Dimuthu Vinayagam

Hypertensive disorders of pregnancy, including pre-eclampsia, are a significant and commonly encountered group of medical disorders of pregnancy. A primary care clinician is ideally placed to screen for, diagnose and, if confident, initiate management in antenatal and postnatal women. Early involvement of maternity services is advised if a hypertensive disorder in pregnancy is suspected or diagnosed. Checking of maternal blood pressure and urinalysis should be encouraged during all routine appointments with pregnant women. The aim of this article is to provide an overview of the hypertensive disorders of pregnancy, their diagnosis and management in primary care, with a review of commonly used antihypertensive agents in current UK clinical practice.

Objectives: To construct reference ranges for stroke volume, cardiac output and systemic vascular resistance (SVR) in normal pregnancy for the NICOM® device, and to explore associations between maternal characteristics and these hemodynamic variables.Methods: This was a prospective cohort study of healthy singleton pregnancies between 10 and 40 weeks' gestation attending a tertiary referral hospital between September 2012 and May 2018. Measurements of stroke volume, cardiac output and SVR were obtained throughout pregnancy using NICOM, a non‐invasive device based on bioreactance technology. NICOM device‐specific reference ranges were created with respect to gestational age and maternal characteristics. Once the distribution of the data had been determined with respect to the gestational age, patient characteristics were added to the model to test whether they provided a significant improvement in prediction of the median value. The effect was assessed of maternal weight, height, smoking status, conception using assisted reproductive technology, nulliparity and ethnicity.Results: We included 411 women in this study. The relationships between cardiac variables and gestational age observed in the NICOM‐specific reference ranges are consistent with previous findings, with increasing cardiac output values until around 35 weeks and a decrease thereafter until term, and decreasing SVR until around 36 weeks, followed by an increase towards 40 weeks. Stroke volume showed a small linear increase across gestation with lower variability in observations close to term. Maternal weight, height and age were associated with cardiac output (all P < 0.05) and SVR (all P < 0.01), whilst maternal weight and height were associated with stroke volume (both P < 0.001). Ethnicity was significantly associated with stroke volume (P = 0.001) but not with cardiac output or SVR.Conclusions: This study presents device‐specific reference ranges for stroke volume, cardiac output and SVR for the NICOM device in healthy pregnancy and describes the maternal characteristics that are associated with the values of these hemodynamic measurements. Studies using NICOM in pregnancy can use these ranges in order to evaluate observations relative to those expected in uncomplicated pregnancy conditional on maternal characteristics. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Objectives: The main aim of this study was to construct reference ranges of maternal central hemodynamic parameters during pregnancy. The second aim was to determine the maternal and pregnancy characteristics that influence these hemodynamic parameters.Methods: This was a prospective cohort study of low‐risk pregnant women attending for routine antenatal care at St George's Hospital, London, UK. Exclusion criteria included any medical disorder present at the time of study recruitment, or development of hypertension or intrauterine fetal growth restriction following study recruitment. Stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were obtained using non‐invasive cardiac output monitoring (USCOM‐1A®). USCOM‐1A utilizes a non‐imaging probe in the suprasternal notch to obtain velocity‐time integrals of transaortic blood flow at the left ventricular outflow tract. Once the distribution of the data with respect to gestational age had been determined, maternal characteristics were added to the model to test whether they provided a significant improvement in the prediction of the median value.Results: The study included 627 women with a singleton pregnancy. The estimated median CO was constant for a maternal age above 32 years, but was around 0.5 L/min higher for women aged ≤ 25 years (P < 0.001). Maternal weight (P < 0.001) and height (P < 0.001) significantly affected CO values and there was a significant interaction (P = 0.002) between them. In women with a height of less than 1.60 m, there was no association between median CO and weight; however, in those with a height exceeding 1.60 m, an increase in weight was associated with an increase in CO. SV was primarily associated with height (P < 0.001), although some positive association with weight (P < 0.001) could also be observed within the normal body‐mass‐index range. Greater height (P < 0.001) was associated with lower median values of SVR, with an estimated difference of around 120 dynes × s/cm⁵ between 1.60 m and 1.80 m. Advancing maternal age was associated with higher median SVR, with an estimated difference of around 50 dynes × s/cm⁵ between 25 and 35 years. Smokers had a lower SVR by 73.5 (95% CI, 8.6–138.4) dynes × s/cm⁵.Conclusion: Maternal hemodynamics are influenced significantly by maternal age, height and weight. We provide USCOM‐1A‐specific reference ranges and a calculator for SV, CO and SVR in uncomplicated pregnancies that correct for maternal age, height and weight. This should enable clinical application and comparison in both uncomplicated and pathological pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Objective: Maternal obesity is associated with significant pregnancy complications and is a risk factor for the development of hypertensive disorders of pregnancy as well as other adverse outcomes. There are few data regarding the hemodynamic aberrations observed in maternal obesity. The aim of this study was to investigate maternal hemodynamics in morbidly obese women.Methods: This was a prospective, case–control study of morbidly obese women (body mass index (BMI) ≥ 40 kg/m²) and controls (BMI 20–29.9 kg/m²). The control population was matched for maternal age and gestational age. BMI was calculated based on maternal height and weight at the time of recruitment to the study, which occurred on the same day as the hemodynamic assessment. Pregnant women in the second or third trimester of pregnancy were included. Women who were found to be hypertensive at any time were excluded from the study. A USCOM‐1A® device was used to assess hemodynamic parameters (heart rate, stroke volume (SV), cardiac output and systemic vascular resistance (SVR)). The parameters were corrected for body surface area (BSA) to provide the SV index (SVI), cardiac index (CI) and SVR index (SVRI). Mann–Whitney U‐test was used to compare the medians of the hemodynamic variables between the two groups.Results: In total, 23 morbidly obese women and 327 controls were included in the analysis. There was no difference in maternal (P = 0.506) or gestational (P = 0.693) age at recruitment between the groups. Mean arterial pressure was higher both at pregnancy booking (90 vs 80 mmHg, P < 0.001) and study recruitment (91 vs 85 mmHg, P < 0.001) in the obese group compared with the controls. Heart rate was higher in the obese group (P = 0.003), but there was no difference in SV (P = 0.271), cardiac output (P = 0.238) or SVR (P = 0.635). Following correction of these parameters for BSA, compared with the control group, SVI (34 vs 45 mL/m², P < 0.001) and CI (2.96 vs 3.64 L/min/m², P < 0.001) were significantly reduced in the obese group, whereas SVRI was significantly higher (2354 vs 1840 dynes × s/cm⁵, P < 0.001).Conclusions: The findings of our study suggest that cardiac function is significantly altered in morbidly obese pregnant women. In order to make appropriate comparisons between individuals, it is imperative that hemodynamic parameters are indexed for BSA, as is standard practice in pediatric cardiology. The novel finding of reduced CI in morbidly obese pregnant women may explain the predisposition to pre‐eclampsia and other adverse outcomes in this population and warrants further investigation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Aim: To identify the independent risk factors for PE development in twin pregnancies and explore the associated perinatal outcomes. Methods: A retrospective cohort study of twin pregnancies was performed at St George’s University Hospital, London. Maternal and neonatal data were obtained from the hospital’s computerised database. The Chi-square test, Mann–Whitney U test and univariate and multiple-logistic regression analyses were performed. Results: We identified a total of 1250 twin pregnancies who were under the care of SGH from 1999 to 2015. Of these, 120 (9.6%) were complicated by pre-eclampsia according to the ISSHP diagnostic criteria. Pre-eclamptic twin pregnancies were significantly associated with the following perinatal outcomes: induction of labour, emergency caesarean delivery, blood loss at delivery, postpartum haemorrhage ≥500 ml, gestational age at delivery, neonatal unit (NNU) admission and birth weight. Maternal BMI (aOR = 1.060, 95%CI = 1.022–1.099, p = 0.002), chronic hypertension (aOR = 3.131, 95%CI= 1.443–6.792, p = 0.004), and nulliparity (aOR = 1.852, 95% CI = 1.185–2.893, p = 0.007) were independent risk factors for the development of PE in a twin gestation. Conclusions: Nulliparity, maternal BMI and chronic hypertension are factors that increase the risk of PE in a twin gestation, such findings hold clinical significance in relation to the management of twin pregnancies in these women.