Steven Thompson

Maternal red blood cell folate concentration at 10–12 weeks gestation and pregnancy outcome

Objective: To determine if maternal circulating red blood cell (RBC) folate concentration in early pregnancy is associated with late gestation pregnancy complications including small for gestational age (SGA) infants, preeclampsia and preterm birth (PTB) in a socioeconomically disadvantaged population. Method: This was a retrospective case control study, conducted at Lyell McEwin Health Service, South Australia, including 400 primiparous women. RBC folate and demographic data were collected at 10–12 weeks gestation. Pregnancy outcome data were obtained from patient case notes. Results: Patients who were folate deficient were more likely to develop pregnancy complications, specifically SGA (OR 6.9, 95% CI 2–24.3) and PTB (OR 5.4 95% CI 1.4–21.2). Those who were folate insufficient were also at increased risk of SGA (OR 3.0, 95% CI 1.3–7.7). No association between folate and preeclampsia was found. Women who were supplementing with folic acid delivered infants who were 179 g heavier (5.5% increased birth weight, P = 0.003) and 4.5 days later, compared to those who did not supplement. Furthermore, low RBC folate was associated with cigarette smoking (P < 0.001). Conclusions: Maternal RBC folate concentration in early pregnancy is associated with SGA and PTB, but not with preeclampsia.

Single-Nucleotide Polymorphisms in the KDR Gene in Pregnancies Complicated by Gestational Hypertensive Disorders and Small-for-Gestational-Age Infants

Introduction: Pregnancies complicated by preeclampsia and small-for-gestational-age (SGA) infants share placental vascular abnormalities and both disorders confer increased risk of later life coronary artery disease. Kinase insert domain receptor (KDR) is the main receptor for vascular endothelial growth factor A, a potent angiogenic factor which regulates the development of the placental vasculature. Two polymorphisms in KDR (-604T/C and Val297Ile) are known to be associated with coronary artery disease. We investigated the association of these polymorphisms with preeclampsia, gestational hypertension, and SGA infants. Method: Nulliparous pregnant women, their partners, and infants were recruited to a prospective cohort study (n = 1169). Doppler ultrasound of the uterine and umbilical arteries was performed at 20 weeks of gestation. Preeclampsia, gestational hypertension, and SGA were defined according to international guidelines. DNA extracted from peripheral venous or cord blood was genotyped using the Sequenom MassARRAY system. Multivariable logistic regression was used to compare the odds for the pregnancy complications between the genotype groups adjusting for potential confounders. Results: Among 937 Caucasian pregnancies, 427 (45.6%) were uncomplicated, 75 (8.0%) developed preeclampsia, 102 (10.9%) developed gestational hypertension, and 72 (7.7%) had SGA infants in the absence of maternal hypertensive disease. Paternal and neonatal KDR-604T/C was associated with preeclampsia (adjusted odds ratio [aOR] 1.6, 95% confidence interval [CI] 1.0-3.0 and aOR 2.2, 95% CI 1.0-4.4), SGA (aOR 1.9, 95% CI 1.1-3.3 and aOR 2.2, 95% CI 1.2-3.9), and SGA with abnormal Doppler (aOR 2.7, 95% CI 1.2-5.9 and aOR 3.2, 95% CI 1.2-5.9). Conclusion: Paternal and neonatal carriage of the KDR-604T/C polymorphism is associated with the risk of preeclampsia and SGA infants.

A functional variant in the thrombospondin-1 gene and the risk of small for gestational age infants

Summary.  Introduction: Thrombospondin‐1 (TSP‐1) is a prothrombotic and anti‐angiogenic glycoprotein expressed in the placenta. A functional single nucleotide polymorphism in the TSP‐1 gene (TSP‐1 A2210G) is a risk factor for familial premature myocardial infarction. Small for gestational age (SGA) infants are at increased risk of coronary artery disease in adult life and common genetic factors may underlie both conditions. We investigated the association of TSP‐1 A2210G in SGA infants and their parents. Method: The 3234 nulliparous pregnant women, their partners and babies were recruited in Adelaide and Auckland to a prospective multicenter cohort study. Amongst 2123 Caucasian women, 216 (10.2%) delivered an SGA infant, defined as birth weight < 10th customized centile adjusted for maternal height, weight, parity and ethnicity, as well as gestational age at delivery and infant sex. Uncomplicated pregnancies served as controls (n = 1185). DNA extracted from peripheral/cord blood or buccal swabs was genotyped using Sequenom MassARRAY. Multivariable logistic regression was used to compare the odds of SGA between the genotype groups adjusting for potential confounders. Results: Paternal (adjOR, 1.4; 95% CI 1.0–2.0) and neonatal (adjOR, 1.8; 95% CI, 1.1–2.7) TSP‐1 A2210G associates with SGA. The maternal polymorphism approaches significance for an association with SGA (adjOR, 1.3; 95% CI, 0.9–1.9). Maternal TSP‐1 A2210G associates with a reduced maternal birth weight adjusted for gestational age at delivery (P = 0.03). Conclusion: The TSP‐1 A2210G polymorphism, which is a risk factor for myocardial infarction, is associated with SGA pregnancies, suggesting that this polymorphism may associate with the risk of vascular disorders across the life course.

A functional variant in ANGPT1 and the risk of pregnancies with hypertensive disorders and small-for-gestational-age infants

Pregnancies complicated by pre-eclampsia and small-for-gestational-age (SGA) infants demonstrate impaired placental vascular remodelling. Angiopoietin-1 (ANG-1) is an angiogenic growth factor which regulates vascular integrity and remodelling. The TT genotype of angiopoietin 1 (ANGPT1) rs2507800 polymorphism has been associated with increased plasma ANG-1 levels compared with the AA genotype. We aimed to investigate the association between ANGPT1 rs2507800 polymorphism and pregnancies complicated by gestational hypertensive disorders and SGA infants. We also aimed to investigate whether the polymorphism was associated with abnormal uterine artery Doppler as a surrogate marker of impaired placental vascular remodelling. Genotyping data of 1361 nulliparous pregnant women, 1226 partners and 1190 infants were analysed. The prevalence of ANGPT1 rs2507800 TT genotype was reduced in women with pre-eclampsia [P = 0.01, adjusted odds ratio (aOR), 0.5; 95% confidence interval (CI), 0.3-0.9], hypertensive SGA (P = 0.04, aOR, 0.5; 95% CI, 0.2-0.9) and SGA with abnormal uterine artery Doppler (P = 0.009, aOR, 0.4. 95% CI, 0.2-0.8) compared with women with uncomplicated pregnancy. The prevalence of maternal ANGPT1 rs2507800 TT genotype was reduced in women with increased uterine artery resistance index (P = 0.03, aOR, 0.7; 95% CI, 0.5-0.9) and bilateral notching of the uterine arteries (P = 0.004, aOR, 0.6; 95% CI, 0.4-0.9). These results remained significant after correcting for multiple testing. Maternal ANGPT1 rs2507800 TT genotype is associated with a reduced risk for pre-eclampsia, hypertensive SGA and abnormal uterine artery Doppler. These findings suggest that the TT genotype may protect against these pregnancy disorders by increasing ANG-1 production at the maternal-fetal interface. The ANGPT1 rs2507800 polymorphism may have a potential role in screening women to predict the risk of these pregnancy complications. TRIAL REGISTRY NAME: Screening nulliparous women to identify the combinations of clinical risk factors and/or biomarkers required to predict pre-eclampsia, SGA babies and spontaneous preterm birth.

Circulating IGF1 and IGF2 and SNP genotypes in men and pregnant and non-pregnant women

Circulating IGFs are important regulators of prenatal and postnatal growth, and of metabolism and pregnancy, and change with sex, age and pregnancy. Single-nucleotide polymorphisms (SNPs) in genes coding for these hormones associate with circulating abundance of IGF1 and IGF2 in non-pregnant adults and children, but whether this occurs in pregnancy is unknown. We therefore investigated associations of plasma IGF1 and IGF2 with age and genotype at candidate SNPs previously associated with circulating IGF1, IGF2 or methylation of the INS – IGF2 – H19 locus in men (n=134), non-pregnant women (n=74) and women at 15 weeks of gestation (n=98). Plasma IGF1 concentrations decreased with age (P<0.001) and plasma IGF1 and IGF2 concentrations were lower in pregnant women than in non-pregnant women or men (each P<0.001). SNP genotypes in the INS – IGF2 – H19 locus were associated with plasma IGF1 (IGF2 rs680, IGF2 rs1004446 and IGF2 rs3741204) and IGF2 (IGF2 rs1004446, IGF2 rs3741204 and H19 rs217727). In single SNP models, effects of IGF2 rs680 were similar between groups, with higher plasma IGF1 concentrations in individuals with the GG genotype when compared with GA (P=0.016), or combined GA and AA genotypes (P=0.003). SNPs in the IGF2 gene associated with IGF1 or IGF2 were in linkage disequilibrium, hence these associations could reflect other genotype variations within this region or be due to changes in INS – IGF2 – H19 methylation previously associated with some of these variants. As IGF1 in early pregnancy promotes placental differentiation and function, lower IGF1 concentrations in pregnant women carrying IGF2 rs680 A alleles may affect placental development and/or risk of pregnancy complications.

Polymorphisms in the fibrinolytic pathway genes and the risk of recurrent spontaneous abortion

Impaired fibrinolytic activity is implicated in the pathogenesis of recurrent spontaneous abortion (RSA). This case-control study assessed the prevalence of polymorphisms in fibrinolytic system genes in RSA. Cases comprised 202 Sinhalese women who had experienced at least two first-trimester spontaneous abortions and had no living children; controls were 202 women with no history of spontaneous abortion and two or more living children. The groups were matched for age and ethnicity. DNA was genotyped using the Sequenom MassARRAY system. The PLAUR rs4251923 A (OR 95% CI 2.3 [1.3 to 4.0]), SERBP2 rs6098 A (OR 95% CI 1.4 [1.1 to 1.9]) and SERBP2 rs6103 C alleles (OR 95% CI 1.4 [1.1 to 1.9]) were increased in the RSA group compared with controls. The prevalence of PLAUR rs4251923/ SERBP2 rs6098/ SERBP2 rs6103 GG/AA/CC (OR 95% CI 2.4 [1.2 to 4.9], GA/GA/GC(OR 95% CI 3.9 [1.3 to 11.2]), GA/AA/CC (OR 95% CI 2.9 [1.0 to 8.6] and GA/GG/GG (OR 95% CI 21.3 [1.1 to 410.3]) genotypes were also increased in cases. Polymorphisms in the fibrinolytic system genes are associated with RSA in Sinhalese women. These likely impair implantation.

Insulin family polymorphisms in pregnancies complicated by small for gestational age infants

Being born small for gestational age (SGA) increases the risk for adverse perinatal outcomes and later life vascular and metabolic disorders. The insulin family plays a vital role in intrauterine growth. We investigated the association of functional SNPs in insulin (INS), insulin receptor (INSR) and insulin receptor substrate 2 (IRS2) with small for gestational age (SGA) pregnancies, uterine and umbilical artery Doppler and plasma insulin level. We conducted a nested case-control study of 1401 nulliparous Caucasian women, their partners and babies (216 SGA and 1185 uncomplicated). SGA was defined as a birthweight less than the 10th customized birthweight percentile adjusted for maternal height, weight, parity, ethnicity, gestational age at delivery and infant sex. Uterine and umbilical artery Doppler was performed at 20 ± 1 week gestation. The SNPs in the parent infant trios were genotyped using Sequenom MassARRAY. Plasma insulin was measured by double antibody RIA in 188 healthy non-pregnant adults to assess correlations between SNP genotypes and circulating insulin. Paternal [odds ratio (OR) (95% CI) = 2.2 (1.3-3.9), P = 0.005] and infant [OR (95% CI) = 3.3 (1.7-6.2), P = 0.0001] INSR rs2059806 AA genotype was associated with SGA. Infant INSR rs2059806 A allele was associated with abnormal umbilical artery Doppler [OR (95% CI) = 1.3(1.0-1.7), P = 0.04]. INSR rs2059806 AA homozygous individuals had lower plasma insulin compared with heterozygotes (P = 0.03) and GG homozygotes (P = 0.03). The INSR rs2059806 SNP previously associated with adult vascular and metabolic diseases is also associated with SGA pregnancies. This polymorphism may associate with the risk of vascular and metabolic disorders across the life course.

M13.4 Vitamin D related genes and maternal circulating 250H vitamin D3 associate with pregnancy complications in an Australian population

Prabha Andraweera1, Miss Rachael Nowak1, Steven Thompson1, Vajira Dissanayake2, Rohan Jayasekara2, Gus Dekker3, Claire Roberts1. 1Discipline of Obstetrics and Gynaecology, Research Centre for Reproductive Health, University of Adelaide, Australia; 2Human Genetics Unit, Faculty of Medicine, University of Colombo, Sri-Lanka; 3Women’s and Children’s Division, Lyell McEwin Hospital, Elizabeth Vale, South Australia

M13.1 Association of single nucleotide polymorphisms in cytokine genes with preeclampsia in a Sinhalese population from Sri Lanka

Prabha Andraweera1, Miss Rachael Nowak1, Steven Thompson1, Vajira Dissanayake2, Rohan Jayasekara2, Gus Dekker3, Claire Roberts1. 1Discipline of Obstetrics and Gynaecology, Research Centre for Reproductive Health, University of Adelaide, Australia; 2Human Genetics Unit, Faculty of Medicine, University of Colombo, Sri-Lanka; 3Women’s and Children’s Division, Lyell McEwin Hospital, Elizabeth Vale, South Australia

M9.5 Association of single nucleotide polymorphism in the vascular endothelial growth factor gene with small for gestational age birth

Introduction: Impaired placental angiogenesis is implicated in the pathophysiology of small for gestational age (SGA) infants. Placental expression of vascular endothelial growth factor (VEGF), a potent angiogenic factor which regulates placental angiogenesis, is reduced in SGA pregnancies. We evaluated the association of two functional single nucleotide polymorphisms in the VEGF gene (VEGF+2578C/A and VEGF+936C/T) in SGA pregnancies. Methods: 3196 nulliparous pregnant women, their partners and babies were recruited in Adelaide and Auckland to a prospective multicenter cohort study (SCOPE Study). Amongst 2597 Caucasian women, 269 (10.4%) delivered a SGA infant defined as <10th customised centile (adjusted for gestational age at delivery, infant sex, maternal ethnicity, weight, height and parity). Uncomplicated Caucasian pregnancies served as controls (n=1463). Uterine and umbilical artery Doppler velocimetry was performed at 20 weeks gestation. DNA was extracted from peripheral blood from couples and cord blood from babies. Genotyping was performed using the Sequenom MassARRAY system. Genotype frequency of SGA was compared with controls using dominant and recessive genotype models by logistic regression analysis. ANCOVA was used to compare genotypes with birthweight and placental weight (adjusted for gestational age) in the Caucasian cohort. Results: Neonatal VEGF+936 CT+TT genotypes [dominant model] were increased in SGA (OR: 1.63, 95%CI: 1.1-2.3). Neonatal VEGF+936 CT+TT genotypes were associated with lower birthweight (p=0.005), customised birthweight centile (p=0.03) and placental weight (p=0.04) than CC. Maternal VEGF+936 CT+TT genotypes were associated with increased umbilical artery resistance index (OR: 1.5, 95%CI: 1.1-2.1) and the presence of bilateral uterine artery waveform notching (OR: 1.4, 95%CI: 1.0-1.8) compared to CC. Neonatal VEGF+936 CT+TT genotypes were associated with increased uterine artery resistance index (p=0.004). All associations remained significant after adjusting for confounding factors. Conclusion: The low VEGF producing VEGF+936 CT and TT genotypes associate with increased resistance in the placental circulation. These genotypes confer an increased risk for SGA and may be implicated in impaired placental function.