this is a single-center case-control study with no randomization, so it cannot establish causality; the authors also state that no prior literature was found on umbilical artery Doppler velocimetry in *P. vivax*-infected pregnant women.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.4269/ajtmh.13-0285

Cites

Statistics

Nothing to recompute.

Claims the paper makes

0 of 17 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    At the first evaluation, there were no statistically significant differences in fetal biometry (BPD, HC, AC, FL, and estimated fetal weight) between P. vivax-infected pregnant women and non-infected controls.

    “Table 2 shows no statistically significant differences in BPD, HC, AC, FL, and estimated weight between malaria and control groups on the first assessment”
    Quote in the paperSubstantial claim
  • Findingown data

    There were no differences in umbilical artery resistance index (RI) or pulsatility index (PI) between P. vivax-infected pregnant women and non-infected controls at either evaluation.

    “There were no differences when comparing RI and PI on umbilical arteries between the two groups.”
    Quote in the paperSubstantial claim
  • Findingown data

    At the 26-week evaluation, fetal biometry parameters (BPD, HC, AC, FL, and estimated fetal weight) were significantly lower in P. vivax-infected pregnant women than in non-infected controls.

    “but significant differences were found, with all these parameters being lower in the group with malaria on the 26th week of pregnancy evaluation.”
    Quote in the paperSubstantial claim
  • Findingown data

    Birth length/height was lower in newborns of P. vivax-infected pregnant women than in newborns of non-infected controls.

    “Birth weight and height were lower in newborns in the malaria group than the control group.”
    Quote in the paperSubstantial claim
  • Findingown data

    The frequency of placental thickness greater than 10 mm above gestational age was higher in P. vivax-infected pregnant women (56.7%) than in non-infected controls (6.7%) at the second evaluation (P < 0.001).

    “and 56.7% and 6.7% of patients (P 0.001) on the second evaluation in malaria and control groups, respectively.”
    Quote in the paperSubstantial claim
  • May combine two claims. 8
  • The quote only partly states this claim. 1
  • Classified as probably not a substantial claim. 12

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    In pregnant women with P. vivax infection acquired between 14 and 20 weeks of gestation, fetal heart rate was higher than in non-infected pregnant controls at the first evaluation, but not at the 26-week evaluation.

    “higher FHR in the first evaluation”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    No patient in either the malaria or control group showed zero diastole flow.

    “No patient showed zero diastole flow in both groups.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In malaria-endemic regions, Doppler velocimetry studies have related malaria during pregnancy to maternal-fetal blood flow changes and to fetal growth restriction.

    “In malaria-endemic regions, Doppler velocimetry studies have related malaria during pregnancy with maternal-fetal blood flow changes and also associated the occurrence of this disease during pregnancy to fetal growth restrictions.13,14”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [13] Arbeille, 1998, Fetal cerebral and umbilical artery blood flow changes during pregnancy complicated by malaria

      Not checked in the free run.

    • cites [14] Dorman, 2002, Impaired uteroplacental blood flow in pregnancies complicated by falciparum malaria

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Placental malaria contributes to maternal morbidity and low birth weight in endemic countries.

    “Placental malaria contributes to maternal morbidity and low birth weight in endemic countries.15”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Dent, 2011, Fetal biometrics, umbilical and uterine artery Doppler studies among malaria infected and not infected pregnant women

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    Sample size was estimated with a 5% alpha error and 20% beta error, assuming 35% altered Doppler velocimetry indices in the malaria group and 3.5% in the control group; 25 patients were required, increased to 34 per group to allow for losses.

    “A sample size of 25 patients was, therefore, achieved.This value was increased to a rate of 35% because of presumable losses, and a final number of 34 patients in each group was established.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Maternal anemia is commonly considered a risk factor for poor pregnancy outcomes, mainly low birth weight.

    “Maternal anemia is commonly considered a risk factor for poor pregnancy outcomes, 42 mainly LBW.43”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [42] Lone, 2004, Maternal anaemia and its impact on perinatal outcome

      Not checked in the free run.

    • cites [43] Whittaker, 1996, Serial hematologic changes and pregnancy outcome

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    P. vivax malaria is associated with mild maternal anemia and significantly decreased birth weight.

    “Some studies have reported that P. vivax malaria is associated with mild maternal anemia and significantly decreased birth weight, 25,39,40 but the causative mechanisms have been unclear.5”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [25] Nosten, 1999, Effects of Plasmodium vivax malaria in pregnancy

      Not checked in the free run.

    • cites [39] Whitty, 2005, Malaria in pregnancy

      Not checked in the free run.

    • cites [40] Kochar, 2005, Plasmodium vivax malaria

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    P. vivax-infected erythrocytes cytoadhere in the intervillous space, although to a lesser degree than P. falciparum.

    “Recent studies have also shown that P. vivax-infected erythrocytes cytoadhere in the intervillous space, although to a lesser degree compared with P. falciparum.[4][5][6]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4][5][6]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Intraobserver variability for Doppler velocimetry indices was lower than 11% in both the malaria and control groups.

    “In both groups, intraobserver variability was lower than 11% for Doppler velocimetry indices.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Intraobserver variability for fetal biometry was 3.2 and 3.1 for BPD, 10.4 and 11.2 mm for HC, 9.7 and 10.1 mm for AC, 0.2 and 0.2 mm for FL, and 16.5 and 17.1 g for EFW in the malaria and control groups, respectively.

    “Intraobserver variability was 3.2 and 3.1 for BPD, 10.4 and 11.2 mm for HC, 9.7 and 10.1 mm for AC, 0.2 and 0.2 mm for FL, and 16.5 and 17.1 g for EFW in malaria and control groups, respectively.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Fetal growth rate is higher in the second trimester.

    “It has been shown that fetal growth rate is higher in the second trimester.22”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] Milani, 2005, Differences in size at birth are determined by differences in growth velocity during early prenatal life

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    P. vivax infection acquired between 14 and 20 weeks of gestation does not affect umbilical artery blood flow but does affect fetal biometry in the second trimester and at birth.

    “The results suggest that P. vivax infections at an earlier gestational age do not affect umbilical arteries blood flow but do affect fetal biometry in the second trimester of pregnancy and at birth.”
    • Also stated in: § DISCUSSION · hedged
      “Our results suggest that P. vivax infection between 14 and 20 weeks of gestational age does not seem to interfere with UAs Doppler velocimetry indices, but it does affect fetal biometry both in the second semester of pregnancy and at birth.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The observed differences in fetal biometry and birth outcomes are attributable to P. vivax infection rather than to other unmeasured factors.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    All ultrasound and Doppler scanning were performed by a single observer.

    “All ultrasound and Doppler scanning were performed by a single observer.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Each Doppler index was measured three times, and the mean was used for statistical purposes.

    “Each index was measured three times, and the mean was used for statistical purposes.”
    Quote in the paperNot a substantial claim
14 of 14

  • The paper relies on this without support.

    The control group remained free of malaria infection throughout the follow-up period.

    “As a control group, 34 pregnant women were enrolled who sought care at the FMT-HVD for pre-natal blood testing purposes and did not have malaria.”

  • The paper relies on this without support.

    The observed differences in fetal biometry and birth outcomes are attributable to P. vivax infection rather than to other unmeasured factors.

    “A control group of non-infected pregnant women from the same area was used for comparison.”
2 of 2

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Machado Filho et al. (2014) point out that P.vivax infections in early gestation do not affect blood flow in the umbilical artery, but do affect fetal biometry in the second trimester and at birth.

    “In contrast, Machado Filho et al. (2014) point out that P.vivax infections in early gestation do not affect blood flow in the umbilical artery, but do affect fetal biometry in the second trimester and at birth [106].”

    From Current update on malaria in pregnancy: a systematic review (2025) · cites this paper as Machado Filho et al. (2014)

    The Abstract and Discussion (page numbers not supplied) report no difference in umbilical-artery Doppler indices and lower fetal biometry after P. vivax infection at 14–20 weeks, including lower measurements at birth. The citing sentence states the lack of a blood-flow effect without the source's qualification that the results only suggest this conclusion and need confirmation in a larger study. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • Machado Filho et al. (2014) point out that P.vivax infections in early gestation do not affect blood flow in the umbilical artery, but do affect fetal biometry in the second trimester and at birth.

    “In contrast, Machado Filho et al. (2014) point out that P.vivax infections in early gestation do not affect blood flow in the umbilical artery, but do affect fetal biometry in the second trimester and at birth [106].”

    From Current update on malaria in pregnancy: a systematic review (2025) · cites this paper as [106]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Femur length group means conflict with parity breakdown

    Major

    At 26 weeks, weighting the Table 3 parity-group means gives 45.87 mm for infected women and 46.1 mm for controls, rather than the Table 2 means of 45.2 mm and 46.5 mm.

  • Abdominal circumference group means conflict with parity breakdown

    Major

    At 26 weeks, the Table 3 parity-group means imply overall means of 206.98 mm for infected women and 208.13 mm for controls. Table 2 reports 204.0 mm and 211.6 mm.

  • Biparietal diameter group means conflict with parity breakdown

    Major

    At 26 weeks, the Table 3 primigravidae and multigravidae means, weighted by their stated group sizes, give 62.45 mm for infected women and 62.6 mm for controls-not the 61.2 mm and 63.3 mm reported in Table 2.

  • Estimated fetal weight group means conflict with parity breakdown

    Major

    At 26 weeks, the Table 3 parity-group means imply overall means of 786.62 g for infected women and 800.37 g for controls. Table 2 instead reports 754.7 g and 830.1 g.

  • Head circumference group means conflict with parity breakdown

    Major

    At 26 weeks, weighting the Table 3 parity-group means by their stated sizes gives 234.04 mm for infected women and 235.8 mm for controls. Table 2 instead reports 231.3 mm and 237.2 mm.

  • Control-group primigravidae percentage is incorrect

    Minor

    Table 1 lists 10 primigravidae among 30 controls, which is 33.3%, not 30.0%.

    Reported 30 · recomputed 33.333333

  • Primigravidae comparison has two reported P values

    Minor

    The Results give P = 0.78 for the comparison of primigravidae between groups, while Table 1 gives P = 0.94 for that comparison.

7 of 7

The citation lists haven’t been fetched yet

References 49 · Cited by 26

Authors
Machado Filho, A. C., da Costa, E. P., da Costa, E. P., Reis, I. S., Fernandes, E. A. C., Paim, B. V., & Martinez-Espinosa, F. E.
Affiliations
Fundação de Medicina Tropical (BR)
Venue
The American Society of Tropical Medicine and Hygiene
Publisher
American Society of Tropical Medicine and Hygiene
Published
2014-02-05
Volume
90
Issue
2
Pages
371-376
ISSN
  • 0002-9637 (ISSN-L)
  • 1476-1645
DOI
10.4269/ajtmh.13-0285
PMC
PMC3919251
OpenAlex
W2147908222
Cited by
26
References
49
Citations by year
2026: 1 · 2025: 1 · 2023: 1 · 2022: 2 · 2021: 2 · 2020: 4 · 2019: 1 · 2018: 4 · 2017: 3 · 2016: 4 · 2015: 3
FWCI
3.32
Type
journal article
Language
en
Open access
Locations
  • American Journal of Tropical Medicine and Hygiene (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Malaria Research and Control
  • Health Sciences › Medicine › Obstetrics and Gynecology › Pregnancy and preeclampsia studies
  • Health Sciences › Medicine › Obstetrics and Gynecology › COVID-19 Impact on Reproduction
Keywords
Plasmodium vivax, malaria in pregnancy, fetal growth, umbilical artery Doppler, resistance index, pulsatility index, fetal biometry, fetal heart rate, placental thickness, maternal hemoglobin, birth weight, second trimester
MeSH terms
Birth Weight, Female, Fetal Growth Retardation, Fetus, Gestational Age, Heart Rate, Humans, Infant, Newborn, Placenta, Pregnancy, Pregnancy Complications, Infectious, Umbilical Arteries, Case-Control Studies, Malaria, Vivax, Fetal Development

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

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Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

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