Early prediction of gestational diabetes: a practical model combining clinical and biochemical markers.

BACKGROUND: Gestational diabetes (GDM) is usually diagnosed late in pregnancy, precluding early preventive interventions. This study aims to develop a predictive model based on clinical factors and selected biochemical markers for the early risk assessment of GDM. METHODS: Based on a prospective cohort of 7929 pregnant women from the Quebec City metropolitan area, a nested case-control study was performed including 264 women who developed GDM. Each woman who developed GDM was matched with two women with normal glycemic profile. Risk prediction models for GDM and GDM requiring insulin therapy were developed using multivariable logistic regression analyses, based on clinical characteristics and the measurement of three clinically validated biomarkers: glycated hemoglobin (HbA1c), sex hormone binding globulin (SHBG) and high-sensitivity C-reactive protein (hsCRP) measured between 14 and 17 weeks of gestation. RESULTS: HbA1c and hsCRP were higher and SHBG was lower in women who developed GDM (p<0.001). The selected model for the prediction of GDM, based on HbA1c, SHBG, BMI, past history of GDM, family history of diabetes and soft drink intake before pregnancy yielded an area under the ROC curve (AUC) of 0.79 (0.75-0.83). For the prediction of GDM requiring insulin therapy, the selected model including the same six variables yielded an AUC of 0.88 (0.84-0.92) and a sensitivity of 68.9% at a false-positive rate of 10%. CONCLUSIONS: A simple model based on clinical characteristics and biomarkers available early in pregnancy could allow the identification of women at risk of developing GDM, especially GDM requiring insulin therapy.

Mid-trimester maternal serum AFP and hCG as markers of preterm and term adverse pregnancy outcomes.

OBJECTIVE: To evaluate the predictive values of mid-trimester serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) for preterm and term placenta-mediated adverse pregnancy outcomes (PMAPOs). METHODS: We extracted data for nulliparous women with a singleton pregnancy without aneuploidy or lethal fetal anomalies from a prospective cohort study. Maternal serum AFP and hCG measured between 13 and 17 weeks of gestation and expressed as multiples of the median (MoM) for gestational age were compared between women who developed a PMAPO (preeclampsia, intrauterine growth restriction, fetal death) before term or at term and women who did not develop any of these complications. RESULTS: Among 3466 nulliparous women, maternal serum AFP and hCG levels were available in 2110 and 2125 cases, respectively. Women who developed a PMAPO before term had a higher median level of serum AFP (1.4 vs. 1.1 MoM; P < 0.01) and hCG (1.3 vs. 1.1 MoM; P < 0.01) than controls. A serum hCG > 2.0 MoM was associated with a higher risk of PMAPO before term (RR 4.6; CI 95% 2.3 to 9.1) but had no impact on the risk of PMAPO at term (RR 1.1; CI 95% 0.7 to 1.7). Maternal serum AFP > 2.0 MoM was also associated with a significant increase in the risk of preterm PMAPO (RR 3.9; CI 95% 1.6 to 9.8) but not term PMAPO (RR 1.2; CI 95% 0.6 to 2.3). CONCLUSION: Maternal serum AFP or hCG > 2.0 MoM increases the risk of preterm PMAPO but not term PMAPO in our population. We suggest that women with elevated serum AFP or hCG should receive standard pregnancy care once they have reached 37 weeks of gestation if fetal growth is in the normal range.

Objectif : Évaluer les coefficients de prévision propres aux taux sériques d'alphafœtoprotéine (AFP) et de gonadotrophine chorionique (hCG) constatés au deuxième trimestre pour ce qui est des issues de grossesse indésirables à médiation placentaire (IGIMP) obtenues avant le terme et à terme. Méthodes : Nous avons tiré, d'une étude de cohorte prospective, des données concernant des femmes nullipares ayant connu une grossesse monofœtale exempte d'aneuploïdie ou d'anomalies fœtales mortelles. Nous avons comparé les taux sériques maternels d'AFP et de hCG (mesurés entre 13 et 17 semaines de gestation et exprimés sous forme de multiples de la médiane [MoM] en fonction de l'âge gestationnel) des femmes ayant connu une IGIMP (prééclampsie, retard de croissance intra-utérin, décès fœtal) avant le terme ou à terme à ceux des femmes qui n'en sont pas venues à connaître de telles complications. Résultats : Au sein d'un groupe de 3 466 femmes nullipares, les taux sériques maternels d'AFP et de hCG étaient connus dans 2 110 cas et 2 125 cas, respectivement. Les femmes qui ont connu une IGIMP avant le terme présentaient des valeurs de MoM pour ce qui est des taux sériques d'AFP (1,4 vs 1,1 MoM; P < 0,01) et de hCG (1,3 vs 1,1 MoM; P < 0,01) plus élevées que celles des femmes du groupe témoin. Bien que la constatation d'un taux sérique de hCG > 2,0 MoM ait été associée à un risque accru d'IGIMP avant le terme (RR, 4,6; IC à 95 %, 2,3 - 9,1), elle n'exerçait aucun effet sur le risque d'IGIMP à terme (RR, 1,1; IC à 95 %, 0,7 - 1,7). La constatation d'un taux sérique maternel d'AFP > 2,0 MoM a également été associée à une hausse considérable du risque d'IGIMP avant le terme (RR, 3,9; IC à 95 %, 1,6 - 9,8); le risque d'IGIMP à terme (RR, 1,2; IC à 95 %, 0,6 - 2,3) n'en était toutefois pas affecté. Conclusion : Au sein de la population à l'étude, les taux sériques maternels d'AFP ou de hCG > 2,0 MoM ont entraîné une hausse du risque d'IGIMP avant le terme, mais n'ont pas exercé une influence sur le risque d'IGIMP à terme. Lorsque la croissance fœtale se situe dans la plage normale, les femmes qui présentent des taux sériques élevés d'AFP ou de hCG devraient recevoir des soins de grossesse standard, une fois qu'elles ont atteint 37 semaines de gestation.

Validation of a New Protocol to Collect and Isolate Plasma from Pregnant Women for Noninvasive Prenatal Testing (NIPT).

BACKGROUND: Most laboratories use specialized tubes (e.g., Streck) to recover circulating cell-free DNA (ccfDNA) for noninvasive prenatal testing (NIPT). We validated a low cost, simple procedure for collecting NIPT samples in remote laboratories that avoids highspeed centrifugation. EDTA gel blood sampling tube allows simple separation of plasma from blood cells. Decanted plasma is filtered to remove cell debris. The procedure can be performed within a few minutes after the blood centrifugation step, and ccfDNA-grade plasma can be frozen for transportation. METHODS: We recruited 51 pregnant women and collected blood in one EDTA-gel Greiner tube and two Streck tubes. All tubes were centrifuged at 1600 g x 10 min within 6 h of sample collection. Plasma from EDTA tubes was poured into a syringe cylinder and filtered through a 0.45 µm Millipore filter. Plasma from Streck tubes was recovered with a pipette and one was filtered as above while the second was centrifuged at 16 000 g. The ccfDNA was isolated and NGS sequencing libraries were prepared and sequenced on an Illumina system. Fetal fractions were estimated using SeqFF. This study had a power of 79% to detect a decrease of 1% in fetal fractions with the new method. RESULTS: We did not observe any significant difference between the three procedures for the fetal fraction nor for the quality or quantity of libraries produced. CONCLUSION: EDTA-gel tubes with filtration provide high quality plasma for ccfDNA analysis and can be sent frozen to the NIPT laboratory. This is economical and it frees the laboratory of time-consuming steps.

Early occurrence of metabolic syndrome after hypertension in pregnancy.

OBJECTIVE: The objective of the present study was to evaluate the cardiovascular risk profile and the prevalence of metabolic syndrome among women with a history of pregnancy-induced hypertension (PIH). METHODS: From a cohort of 3,799 nulliparous women prospectively recruited between 1989 and 1997, we performed an observational study on 168 case-control pairs 7.8 years after delivery. Participants were scheduled for a visit with a research nurse to evaluate their cardiovascular risk profile using a questionnaire, anthropometric measurements and blood specimen analysis. RESULTS: One hundred sixty-eight women with prior PIH (105 with gestational hypertension and 63 with preeclampsia) and 168 controls matched for age and year of index delivery were evaluated. The women with PIH (34.6 +/- 4.4 years) were more obese and had higher systolic (115 mm Hg versus 108 mm Hg) and diastolic (75 mm Hg versus 70 mm Hg) blood pressures (P < .001) than the 168 controls (35.1 +/- 4.5 years). They had lower high-density lipoprotein cholesterol level (1.30 mmol/L versus 1.42 mmol/L; P < .001), increased fasting blood glucose concentration (5.2 mmol/L versus 5.0 mmol/L; P = .002), and higher insulin levels (119 versus 91 pmol/L; P < .001). The prevalence of the metabolic syndrome was higher in the PIH group (unadjusted odds ratio = 4.9; 95% confidence interval 2.1-10.9) compared with controls, even after adjustment for confounders (adjusted odds ratio = 3.6; 95% confidence interval 1.4 -9.0). CONCLUSION: In white women in their mid-30s, the prevalence of the metabolic syndrome is 3- to 5-fold increased in those with a history of PIH in their first pregnancy. This emphasizes the importance of long-term follow-up assessment for cardiovascular risk factors in these women.

Problems with the estimation of urine protein by automated assays.

OBJECTIVES: Most clinical laboratories replaced their manual precipitation techniques for the determination of urinary protein with automated dye binding assays or benzethonium chloride-turbidimetric assays. Few studies have validated these assays for the measurement of urinary proteins in the normal range. DESIGN AND METHODS: This study compares four automated assays for the measurement of urinary protein to a manual Ponceau S/TCA precipitation assay. We evaluated the linearity, the precision, the analytical sensitivity, the accuracy and the recovery of different proteins for each assay. RESULTS: All assays showed good linearity with the theoretical concentration of albumin present in the sample. The coefficient of variation was below 10% at a concentration of 0.142 g/L. However, the manual Ponceau S/TCA assay demonstrated superior analytical sensitivity. Accuracy determinations showed a variable positive bias and poor correlations at concentrations below 0.1 g/L when compared to the Ponceau S/TCA assay. Small molecular weight peptides particularly affected the pyrogallol red assays but other urinary components also interfered with the automated assays. CONCLUSIONS: Most automated assays show high imprecision and poor accuracy for the measurement of urinary protein in the normal range. The Ponceau S/TCA offers a precise and accurate manual alternative to these automated assays.

Absence of association between serum folate and preeclampsia in women exposed to food fortification.

OBJECTIVE: To evaluate serum folate concentration early in pregnancy and any association with hypertensive disorders of pregnancy in a population exposed to folic acid supplementation and food fortification. METHODS: This is a nested case-control study based on a prospective cohort of 7,929 pregnant women recruited in the Quebec City metropolitan area, including 214 participants who developed a hypertensive disorder of pregnancy and 428 normotensive participants in the control group matched for parity, multiple pregnancy, smoking status, gestational, and maternal age at inclusion, and duration of blood sample storage. Serum folate levels were measured at a mean of 14 weeks of gestation. RESULTS: More than 98% of the participants took folic acid or multivitamins before the end of the first trimester. Mean serum folate levels were accordingly high and there were no differences between women who further developed a hypertensive disorder of pregnancy compared with women in the control group (60.1 nmol/L compared with 57.9 nmol/L; P=.51). The proportion of participants with serum folate below the 10th percentile (less than 22.3 nmol/L) of age-matched women in our outpatient population was similar between groups (P=.66) and no participant had levels generally defined as folate deficiency (less than 10 nmol/L). CONCLUSION: In a general cohort of pregnant women benefiting from a national policy of folic acid food fortification combined with a high adherence to folic acid supplementation, serum folate levels are high and do not differ between women who develop a hypertensive disorder of pregnancy and women who remain normotensive. Further supplementation with higher doses is unlikely to be beneficial in such populations. LEVEL OF EVIDENCE: II.

The combination of ApoCIII, hepatic lipase and hormono sensitive lipase gene polymorphisms suggests an association with susceptibility to gestational hypertension.

Dyslipidemia and insulin resistance contribute to the endothelial cell dysfunction in hypertensive disorders of pregnancy (HDP) and increase the long-term risk of cardiovascular disease (CVD). The genes linking susceptibility to gestational hypertension (GH) and/or preeclampsia (PE) to the long-term risk of CVD are still unknown. We evaluated the potential association between 14 polymorphisms from six genes involved in lipid metabolism and insulin action and the risk of HDP: namely the lipoprotein lipase (LPL), hepatic lipase (LIPC), hormone sensitive lipase (LIPE), cholesteryl ester transfer protein (CETP), ApoCIII and ApoE gene polymorphisms. Overall, 169 women with HDP [proteinuria (PE) and gestational hypertension without proteinuria (GH)] and 169 controls matched for age and year of delivery were genotyped. Homozygosity of the -514T allele of the -514C > T polymorphism (LIPC gene) decreased the risk of GH (OR = 0.17, CI(95): 0.02-0.76), while there were more -60G carriers of the -60C > G LIPE gene polymorphism (OR = 3.51, CI(95):1.02-12.10) among GH cases, but not in PE cases. The common ApoCIII two-locus -482CC/3238CC genotype was lower in women with GH compared with controls (OR = 0.53, CI(95): 0.3-0.9). The combined frequency of at-risk genotypes was higher in cases of GH compared with controls [one at-risk genotype: OR = 3.38 (95% CI: 0.48-41.8); two or more at-risk genotypes: OR = 7.14 (95% CI: 1.21-92.3, P = 0.01)], suggesting a gene-dose effect. We conclude that the combined effect of LIPC, LIPE and ApoCIII gene polymorphisms may increase the likelihood of GH, but seemingly not of PE.

Previous hypertensive disease of pregnancy is associated with alterations of markers of insulin resistance.

Insulin resistance syndrome has been observed in women with hypertensive disease of pregnancy, but few studies evaluated the presence of the syndrome a few years after delivery. The objective of this study was to evaluate the presence of insulin resistance and its metabolic alterations in these women compared with those who had a normal pregnancy. We performed an observational study in 168 women with previous hypertensive disease of pregnancy and 168 control subjects with normal pregnancy contacted, on average, 7.8 years after their first delivery (mean age: 34.8 years). Complete blood lipid profile, insulin, glucose, homocysteine, adipokins, and markers of inflammation were measured. Also, an oral glucose tolerance test was performed in 146 case and 135 control subjects. Case subjects were more overweight compared with control subjects. We found significantly lower high-density lipoprotein cholesterol and adiponectin levels and higher apolipoprotein (apo) apoB/apoA1 ratio, homocysteine, leptin, and insulin levels among case subjects compared with control subjects (P

Prevalence of HFE gene C282Y and H63D mutations in a French-Canadian population of neonates and in referred patients.

Hereditary hemochromatosis is a genetic disease characterized by exaggerated absorption of intestinal iron leading to its accumulation in some organs over the years. Its prevalence is estimated to be 3-5/1000 in Caucasians. A single mutation, C282Y in the HFE gene explains 80-90% of all diagnosed cases in populations of northwestern European ancestry. The importance of another frequent mutation in this gene, H63D, as well as of C282Y/H63D compound heterozygotes, is still a matter of debate. We estimated the prevalence of these mutations in newborns from a genetically well defined French-Canadian population, in Quebec City. We compared genotype and allele frequencies between neonates and referred patients for HFE molecular analysis. We genotyped anonymous-unlinked cord blood samples for C282Y (n = 881) and H63D (n = 870) mutations from neonates. Referred patients (n = 1084) were genotyped in two different laboratories and pooled after verifying the similarity of both groups. No C282Y homozygote was found in neonates (allele frequency = 0.043). However, we identified 163 C282Y homozygotes (15%) among 1084 referred patients leading to a, not surprising, 97-fold enrichment of this genotype. We found a similar proportion of genotypes homozygous for H63D in both groups suggesting a weak association with the disease. However, we found a 5-fold enrichment of compound heterozygotes in the referred group. Fewer C282Y homozygotes were observed in the French-Canadian population than in northwest Europe populations. However, the strong enrichment of homozygotes between the neonates and the referred patients is an argument in favour of screening for this lethal disease.

Pathophysiology and maternal biologic markers of preeclampsia.

Preeclampsia-increased blood pressure and proteinuria appearing after the twentieth week of pregnancy--is a major cause of materal and neonatal morbidity, leading to iatrogenic prematurity. Several lines of evidence suggest that the disorder is owing to diminished invasion of spiral arteries by trophoblastic cells, followed by reduced perfusion of the fetoplacental unit and oxidative stress. These alterations, in the presence of maternal predisposition, lead to endothelial dysfunction and occurrence of the clinical syndrome of preeclampsia (multisystemic lesions). Although the pathophysiology of preeclampsia is still unknown, progress has been made during the past 10 yr, and the early identification of at-risk women with the use of biochemical; ultrasonographic; and, more recently, genetic susceptibility markers has been the subject of intense research. In the present review, markers of maternal predisposition, placental implantation, oxidative stress, vasomotor regulation, and endothelial dysfunction are investigated as candidate markers in the early prediction of preeclampsia. Unfortunately, at the present time, no marker has been proven to have a clinically useful predictive performance in the general pregnant population, and, therefore, more research in that area is warranted.

Population prevalence of APOE, APOC3 and PPAR-alpha mutations associated to hypertriglyceridemia in French Canadians.

Hypertriglyceridemia (HTG) is known as a common metabolic disorder associated with increased production, decrease catabolism and/or decreased hepatic uptake of triglyceride (TG)-rich particles. We assessed, in the Quebec City population, the allele frequency and haplotype distributions of mutations in genes related to HTG, such as the apolipoprotein E (APOE) (C112R and C158R), the apolipoprotein CIII (APOC3) (C-482T and C3238G) and the peroxisome proliferator-activated receptor alpha (PPARalpha) (L162V) genes. A total of 938 anonymous unlinked newborns from the metropolitan Quebec City area have been genotyped. Allele frequencies observed in the Quebec City population differed from known frequencies determined in other Caucasian populations. The co-transmitted allele distribution between the two-marker genotypes APOE/APOC3(C3238G) and APOC3(C-482T)/PPARalpha(L162V) presented a weak deviation from the assumption of genetic independence. Also, we observed a non-independent distribution of the T-482/G3238 allele combinations within the APOC3 gene, suggesting strong linkage disequilibrium between the C-482T and C3238G polymorphisms. Moreover, comparisons of allele frequencies observed in the population of Québec City to those obtained in other Caucasian populations suggested that the population of Québec City may be at a lower risk of developing HTG due to APOE, APOC3 and PPARalpha genetic variants. However, the strong linkage disequilibrium and the two-marker genotype distributions observed in the APOC3 gene suggest that these two variants may functionally interact in the Québec City population.