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Kember AJ, Anderson JL, House SC, Reuter DG, Goergen CJ, Hobson SR. Impact of maternal posture on fetal physiology in human pregnancy: a narrative review. Front Physiol 2024; 15:1394707. [PMID: 38827993 PMCID: PMC11140392 DOI: 10.3389/fphys.2024.1394707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 04/24/2024] [Indexed: 06/05/2024] Open
Abstract
In numerous medical conditions, including pregnancy, gravity and posture interact to impact physiology and pathophysiology. Recent investigations, for example, pertaining to maternal sleeping posture during the third trimester and possible impact on fetal growth and stillbirth risk highlight the importance and potential clinical implications of the subject. In this review, we provide an extensive discussion of the impact of maternal posture on fetal physiology from conception to the postpartum period in human pregnancy. We conducted a systematic literature search of the MEDLINE database and identified 242 studies from 1991 through 2021, inclusive, that met our inclusion criteria. Herein, we provide a synthesis of the resulting literature. In the first section of the review, we group the results by the impact of maternal posture at rest on the cervix, uterus, placenta, umbilical cord, amniotic fluid, and fetus. In the second section of the review, we address the impact on fetal-related outcomes of maternal posture during various maternal activities (e.g., sleep, work, exercise), medical procedures (e.g., fertility, imaging, surgery), and labor and birth. We present the published literature, highlight gaps and discrepancies, and suggest future research opportunities and clinical practice changes. In sum, we anticipate that this review will shed light on the impact of maternal posture on fetal physiology in a manner that lends utility to researchers and clinicians who are working to improve maternal, fetal, and child health.
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Affiliation(s)
- Allan J. Kember
- Temerty Faculty of Medicine, Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON, Canada
- Shiphrah Biomedical Inc., Toronto, ON, Canada
| | - Jennifer L. Anderson
- Larner College of Medicine, University of Vermont, Burlington, VT, United States
| | - Sarah C. House
- Temerty Faculty of Medicine, Medical Education, University of Toronto, Toronto, ON, Canada
| | - David G. Reuter
- Cardiac Innovations, Seattle Children’s Hospital, Seattle, WA, United States
| | - Craig J. Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Sebastian R. Hobson
- Temerty Faculty of Medicine, Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON, Canada
- Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Maternal-Fetal Medicine Division, Mount Sinai Hospital, Toronto, ON, Canada
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DeVore GR, Polanco B, Lee W, Fowlkes JB, Peek EE, Putra M, Hobbins JC. Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile). Am J Obstet Gynecol 2024:S0002-9378(24)00530-1. [PMID: 38842845 DOI: 10.1016/j.ajog.2024.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/20/2024] [Accepted: 04/22/2024] [Indexed: 06/07/2024]
Abstract
BACKGROUND Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question. OBJECTIVE This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus. STUDY DESIGN A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Kruskal-Wallis test. A P value of <.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included. RESULTS A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001). CONCLUSION Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.
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Affiliation(s)
- Greggory R DeVore
- Fetal Diagnostic Centers, Pasadena, Tarzana, and Lancaster, CA; Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI.
| | - Bardo Polanco
- Fetal Diagnostic Centers, Pasadena, Tarzana, and Lancaster, CA
| | - Wesley Lee
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX
| | - Jeffrey Brian Fowlkes
- Departments of Radiology and Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - Emma E Peek
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO
| | - Manesha Putra
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO
| | - John C Hobbins
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO
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Coleman J, Grewal S, Warland J, Hobson S, Liu K, Kember A. Maternal positional therapy for fetal growth and customised birth weight centile benefit in a Bayesian reanalysis of a double-blind, sham-controlled, randomised clinical trial. BMJ Open 2024; 14:e078315. [PMID: 38684260 PMCID: PMC11057287 DOI: 10.1136/bmjopen-2023-078315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 03/28/2024] [Indexed: 05/02/2024] Open
Abstract
OBJECTIVES To update the Ghana PrenaBelt Trial's (GPT) primary outcome data with the latest fetal growth standard and reanalyse it. To estimate the posterior probability, under various clinically relevant prior probabilities, of maternal nightly positional therapy (PT) throughout the third-trimester having a beneficial effect on customised birth weight centile (CBWC) using Bayesian analyses. DESIGN A reanalysis of a double-blind, sham-controlled, randomised clinical trial. SETTING A single, tertiary-level centre in Accra, Ghana. PARTICIPANTS Two-hundred participants entered, 181 completed and 167 were included in the final analysis. Participants were Ghanaian, healthy, aged 18-35 years, with low-risk, singleton pregnancies in their third-trimester, with Body Mass Index<35 kg/m2 at the first antenatal appointment for the index pregnancy and without known fetal abnormalities, pregnancy complications or medical conditions complicating sleep. INTERVENTIONS Participants were randomised to receive treatment with either a PT or sham-PT device. PRIMARY AND SECONDARY OUTCOME MEASURES The primary outcome was the CBWC using the latest Perinatal Institute, Gestation-Related Optimal Weight calculator. Using Bayesian methods, posterior probabilities of achieving a greater than 0%, 5% and 10% benefit in CBWC with PT were estimated. There was no secondary outcome. RESULTS The median (IQR) CBWC was 42% (15-71) and 28% (9-52) in the PT and sham-PT groups, respectively (difference 8.4%; 95% CI -0.30 to 18.2; p=0.06). For achieving a >0%, >5% and >10% gain in CBWC with PT, the posterior probabilities were highly probable, probable and unlikely, respectively, given a range of prior probabilities reflecting varying degrees of pre-existing enthusiasm and scepticism. CONCLUSIONS Maternal nightly PT throughout the third-trimester did not have a statistically significant effect on CBWC on a frequentist analysis using the latest fetal growth standard. However, from a Bayesian analysis, clinicians can infer that PT is likely to benefit fetal growth but with a modest effect size. TRIAL REGISTRATION NUMBER NCT02379728.
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Affiliation(s)
- Jerry Coleman
- Obstetrics & Gynaecology, Korle Bu Teaching Hospital, Accra, Greater Accra, Ghana
| | - Sahibjot Grewal
- University of Toronto Faculty of Medicine, Toronto, Ontario, Canada
| | - Jane Warland
- The University of Adelaide Faculty of Health and Medical Sciences, Adelaide, South Australia, Australia
| | - Sebastian Hobson
- Department of Obstetrics & Gynaecology, University of Toronto Faculty of Medicine, Toronto, Ontario, Canada
- Maternal-Fetal Medicine Division, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Kuan Liu
- Institute of Health Policy, Management, and Evaluation, University of Toronto Dalla Lana School of Public Health, Toronto, Ontario, Canada
| | - Allan Kember
- Department of Obstetrics & Gynaecology, University of Toronto Faculty of Medicine, Toronto, Ontario, Canada
- Institute of Health Policy, Management, and Evaluation, University of Toronto Dalla Lana School of Public Health, Toronto, Ontario, Canada
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Katz J, Sanapo L, Bublitz MH, Guillen M, Avalos A, Aldana A, Wilson D, Bourjeily G. Longitudinally assessed maternal sleep position, measures of breathing during sleep, and fetal growth in high-risk pregnancies. Sleep 2024; 47:zsad315. [PMID: 38108687 PMCID: PMC10851852 DOI: 10.1093/sleep/zsad315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/27/2023] [Indexed: 12/19/2023] Open
Abstract
STUDY OBJECTIVES Subjective recall of supine sleep during pregnancy has been linked to increased risk of stillbirth, but longitudinal, objective data are lacking. We aimed to examine how sleep position and breathing parameters change throughout pregnancy, and investigated associations between maternal supine sleep, assessed objectively in early and late gestation, and fetal growth velocity in high-risk women. METHODS Women with singleton pregnancies and body mass index (BMI) ≥27 kg/m2 underwent level-III sleep apnea testing. Sleep position was assessed by accelerometry. We derived percentiles of estimated fetal weight and birthweight using FetalGPSR software, then calculated growth velocity as change in percentile/week between the second-trimester anatomy scan and birth. RESULTS In total, 446 women were included, with N = 126 in the longitudinal sleep pattern analysis and N = 83 in the fetal growth analysis. Sleep-onset position and predominant sleep position were significantly correlated in both early (p = 0.001) and late (p < 0.01) pregnancy. However, supine going-to-bed position predicted predominant supine sleep in only 47% of women. Between early and late pregnancy there was a reduction in predominant supine sleepers (51.6% to 30.2%). Percent of sleep spent supine and oxygen desaturation index, in the third trimester, were significantly associated after BMI adjustment (B = 0.018, p = 0.04). Models did not suggest significant effects of early or late pregnancy supine sleep on growth velocity (p > 0.05). CONCLUSIONS Going-to-bed position predicts predominant supine sleep in less than half of women with overweight and obesity. Time spent supine throughout pregnancy correlates with measures of sleep-disordered breathing. Maternal sleep position patterns did not affect fetal growth velocity in this high-risk population, but the study was not powered to detect differences.
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Affiliation(s)
- Juliana Katz
- Warren Alpert Medical School of Brown University, Providence, RI, USA
- Departments of Medicine and Psychiatry and Human Behavior
| | - Laura Sanapo
- Warren Alpert Medical School of Brown University, Providence, RI, USA
- Departments of Medicine and Psychiatry and Human Behavior
- Department of Medicine and Psychiatry and Human Behavior, The Miriam Hospital, Women’s Medicine Collaborative, Providence, RI, USA
| | - Margaret H Bublitz
- Warren Alpert Medical School of Brown University, Providence, RI, USA
- Departments of Medicine and Psychiatry and Human Behavior
- Department of Medicine and Psychiatry and Human Behavior, The Miriam Hospital, Women’s Medicine Collaborative, Providence, RI, USA
| | - Melissa Guillen
- Department of Medicine and Psychiatry and Human Behavior, The Miriam Hospital, Women’s Medicine Collaborative, Providence, RI, USA
| | - Ashanti Avalos
- Department of Medicine and Psychiatry and Human Behavior, The Miriam Hospital, Women’s Medicine Collaborative, Providence, RI, USA
| | - Annaly Aldana
- Department of Medicine and Psychiatry and Human Behavior, The Miriam Hospital, Women’s Medicine Collaborative, Providence, RI, USA
| | - Danielle Wilson
- School of Engineering and Computer Science, Institute for Breathing and Sleep, Austin Health, VIC, Brisbane Qld, Australia
| | - Ghada Bourjeily
- Warren Alpert Medical School of Brown University, Providence, RI, USA
- Departments of Medicine and Psychiatry and Human Behavior
- Department of Medicine and Psychiatry and Human Behavior, The Miriam Hospital, Women’s Medicine Collaborative, Providence, RI, USA
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Saini BS, Ducas R, Darby JRT, Marini D, Sun L, Macgowan CK, Windrim R, Kingdom JC, Wald RM, Morrison JL, Seed M. Feasibility of MRI assessment of maternal-fetal oxygen transport and consumption relative to maternal position in healthy late gestational pregnancies. J Physiol 2023; 601:5413-5436. [PMID: 37906114 DOI: 10.1113/jp285097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/16/2023] [Indexed: 11/02/2023] Open
Abstract
Late gestational supine positioning reduces maternal cardiac output due to inferior vena caval (IVC) compression, despite increased collateral venous return. However, little is known about the impact of maternal position on oxygen (O2 ) delivery and consumption of the gravid uterus, fetus, placenta and lower limbs. We studied the effects of maternal positioning on these parameters in 20 healthy pregnant subjects at 36 ± 2 weeks using magnetic resonance imaging (MRI); a follow-up MRI was performed 6-months postpartum (n = 16/20). MRI techniques included phase-contrast and T1/T2 relaxometry for blood flow and oximetry imaging, respectively. O2 transport was measured in the following vessels (bilateral where appropriate): maternal abdominal descending aorta (DAoabdo ), IVC, ovarian, paraspinal veins (PSV), uterine artery (UtA) and external iliacs, and umbilical. Maternal cardiac output was measured by summing DAothoracic and superior vena cava flows. Supine mothers (n = 6) had lower cardiac output and O2 delivery in the DAoabdo , UtA and external iliac arteries, and higher PSV flow than those in either the left (n = 8) or right (n = 6) lateral positions during MRI. However, O2 consumption in the gravid uterus, fetus, placenta and lower limbs was unaffected by maternal positioning. The ratio of IVC/PSV flow decreased in supine mothers while ovarian venous flow and O2 saturation were unaltered, suggesting a major route of pelvic venous return unaffected by maternal position. Placental-fetal O2 transport and consumption were similar between left and right lateral maternal positions. In comparison to non-pregnant findings, DAoabdo and UtA O2 delivery and pelvic O2 consumption increased, while lower-limb consumption remained constant , despite reduced external iliac artery O2 delivery in late gestation. KEY POINTS: Though sleeping supine during the third trimester is associated with an increased risk of antepartum stillbirth, the underlying biological mechanisms are not fully understood. Maternal cardiac output and uteroplacental flow are reduced in supine mothers due to inferior vena caval compression from the weight of the gravid uterus. This MRI study provides a comprehensive circulatory assessment, demonstrating reduced maternal cardiac output and O2 delivery (uteroplacental, lower body) in supine compared to lateral positioning; however, O2 consumption (gravid uterus, fetus, placenta, lower limbs) was preserved. Unlike other mammalian species, the ovarian veins conduct substantial venous return from the human pregnant uterus that is unaffected by maternal positioning. Lumbar paraspinal venous flow increased in supine mothers. These observations may have important considerations during major pelvic surgery in pregnancy (i.e. placenta percreta). Future studies should address the importance of maternal positioning as a potential tool to deliver improved perinatal outcomes in pregnancies with compromised uteroplacental O2 delivery.
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Affiliation(s)
- Brahmdeep S Saini
- Heart Centre, Division of Cardiology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Robin Ducas
- Department of Internal Medicine, Section of Cardiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jack R T Darby
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Davide Marini
- Heart Centre, Division of Cardiology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Liqun Sun
- Heart Centre, Division of Cardiology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Christopher K Macgowan
- Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Medical Biophysics, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Rory Windrim
- Department of Obstetrics and Gynaecology, Maternal-Fetal Medicine Division, Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Obstetrics and Gynaecology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - John C Kingdom
- Department of Obstetrics and Gynaecology, Maternal-Fetal Medicine Division, Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Obstetrics and Gynaecology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Rachel M Wald
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Janna L Morrison
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mike Seed
- Heart Centre, Division of Cardiology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Obstetrics and Gynaecology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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Kember AJ, Selvarajan R, Park E, Huang H, Zia H, Rahman F, Akbarian S, Taati B, Hobson SR, Dolatabadi E. Vision-based detection and quantification of maternal sleeping position in the third trimester of pregnancy in the home setting-Building the dataset and model. PLOS DIGITAL HEALTH 2023; 2:e0000353. [PMID: 37788239 PMCID: PMC10547173 DOI: 10.1371/journal.pdig.0000353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 08/17/2023] [Indexed: 10/05/2023]
Abstract
In 2021, the National Guideline Alliance for the Royal College of Obstetricians and Gynaecologists reviewed the body of evidence, including two meta-analyses, implicating supine sleeping position as a risk factor for growth restriction and stillbirth. While they concluded that pregnant people should be advised to avoid going to sleep on their back after 28 weeks' gestation, their main critique of the evidence was that, to date, all studies were retrospective and sleeping position was not objectively measured. As such, the Alliance noted that it would not be possible to prospectively study the associations between sleeping position and adverse pregnancy outcomes. Our aim was to demonstrate the feasibility of building a vision-based model for automated and accurate detection and quantification of sleeping position throughout the third trimester-a model with the eventual goal to be developed further and used by researchers as a tool to enable them to either confirm or disprove the aforementioned associations. We completed a Canada-wide, cross-sectional study in 24 participants in the third trimester. Infrared videos of eleven simulated sleeping positions unique to pregnancy and a sitting position both with and without bed sheets covering the body were prospectively collected. We extracted 152,618 images from 48 videos, semi-randomly down-sampled and annotated 5,970 of them, and fed them into a deep learning algorithm, which trained and validated six models via six-fold cross-validation. The performance of the models was evaluated using an unseen testing set. The models detected the twelve positions, with and without bed sheets covering the body, achieving an average precision of 0.72 and 0.83, respectively, and an average recall ("sensitivity") of 0.67 and 0.76, respectively. For the supine class with and without bed sheets covering the body, the models achieved an average precision of 0.61 and 0.75, respectively, and an average recall of 0.74 and 0.81, respectively.
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Affiliation(s)
- Allan J. Kember
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Canada
- Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Canada
- Shiphrah Biomedical Inc., Toronto, Canada
| | - Rahavi Selvarajan
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
| | - Emma Park
- Shiphrah Biomedical Inc., Toronto, Canada
| | - Henry Huang
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Hafsa Zia
- Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Farhan Rahman
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
| | | | - Babak Taati
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
- Vector Institute, Toronto, Canada
- Department of Computer Science, University of Toronto, Toronto, Canada
| | - Sebastian R. Hobson
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Canada
- Department of Obstetrics and Gynaecology, Maternal-Fetal Medicine Division, Mount Sinai Hospital, Toronto, Canada
| | - Elham Dolatabadi
- Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Canada
- Vector Institute, Toronto, Canada
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Yang Q, Sanderson E, Tilling K, Borges MC, Lawlor DA. Exploring and mitigating potential bias when genetic instrumental variables are associated with multiple non-exposure traits in Mendelian randomization. Eur J Epidemiol 2022; 37:683-700. [PMID: 35622304 PMCID: PMC9329407 DOI: 10.1007/s10654-022-00874-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/18/2022] [Indexed: 12/19/2022]
Abstract
With the increasing size and number of genome-wide association studies, individual single nucleotide polymorphisms are increasingly found to associate with multiple traits. Many different mechanisms could result in proposed genetic IVs for an exposure of interest being associated with multiple non-exposure traits, some of which could bias MR results. We describe and illustrate, through causal diagrams, a range of scenarios that could result in proposed IVs being related to non-exposure traits in MR studies. These associations could occur due to five scenarios: (i) confounding, (ii) vertical pleiotropy, (iii) horizontal pleiotropy, (iv) reverse causation and (v) selection bias. For each of these scenarios we outline steps that could be taken to explore the underlying mechanism and mitigate any resulting bias in the MR estimation. We recommend MR studies explore possible IV-non-exposure associations across a wider range of traits than is usually the case. We highlight the pros and cons of relying on sensitivity analyses without considering particular pleiotropic paths versus systematically exploring and controlling for potential pleiotropic or other biasing paths via known traits. We apply our recommendations to an illustrative example of the effect of maternal insomnia on offspring birthweight in UK Biobank.
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Affiliation(s)
- Qian Yang
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK.
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
| | - Eleanor Sanderson
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Kate Tilling
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- National Institute for Health Research Bristol Biomedical Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK
| | - Maria Carolina Borges
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Deborah A Lawlor
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- National Institute for Health Research Bristol Biomedical Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK
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Wilson DL, Fung AM, Pell G, Skrzypek H, Barnes M, Bourjeily G, Walker SP, Howard ME. Polysomnographic analysis of maternal sleep position and its relationship to pregnancy complications and sleep-disordered breathing. Sleep 2022; 45:6527683. [PMID: 35150285 PMCID: PMC8996027 DOI: 10.1093/sleep/zsac032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/12/2022] [Indexed: 11/14/2022] Open
Abstract
Links between supine "going to sleep" position and stillbirth risk have led to campaigns regarding safe maternal sleep position. This study profiles the distribution of sleep positions overnight and relationships to sleep onset position during pregnancy, and the relationships between supine sleep, sleep-disordered breathing (SDB), and pregnancy outcomes. Data from three prospective cohort studies evaluating SDB in healthy and complicated pregnancies were pooled. All participants underwent one night of polysomnography in late pregnancy and birth outcome data were collected. 187 women underwent polysomnography at a median gestation of 34 weeks'. The left lateral position was preferred for falling asleep (52%) compared to supine (14%), but sleep onset position was the dominant sleep position overnight in only half (54%) of women. The median percentage of sleep time in the supine position was 24.2%; women who fell asleep supine spent more time supine overnight compared to those who began non-supine (48.0% (30.0,65.9) vs. 22.6% (5.7,32.2), p < .001). Women with growth-restricted fetuses were more likely to fall asleep supine than those with well-grown fetuses (36.6% vs. 7.5%, p < .001). Positional SDB was observed in 46% of those with an RDI ≥ 5. Sleep onset position was the dominant position overnight for half of the sample, suggesting that sleep onset position is not always a reliable indicator of body position overnight. Supine sleep was related to fetal growth restriction and birthweight at delivery, though causality cannot be inferred. It is critical that we pursue research into verifying the important relationship between supine sleep and increased stillbirth risk, and the mechanisms behind it.
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Affiliation(s)
- Danielle L Wilson
- Corresponding author. Danielle L. Wilson, Institute for Breathing and Sleep, Level 5 Harold Stokes Building, Austin Health, Heidelberg, Victoria, Australia.
| | - Alison M Fung
- Mercy Perinatal, Mercy Hospital for Women, Heidelberg, Victoria, Australia
| | - Gabrielle Pell
- Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Victoria, Australia
| | - Hannah Skrzypek
- Mercy Perinatal, Mercy Hospital for Women, Heidelberg, Victoria, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Ghada Bourjeily
- Department of Medicine, The Miriam Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
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Wilson DL, Fung AM, Skrzypek H, Pell G, Barnes M, Howard ME, Walker SP. Maternal sleep behaviours preceding fetal heart rate events on cardiotocography. J Physiol 2022; 600:1791-1806. [DOI: 10.1113/jp282528] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/17/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Danielle L. Wilson
- Institute for Breathing and Sleep, Austin Health Heidelberg Victoria Australia
- Department of Obstetrics and Gynaecology University of Melbourne Parkville Victoria Australia
| | - Alison M. Fung
- Mercy Perinatal Mercy Hospital for Women Heidelberg Victoria Australia
| | - Hannah Skrzypek
- Department of Obstetrics and Gynaecology University of Melbourne Parkville Victoria Australia
- Mercy Perinatal Mercy Hospital for Women Heidelberg Victoria Australia
| | - Gabrielle Pell
- Department of Obstetrics and Gynaecology University of Melbourne Parkville Victoria Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health Heidelberg Victoria Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
| | - Mark E. Howard
- Institute for Breathing and Sleep, Austin Health Heidelberg Victoria Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
| | - Susan P. Walker
- Department of Obstetrics and Gynaecology University of Melbourne Parkville Victoria Australia
- Mercy Perinatal Mercy Hospital for Women Heidelberg Victoria Australia
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10
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O’Brien LM. Sleep in Pregnancy. Respir Med 2022. [DOI: 10.1007/978-3-030-93739-3_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Dow ML, Dugan SR. Hypothesis: A wearable device may help COVID-19 patients improve lung function. Med Hypotheses 2020; 146:110443. [PMID: 33309339 PMCID: PMC7716723 DOI: 10.1016/j.mehy.2020.110443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 11/29/2020] [Indexed: 12/15/2022]
Abstract
Managing respiratory status of patients with COVID-19 is a high resource, high risk healthcare challenge. Interventions that decrease need for invasive respiratory support and utilization of bedside staff would benefit patients and healthcare personnel alike. Proning has been established as optimal positioning that may reduce the need for escalation of respiratory support. We propose a new application of a wearable device to decrease supine positioning and ameliorate these risks.
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Affiliation(s)
- Margaret L Dow
- Mayo Clinic, Rochester, MN, United States; Smart Human Dynamics, San Francisco, CA, United States.
| | - Stephen R Dugan
- Mayo Clinic, Rochester, MN, United States; Smart Human Dynamics, San Francisco, CA, United States
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12
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Akselsson A, Lindgren H, Skokic V, Rådestad I. A decrease in cesarean sections and labor inductions among Swedish women by awareness of fetal movements with the Mindfetalness method. BMC Pregnancy Childbirth 2020; 20:577. [PMID: 32998708 PMCID: PMC7528254 DOI: 10.1186/s12884-020-03268-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/18/2020] [Indexed: 12/05/2022] Open
Abstract
Background Maternal perception of decreased fetal movements is commonly used to assess fetal well-being. However, there are different opinions on whether healthcare professionals should encourage maternal observation of fetal movements, as researchers claim that raising awareness increases unnecessary interventions, without improving perinatal health. We aimed to investigate whether cesarean sections and labor induction increase by raising women’s awareness of fetal movements through Mindfetalness. Further, we aimed to study perinatal health after implementing Mindfetalness in maternity care. Methods In a cluster randomized controlled trial, 67 maternity clinics were allocated to Mindfetalness or routine care. In the Mindfetalness group, midwives distributed a leaflet telling the women to focus on the character, strength and frequency of the fetal movements without counting each movement. The instruction was to do so for 15 min daily when the fetus was awake, from gestational week 28 until birth. In this sub-group analysis, we targeted women born in Sweden giving birth from 32 weeks’ gestation. We applied the intention-to-treat principle. Results The Mindfetalness group included 13,029 women and the Routine-care group 13,456 women. Women randomized to Mindfetalness had less cesarean sections (18.4% vs. 20.0%, RR 0.92, CI 0.87–0.97) and labor inductions (19.2% vs. 20.3%, RR 0.95, CI 0.90–0.99) compared to the women in the Routine-care group. Less babies were born small for gestational age (8.5% vs. 9.3%, RR 0.91, CI 0.85–0.99) in the Mindfetalness group. Women in the Mindfetalness group contacted healthcare due to decreased fetal movements to a higher extent than women in the Routine care group (7.8% vs. 4.3%, RR 1.79, CI 1.62–1.97). The differences remain after adjustment for potential confounders. Conclusions Raising awareness about fetal movements through Mindfetalness decreased the rate of cesarean sections, labor inductions and small-for-gestational age babies. Trial registration ClinicalTrials.gov (NCT02865759). Registered 12 August 2016, www.clinicaltrials.gov.
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Affiliation(s)
- Anna Akselsson
- Sophiahemmet University, Stockholm, Sweden. .,Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden.
| | - Helena Lindgren
- Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Viktor Skokic
- Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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13
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Ishkova A, Wilson DL, Howard ME, Walker SP, Barnes M, Nicholas CL, Jordan AS. The effect of body position on maternal cardiovascular function during sleep and wakefulness in late pregnancy. J Matern Fetal Neonatal Med 2020; 35:2545-2554. [PMID: 32669005 DOI: 10.1080/14767058.2020.1789583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION An association between the increased risk of late stillbirth and the maternal supine sleeping position has been recently established. The risk of stillbirth following supine sleep has been suspected to occur as a result of aortocaval compression by the gravid uterus. A number of studies conducted during wakefulness have reported compromised cardiovascular function during supine rest, as demonstrated by reductions in cardiac output, blood pressure and utero-placental blood flow. It remains unclear whether similar effects are also present during sleep, due to the presence of key sleep-specific changes in cardiovascular function. OBJECTIVE To investigate the changes in maternal cardiovascular function between the supine and left-lateral positions during wakefulness and non-rapid eye movement (NREM) sleep in late pregnancy. METHODS Twenty-nine women with a singleton pregnancy between 24.7 and 36.7 weeks' gestation participated in a single overnight sleep study. Physiological measures (blood pressure, heart rate, heart rate variability - HRV, and pulse arrival time - PAT) were measured and recorded throughout the night using standard polysomnography equipment and the Portapres Model-2 device. As the present study evaluated cardiovascular changes during natural rest and sleep in pregnancy, participants were not given explicit instructions on which position to adopt. Body position was continuously recorded using a position monitor and verified with video recording. RESULTS No changes in systolic, diastolic or mean arterial blood pressure were observed between the left-lateral and supine positions during wakefulness or sleep. However, heart rate was significantly higher in the supine position compared to the left during wakefulness (p= .03), with a similar trend present during sleep (p= .11). A significantly shorter PAT was measured in the supine position (compared to the left) during wakefulness (p= .01) and sleep (p= .01). No change in HRV measures was observed between the left and supine positions in either state. CONCLUSION Blood pressure did not appear to differ significantly between the left-lateral and supine positions during wakefulness and sleep. The lack of blood pressure differences may reflect elevated sympathetic activity during rest and sleep in the supine position (compared to the left), suggesting that some degree of compensation for aortocaval compression may still be possible during sleep.
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Affiliation(s)
- Anna Ishkova
- Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Australia
| | - Danielle L Wilson
- Austin Health, Institute for Breathing and Sleep, Heidelberg, Australia.,Mercy Perinatal, Mercy Hospital for Women, Heidelberg, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | - Mark E Howard
- Austin Health, Institute for Breathing and Sleep, Heidelberg, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | - Susan P Walker
- Mercy Perinatal, Mercy Hospital for Women, Heidelberg, Australia.,Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Australia
| | - Maree Barnes
- Austin Health, Institute for Breathing and Sleep, Heidelberg, Australia
| | - Christian L Nicholas
- Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Australia.,Austin Health, Institute for Breathing and Sleep, Heidelberg, Australia
| | - Amy S Jordan
- Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Australia.,Austin Health, Institute for Breathing and Sleep, Heidelberg, Australia
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Akselsson A, Lindgren H, Georgsson S, Pettersson K, Steineck G, Skokic V, Rådestad I. Mindfetalness to increase women's awareness of fetal movements and pregnancy outcomes: a cluster-randomised controlled trial including 39 865 women. BJOG 2020; 127:829-837. [PMID: 31971325 DOI: 10.1111/1471-0528.16104] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine whether a method for raising women's awareness of fetal movements, Mindfetalness, can affect pregnancy outcomes. DESIGN Cluster-randomised controlled trial. SETTING Sixty-seven maternity clinics in Stockholm, Sweden. POPULATION Women with singleton pregnancy with birth from 32 weeks' gestation. METHODS Women registered at a clinic randomised to Mindfetalness were assigned to receive a leaflet about Mindfetalness (n = 19 639) in comparison with routine care (n = 20 226). Data were collected from a population-based register. MAIN OUTCOME MEASURES Apgar score <7 at 5 minutes after birth, visit to healthcare due to decrease in fetal movements. Other outcomes: Apgar score <4 at 5 minutes after birth, small-for-gestational-age and mode of delivery. RESULTS No difference (1.1 versus 1.1%, relative risk [RR] 1.0; 95% CI 0.8-1.2) was found between the Mindfetalness group and the Routine care group for a 5-minute Apgar score <7. Women in the Mindfetalness group contacted healthcare more often due to decreased fetal movements (6.6 versus 3.8%, RR 1.72; 95% CI 1.57-1.87). Mindfetalness was associated with a reduction of babies born small-for-gestational-age (RR 0.95, 95% CI 0.90-1.00), babies born after gestational week 41+6 (RR 0.91, 95% CI 0.83-0.98) and caesarean sections (19.0 versus 20.0%, RR 0.95; 95% CI 0.91-0.99). CONCLUSIONS Mindfetalness did not reduce the number of babies born with an Apgar score <7. However, Mindfetalness was associated with the health benefits of decreased incidence of caesarean section and fewer children born small-for-gestational-age. TWEETABLE ABSTRACT Introducing Mindfetalness in maternity care decreased caesarean sections but had no effect on the occurrence of Apgar scores <7.
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Affiliation(s)
- A Akselsson
- Department of Women and Children's Health, Karolinska Institutet, Sophiahemmet University, Stockholm, Sweden
| | - H Lindgren
- Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - S Georgsson
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, The Swedish Red Cross University College, Stockholm, Sweden
| | - K Pettersson
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - G Steineck
- Sahlgrenska Academy, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden
| | - V Skokic
- Sahlgrenska Academy, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden
| | - I Rådestad
- Sophiahemmet University, Stockholm, Sweden
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