Prevention of Preeclampsia and Intrauterine Growth Restriction With Aspirin Started in Early Pregnancy: A Meta-Analysis

Stroke and pregnancy: clinical presentation, evaluation, treatment, and epidemiology

Stroke is a neurological emergency that carries a risk of morbidity and mortality. Recent studies have shown that the incidence of stroke, although rare, is increasing in pregnant females. In this review, stroke and other vasculopathies in the pregnant and postpartum female are examined. A discussion of the symptoms and clinical presentation of stroke is provided and the current guideline for treatment of stroke in pregnancy. Finally, the data illustrating the recent increases in stroke incidence are outlined.

Maternal characteristics, mean arterial pressure and serum markers in early prediction of preeclampsia

OBJECTIVES

In a previous study, we have described the predictive value of first-trimester Pregnancy-Associated Plasma Protein-A (PAPP-A), free β-subunit of human Chorionic Gonadotropin (fβ-hCG), Placental Growth Factor (PlGF) and A Disintegrin And Metalloprotease 12 (ADAM12) for early onset preeclampsia (EO-PE; delivery <34 weeks). The objective of the current study was to obtain the predictive value of these serum makers combined with maternal characteristics and first-trimester maternal mean arterial blood pressure (MAP) in a large series of patients, for both EO-PE and late onset PE (LO-PE; delivery ≥ 34 weeks).

METHODS

This was a nested case-control study, using stored first-trimester maternal serum from women who developed EO-PE (n = 68) or LO-PE (n = 99), and 500 uncomplicated singleton pregnancies. Maternal characteristics, MAP, and pregnancy outcome were collected for each individual woman and used to calculate prior risks for PE in a multiple logistic regression model. Models containing prior PE risks, serum markers, and MAP were developed for the prediction of EO-PE and LO-PE. The model-predicted detection rates (DR) for fixed 10% false-positive rates were calculated for EO-PE and LO-PE with or without the presence of a small-for-gestational age infant (SGA, birth weight <10(th) centile).

RESULTS

The best prediction model included maternal characteristics, MAP, PAPP-A, ADAM12, and PlGF, with DR of 72% for EO-PE and 49% for LO-PE. Prediction for PE with concomitant SGA was better than for PE alone (92% for EO-PE and 57% for LO-PE).

CONCLUSION

First-trimester MAP, PAPP-A, ADAM12, and PlGF combined with maternal characteristics and MAP are promising markers in the risk assessment of PE, especially for EO-PE complicated by SGA.

Fetoplacental oxygenation in an intrauterine growth restriction rat model by using blood oxygen level-dependent MR imaging at 4.7 T

PURPOSE

To investigate blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging in an intrauterine growth restriction (IUGR) rat model as a noninvasive in vivo tool to evaluate the response of the fetoplacental units (FPUs) to oxygenation

MATERIALS AND METHODS

All procedures were approved by the animal care committee. The study was performed between February and July 2010. The IUGR model based on the ligation of the left uterine vascular pedicle at embryonic day 17 of gestation was validated by weighing placentas and fetuses after MR imaging. FPUs in the left and right uterine horns were IUGR cases and controls, respectively. A small-animal 4.7-T MR imager was used. Multiple gradient-echo sequence (repetition time msec/echo time msec, 800/1.8-49.8) was performed at embryonic day 19. T2* relaxation time was measured before and after maternal hyperoxygenation for live FPUs in placenta, fetal liver, and brain. The effect of hyperoxygenation on BOLD MR imaging was analyzed with change in T2* between hyperoxygenation and ambient air. After dissection, live fetuses from both horns were identified and weighed. Changes in T2* were compared based on Student t tests. A mixed model was used to compare BOLD effect among horns and organs.

RESULTS

Sixteen rats were studied. There was a significant fetal weight decrease in the IUGR FPUs (-21.9%; P < .001). Change in T2* differed significantly between IUGR cases and controls for placenta (5.25 msec vs 11.25 msec; P < .001) and fetal brain (3.7 msec vs 7.17 msec; P = .02), whereas there was no significant difference in the fetal liver (2.72 msec vs 3.18 msec; P = .47).

CONCLUSION

BOLD MR imaging at 4.7 T can be used to evaluate the response to oxygenation in normal and IUGR FPUs. This technique has a potential role in the assessment of human pregnancy.

Four cases of fetal intra-abdominal umbilical vein varix: a single centre's approach to management

Fetal intra-abdominal umbilical vein (FIUV) varix is a rare prenatal abnormality characterised by a focal intrahepatic or extrahepatic dilatation of the intra-abdominal portion of the umbilical vein. Usually, it is an isolated finding, but in some cases it can be associated to other fetal anomalies. Thrombosis is a possible complication of FIUV varix and it can lead to poor fetal or neonatal outcome. We describe four consecutive cases of FIUV varix diagnosed in our Unit and managed with low-dose aspirin (LDA) prophylaxis until the 35th week of gestation. None of the fetuses developed thrombosis of the varix and the neonatal outcomes were good in all the cases.

Risk factors of superimposed preeclampsia in women with essential chronic hypertension treated before pregnancy

Objective

To determine risk factors of superimposed preeclampsia in women with essential chronic hypertension receiving antihypertensive therapy prior to conception.

Methods

A retrospective study of 211 patients that analyzed risk factors of superimposed preeclampsia at first prenatal visit. Variables with a p<.1 at univariate analysis were included in a logistic regression analysis. P<.05 was considered as significant.

Results

Superimposed preeclampsia occurred in 49 (23.2%) women. In logistic regression analysis, previous preeclampsia [OR: 4.05 (1.61–10.16)], and mean arterial blood pressure of 95 mmHg or higher [OR: 4.60 (1.94–10.93)] were associated with increased risk of superimposed preeclampsia. When both variables were present, sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio for superimposed preeclampsia were 43%, 94%, 70%, 85%, and 7.71 (95% CI: 3.20–18.57), respectively.

Conclusion

In essential chronic hypertensive women, previous preeclampsia and mean arterial blood pressure of 95 mmHg or higher are associated with increased risks of superimposed preeclampsia.

Prevention of perinatal death and adverse perinatal outcome using low-dose aspirin: a meta-analysis

OBJECTIVE

To compare early vs late administration of low-dose aspirin on the risk of perinatal death and adverse perinatal outcome.

METHODS

Databases were searched for keywords related to aspirin and pregnancy. Only randomized controlled trials that evaluated the prophylactic use of low-dose aspirin (50-150 mg/day) during pregnancy were included. The primary outcome combined fetal and neonatal death. Pooled relative risks (RR) with their 95% CIs were compared according to gestational age at initiation of low-dose aspirin (≤ 16 vs > 16 weeks of gestation).

RESULTS

Out of 8377 citations, 42 studies (27 222 women) were included. Inclusion criteria were risk factors for pre-eclampsia, including: nulliparity, multiple pregnancy, chronic hypertension, cardiovascular or endocrine disease, prior gestational hypertension or fetal growth restriction, and/or abnormal uterine artery Doppler. When compared with controls, low-dose aspirin started at ≤ 16 weeks' gestation compared with low-dose aspirin started at >16 weeks' gestation was associated with a greater reduction of perinatal death (RR = 0.41 (95% CI, 0.19-0.92) vs 0.93 (95% CI, 0.73-1.19), P = 0.02), pre-eclampsia (RR = 0.47 (95% CI, 0.36-0.62) vs 0.78 (95% CI, 0.61-0.99), P < 0.01), severe pre-eclampsia (RR = 0.18 (95% CI, 0.08-0.41) vs 0.65 (95% CI, 0.40-1.07), P < 0.01), fetal growth restriction (RR = 0.46 (95% CI, 0.33-0.64) vs 0.98 (95% CI, 0.88-1.08), P < 0.001) and preterm birth (RR = 0.35 (95% CI, 0.22-0.57) vs 0.90 (95% CI, 0.83-0.97), P < 0.001).

CONCLUSION

Low-dose aspirin initiated at ≤ 16 weeks of gestation is associated with a greater reduction of perinatal death and other adverse perinatal outcomes than when initiated at >16 weeks.

Nonsteroidal anti-inflammatory drugs during pregnancy and the initiation of lactation

Nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin, which are available as "over-the counter" medications in most countries, are widely used by both pregnant and lactating women. They are popular non-opioid analgesics for the treatment of pain after vaginal and operative delivery. In addition, NSAIDs are used for tocolysis in premature labor, and low-dose aspirin has a role in the prevention of preeclampsia and recurrent miscarriage in antiphospholipid syndrome. NSAIDs and aspirin may affect fertility and increase the risk of early pregnancy loss. In the second trimester their use is considered reasonably safe, but has been associated with fetal cryptorchism. In the third trimester, NSAIDs and aspirin are usually avoided because of significant fetal risks such as renal injury, oligohydramnios, constriction of the ductus arteriosus (with potential for persistent pulmonary hypertension in the newborn), necrotizing enterocolitis, and intracranial hemorrhage. Maternal administration or ingestion of most NSAIDs results in low infant exposure via breastmilk, such that both cyclooxygenase-1 and cyclooxygenase-2 inhibitors are generally considered safe, and preferable to aspirin, when breastfeeding.

Maternal plasma concentrations of angiogenic/antiangiogenic factors in the third trimester of pregnancy to identify the patient at risk for stillbirth at or near term and severe late preeclampsia

OBJECTIVE

To determine whether maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) at 30-34 weeks of gestation can identify patients at risk for stillbirth, late preeclampsia, and delivery of small-for-gestational-age (SGA) neonates.

STUDY DESIGN

A prospective cohort study included 1269 singleton pregnant women from whom blood samples were obtained at 30-34 weeks of gestation and who delivered at >34 weeks of gestation. Plasma concentrations of PlGF, sEng, and sVEGFR-1 were determined by enzyme-linked immunosorbent assay.

RESULTS

The prevalence of late (>34 weeks of gestation) preeclampsia, severe late preeclampsia, stillbirth, and SGA was 3.2% (n = 40), 1.8% (n = 23), 0.4% (n = 5), and 8.5% (n = 108), respectively. A plasma concentration of PlGF/sEng <0.3 MoM was associated with severe late preeclampsia (adjusted odds ratio, 16); the addition of PlGF/sEng to clinical risk factors increased the area under the receiver-operating characteristic curve from 0.76 to 0.88 (P = .03). The ratio of PlGF/sEng or PlGF/sVEGFR-1 in the third trimester outperformed those obtained in the first or second trimester and uterine artery Doppler velocimetry at 20-25 weeks of gestation for the prediction of severe late preeclampsia (comparison of areas under the receiver-operating characteristic curve; each P ≤ .02). Both PlGF/sEng and PlGF/sVEGFR-1 ratios achieved a sensitivity of 74% with a fixed false-positive rate of 15% for the identification of severe late preeclampsia. A plasma concentration of PlGF/sVEGFR-1 <0.12 MoM at 30-34 weeks of gestation had a sensitivity of 80%, a specificity of 94%, and a likelihood ratio of a positive test of 14 for the identification of subsequent stillbirth. Similar findings (sensitivity 80%; specificity 93%) were observed in a separate case-control study.

CONCLUSION

Risk assessment for stillbirth and severe late preeclampsia in the third trimester is possible with the determination of maternal plasma concentrations of angiogenic and antiangiogenic factors at 30-34 weeks of gestation.

Placental protein 13 (PP13): a new biological target shifting individualized risk assessment to personalized drug design combating pre-eclampsia

BACKGROUND

Pre-eclampsia affects 2-7% of all pregnant women and is a major cause of maternal and fetal morbidity and mortality. The etiology of pre-eclampsia is still unknown but it is well documented that impaired placentation is a major contributor to its development. One of the placenta-specific proteins is placental protein 13 (PP13). Lower first trimester levels of maternal serum PP13 and its encoding placental mRNA are associated with the development of both early and late-onset severe pre-eclampsia. In cases where this protein is mutated, the frequency of pre-eclampsia is higher.

METHODS

19 out of 68 studies on PP13, published between January 2006 and September 2012, were used to evaluate the value of maternal blood PP13 as a marker of pre-eclampsia.

RESULTS

A meta-analysis presented in this review shows that low serum levels of PP13 in the first trimester of pregnancy can predict the development of pre-eclampsia later in pregnancy. Although some functions of this protein have been assessed in in vitro experiments, the in vivo functions of PP13 are still unknown, especially when circulating in the maternal bloodstream. A recent pilot study has shown that in gravid rats PP13 causes significant vasodilatation, reduced blood pressure and increased maternal uterine artery remodeling.

CONCLUSION

Reviewing these effects of PP13, the authors propose the use of PP13 as a new drug candidate. Replenishing PP13 in those women with low serum levels early in pregnancy may help prepare their vasculature for pregnancy. This novel pharmacological approach to combat pre-eclampsia is presented as a new direction to transfer from individualized risk to personalized prevention.

Preeclampsia-like symptoms induced in mice by fetoplacental expression of STOX1 are reversed by aspirin treatment

Preeclampsia (PE) is a common human-specific pregnancy disorder defined by hypertension and proteinuria during gestation and responsible for maternal and fetal morbimortality. STOX1, encoding a transcription factor, was the first gene associated with PE as identified by positional cloning approaches. Its overexpression in choriocarcinoma cells mimics the transcriptional consequences of PE in the human placenta. Here, we created transgenic mouse strains overexpressing human STOX1. Wild-type female mice crossed with transgenic male mice reproduce accurately the symptoms of severe PE: gestational hypertension, proteinuria, and elevated plasma levels of soluble fms-like tyrosine kinase 1 and soluble endoglin. Placental and kidney histology were altered. Symptoms were prevented or alleviated by aspirin treatment. STOX1-overexpressing mice constitute a unique model for studying PE, allow testing therapeutic approaches, and assessing the long-term effects of the preeclamptic syndrome.

The Role of Ultrasound in the Diagnosis of Complications Associated with Maternal Diabetes

Gestational diabetes mellitus (GDM) is defined as glucose intolerance that begins or is first recognized during pregnancy. Numerous clinical factors are associated with an increased likelihood of GDM, such as increasing age, obesity, ethnicity, family history of diabetes and past obstetric history. There is a well-documented relationship between maternal hyperglycemia and increased rate of macrosomia, cesarean section, stillbirth, fetal congenital malformations, shoulder dystocia, hypoglycemia, hyperbilirubinemia, pre-eclampsia, preterm delivery, childhood obesity, and increased risk of maternal development of type 2 DM later on in her life. This case-based review is designed to provide health care workers a framework on using various ultrasound imaging modalities in early detection of the effects of gestational diabetes, and the specific conditions and/or anomalies seen in diabetic pregnancies.

How to cite this article

Appleton K, Barnard J, Jantz AK, Pooh R, Comas-Gabriel C, Kupesic-Plavsic S. The Role of Ultrasound in the Diagnosis of Complications Associated with Maternal Diabetes. Donald School J Ultrasound Obstet Gynecol 2013;7(4):506-515.

[Hypertension in pregnancy: the current state of the art]

Hypertension complicates 6-8% of pregnancies and includes the following four conditions: hypertension preceding pregnancy or documented before the 20th week of gestation; pre-eclampsia (PE)/eclampsia; chronic hypertension with superimposed pre-eclampsia; and gestational hypertension. The latter is defined as a significant rise in blood pressure after the 20th week of pregnancy in previously normotensive women, to over 140/90 mmHg. When blood pressure remains above 160/110 mmHg, it is considered severe. PE is defined as the presence of proteinuria (> or = 300 mg/24 h) in pregnant women with hypertension. The hypertensive syndromes of pregnancy are among the leading causes of maternal and fetal morbidity and mortality and anti-hypertensive treatment is part of the therapeutic arsenal used to prevent serious complications. Although the role of utero-placental insufficiency due to deficient migration of trophoblasts to the spiral arteries is universally accepted, the pathophysiology of PE remains largely unknown and is the subject of debate. No effective ways of predicting or preventing PE have been found, which highlights the need for further research in this field. This review aims primarily to evaluate recent advances in our understanding of the pathophysiology of gestational hypertension and especially PE, and new ways of predicting PE. Additionally, we present a brief review on the diagnosis, prevention and treatment of PE.

Preeclampsia - Aetiology, Current Diagnostics and Clinical Management, New Therapy Options and Future Perspectives

Preeclampsia is a multisystem disease for which the exact causes have not yet been sufficiently clarified. However, in the past few years it has become clear that a placental imbalance between angiogenic and anti-angiogenic proteins is the decisive pathogenetic factor for the occurrence of preeclampsia. With the possibility to measure these angiogenic factors (sFlt-1/PlGF ratio) in maternal blood full new diagnostic possibilities have been opened that enable the certain diagnosis or exclusion of the diseases as well as a short-term prognosis to be made. In secondary prevention the current data situation for ASA confirms a moderate but measurable utility. The management concept depends on gestational age. In the case of early clinical manifestations (< 34th week of pregnancy) the clinical management in a perinatal centre remains unchanged with foeto-maternal monitoring and induction of pulmonary maturation, symptomatic therapy under careful blood pressure lowering and determination of the optimal delivery time. A balance must be made here between foetal immaturity and maternal risks upon prolongations. The pathomechanism of anti-angiogenic overload with sFlt-1 provides a starting point for first therapeutic interventions. The present article gives an overview of current diagnostic options and presents possible future therapeutic perspectives for discussion.

Prevention of preeclampsia

Preeclampsia (PE) affects around 2-5% of pregnant women. It is a major cause of maternal and perinatal morbidity and mortality. In an attempt to prevent preeclampsia, many strategies based on antenatal care, change in lifestyle, nutritional supplementation, and drugs have been studied. The aim of this paper is to review recent evidence about primary and secondary prevention of preeclampsia.

Maternal risk factors for low birth weight for term births in a developed region in China: a hospital-based study of 55,633 pregnancies

Low birth weight (LBW) is an important risk factor for neonatal and infant mortality and morbidity in adults.. However, no large scale study on the prevalence of LBW and related maternal risk factors in China has been published. To explore the effects of maternal factors on LBW for term birth in China, we conducted a hospital-based retrospective study of 55, 633 Chinese pregnancy cases between 2001 and 2008. Maternal sociodemographic data, history of infertility and contraceptive use were obtained. Their medical status and diseases during pre-pregnancy were examined by physical examination at the first antenatal care visit. Maternal medical status before childbirth and pregnancy outcomes, including body weight, infant gender, multiple pregnancy and congenital anomalies, were recorded. Univariate and multivariate logistic regression, and linear regression were used to investigate the relationship between maternal factors and term LBW. The general incidence of term LBW was 1.70% in the developed area of China. After preliminary analysis using the univariate model, low primary education, anemia, hypertensive disorders, placental previa, oligohydramnios and premature rupture of membrane were predicted as independent factors of term LBW in the multivariate model. Furthermore, the decrease in annual frquencies of these risk factors were major causes of gradual decline in the incidence of LBW (from 2.43% in 2001 to 1.21% in 2008). The study demonstrated that among maternal factors, primary education, anemia and hypertensive disorders could contribute to LBW for term birth even in the most developed area of China.

First trimester serum markers to predict preeclampsia

A variety of different biomarkers to predict preeclampsia have been identified in the last ten years. Most of these markers have been detected and quantified in maternal blood, and their potency to predict preeclampsia prior to the onset of clinical symptoms has been evaluated. The amount of such markers depends on various conditions, including the source of the marker (fetal/placental and/or maternal), the interaction of this marker with other proteins in maternal blood as well as the stability of the markers during freezing and thawing. Here we describe two of the putative early, first trimester biomarkers, placental protein 13 and placental growth factor. There is still the hope that - even in the absence of any treatment regimen today - such predictive markers will help to speed the development of a cure for preeclampsia.

Maternal serum soluble endoglin at 30-33 weeks in the prediction of preeclampsia

OBJECTIVE

To investigate the potential value of maternal serum concentration of soluble endoglin (sEng) at 30-33 weeks' gestation in the prediction of preeclampsia (PE) developing at or after 34 weeks.

METHODS

Serum sEng was measured at 11-13 and at 30-33 weeks' gestation in a case-control study of 50 cases that developed PE at or after 34 weeks and 250 unaffected controls. Regression analysis was used to determine which of the factors amongst the maternal characteristics were significant predictors of first- and third-trimester log10 sEng in the control group. The measured values of sEng were converted into multiples of the unaffected median (MoM) and the MoM values in the PE and controls were compared.

RESULTS

The median sEng MoM at 30-33 weeks was significantly higher in the PE group (1.39, IQR 0.94-2.18) than in the controls (0.95, IQR 0.77-1.19), but at 11-13 weeks there was no significant difference between the groups. In screening by a combination of maternal characteristics and third-trimester sEng, the detection rates of intermediate- and late-PE, at a false-positive rate of 10%, were 64.3 and 50.0%, respectively.

CONCLUSION

Screening by maternal characteristics and sEng at 30-33 weeks could identify most pregnancies that will subsequently develop PE.

Assessment of Foetal DNA in Maternal Blood - A Useful Tool in the Hands of Prenatal Specialists

Over the last few years, first trimester screening between 11+ and 13+ weeks of gestation has become one of the most important ultrasound examinations in pregnancy, as it allows physicians to predict several pregnancy complications including pre-eclampsia or pre-term birth. Screening for trisomies 21/18 and 13 using maternal and gestational age, foetal nuchal translucency, and maternal serum biochemistry was formerly the main reason for first trimester screening. However, today this is only one part of the overall examination. In the near future, the analysis of foetal DNA obtained from maternal blood will be used to supplement first trimester screening for aneuploidy or even replace current screening methods. In this review we show how prenatal medicine specialists can use foetal DNA analysis.

Combined screening for preeclampsia and small for gestational age at 11-13 weeks

OBJECTIVE

To combine a specific algorithm for small for gestational age (SGA) without preeclampsia (PE) and another algorithm for PE in the prediction of SGA and PE.

METHODS

This was a screening study of singleton pregnancies at 11-13 weeks including 1,426 (2.3%) that subsequently developed PE, 3,168 (5.1%) that delivered SGA neonates and 57,458 that were unaffected by PE and SGA. We developed a prediction algorithm for SGA requiring delivery before 37 weeks' gestation (preterm-SGA) from maternal characteristics, uterine artery pulsatility index, mean arterial pressure, serum pregnancy-associated plasma protein-A and placental growth factor multiple of the median values. We then examined the performance of this algorithm individually and in combination with a previously reported algorithm for early-PE in the prediction of SGA and PE.

RESULTS

When screen positivity was defined by risk cutoff of 1:200 using the algorithm for early-PE and the risk cutoff of 1:150 using the algorithm for preterm-SGA, the false positive rate was 10.9% and the detection rates of early-PE, late-PE, preterm-SGA and term-SGA were 95.3, 45.6, 55.5 and 44.3%, respectively.

CONCLUSIONS

Effective first-trimester screening for early-PE and preterm-SGA can be provided by the combined use of the specific algorithms.

Comparison of two different sites of measurement for transabdominal uterine artery Doppler velocimetry at 11-13 weeks

OBJECTIVES

To compare the feasibility of two transabdominal approaches for performing first-trimester uterine artery (UtA) Doppler and to evaluate the correlation with pulsatility index (PI) in the second trimester.

METHODS

This was a prospective longitudinal Doppler study of the uterine arteries at 11-13 and 21-22 weeks' gestation. Transabdominal ultrasound and color Doppler were used to measure the UtA-PI of the ascending branch of the uterine artery at the level of the internal cervical os (Site A) and at the level of the apparent crossover with the external iliac artery (Site B) at 11-13 weeks, and at Site B only at 21-22 weeks. In all cases the measured left and right PI were converted to a multiple of the median (MoM) for gestational age, and the intercorrelation between the measurements at different sites and gestational ages was calculated using non-parametric analysis (Spearman's rank correlation).

RESULTS

Satisfactory measurements were obtained at 11-13 weeks from both uterine arteries in all 81 women at Site A and in 50 (62%; 95% CI, 50-72%) at Site B (P < 0.01). Measurements were obtained at Site B at 21-22 weeks in all cases. In the 50 cases with measurements from both sites at 11-13 weeks, the correlation of PI-MoMs between Sites A and B at 11-13 weeks was only moderate (ρ = 0.61). The correlation between first-trimester UtA-PI MoMs at Site A and second-trimester UtA-PI MoMs was stronger than that between first-trimester UtA-PI MoMs at Site B and second-trimester UtA-PI MoMs (ρ = 0.73 vs ρ = 0.47, P < 0.01).

CONCLUSION

Evaluation of UtA-PI at 11-13 weeks can be achieved at the level of the internal cervical os in a greater proportion of women than at the level of the apparent crossover with the external iliac vessels, and the measurements obtained correlate better with second-trimester UtA-PI.

ASPIRIN ADMINISTRATION FOR PREVENTION OF ADVERSE PREGNANCY OUTCOMES

The prophylactic use of low-dose aspirin for prevention of preeclampsia has been an important research question in obstetrics for the last three decades. In 1979, Crandon and Isherwood observed that nulliparous women who had taken aspirin regularly during pregnancy were less likely to have preeclampsia than women who did not. In 1985, Beaufils et al published the first randomized trial suggesting that 150 mg aspirin and 300 mg dipyridamole daily from 3 months’ gestation onwards decreased the risk of preeclampsia, fetal growth restriction and stillbirth in high-risk women. Subsequently, more than 50 trials have been carried out throughout the world and a meta-analysis of these studies reported that the administration of low-dose aspirin in high-risk pregnancies is associated with a decrease in the rate of preeclampsia by approximately 10%. Consequently, several national professional bodies recommend that high-risk pregnancies should be treated with aspirin (50–150 mg daily).

Competing risks model in early screening for preeclampsia by biophysical and biochemical markers

OBJECTIVE

To develop models for prediction of preeclampsia (PE) based on maternal characteristics, biophysical and biochemical markers at 11-13 weeks' gestation in which the gestation at the time of delivery for PE is treated as a continuous variable.

METHODS

This was a screening study of singleton pregnancies at 11-13 weeks including 1,426 (2.4%) that subsequently developed PE and 57,458 that were unaffected by PE. We developed a survival time model for the time of delivery for PE in which Bayes' theorem was used to combine the prior information from maternal characteristics with uterine artery pulsatility index (PI), mean arterial pressure (MAP), serum pregnancy-associated plasma protein-A (PAPP-A) and placental growth factor (PLGF) multiple of the median (MoM) values.

RESULTS

In pregnancies with PE, there was a linear correlation between MoM values of uterine artery PI, MAP, PAPP-A and PLGF with gestational age at delivery and therefore the deviation from normal was greater for early than late PE for all four biomarkers. Screening by maternal characteristics, biophysical and biochemical markers detected 96% of cases of PE requiring delivery before 34 weeks and 54% of all cases of PE at a fixed false-positive rate of 10%.

CONCLUSIONS

A new model has been developed for effective first-trimester screening for PE.

Beyond the placental bed: placental and systemic determinants of the uterine artery Doppler waveform

The uterine artery Doppler waveform has been extensively investigated, though its widespread clinical use as a predictor of adverse pregnancy outcome remains under debate. The determinants of the waveform have classically been ascribed to transformation of the spiral arteries and the development of a low resistance uteroplacental circulation, failure of which predisposes to pre-eclampsia, fetal growth restriction and other adverse outcomes. It has become increasingly evident that although spiral artery transformation determines in some part the characteristics of the Doppler waveform, factors pertaining to maternal vascular and endothelial function are also important.

A competing risks model in early screening for preeclampsia

OBJECTIVE

It was the aim of this study to develop models for the prediction of preeclampsia (PE) based on maternal characteristics and biophysical markers at 11-13 weeks' gestation in which gestation at the time of delivery for PE is treated as a continuous variable.

METHODS

This was a screening study of singleton pregnancies at 11-13 weeks including 1,426 (2.4%) cases that subsequently developed PE and 57,458 cases that were unaffected by PE. We developed a survival time model for the time of delivery for PE in which Bayes' theorem was used to combine the prior information from maternal characteristics with the uterine artery pulsatility index (PI) and the mean arterial pressure (MAP), using multiple of the median values.

RESULTS

The risk for PE increased with maternal age, weight, Afro-Caribbean and South Asian racial origin, previous pregnancy with PE, conception by in vitro fertilization and a medical history of chronic hypertension, type 2 diabetes mellitus as well as systemic lupus erythematosus or antiphospholipid syndrome. In pregnancies with PE, there was an inverse correlation between multiple of the median values of the uterine artery PI and MAP with gestational age at delivery. Screening by maternal characteristics, uterine artery PI and MAP detected 90% of PE cases requiring delivery before 34 weeks and 57% of all PE cases at a fixed false-positive rate of 10%.

CONCLUSIONS

A new model has been developed for effective first-trimester screening for PE.

Birthweight with gestation and maternal characteristics in live births and stillbirths

OBJECTIVE

To establish a normal range of birthweight with gestational age (GA) at delivery and examine the contribution of maternal characteristics in defining growth restriction in stillbirths.

METHODS

In 69,895 normal singleton pregnancies, regression analysis was used to determine the association of birthweight with GA and maternal characteristics. The proportion of 290 stillbirths classified as small for GA depending on inclusion or exclusion of maternal characteristics was determined.

RESULTS

In normal pregnancies, there was a polynomial association between birthweight and GA. Birthweight increased with maternal weight, height and parity and was lower in Africans and South Asians than in Caucasians. Birthweight for GA was reduced in antepartum stillbirths (n = 243; p < 0.0001) but not in intrapartum stillbirths (n = 47; p = 0.334). There was no significant difference in the proportion of antepartum stillbirths with birthweight below the 10th percentile when birthweight was corrected for GA only compared to correction for GA and maternal characteristics (53.1 vs. 54.3%). The birthweight was below the 10th percentile in 71.8% of antepartum stillbirths at <32 weeks' gestation, in 47.2% at 33-36 weeks and in 31.5% at ≥37 weeks.

CONCLUSION

Correction of birthweight for maternal characteristics does not alter the proportion of stillbirths that are small for GA.

Maternal hemodynamics at 11-13 weeks' gestation and risk of pre-eclampsia

OBJECTIVE

Women who develop pre-eclampsia are at increased risk of cardiovascular disease and stroke in the subsequent decades. Individuals with cardiovascular disorders have increased central aortic systolic blood pressure (SBP(Ao) ) and arterial stiffness, as assessed by pulse wave velocity (PWV) and augmentation index (AIx). The aim of this study was to examine the potential value of assessment of SBP(Ao) , PWV and AIx at 11-13 weeks' gestation in identifying women who subsequently develop pre-eclampsia.

METHODS

This was a screening study for pre-eclampsia in singleton pregnancies at 11 + 0 to 13 + 6 weeks' gestation. Maternal history and characteristics were recorded and PWV, AIx (adjusted to a heart rate of 75 beats per min (AIx-75)) and SBP(Ao) measured. We compared these parameters in women who developed pre-eclampsia (n = 181) with those in unaffected controls (n = 6766) and examined their performance in screening for pre-eclampsia.

RESULTS

In the pre-eclampsia group, compared to unaffected controls, there was an increase in AIx-75 (1.13 vs. 1.00 multiples of the median (MoM); P < 0.0001), PWV (1.06 vs. 1.00 MoM; P < 0.0001) and SBP(Ao) (1.09 vs. 1.00 MoM; P < 0.0001). In screening for pre-eclampsia by a combination of maternal variables and log(10) AIx-75 MoM, log(10) PWV MoM and log(10) SBP(Ao) MoM, the estimated detection rate was 56.9% at a false-positive rate of 10%.

CONCLUSION

Compared with women who remain normotensive, women who develop pre-eclampsia have higher SBP(Ao) and arterial stiffness, which is apparent from the first trimester of pregnancy.

Molecular mechanisms regulating the vascular prostacyclin pathways and their adaptation during pregnancy and in the newborn

Prostacyclin (PGI(2)) is a member of the prostanoid group of eicosanoids that regulate homeostasis, hemostasis, smooth muscle function and inflammation. Prostanoids are derived from arachidonic acid by the sequential actions of phospholipase A(2), cyclooxygenase (COX), and specific prostaglandin (PG) synthases. There are two major COX enzymes, COX1 and COX2, that differ in structure, tissue distribution, subcellular localization, and function. COX1 is largely constitutively expressed, whereas COX2 is induced at sites of inflammation and vascular injury. PGI(2) is produced by endothelial cells and influences many cardiovascular processes. PGI(2) acts mainly on the prostacyclin (IP) receptor, but because of receptor homology, PGI(2) analogs such as iloprost may act on other prostanoid receptors with variable affinities. PGI(2)/IP interaction stimulates G protein-coupled increase in cAMP and protein kinase A, resulting in decreased [Ca(2+)](i), and could also cause inhibition of Rho kinase, leading to vascular smooth muscle relaxation. In addition, PGI(2) intracrine signaling may target nuclear peroxisome proliferator-activated receptors and regulate gene transcription. PGI(2) counteracts the vasoconstrictor and platelet aggregation effects of thromboxane A(2) (TXA(2)), and both prostanoids create an important balance in cardiovascular homeostasis. The PGI(2)/TXA(2) balance is particularly critical in the regulation of maternal and fetal vascular function during pregnancy and in the newborn. A decrease in PGI(2)/TXA(2) ratio in the maternal, fetal, and neonatal circulation may contribute to preeclampsia, intrauterine growth restriction, and persistent pulmonary hypertension of the newborn (PPHN), respectively. On the other hand, increased PGI(2) activity may contribute to patent ductus arteriosus (PDA) and intraventricular hemorrhage in premature newborns. These observations have raised interest in the use of COX inhibitors and PGI(2) analogs in the management of pregnancy-associated and neonatal vascular disorders. The use of aspirin to decrease TXA(2) synthesis has shown little benefit in preeclampsia, whereas indomethacin and ibuprofen are used effectively to close PDA in the premature newborn. PGI(2) analogs have been used effectively in primary pulmonary hypertension in adults and have shown promise in PPHN. Careful examination of PGI(2) metabolism and the complex interplay with other prostanoids will help design specific modulators of the PGI(2)-dependent pathways for the management of pregnancy-related and neonatal vascular disorders.

Predictive value of sequential models of uterine artery Doppler in pregnancies at high risk for pre-eclampsia

OBJECTIVE

To evaluate the performance of models described previously for the prediction of pre-eclampsia (PE), based on the sequential evaluation of uterine artery resistance at 11-13 weeks and 19-22 weeks, in a high-risk population.

METHODS

This was a prospective study in 135 women with singleton pregnancies and at least one of the following high-risk conditions: PE and/or intrauterine growth restriction in a previous pregnancy, chronic hypertension, pregestational diabetes, renal disease, body mass index > 30 kg/m(2) , autoimmune disease (systemic lupus erythematosus, antiphospholipid syndrome or rheumatoid arthritis) and thrombophilia. Mean uterine artery pulsatility index (mUtA-PI) at 11-13 and at 19-22 weeks' gestation was measured and analyzed according to quantitative and semi-quantitative models, to predict late PE (resulting in delivery ≥ 34 weeks) and early PE (delivery < 34 weeks).

RESULTS

Late PE developed in 21 (15.6%) pregnancies and early PE in six (4.4%). Using mUtA-PI, the detection rates of late and early PE for a false-positive rate of 10% were 14.3% and 33.3%, respectively, at 11-13 weeks, and 19.0% and 66.7%, respectively, at 19-22 weeks. Using a semi-quantitative approach, the group of pregnant women with mUtA-PI ≥ 90(th) percentile at both 11-13 and 19-22 weeks had a greater risk for early PE (odds ratio, 21.4 (95% CI, 2.5-184.7)) compared with the group with mUtA-PI < 90(th) percentile at both periods. Using a quantitative approach, there was relative worsening in the mUtA-PI (multiples of the median) from the first to the second trimester in all cases of early PE.

CONCLUSION

The application of semi-quantitative and especially quantitative models to evaluate sequential changes in uterine artery Doppler findings between the first and second trimesters could be of additional value in assessing high-risk women regarding their true risk of developing early PE.

Preeclampsia complicated by advanced maternal age: a registry-based study on primiparous women in Finland 1997-2008

Background

Preeclampsia is a frequent syndrome and its cause has been linked to multiple factors, making prevention of the syndrome a continuous challenge. One of the suggested risk factors for preeclampsia is advanced maternal age. In the Western countries, maternal age at first delivery has been steadily increasing, yet few studies have examined women of advanced maternal age with preeclampsia. The purpose of this registry-based study was to compare the obstetric outcomes in primiparous and preeclamptic women younger and older than 35 years.

Methods

The registry-based study used data from three Finnish health registries: Finnish Medical Birth Register, Finnish Hospital Discharge Register and Register of Congenital Malformations. The sample contained women under 35 years of age (N = 15,437) compared with those 35 and over (N = 2,387) who were diagnosed with preeclampsia and had their first singleton birth in Finland between 1997 and 2008. In multivariate modeling, the main outcome measures were Preterm delivery (before 34 and 37 weeks), low Apgar score (5 min.), small-for-gestational-age, fetal death, asphyxia, Cesarean delivery, induction, blood transfusion and admission to a Neonatal Intensive Care Unit.

Results

Women of advanced maternal age (AMA) exhibited more preeclampsia (9.4%) than younger women (6.4%). They had more prior terminations (<0.001), were more likely to have a body mass index (BMI) >25 (<0.001), had more in vitro fertilization (IVF) (<0.001) and other fertility treatments (<0.001) and a higher incidence of maternal diabetes (<0.001) and chronic hypertension (<0.001). Multivariate logistic regression indicated that women of AMA had higher rates of: preterm delivery before 37 weeks 19.2% (OR 1.39 CI 1.24 to 1.56) and before 34 weeks 8.7% (OR 1.68 CI 1.43 to 2.00) low Apgar scores at 5 min. 7.1% (OR 1.37 CI 1.00 to 1.88), Small-for-Gestational Age (SGA) 26.5% (OR 1.42 CI 1.28 to 1.57), Asphyxia 12.1% (OR 1.54 CI 1.34 to 1.77), Caesarean delivery 50% (OR 2.02 CI 1.84 to 2.20) and admission to a Neonatal Intensive Care Unit (NICU) 31.6% (OR 1.45 CI 1.32 to 1.60).

Conclusions

Preeclampsia is more common in women with advanced maternal age. Advanced maternal age is an independent risk factor for adverse outcomes in first-time mothers with preeclampsia.