Resting Hemodynamics and Response to Exercise Using the 6-Minute Walk Test in Late Pregnancy: An International Prospective Multicentre Study.

BACKGROUND: Cardiac disease is the leading cause of maternal death. Assessment of cardiovascular fitness is important in pregnant women because it is linked to increased risk of cardiac disease but is rarely undertaken or studied. The 6-Minute Walk Test (6MWT) is a safe exercise test but is not used in pregnancy. We determined the 95% reference interval for resting heart rate (HR) and distance walked for the 6MWT, as well as hemodynamic recovery variables, and quantified expectations and actual experiences of exertion and breathlessness with exercise in late pregnancy. METHODS: After institutional research board approval (Australian and New Zealand Clinical Trials Registry Number: 12615000964516), 300 healthy term nulliparous pregnant women performed the 6MWT at 3 tertiary referral obstetric hospitals using a standardized protocol. Each woman underwent two 6MWT with maximum 15-minute recovery period after each test. Hemodynamic variables were measured at rest and after exercise. Participants were asked 4 questions, 2 regarding expectation and 2 regarding actual experience, using the Rating of Perceived Exertion scale and Modified Borg Dyspnea scale. RESULTS: Participant characteristics and resting variables were mean (standard deviation [SD]); age, 31 years (4.2 years); body mass index, 27 kg/m (2.9 kg/m); gestational age, 37 weeks (1.3 weeks); HR, 85 bpm (10.8 bpm) with 95% reference interval 64-106 bpm; systolic blood pressure, 112 mm Hg (10.2 mm Hg); diastolic blood pressure, 72 mm Hg (8.6 mm Hg); oxygen saturation, 98% (0.9%); and respiratory rate, 18 breaths/min (5.7 breaths/min). The mean (SD) average distance walked was 488 m (94.9 m) with a speed of 3.0 mph (0.64 mph) with a 95% reference interval of 302-674 m. The mean (SD) HR increase with exercise was 12 bpm (11.0 bpm) with a median [quartile] recovery time of 5.0 minutes [1-8 minutes]. A lower resting HR was associated with increased distance walked (r = -0.207; 95% confidence interval, -0.313 to -0.096; P < .001). A greater HR change with exercise was associated with increased recovery time from exercise (r = 0.736; 95% confidence interval, 0.697-0.784; P < .001). Sixty-three percent and 83% of participants, respectively, expected to be more exerted and breathless than they actually were with exercise. CONCLUSIONS: The 6MWT is feasible and applicable in term pregnant women. The reference intervals for resting HR and distance walked in the 6MWT have been generated. HR increases by approximately 12 bpm with submaximal exercise, and half of the women recovered within 5 minutes of submaximal exercise. Women expected to be more exerted and breathless than they actually were with exercise.

The prone position in healthy pregnant women and in women with preeclampsia - a pilot study.

BACKGROUND: The prone position is rarely used in medical settings in pregnancy. There is no published information about the prone position in women with preeclampsia. This study examined the feasibility and acceptability of the prone position in pregnant women, and the short-term effect of the prone position on blood pressure (BP) in term healthy pregnant women and in women with preeclampsia. METHODS: After ethics approval, written consent and trial registration (ACTRN:12615000160538 registered 18/02/2015, date of first participant enrolled 03/03/2015), 50 healthy term pregnant women and 15 women with preeclampsia had BP, heart rate (HR), oxygen saturation (SpO2), respiratory rate (RR), fetal heart rate (FHR) and comfort levels measured in two positions: left lateral, and prone. Measurements were after five minutes rest in each position. RESULTS: Mean ± SD age, gestation and body mass index for healthy pregnant women was 33 ± 4.1 years, 38 ± 1.0 weeks and 27 ± 3.2 kg.m- 2 and for women with preeclampsia was 32 ± 4.7 years, 36 ± 3.4 weeks, 31 ± 5.6 kg.m- 2 respectively. No clinically significant changes occurred in healthy pregnant women in the prone position. Systolic BP was reduced in the prone position in women with preeclampsia (P = 0.019, mean difference - 6.6 mmHg, 95% confidence interval - 11.9 to - 1.3 mmHg). 33% of women with preeclampsia experienced a 10 mmHg or greater reduction in systolic BP in the prone position. 42% of healthy pregnant women and 47% of women with preeclampsia preferred the prone position to lateral. CONCLUSIONS: This is the first study to examine the prone position in women with preeclampsia. For short periods of time the prone position is feasible and comfortable in pregnant women including those at term. The prone position may reduce systolic BP in women with preeclampsia without obvious adverse effects. Larger studies with women lying for longer periods in the prone position are required. Pregnancy should not be a contraindication to the prone position for short periods of time. TRIAL REGISTRATION: ACTRN:12615000160538.

Increased duration of illness is associated with reduced volume in right medial temporal/anterior cingulate grey matter in patients with chronic schizophrenia.

It is unclear whether the neuroanatomical abnormalities associated with schizophrenia change over the course of the disorder. We addressed this issue by examining whether the magnitude of structural brain abnormalities in patients with chronic schizophrenia was related to their duration of illness. Thirty-nine subjects with schizophrenia (34 male, 5 female, range of illness duration 2-31 years) were scanned using magnetic resonance imaging. Images were segmented into grey and white matter, cerebrospinal fluid and dura/blood vessels using the Structural Magnetic Resonance Toolkit (SMaRT). Voxel-based analysis identified brain areas whose volume varied significantly with time since the first onset of psychosis. Right medial temporal, medial cerebellar and bilateral anterior cingulate grey matter volume, and white matter volume in the right posterior limb of the internal capsule, were all negatively correlated with illness duration (p < 0.002). Conversely, illness duration was positively correlated with the volume of the right globus pallidus (p < 0.002). These correlations were not a function of chronological age or age at illness onset. The inverse correlation between right frontal, temporal and cerebellar volumes and the time since the onset of schizophrenia could reflect progressive tissue loss following the first episode of the disorder.