This study was designed to examine the relationship between foot impact force and the magnitudes of the changes in markers of intravascular hemolysis during distance running. Fourteen male distance runners (VO2 max = 66.1 +/- 5.0 ml.kg-1.min-1, mean +/- SD) completed two treadmill runs and a resting control procedure. The two treadmill tests involved running at 215 m.min-1 for 10,000 footstrikes at elevations of either +6% (uphill) or -6% (downhill). Mean foot impact force was 11% greater with the downhill than the uphill running. The three procedures were ordered randomly and separated by 7 days. Hemoglobin concentration (Hb), hematocrit (Hct), plasma free hemoglobin (PFHb), and haptoglobin (Hp) concentrations were assayed in blood samples collected via venipuncture 15 min and immediately before exercise, and immediately, 1 h, and 2 h after the exercise. Repeated measures ANOVA revealed that Hp was significantly decreased and PFHb was significantly increased after treadmill running (P less than 0.05) and that these changes were significantly greater with downhill than uphill running (P less than 0.05). These findings support the theory that mechanical trauma to red blood cells occurring at footstrike is a major cause of hemolysis during running.

Key pointsr Fetal behavioural state in healthy late gestation pregnancy is affected by maternal position. r Fetal state 1F is more likely to occur in maternal supine or right lateral positions. r Fetal state 4F is less likely to occur when the woman lies supine or semi-recumbent. r Fetal state change is more likely when the woman is supine or semi-recumbent. r Fetal heart rate variability is affected by maternal position with variability reduced in supine and semi-recumbent positions.Abstract Fetal behavioural states (FBS) are measures of fetal wellbeing. In acute hypoxaemia, the human fetus adapts to a lower oxygen consuming state with changes in the cardiotocograph and reduced fetal activity. Recent studies of late gestation stillbirth described the importance of sleep position in the risk of intrauterine death. We designed this study to assess the effects of different maternal positions on FBS in healthy late gestation pregnancies under controlled conditions. Twenty-nine healthy women had continuous fetal ECG recordings under standardized conditions in four randomly allocated positions, left lateral, right lateral, supine and semi-recumbent. Two blinded observers, assigned fetal states in 5 min blocks. Measures of fetal heart rate variability were calculated from ECG beat to beat data. Compared to state 2F, state 4F was less likely to occur when women were semi-recumbent [odds ratio (OR) = 0.11, 95% confidence interval (95% CI) 0.02, 0.55], and supine (OR = 0.27, 95% CI 0.07, 1.10). State 1F was more likely on the right (OR = 2.36, 95% CI 1.11, 5.04) or supine (OR = 4.99, 95% CI 2.41, 10.43) compared to the left. State change was more likely when the mother was semi-recumbent (OR = 2.17, 95% CI 1.19, 3.95) or supine (OR = 2.67, 95% CI 1.46, 4.85). There was a significant association of maternal position to mean fetal heart rate. The measures of heart rate variability (SDNN and RMSSD) were reduced in both semi-recumbent and supine positions. In healthy late gestation pregnancy, maternal position affects FBS and heart rate variability. These effects are likely fetal adaptations to positions which may produce a mild hypoxic stress. Abbreviations CI, confidence interval; CTG, cardiotocograph; FBS, fetal behavioural state; FHR, fetal heart rate; FHRV, fetal heart rate variability; OR, odds ratio; P aO2 , arterial partial pressure of oxygen; RR interval, interval between successive R waves on the electrocardiograph; RMSSD, root mean square of successive differences (in the RR interval); SDNN, standard deviation of the RR interval.

Fetal behavioural states (FBS) are measures of fetal wellbeing. Maternal position affects FBS with supine position being associated with an increased likelihood of fetal quiescence consistent with the human fetus adapting to a lower oxygen consuming state. Several studies have now confirmed the association between sleep position and risk of late intrauterine death. We designed this study to observe the effects of maternal sleep positions overnight in healthy late gestation pregnancy. Twenty-nine healthy women had continuous fetal ECG recordings overnight. Two blinded observers assigned fetal states in 5 min blocks. Measures of fetal heart rate variability (FHRV) were calculated from ECG beat to beat data. Maternal position was determined from infrared video recording. Compared to state 2F (active sleep), 4F (active awake-high activity) occurred almost exclusively when the mother was in a left or right lateral position. State 1F (quiet sleep) was more common when the mother was supine [odds ratio (OR) 1.30, 95% confidence interval (CI) 1.11-1.52] and less common on the maternal right side with the left being the referent position (OR 0.81, 95% CI, 0.70-0.93). State 4F was more common between 21.00 and 01.00 h than between 01.00 and 07.00 h (OR 2.83, 95% CI 2.32-3.47). In each fetal state, maternal position had significant effects on fetal heart rate and measures of FHRV. In healthy late gestation pregnancy, maternal sleep position affects FBS and heart rate variability. These effects are probably fetal adaptations to positions which may produce a mild hypoxic stress.

BackgroundThe New Zealand (NZ) Ministry of Health ethnicity data protocols recommend that people of South Asian (SAsian) ethnicity, other than Indian, are combined with people of Japanese and Korean ethnicity at the most commonly used level of aggregation in health research (level two). This may not work well for perinatal studies, as it has long been observed that women of Indian ethnicity have higher rates of adverse pregnancy outcomes, such as perinatal death. It is possible that women of other SAsian ethnicities share this risk.AimsThis study was performed to identify appropriate groupings of women of SAsian ethnicity for perinatal research.Materials and MethodsNational maternity and neonatal data, and singleton birth records between 2008 and 2017 were linked using the Statistics NZ Integrated Data Infrastructure. Socio‐demographic risk profiles and pregnancy outcomes were compared between 15 ethnic groups. Recommendations were made based on statistical analyses and cultural evaluation with members of the SAsian research community.ResultsSimilarities were observed between women of Indian, Fijian Indian, South African Indian, Sri Lankan, Bangladeshi and Pakistani ethnicities. A lower‐risk profile was seen among Japanese and Korean mothers. Risk profiles of women of combined Indian‐Māori, Indian‐Pacific and Indian‐New Zealand European ethnicity more closely represented their corresponding non‐Indian ethnicities.ConclusionsBased on these findings, we suggest a review of current NZ Ministry of Health ethnicity data protocols. We recommend that researchers understand the risk profiles of participants prior to aggregation of groups in research, to mitigate risks associated with masking differences.

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