Fetal Size in a Rural Melanesian Population with Minimal Risk Factors for Growth Restriction: An Observational Ultrasound Study from Papua New Guinea

Unger, Holger W.; Karl, Stephan; Wangnapi, Regina; Siba, Peter; Mola, Glen; Walker, Jane; Müeller, Ivo; Ome, Maria; Rogerson, Stephen J.

doi:10.4269/ajtmh.14-0423

Cited by 5 publications

(6 citation statements)

References 41 publications

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“…The research was approved by the PNG Institute of Medical Research, the PNG Medical Research Advisory Council and the Melbourne Health Human Research Ethics Committee, as previously described [23, 26]. …”

Section: Methodsmentioning

confidence: 99%

“…MCA flow was interrogated from near field MCAs only using a transtemporal view: flow velocity waveforms were obtained from the area where the MCA joins the Circle of Willis. Fetal abdominal circumference (AC), HC and FL were measured as previously described [26]. Fetal weights were estimated using a formula developed by Hadlock et al [37] using a combination of all three measurements (or AC plus FL when HC could not be measured adequately due to fetal position, n = 9).…”

Section: Methodsmentioning

confidence: 99%

“…Of 90 randomly selected UA Doppler stills, all were deemed of good quality (adequate cord position, adequate and good quality wave obtained, adequate Doppler beam placement). Quality control criteria and results of fetal size parameters for this cohort have previously been reported [26]. …”

Section: Methodsmentioning

confidence: 99%

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Effects of Plasmodium falciparum infection on umbilical artery resistance and intrafetal blood flow distribution: a Doppler ultrasound study from Papua New Guinea

Ome-Kaius

Karl

Wangnapi

et al. 2017

Malar J

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BackgroundDoppler velocimetry studies of umbilical artery (UA) and middle cerebral artery (MCA) flow help to determine the presence and severity of fetal growth restriction. Increased UA resistance and reduced MCA pulsatility may indicate increased placental resistance and intrafetal blood flow redistribution. Malaria causes low birth weight and fetal growth restriction, but few studies have assessed its effects on uteroplacental and fetoplacental blood flow.MethodsColour-pulsed Doppler ultrasound was used to assess UA and MCA flow in 396 Papua New Guinean singleton fetuses. Abnormal flow was defined as an UA resistance index above the 90th centile, and/or a MCA pulsatility index and cerebroplacental ratio (ratio of MCA and UA pulsatility index) below the 10th centile of population-specific models fitted to the data. Associations between malaria (peripheral infection prior to and at ultrasound examination, and any gestational infection, i.e., ‘exposure’) and abnormal flow, and between abnormal flow and birth outcomes, were estimated.ResultsOf 78 malaria infection episodes detected before or at the ultrasound visit, 62 (79.5%) were Plasmodium falciparum (34 sub-microscopic infections), and 16 were Plasmodium vivax. Plasmodium falciparum infection before or at Doppler measurement was associated with increased UA resistance (adjusted odds ratio (aOR) 2.3 95% CI 1.0–5.2, P = 0.047). When assessed by ‘exposure’, P. falciparum infection was significantly associated with increased UA resistance (all infections: 2.4, 1.1–4.9, P = 0.024; sub-microscopic infections 2.6, 1.0–6.6, P = 0.051) and a reduced MCA pulsatility index (all infections: 2.6, 1.2–5.3, P = 0.012; sub-microscopic infections: 2.8, 1.1–7.5, P = 0.035). Sub-microscopic P. falciparum infections were additionally associated with a reduced cerebroplacental ratio (3.64, 1.22–10.88, P = 0.021). There were too few P. vivax infections to draw robust conclusions. An increased UA resistance index was associated with histological evidence of placental malaria (5.1, 2.3–10.9, P < 0.001; sensitivity 0.26, specificity 0.93). A low cerebroplacental Doppler ratio was associated with concurrently measuring small-for-gestational-age, and with low birth weight.Discussion/conclusionBoth microscopic and sub-microscopic P. falciparum infections impair fetoplacental and intrafetal flow, at least temporarily. Increased UA resistance has high specificity but low sensitivity for the detection of placental infection. These findings suggest that interventions to protect the fetus should clear and prevent both microscopic and sub-microscopic malarial infections. Trial Registration ClinicalTrials.gov NCT01136850. Registered 06 April 2010Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-017-1689-z) contains supplementary material, which is available to authorized users.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Effects of Plasmodium falciparum infection on umbilical artery resistance and intrafetal blood flow distribution: a Doppler ultrasound study from Papua New Guinea

Ome-Kaius

Karl

Wangnapi

et al. 2017

Malar J

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“…Data collection for this research was conducted between November 2009 and December 2012 at eight health facilities in the Madang municipality on the North coast of PNG. The burden of low birthweight in the study area is high [ 24 – 27 ], and pregnancy care is largely provided by government or church-based health centres with no or limited access to ultrasound.…”

Section: Methodsmentioning

confidence: 99%

Preterm or Not – An Evaluation of Estimates of Gestational Age in a Cohort of Women from Rural Papua New Guinea

et al. 2015

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BackgroundKnowledge of accurate gestational age is required for comprehensive pregnancy care and is an essential component of research evaluating causes of preterm birth. In industrialised countries gestational age is determined with the help of fetal biometry in early pregnancy. Lack of ultrasound and late presentation to antenatal clinic limits this practice in low-resource settings. Instead, clinical estimators of gestational age are used, but their accuracy remains a matter of debate.MethodsIn a cohort of 688 singleton pregnancies from rural Papua New Guinea, delivery gestational age was calculated from Ballard score, last menstrual period, symphysis-pubis fundal height at first visit and quickening as well as mid- and late pregnancy fetal biometry. Published models using sequential fundal height measurements and corrected last menstrual period to estimate gestational age were also tested. Novel linear models that combined clinical measurements for gestational age estimation were developed. Predictions were compared with the reference early pregnancy ultrasound (<25 gestational weeks) using correlation, regression and Bland-Altman analyses and ranked for their capability to predict preterm birth using the harmonic mean of recall and precision (F-measure).ResultsAverage bias between reference ultrasound and clinical methods ranged from 0–11 days (95% confidence levels: 14–42 days). Preterm birth was best predicted by mid-pregnancy ultrasound (F-measure: 0.72), and neuromuscular Ballard score provided the least reliable preterm birth prediction (F-measure: 0.17). The best clinical methods to predict gestational age and preterm birth were last menstrual period and fundal height (F-measures 0.35). A linear model combining both measures improved prediction of preterm birth (F-measure: 0.58).ConclusionsEstimation of gestational age without ultrasound is prone to significant error. In the absence of ultrasound facilities, last menstrual period and fundal height are among the more reliable clinical measures. This study underlines the importance of strengthening ultrasound facilities and developing novel ways to estimate gestational age.

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“…28 Despite the low-risk status of the pregnant women followed with serial ultrasonology for EFW and birthweight, use of the Hadlock formula (Caucasian) or Congolese standard 14 overestimated the percentage of Papua New Guinea fetuses considered <10 th percentile.…”

Section: Commentmentioning

confidence: 99%

Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

Louis

Grewal

Albert

et al. 2015

American Journal of Obstetrics and Gynecology

378

324

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Objective Fetal growth is associated with long-term health yet no appropriate standards exist for the early identification of under- or over-grown fetuses. We sought to develop contemporary fetal growth standards for four self-identified U.S. racial/ethnic groups. Study Design We recruited for prospective follow-up 2,334 healthy women with low-risk, singleton pregnancies from 12 community and perinatal centers between July 2009 and January 2013. The cohort comprised: 614 (26%) non-Hispanic Whites, 611 (26%) non-Hispanic Blacks, 649 (28%) Hispanics, and 460 (20%) Asians. Women were screened at 8w0d to 13w6d for maternal health status associated with presumably normal fetal growth (aged 18–40 years; body mass index 19.0–29.9 kg/m2; healthy lifestyles and living conditions; low-risk medical and obstetrical history); 92% of recruited women completed the protocol. Women were randomized among four ultrasonology schedules for longitudinal fetal measurement using the Voluson E8 GE Healthcare. In-person interviews and anthropometric assessments were conducted at each visit; medical records were abstracted. The fetuses of 1,737 (74%) women continued to be low-risk (uncomplicated pregnancy, absent anomalies) at birth, and their measurements were included in the standards. Racial/ethnic-specific fetal growth curves were estimated using linear mixed models with cubic splines. Estimated fetal weight and biometric parameter percentiles (5th, 50th, 95th) were determined for each gestational week and comparisons made by race/ethnicity, with and without adjustment for maternal and socio-demographic factors. Results Estimated fetal weight differed significantly by race/ethnicity after 20 weeks. Specifically at 39 weeks, the 5th, 50th, and 95th percentiles were 2790, 3505, and 4402 grams for White, 2633, 3336, and 4226 grams for Hispanic, 2621, 3270, and 4078 grams for Asian, and 2622, 3260, and 4053 grams for Black women (adjusted global p<0.001). For individual parameters, racial/ethnic differences by order of detection were: humerus and femur lengths (10 weeks), abdominal circumference (16 weeks), head circumference (21 weeks), and biparietal diameter (27 weeks). The study-derived standard based solely on the White group erroneously classifies as much as 15% of non-White fetuses as growth-restricted (estimated fetal weight < 5th percentile). Conclusions Significant differences in fetal growth were found among the four groups. Racial/ethnic-specific standards improve the precision in evaluating fetal growth.

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Fetal Size in a Rural Melanesian Population with Minimal Risk Factors for Growth Restriction: An Observational Ultrasound Study from Papua New Guinea

Cited by 5 publications

References 41 publications

Effects of Plasmodium falciparum infection on umbilical artery resistance and intrafetal blood flow distribution: a Doppler ultrasound study from Papua New Guinea

Effects of Plasmodium falciparum infection on umbilical artery resistance and intrafetal blood flow distribution: a Doppler ultrasound study from Papua New Guinea

Preterm or Not – An Evaluation of Estimates of Gestational Age in a Cohort of Women from Rural Papua New Guinea

Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

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