External validation of a prediction model on vaginal birth after caesarean in a The Netherlands: a prospective cohort study.

Objectives: Discussing the individual probability of a successful vaginal birth after caesarean (VBAC) can support decision making. The aim of this study is to externally validate a prediction model for the probability of a VBAC in a Dutch population.

Methods: In this prospective cohort study in 12 Dutch hospitals, 586 women intending VBAC were included.

External validation and clinical utility of prognostic prediction models for gestational diabetes mellitus: A prospective cohort study.

Introduction: We performed an independent validation study of all published first trimester prediction models, containing non-invasive predictors, for the risk of gestational diabetes mellitus. Furthermore, the clinical potential of the best performing models was evaluated.

Material And Methods: Systemically selected prediction models from the literature were validated in a Dutch prospective cohort using data from Expect Study I and PRIDE Study.

External Validation and Clinical Usefulness of First Trimester Prediction Models for the Risk of Preeclampsia: A Prospective Cohort Study.

Introduction: This study assessed the external validity of all published first trimester prediction models for the risk of preeclampsia (PE) based on routinely collected maternal predictors. Moreover, the potential utility of the best-performing models in clinical practice was evaluated.

Material And Methods: Ten prediction models were systematically selected from the literature.

Prediction models for the risk of spontaneous preterm birth based on maternal characteristics: a systematic review and independent external validation.

Introduction: Prediction models may contribute to personalized risk-based management of women at high risk of spontaneous preterm delivery. Although prediction models are published frequently, often with promising results, external validation generally is lacking. We performed a systematic review of prediction models for the risk of spontaneous preterm birth based on routine clinical parameters.

Homeostatic model assessment of beta cell function predicting abnormal oral glucose tolerance testing in pregnancy: a systematic review and meta-analysis.

Background: Gestational diabetes mellitus (GDM) complicates 1-14% of pregnancies and relates to increased risk of adverse obstetric outcomes. Currently GDM is diagnosed using an oral glucose tolerance test (OGTT), which is burdensome and time intensive.

Objective: To compare current literature on whether the homeostatic model assessment beta cell function (HOMA-β) is an accurate predictor of an abnormal OGTT in pregnant women.

Practice variation of vaginal birth after cesarean and the influence of risk factors at patient level: a retrospective cohort study.

Introduction: Large practice variation exists in mode of delivery after cesarean section, suggesting variation in implementation of contemporary guidelines. We aim to evaluate this practice variation and to what extent this can be explained by risk factors at patient level.

Material And Methods: This retrospective cohort study was performed among 17 Dutch hospitals in 2010.

Prediction of postpartum hemorrhage in women with gestational hypertension or mild preeclampsia at term.

Objective: To assess whether postpartum hemorrhage can be predicted in women with gestational hypertension or mild preeclampsia at term.

Design: A cohort study in which we used data from our multicentre randomized controlled trial (HYPITAT trial).

Setting: The study was conducted in 38 hospitals in the Netherlands between 2005 and 2008.

SIMPLE: implementation of recommendations from international evidence-based guidelines on caesarean sections in the Netherlands. Protocol for a controlled before and after study.

Background: Caesarean section (CS) rates are rising worldwide. In the Netherlands, the most significant rise is observed in healthy women with a singleton in vertex position between 37 and 42 weeks gestation, whereas it is doubtful whether an improved outcome for the mother or her child was obtained. It can be hypothesized that evidence-based guidelines on CS are not implemented sufficiently.

Is it useful to measure C-reactive protein and leukocytes in patients with prelabor rupture of membranes?

Neonatal infection is the main complication of prelabor rupture of membranes (PROM). We studied the accuracy of measuring C-reactive protein (CRP) and leukocytes in maternal serum to predict neonatal infection. We performed a retrospective cohort study in two hospitals in the Netherlands between 2003 and 2006.

Blunted autonomic response to volume expansion in formerly preeclamptic women with low plasma volume.

Objective: We hypothesize that low plasma volume in normotensive formerly preeclamptic women reflects reduced venous storage capacity. To test this hypothesis, we compared circulatory and autonomic responses to acute volume loading between women with low and those with normal plasma volume.

Methods: In 24 normotensive formerly preeclamptic women at least 6 months postpartum, we administered 500 mL of iso-oncotic fluid by constant intravenous infusion in 30 minutes, while recording changes in heart rate, blood pressure, cardiac output, and measuring active plasma renin and alpha-atrial natriuretic peptide concentrations.

Imperforate hymen: a cause of abdominal pain in female adolescents.

A 16-year-old girl presented with primary amenorrhea and had had cyclical abdominal pain for almost a year. At examination we observed a painful mass in the lower abdomen and normal secondary sex characteristics. Perineal examination showed a bluish bulging hymen.

Endothelium-dependent vasodilatation in formerly preeclamptic women correlates inversely with body mass index and varies independently of plasma volume.

Endothelial dysfunction and a subnormal plasma volume predispose to preeclampsia. The authors determine whether endothelium-dependent vasodilatation is lower in formerly preeclamptic women, explore whether endothelial dysfunction coincides with low plasma volume, and determine if endothelial dysfunction correlates with circulating endothelial stressors. In formerly preeclamptic women and controls, the authors estimated changes in forearm blood flow after arterial occlusion.

A low plasma volume in formerly preeclamptic women predisposes to the recurrence of hypertensive complications in the next pregnancy.

Background: Formerly preeclamptic women with a subnormal plasma volume (PV) have an increased risk to develop a hypertensive disorder in a subsequent pregnancy as compared to women with normal PV. In the current study we tested the hypothesis that formerly preeclamptic women who develop recurrent disease in their next pregnancy differ from their counterparts with an uneventful next pregnancy by a lower pre-pregnant PV, a lower venous capacitance, smaller rises in these indices in early pregnancy, a lower renal adaptive response, and a lower response to mild exercise.

Patients And Methods: We enrolled 33 formerly preeclamptic women in this study.

Low plasma volume coincides with sympathetic hyperactivity and reduced baroreflex sensitivity in formerly preeclamptic patients.

Background: Preeclampsia is associated with enhanced sympathetic activity as well as subnormal plasma volume. Meanwhile, in over 50% of these complicated pregnancies, the subnormal plasma volume has been found to persist for a prolonged period after pregnancy. The objective of this study is to test the hypothesis that in normotensive formerly-preeclamptic women, persistence of a subnormal plasma volume coincides with enhanced sympathetic activity and with it, an altered autonomic control of blood pressure.

Vascular expression of adrenomedullin is increased in Wistar rats during early pregnancy.

Objective: Circulating levels of adrenomedullin (ADM)--a vasodilator peptide with long-lasting effects--increase in the course of pregnancy. Neither the site nor the concomitant rate of ADM synthesis in pregnancy is known. The aim of this study was to test the hypothesis that the rise in plasma levels of ADM during pregnancy is paralleled by increased gene expression and protein levels in the vascular bed.

Formerly preeclamptic women with a subnormal plasma volume are unable to maintain a rise in stroke volume during moderate exercise.

Introduction: In formerly preeclamptic women with a low plasma volume, the recurrence rate of preeclampsia is higher than in women with a normal prepregnant plasma volume. In a recent study, we demonstrated that the low plasma volume subgroup also had a subnormal venous capacitance. In the present study, we determined the impact of subnormal plasma volume on the hemodynamic response to moderate exercise.

Maternal nonpregnant vascular function correlates with subsequent fetal growth.

Objective: Evidence is accumulating that fetal growth is influenced by preexisting maternal disorder(s) hampering endothelial function. We tested the hypothesis that in nonpregnant normotensive, formerly preeclamptic women, vascular function predicts the development of fetal growth restriction.

Methods: In 60 formerly preeclamptic women, we measured central hemodynamic and vascular and clotting function mid follicular phase during the menstrual cycle.

Pre-pregnant prediction of recurrent preeclampsia in normotensive thrombophilic formerly preeclamptic women receiving prophylactic antithrombotic medication.

Background: Both hemodynamic abnormalities and thrombophilia predispose to pregnancy-associated vascular complications such as fetal growth restriction, stillbirth, preeclampsia, and placental abruption. Antithrombotic treatment may reduce the risk for these events. In this study we tested the hypothesis that in normotensive thrombophilic formerly preeclamptic women certain alterations in hemodynamic function as measured under nonpregnant conditions predict the development of hypertensive disorders and/or fetal growth restriction in the subsequent pregnancy.

A subnormal plasma volume in formerly preeclamptic women is associated with a low venous capacitance.

Objective: Pregnancy induces a smaller rise in plasma volume in formerly preeclamptic women with a pre-existent subnormal plasma volume than in their counterparts with a normal plasma volume. These women also have a three times higher recurrence rate of pregnancy-induced hypertensive disorders. In this study we tested the hypothesis that a subnormal plasma volume in these women is related to a lower capacitance of their venous compartment.

Low plasma volume following pregnancy complicated by pre-eclampsia predisposes for hypertensive disease in a next pregnancy.

Objective: A large number of women with a history of pre-eclampsia/HELLP have a low plasma volume at least six months postpartum. The objective of this study was to determine whether a low plasma volume in formerly pre-eclamptic women and HELLP patients is associated with an increased risk for recurrent hypertensive complications in a next pregnancy.

Design: Prospective observational study.

Hemodynamic changes in pseudopregnancy in chronically instrumented, conscious rats are preserved after hysterectomy.

Hemodynamic changes in early-pregnant and pseudopregnant rats are comparable, indicating that the trophoblast does not contribute to these changes. It is unclear whether the presence of the uterus is needed for the normal early-pregnancy hemodynamic adaptation. In this study we tested the hypothesis that uterine factors do not contribute to the systemic hemodynamic changes in early pseudopregnancy.