S. M. J. van Kuijk

Vaginal birth after a caesarean section: the development of a Western European population‐based prediction model for deliveries at term

To develop and internally validate a model that predicts the outcome of an intended vaginal birth after caesarean (VBAC) for a Western European population that can be used to personalise counselling for deliveries at term.

Cardiovascular disease risk is only elevated in hypertensive, formerly preeclamptic women

To analyse the predicted 10‐ and 30‐year risk scores for cardiovascular disease (CVD) in patients who experienced preeclampsia (PE) 5–10 years previously compared with healthy parous controls.

Physiological adaptation of maternal plasma volume during pregnancy: a systematic review and meta-analysis

To describe the physiological pattern of gestational plasma volume adjustments in normal singleton pregnancy and compare this with the pattern in pregnancies complicated by pregnancy‐induced hypertension, pre‐eclampsia or fetal growth restriction.OBJECTIVE The aim of this systematic review and meta-analyses was to comprehensively describe the physiological pattern of gestational plasma volume adjustments during human singleton pregnancies and compare this to the pattern of pregnancies complicated by pregnancy-induced hypertension, preeclampsia or fetal growth restriction. METHODS We performed a meta-analysis of the current literature on plasma volume adjustments during physiological and complicated pregnancies. Literature was retrieved from PubMed (NCBI) and Embase (Ovid) databases. Included studies needed to report a reference plasma volume measurement (non-pregnant control group, pre-pregnancy, or post-partum) and plasma volume measurements during a predetermined gestational age. Mean differences between reference and pregnant plasma volume measurements were calculated for predefined intervals of gestational age using random-effects model described by DerSimonian and Laird. RESULTS 30 studies were included for meta-analysis with publication dates ranging from 1934 to 2007. Plasma volume started to increase in the first weeks of pregnancy with the steepest increase during the second trimester. Plasma volume continued to increase in the third trimester with a pooled maximum increase of 1.13 L [1.07; 1.19 L] (45.6% [43.0%; 48.1%]) compared to reference during physiologic pregnancies. The plasma volume expansion in gestational hypertensive and growth restricted complicated pregnancies was 0.80 L [0.59; 1.02 L] (32.3% [23.6%; 41.1%]) in the third trimester and was lower compared to physiologic pregnancies (P<0.0001). CONCLUSIONS During physiological human pregnancy, plasma volume increases on average more than 1 litre as compared to non-pregnant conditions. In pregnancy complicated by pregnancy-induced hypertension, preeclampsia or fetal growth restriction, third trimester plasma volume increase is 13.3% lower.

Predicting successful intended vaginal delivery after previous caesarean section: external validation of two predictive models in a Dutch nationwide registration-based cohort with a high intended vaginal delivery rate

To externally validate two models from the USA (entry‐to‐care [ETC] and close‐to‐delivery [CTD]) that predict successful intended vaginal birth after caesarean (VBAC) for the Dutch population.

Predicting successful vaginal birth after Cesarean section using a model based on Cesarean scar features examined by transvaginal sonography

Several models that estimate the probability of successful vaginal birth after Cesarean section (VBAC) have been published and many achieve reasonable predictive performance in terms of discrimination and calibration1. Naji et al.2 presented an innovative and interesting prediction model by introducing novel predictors derived from sonographic measurement of the Cesarean scar. This model was developed within a cohort of just 131 women with one previous Cesarean section. The final model consists of four variables: maternal age, prior VBAC, residual myometrial thickness (RMT) and change in RMT from the first to the second trimester. It is notable that the presented model has extraordinary results regarding discriminative performance, with an area under the receiver–operating characteristics curve (AUC) of 0.94, close to the theoretical maximum of 1. These positive results can be attributed to the introduction of the Cesarean scar variables, since their addition leads to a remarkable improvement in the AUC from 0.62 to 0.94. However, the introduction of Cesarean scar variables deserves further attention. The association of these variables with the probability of successful trial of VBAC was reported by Naji et al. in an earlier study using the same data3. There is no plausible mechanism that explains why these variables have such an impact on the probability of success. Furthermore, rather than choosing predictors based on observed significant relations to outcome variables in the same dataset, contemporary methodological guidelines for prediction research state that predictors should be chosen based on preselection4, a method that results in higher external validity and less overfitting. Therefore, we would like to emphasize the importance of external validation of these predictors in other data. Additionally, the need for external validation is shown when looking into studies on interand intraobserver validity of the RMT measurements. These studies use cut-off values of 2.4–3.5 mm for evaluating reproducibility and state that overall interobserver differences are ≤ 1 mm for 77.5–88% of observers5,6. However, in the model RMT is entered in millimeters while predicted probability increases per millimeter with a coefficient (beta) of 1.44. Therefore, a variability of 1 mm between measurements compromises the model’s performance. To be more explicit, the 32-year-old patient without a previous VBAC, with an RMT of 2.7 mm and an RMT decrease of 1.5 mm, has a predicted probability of successful trial of VBAC of 36%; however, if 3.7 mm instead of 2.7 mm had been measured for the RMT, the predicted probability would have increased to 71%.

Maternal cardiac adaptation to subsequent pregnancy in formerly pre-eclamptic women according to recurrence of pre-eclampsia.

Left‐ventricular remodeling in women with pre‐eclampsia (PE) is concentric rather than eccentric, and tends to persist postpartum, particularly after early‐onset PE. This study was designed to determine whether prepregnancy cardiac geometry and function along with cardiac adaptation to the subsequent pregnancy in former early‐onset PE patients differs between those who do and those who do not develop recurrent PE later on in their second pregnancy.

Spinal cord stimulation in experimental chronic painful diabetic polyneuropathy: Delayed effect of High-frequency stimulation.

Spinal cord stimulation (SCS) has been shown to provide pain relief in painful diabetic polyneuropathy (PDPN). As the vasculature system plays a great role in the pathophysiology of PDPN, a potential beneficial side‐effect of SCS is peripheral vasodilation, with high frequency (HF) SCS in particular. We hypothesize that HF‐SCS (500 Hz), compared with conventional (CON) or low frequency (LF)‐SCS will result in increased alleviation of mechanical hypersensitivity in chronic experimental PDPN.

Prevalence of asymptomatic heart failure in formerly pre-eclamptic women: a cohort study

After pre‐eclampsia (PE), the prevalence of structural heart disease without symptoms, i.e. heart failure Stage B (HF‐B), may be as high as one in four women in the first year postpartum. We hypothesize that a significant number of formerly pre‐eclamptic women with HF‐B postpartum are still in their resolving period and will not have HF‐B during follow‐up.

Early pregnancy circulatory adaptation and recurrent hypertensive disease: an explorative study.

Introduction: Hypertensive pregnancy disorders are assumed to be preceded by defective spiral artery remodeling. Whether this localized aberration at the implantation site affects the initial maternal systemic cardiovascular and renal adaptation to pregnancy is unclear. We explored in a high-risk population, whether the initial systemic maternal adaptation to pregnancy differs between women who do and do not develop a recurrent hypertensive disorder later on in pregnancy. Methods: We enrolled 61 normotensive women with a previous hypertensive disorder of pregnancy and subdivided them into 2 subgroups, based on whether or not their next pregnancy remained uneventful (n = 33) or became complicated by a recurrent hypertensive disorder (n = 28). We measured before pregnancy and again at 18 ± 2 weeks of gestation cardiac output, blood pressure, plasma volume, creatinine clearance, and calculated total peripheral vascular resistance from cardiac output and blood pressure. Result: Both subgroups responded to pregnancy with an increase in cardiac output, plasma volume, heart rate, and creatinine clearance, and a decrease in blood pressure and total peripheral vascular resistance. Women who developed a recurrent hypertensive disorder differed from their counterparts with an uneventful next pregnancy by smaller pregnancy-induced increases in creatinine clearance (19% vs 31%, P = .035) and cardiac output (10% vs 20%, P = .035), respectively. Conclusion: The initial systemic cardiovascular and renal adaptations to pregnancy in women who develop a recurrent gestational hypertensive disorder differ from those in their counterparts with an uneventful next pregnancy by smaller rises in creatinine clearance and cardiac output.

Decreased endothelial function and increased subclinical heart failure in women several years after pre‐eclampsia

Pre‐eclampsia (PE) is associated with both postpartum endothelial dysfunction and asymptomatic structural heart alterations consistent with heart failure Stage B (HF‐B). In this study, we assessed the relationship between endothelial function, measured by flow‐mediated dilation (FMD), and HF‐B in women with a history of PE.