Development of four influential NMR signals over time.

<p>Proton NMR spectra of all three urine samples from one healthy participant, showing the region between 0.5 and 0.9 ppm; normalized to the creatinine concentration, BXR baseline correction not yet applied in order to preserve the shape of the broader peaks. The four highlighted signals increase from visit V1 (red line, gest. week 8–20) to V2 (green line, gest. week 26–30) and then disappear at V3 (blue line, 10–16 weeks post partum).</p

PLS-DA validation results for dummy matrices of ethnic background at the three visits.

a<p>Excluding South America, n = 12.</p>b<p>S.Asia: South Asia;</p>c<p>E.Asia: East Asia;</p>d<p>ME.CA.NA.: Middle East, Central Asia and North Africa.</p

Fetal growth trajectories in pregnancies of European and South Asian mothers with and without gestational diabetes, a population-based cohort study

<div><p>Objective</p><p>Our aim was to examine the impact of gestational diabetes (GDM), from before the GDM-diagnosis is made, on fetal growth trajectories, and to compare it in Europeans and South Asians; two ethnic groups with dissimilar fetal growth patterns.</p><p>Methods</p><p>We studied European (n = 349) and South Asian (n = 184) pregnant women, from the population-based STORK-Groruddalen cohort in Oslo, Norway. Mothers were enrolled in early pregnancy, screened for GDM in gestational week 28 ±2, and classified as “non-GDM”, “mild GDM” or “moderate/severe GDM”. We measured fetal head circumference, abdominal circumference and femur length by ultrasound, and estimated fetal weight in gestational week 24, 32 and 37, and performed corresponding measurements at birth.</p><p>Results</p><p>In non-GDM pregnancies, South Asian fetuses (n = 156) had a slower growth from gestational week 24, compared with Europeans (n = 310). More than two thirds of the European mothers later diagnosed with GDM were overweight or obese in early pregnancy, while this was not observed in South Asians. Fetuses of GDM mothers tended to be smaller than fetuses of non-GDM mothers in week 24, but thereafter grew faster until birth. This pattern was especially pronounced in fetuses of South Asian mothers with moderate/severe GDM. In week 24 these fetuses had a -0.95 SD (95% CI: -1.53, -0.36) lower estimated fetal weight than their non-GDM counterparts. In contrast, at birth they were 0.45 SD (0.09, 0.81) larger.</p><p>Conclusions</p><p>Offspring of GDM mothers were smaller in mid pregnancy, but subsequently grew faster until birth, compared with offspring of non-GDM mothers. This pattern was most prominent in South Asian mothers with moderate to severe GDM. However, the most remarkable characteristic of these fetuses was not a large size at birth, but the small size in mid pregnancy, before the GDM diagnosis was set.</p></div

Median concentrations (IQR) of profiled compounds relative to creatinine concentration at the three visits, and patient-wise fold-change between visits.

a<p>While the median (IQR) values are reported on their natural scale, all parametric statistical tests were carried out using the log-transformed, normally distributed variables.</p>b<p>Visit V1: gestational week 8–20; V2: gestational week 26–30; V3∶10–16 weeks post partum.</p>c<p>Urea is affected by NMR water suppression.</p>d<p>Broader spectral signal; measured before subtracting BXR baseline.</p>e<p>Compound very dilute to undetectable in a substantial number of samples; reported concentration may represent noise.</p>f<p>Concentration of creatinine is reported as absolute mM before normalization.</p>g<p>No conclusive identification, quantified as stated.</p>x<p>Concentrations of unidentified signals in arbitrary units, but nonetheless individually normalized to creatinine.</p

Selected substances and signals differing between the WHO classes (healthy, diabetes) at visits V1 and V2.

a<p>Visit V1: gestational week 8–20; V2: gestational week 26–30.</p>x<p>Concentrations of unidentified signals in arbitrary units, but nonetheless normalized to creatinine.</p

Validation results and most influential compounds of pairwise PLS-DA models from the log-transformed concentration variables with respect to the three visits.

a<p>A high ratio between Q² and R² confirms the validity of the models.</p>b<p>The number of misclassifications (NMC) of the PLS-DA models relative to the random result from permutation testing serves as a performance estimate; 95% CI of the estimates in parentheses.</p>c<p>Spectral signals that could not be assigned to known metabolites are referred to as “Unknown”, along with the locations of their NMR signals. Arrows denote relative increase or decrease between visits. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052399#pone-0052399-t002" target="_blank">Table 2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052399#pone-0052399-g002" target="_blank">Fig. 2</a>.</p

Lactose and an unidentified compound dominate the urinary changes during pregnancy.

<p>Scatter plot of concentrations (relative to creatinine concentration; log axes) of lactose and an unidentified substance with an NMR signal at 0.62 ppm. Red circles, green triangles and filled blue circles for visit V1 (gestational week 8–20), V2 (gestational week 26–30) and V3 (10–16 weeks post partum), respectively. Note how these two compounds alone reproduce a clustering similar to that in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052399#pone-0052399-g001" target="_blank">Fig. 1</a>.</p

Selected substances and signals differing between the three graded classes (healthy, GDM with mild hyperglycemia, GDM with pronounced hyperglycemia) at visits V1 and V2.

a<p>Visit V1: gestational week 8–20; V2: gestational week 26–30.</p>b<p>Classification by graded criteria based on modified IADPSG definitions and the HAPO study: Healthy, normoglycemic (G0); GDM with relatively mild hyperglycemia (G1) or with more pronounced hyperglycemia (G2). Thresholds are defined in the Materials section.</p>x<p>Concentrations of unidentified signals in arbitrary units, but nonetheless normalized to creatinine.</p

Citrate concentration and relative change during and after pregnancy, by degree of hyperglycemia.

<p>Median concentration (±95% CI of the median as dashed lines) of urine citrate concentration relative to creatinine levels at the three visits (V1: gestational week 8–20; V2: gestational week 26–30; V3∶10–16 weeks post partum), shown separately in red, green and blue, respectively, for the three graded classes based on modified IADPSG definitions and the HAPO study (G0: healthy, normoglycemic; G1: GDM with relatively mild hyperglycemia; G2: GDM with more pronounced hyperglycemia). Insets show the mean patient-wise relative fold-change (±95% CI of the mean, based on log values) between visits V1 and V2 (panel A), and V2 and V3 (panel B), respectively. Note the sharper rise and subsequent fall of urinary citrate associated with the severity of GDM.</p

Ethnic differences in fetal size and growth in non-GDM pregnancies.

<p>Mean difference in z-score for estimated fetal weight (black circles), head circumference (HC, black squares), abdominal circumference (AC, white circles) and femur length/length (white squares), in South Asian non-GDM, compared with European non-GDM pregnancies, at four time points (gestational week 24, 32 and 37 during pregnancy and at birth). Estimates are gestational age specific z-scores extracted from a linear mixed model, adjusted for maternal parity and fetal gender. Ethnic Europeans are reference group, represented by the zero-line.</p