Genome profiles in maternal blood during early onset preeclampsia and towards term.

AIMS: inflammatory processes are present during preeclampsia and in normal pregnancy. Maternal inflammatory reactions may change towards term. Our objective was to evaluate genome signaling in blood during preeclampsia and towards term using microarrays. METHODS: RNA microarrays (Illumina) were conducted on blood from preeclamptic pregnancies delivered preterm, normal pregnancies at term and normal pregnancies at gestational week 31. Two statistical methods (Q-value cut-off 1%) identified data structures in the three groups and retrieved activated genes along a time axis and a diseased-healthy axis. Signaling genes were localized within known pathways and gene sets, and genes associated with inflammation were identified. RESULTS: early onset preeclampsia and term pregnancies both showed distinct expression patterns when compared to normal pregnancy at gestational week 31. In preeclampsia, 19 genes were differentially expressed, including a down-regulation of CC-chemokine receptor 3 (CCR3). Among the 183 differentially expressed genes towards term, tumor necrosis factor superfamily member 15 (TNFSF15) was up-regulated and interferon-γ receptor 2 (IFNGR2) and CXC-chemokine receptor type 4 (CXCR4) were down-regulated. Seven of the genes were similarly changed during preeclampsia and towards term. CONCLUSIONS: a possible type 1 immune response was identified both during preeclampsia and towards term. In pre-eclampsia a premature activation of leucocytes might be present.

Placenta weight in pre-eclampsia.

OBJECTIVE: Preterm and term pre-eclampsia may differ in etiology. This could be reflected in differences in placenta weight. Therefore, we compared placenta weight in pregnancies with preterm or term pre-eclampsia to placenta weight in pregnancies without pre-eclampsia. DESIGN: Population study. SETTING: Medical Birth Registry of Norway. POPULATION: All singleton pregnancies in Norway from 1999 through 2004 delivered at or after 21 weeks' gestation (n=317,688). METHODS: Placenta weight in pregnancies without pre-eclampsia (n=304,875) was compared to placenta weight in pregnancies with preterm pre-eclampsia (delivery before week 37 of pregnancy, n=3,070) and term pre-eclampsia (delivery on or after week 37 of pregnancy, n=9,743). Placenta weight z-scores were calculated to adjust for offspring sex and length of gestation, and grouped in tenths. Placenta weight according to pre-eclampsia status is presented as proportions within each tenth. MAIN OUTCOME MEASURES: Pre-eclampsia status. RESULTS: In preterm pre-eclampsia, placentas were over-represented in the two lowest (33.8%; 95% CI 32.1-35.5) and under-represented in the two highest (13.1%; 95% CI 11.9-14.3) tenths of placenta weight compared to pregnancies without pre-eclampsia (20%). In term pre-eclampsia, placentas were over-represented in the two lowest (22.0%; 95% CI 21.2-22.8) and the two highest (22.7%; 95% CI 21.9-23.6) placenta weight groups. Mean placenta weight z-score was higher in term pre-eclampsia compared to pregnancies without pre-eclampsia. CONCLUSIONS: Small placentas were associated with pre-eclampsia, and more strongly with preterm than term pre-eclampsia. In term pre-eclampsia, the association with placenta weight was u-shaped, yielding higher proportions of both low and high placenta weight compared to pregnancies without pre-eclampsia.

Changes in the prevalence of pre-eclampsia in Akershus County and the rest of Norway during the past 35 years.

BACKGROUND: Pre-eclampsia, the etiology of which is unknown, is an important cause of maternal morbidity and mortality. In Norway there has been a substantial change in lifestyle since 1970. Akershus is a growing urban county. The aim of this study was to identify changes in the prevalence of pre-eclampsia in Akershus County and the rest of Norway during the past 35 years. METHODS: The study is population-based and retrospective. Deliveries are registered per inhabitant and pre-eclampsia per delivery. Prevalence and prevalence ratios are calculated with 95% confidence intervals. Poisson regression analysis is used for assessment of trends. RESULTS: The frequency of deliveries declined from 1.9% to 1.4% for Akershus County and from 1.7% to 1.3% in the rest of Norway. The prevalence of pre-eclampsia increased from 3.1% to 3.7% for Akershus County and from 3.3% to 4.5% in the rest of Norway. CONCLUSIONS: The increase in the prevalence of pre-eclampsia and the difference between Akershus and the rest of Norway are not likely to be explained by changes in genetic material. Altered registration routines throughout Norway since 1998 may influence the observations, and better registration routines may contribute to the observed lower prevalence in Akershus. Changes in lifestyle factors most likely explain the overall increase in the prevalence of pre-eclampsia.