Association of objectively measured physical fitness during pregnancy with maternal and neonatal outcomes. The GESTAFIT Project

RESEARCH ARTICLE Associa ion o objec i ely measu ed physical i ness du ing p egnancy wi h ma e nal and neona al ou comes. The GESTAFIT P ojec Lau a Baena-Ga cı ´a 1☯ , I ene Coll-RiscoID 2,3☯ *, Olga Oco ´n-He na ´ndez 4 , Lidia Rome o- Galla do 3,4,5 , Ped o Acos a-Manzano 3,4,5 , Linda May 6 , Vi ginia A. Apa icio 2,3 1Depa men o Nu sing, Facul y o Heal h Sciences, Uni e si y o G anada, G anada, Spain, 2Depa men o Physiology, "Jose ´Ma aix Ve du ´" Ins i u e o Nu i ion and Food Technology (INYTA) and Biomedical Resea ch Cen e (CIBM), Uni e si y o G anada, G anada, Spain, 3Spo and Heal h Uni e si y Resea ch Ins i u e (iMUDS), Uni e si y o G anada, G anada, Spain, 4UGC o Gynaecology and Obs e ics, “San Cecilio” Uni e si y Hospi al, G anada, Spain, 5Depa men o Physical Educa ion and Spo s, Facul y o Spo Sciences, Uni e si y o G anada, G anada, Spain, 6Depa men o Founda ional Science and Resea ch, School o Den al Medicine, Eas Ca olina Uni e si y, G een ille, NC, Uni ed S a es o Ame ica ☯These au ho s con ibu ed equally o his wo k. *[email p o ec ed] Abs ac Aim To analyse i) he associa ion o physical i ness du ing ea ly second imes e and la e p eg- nancy wi h ma e nal and neona al ou comes; and ii) o in es iga e whe he physical i ness is associa ed wi h he ype o bi h ( aginal o caesa ean sec ion). Me hods P egnan women om he GESTAFIT P ojec (n = 159) pa icipa ed in his longi udinal s udy. Ma e nal physical i ness including uppe - and lowe -body s eng h, ca dio espi a o y i ness (CRF) and lexibili y we e measu ed h ough objec i e physical i ness es s a he 16 h and 34 h ges a ional weeks. Ma e nal and neona al ou comes we e collec ed om obs e ic medical eco ds. Umbilical a e ial and enous blood gas pH and pa ial p essu e o ca bon dioxide (PCO 2 ) and oxygen (PO 2 ), we e assessed. Resul s A he 16 h week, g ea e uppe -body muscle s eng h was associa ed wi h g ea e neona al bi h weigh ( = 0.191, p<0.05). Ma e nal lexibili y was associa ed wi h a mo e alkaline a e- ial pH ( = 0.220, p<0.05), highe a e ial PO 2 ( = 0.237, p<0.05) and lowe a e ial PCO 2 ( = -0.331, p<0.01) in umbilical co d blood. Ma e nal CRF a he 16 h ges a ional week was ela ed o highe a e ial umbilical co d PO 2 ( = 0.267, p<0.05). The women who had cae- sa ean sec ions had lowe CRF (p<0.001) a he 16 h ges a ional week and wo se clus e ed o e all physical i ness, bo h a he 16 h (-0.227, p = 0.003, con idence in e al (CI): -0.376, -0.078) and 34 h ges a ional week (-0.223; p = 0.018; CI: -0.432, -0.015) compa ed wi h he women who had aginal bi hs. PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 1 / 18 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Ci a ion: Baena-Ga cı ´a L, Coll-Risco I, Oco ´n- He na ´ndez O, Rome o-Galla do L, Acos a-Manzano P, May L, e al. (2020) Associa ion o objec i ely measu ed physical i ness du ing p egnancy wi h ma e nal and neona al ou comes. The GESTAFIT P ojec . PLoS ONE 15(2): e0229079. h ps://doi. o g/10.1371/jou nal.pone.0229079 Edi o : Zhong-Cheng Luo, Moun Sinai Heal h Sys em, Uni e si y o To on o, CANADA Recei ed: May 14, 2019 Accep ed: Janua y 29, 2020 Published: Feb ua y 18, 2020 Copy igh : ©2020 Baena-Ga cı ´a e al. This is an open access a icle dis ibu ed unde he e ms o he C ea i e Commons A ibu ion License, which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal au ho and sou ce a e c edi ed. Da a A ailabili y S a emen : All ele an da a a e wi hin he manusc ip and i s Suppo ing In o ma ion iles. Funding: This s udy was pa o VAA ellowship om he Andalucı ´a Talen -Hub P og am, launched by he Andalusian Knowledge Agency, co- unded by he Eu opean Union’s Se en h F amewo k P og am, Ma ie Skłodowska-Cu ie ac ions (COFUND–G an Ag eemen nº291780) and he Jun a de Andalucı ´a. ICR (g an numbe : FPU13/ Conclusion Inc easing physical i ness du ing p egnancy may p omo e be e neona al ou comes and is associa ed wi h a dec ease in he isk o caesa ean sec ion. This ial was egis e ed a ClinicalT ials.go (NCT02582567) on Oc obe 20, 2015. In oduc ion Resea ch con inues o con i m ha exe cise du ing p egnancy con ibu es o heal hie ou - comes o bo h he mo he and he e us [1,2]. Consequen ly, exe cise is cu en ly ecom- mended in all low isk p egnancies [1]. Exe cise du ing p egnancy has been ela ed o an enhanced e iciency o he placen a [3] and he placen al u e ine pe usion [4], a lowe a e o caesa ean sec ions [1], and op imal bi h weigh [5]. Imp o ed physical i ness is usually obse ed in women who exe cise du ing p egnancy [6] and is associa ed wi h be e pe ina al heal h ou comes [7,8]. Howe e , while i is well-es ablished ha physical ac i i y imp o es bi h ou comes [9–11], s udies looking a he ela ionships be ween objec i e assessmen s o i ness and deli e y ype, ges a ional age, du a ion o labou s ages, bi h weigh and alues o umbilical co d blood gas a e limi ed. The causes o caesa ean sec ions and how o educe caesa ean sec ion a es a e now a spo - ligh o esea ch as his ype o deli e y has been associa ed wi h an inc eased isk o in ec ion compa ed wi h aginal deli e ies, highe wound dehiscence, haemo hage and educed e il- i y [12–14], as well as an inc eased isk o alle gies, ype 1 diabe es o espi a o y p oblems [15] in in an s, among o he complica ions. Fu he mo e, i is no ewo hy ha in 2016 in Spain he e we e 22% caesa ean sec ions in public hospi als [16], highe han he 15% a e ec- ommended by he Wo ld Heal h O ganiza ion [17]. The e o e, i is o g ea impo ance o clinical p ac ice o analyse he associa ions be ween ma e nal a iables and imp o emen s in he a es o caesa ean sec ions. Du ing p egnancy, u e ine blood low is c ucial o app op ia e nu ien and gas exchange wi h he e us [18]. I is widely known ha he umbilical co d blood pH analysis p o ides i al in o ma ion abou neona al heal h s a us and e lec s physiological esponse o complica ions ha may occu du ing labou [19]. We p e iously ound ha highe le els o ligh o mode a e physical ac i i y du ing p egnancy we e associa ed wi h g ea e umbilical a e ial oxygen sa u- a ion and highe le els o enous co d blood pH; con e sely, we showed ha highe le els o seden a y ime du ing p egnancy we e ela ed o wo se p egnancy ou comes [10]. Howe e , i is unknown whe he ma e nal physical i ness is also a key ac o o imp o e bi h ou comes such as ges a ional age, du a ion o labou , bi h weigh and alues o umbilical co d blood gas. This s udy highligh s he impo ance o app opia e le els and quali y o i ness ha should be emphazised in exe cise p og ams in o de o imp o e bi h ou comes. Fu he mo e, he associa ion o ma e nal physical i ness wi h e al acid-base balance has no been s udied. The measu emen o gases in he umbilical co d blood is a gold s anda d in he de e mina ion o he oe al acid-base balance [20]. In addi ion, he de e mina ion o PCO 2 is impo an , since highe le els o PCO 2 and a low pH le el indica e a s a e o e al acidosis [19,21]. On he o he hand, CO 2 p oduc ion is p opo ional o oxygen consump ion [22], so he in e p e a ion o PO 2 le els and oxygen sa u a ion also p o ides undamen al in o ma ion o de e mine he e ec i eness o he e al compensa o y mechanisms and he s a e o he placen a. The e o e, he aims o his s udy we e: i) o analyse he associa ion o ma e nal physical- i ness measu es du ing he ea ly second imes e and la e p egnancy wi h ma e nal (ges a ional age a bi h Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 2 / 18 01993) was suppo ed by he Spanish Minis y o Educa ion. This s udy was also pa ially unded by he Regional Minis y o Heal h o he Jun a de Andalucı ´a (PI-0395-2016) and he Uni e si y o G anada, Plan P opio de In es igacio ´n 2016, Excellence ac ions: Uni s o Excellence; Uni o Excellence on Exe cise and Heal h (UCEES). The unde s had no ole in s udy design, da a collec ion and analysis, decision o publish, o p epa a ion o he manusc ip . Compe ing in e es s: The au ho s ha e decla ed ha no compe ing in e es s exis . and leng h o he i s and second s ages o labou ) and neona al (bi h weigh and umbilical co d blood gas alues) ou comes; ii) o in es iga e whe he ma e nal physical- i ness du ing he ea ly second imes e and la e p egnancy may in luence he ype o bi h (i.e. aginal o caesa ean sec ion). Acco dingly, we hypo hesized ha ma e nal physical- i ness may be posi- i ely associa ed wi h imp o ed ma e nal and neona al ou comes. The aim o he s udy was o be e unde s and he in luence o ma e nal i ness du ing p egnancy on ma e nal and neona- al ou comes. Ma e ials and me hods S udy popula ion The de ailed p ocedu es, inclusion and exclusion c i e ia (S1 Table) o he GESTA ion and FITness (GESTAFIT) P ojec we e published elsewhe e [23]. Ini ially, his s udy was based on a andomized con ol ial design, ha was modi ied in o de o ensu e e en ion o women in he con ol g oup. Thus, women we e alloca ed ei he o an exe cise o a con ol g oup depending on hei pe sonal p e e ence and con enience o a end he in e en ion sessions and he wa e hey had been ec ui ed o . In his way, high d opou a es we e a oided, which is one o he mos equen me hodological ba ie s in an ena al exe cise esea ch, as p e i- ously a gued [24]. B ie ly, he in e en ion g oup unde wen a supe ised ae obic and s eng h aining in e en ion om he 17 h ges a ional week un il deli e y. A o al o 384 p egnan women we e in o med abou he P ojec du ing hei 12 h ges a ional week isi o he obs e i- cian a he “San Cecilio” Uni e si y Hospi al and “Vi gen de las Nie es” Uni e si y Hospi al (G anada, sou he n Spain). A inal numbe o 159 women we e in e es ed in pa icipa ing and signed an in o med consen . The GESTAFIT s udy was app o ed by he E hics Commi ee on Clinical Resea ch o G anada, Go e nmen o Andalusia, Spain (code: GESTAFIT-0448-N-15, app o ed on 19/05/2015). P ocedu es The i s e alua ion o he s udy was comple ed a he 16 h week o ges a ion (±2 weeks). Women comple ed a sel - epo ed ques ionnai e, an an h opome ic assessmen , and physical i ness es s. On he 34 h week o ges a ion (±2 weeks), he second assessmen o physical i ness es s and heigh and weigh was conduc ed. Bi h and obs e ic ou comes o he cu en p eg- nancy we e collec ed om he digi al medical eco ds ( he p egnancy heal h documen and he pa og am). Sampling o he umbilical co d occu ed 3 minu es a e bi h. Measu emen s Ma e nal sociodemog aphic da a. Sociodemog aphic da a (age, numbe o child en; ma i al, educa ional and wo king s a us) we e assessed wi h a sel - epo ed ques ionnai e. A esea ch s a was p esen a all imes o any needed explana ion o ins uc ion. Ma e nal an h opome ic assessmen . Heigh and weigh we e measu ed using a s adi- ome e (Seca 22, Hambu g) and a scale (InBody R20; Biospace, Seoul, Ko ea), espec i ely. Body mass index was calcula ed as: weigh (Kg)/heigh (m 2 ). P egnancy heal h. The “P egnancy Heal h Documen ” (Ca illa del emba azo in Spanish) is gi en o all p egnan women by he Andalusian egional go e nmen , and i con ains obs e - ic and medical da a eco ded du ing all he leng h o he p egnancy and we e collec ed o he p esen s udy. In his way, in o ma ion abou p e ious p egnancies, bi hs, and gynaecological an eceden s we e ob ained. The ges a ional age was calcula ed by he da e o he las mens ua- ion co ec ed o cycles o 28 days and subsequen ly co ec ed by ul asound, i needed [25], Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 3 / 18 and was used o an accu a e iming o he e alua ions a he 16 h and he 34 h weeks o p egnancy. Bi h ou comes. All da a ela ed o he ype o bi h (spon aneous aginal, ins umen al o caesa ean), ges a ional week a bi h, use o epidu al analgesia, leng h o each s age o labou , o sp ing sex, neona al weigh and Apga es we e ob ained om pe ina al obs e ic eco ds (pa og am) om he Hospi al a e bi h. The cause (unplanned o planned, and whe he i was elec ed o physiological easons) o caesa ean sec ions was anno a ed. We only had access o he pa og ams and samples o women who ga e bi h in he Public Hospi als app o ed by he E hics Commi ee. Howe e , he ype o deli e y was eco ded o all women. The placen a was collec ed immedia ely a e he deli e y and he placen al su ace clo s we e emo ed. The amnion was cu om he basal a ea and he umbilical co d was comple ely cu . Subsequen ly, placen a was weigh ed wi h a 3.200 kg P ecision G am Scale (Ohaus Com- pass TM , USA). Umbilical co d blood gas. Fo he umbilical co d blood sampling, a ained midwi e pe - o med a double clamping o he umbilical co d h ee minu es a e bi h, wi h a minimum dis ance be ween bo h clamps o 10 cen ime es. A p e-hepa inized 1mL sy inge was used o blood ex ac ion. Blood samples we e aken om bo h, umbilical a e y and ein. Pa ial p es- su e o ca bon dioxide (PCO2), pa ial p essu e o oxygen (PO2), oxygen sa u a ion and pH we e analysed using a blood analyse (GEM P emie 4000; Ins umen a ion Labo a o y, Bed- o d, MA, USA). Physical i ness. Physical i ness was assessed in he ollowing o de o a oid po en ially induced a igue om o he es s: Uppe -body muscula s eng h. Hand g ip s eng h was measu ed wi h digi al dynamome y (TKK 5101 G ip-D; Takey, Tokyo, Japan) a e adjus ing o he hand size o an op imal g ip [26]. The es was pe o med wice wi h bo h hands, wi h a es o 30 seconds and al e na ing hands. The inal alue was calcula ed as a mean o he wo alues om each hand. Lowe -body muscula s eng h. Muscula s eng h o he lowe -body was measu ed h ough he 30-second Chai S and es . This es coun s he maximum numbe o epe i ions com- ple ed in 30 seconds, wi h a ull s and o a si ing posi ion and back s aigh up as one epi i- ion. The pa icipan s pe o med one ial a e a amilia iza ion ial [27]. Flexibili y.The Back Sc a ch es was used o assess uppe -body lexibili y. The es consis s in measu ing he o e all shoulde ange o mo ion by measu ing he dis ance be ween he middle inge s coming oge he behind he back. The Back Sc a ch es ou come is posi i e o highe lex- ibili y (i.e. hands o e lapping behind he back) and nega i e o lowe lexibili y (i.e. g ea e dis- ance be ween middle inge s behind he back). This es was done wice wi h bo h hands and he inal sco e was calcula ed as he mean be ween he wo a emp s o each a m [27]. Ca dio espi a o y i ness. Maximal oxygen in ake (VO 2max ) was es ima ed (ml/Kg/min) h ough he Modi ied B uce eadmill p o ocol [28], a submaximal, inc emen al, mul is age, con inuous eadmill es . The es consis s o p og essi e inc emen s in he wo kload and eloci y e e y 3 minu es o de e mine limi s o maximal exe ion. Women we e asked o walk on he eadmill du ing he es un il he ma e nal hea a e eached 75% o he age-p edic ed maximal hea a e; i he pa icipan eques ed o end he eadmill es , hen he es was also s opped be o e eaching he hea a e alue. Al hough submaximal eadmill es ing is com- mon and sa e du ing p egnancy, women we e secu ed wi h a ha ness du ing he es o p e en any consequences om a all. This es has been p e iously used and shown o be sa e in p eg- nan women [28,29]. S a is ical analyses. We employed desc ip i e s a is ics [mean (s anda d de ia ion, SD)] o quan i a i e a iables and numbe o cases and pe cen age (%) o ca ego ical a iables. All he a iables we e checked o no mali y o dis ibu ion h ough ku osis and skewness Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 4 / 18 analyses be o e he analyses. All he ou come a iables easonably me his assump ion. The associa ions o physical i ness le els wi h ma e nal (ges a ional age a bi h and leng h o he i s and second s ages o labou ) and neona al (bi h weigh and umbilical co d blood gas al- ues) ou comes we e assessed wi h pa ial co ela ions a e adjus ing o ma e nal age, pa i y and BMI (Table 2). The associa ions o physical i ness le els wi h du a ion o he i s and sec- ond labou s ages, as well as neona al ou comes we e also adjus ed o epidu al analgesia, excep o he a iable “bi h weigh ” which was only u he adjus ed o ges a ional age. Since some a iables (ges a ional age a bi h, bi h weigh , du a ion o he i s and second s ages o labo and ins umen al deli e y) p e iously showed weak associa ions wi h ou come a iables (p>0.02), we pe o med seconda y analyses o assess hei ole as po en ial con ounde s. Changes be ween p e (16 h week) and pos (34 h week) e alua ions esul s o i ness es s we e analysed ia epea ed measu es T-Tes s (S2 Table). Subsequen ly, he changes (pos –p e) we e included in he linea eg ession analyses (Table 3) as p edic o a iables, whe eas he bi h ou comes we e included as ou come a iables in sepa a e models. Rele an con ounde s sugges ed by p e ious li e a u e wi h signi ican ela ionship wi h he ou comes, ha in lu- enced he ela ionship be ween he independen and dependen a iable (i.e. B o he indepen- den had a meaning ul change (p>0.05) when adding he a iable), we e included in he models. Depending on he aim o he analysis, he models we e adjus ed o none con ounde , o baseline alues o ca dio espi a o y i ness (CRF), o o baseline alues, age, pa i y, weigh change (pos –p e), and exe cise in e en ion (only a he 34 h -week analysis). The a iables showing he du a ion o he i s and second labou s ages, as well as neona al bi h ou comes we e addi ionally adjus ed o epidu al analgesia (as independen a iable), excep o he a i- able “bi h weigh ” which was only u he adjus ed o ges a ional age. Logis ic eg ession analysis was also employed o explo e he associa ions be ween physical i ness le els (p edic o a iable) and he chances o ha ing a aginal deli e y (spon aneous and ins umen al) o caesa ean sec ion (ou come a iable) (Table 4). We adjus ed he analysis o he abo e-men ioned co a ia es. We also conside ed “place o bi h” as a po en ial con- ounde due o he di e ences o caesa ean sec ion a ios be ween p i a e and public hospi als in Spain [30]. Hence, we decided o check wi h he Chi-squa ed es i he ype o hospi al migh ha e any in luence on ou come a iables. Gi en ha we ound s a is ically signi ican di e ences in bi h ou comes be ween p i a e and public hospi als wi hin ou da a, we decided o include his a iable as a po en ial con ounde . Finally, in he GESTAFIT p ojec [23], a concu en physical exe cise p og am was pe o med. We ha e also adjus ed all he models o he exe cise in e en ion (con ol o in e en ion). We c ea ed a clus e ed o e all physical i ness (Z-sco e) as he mean o he s anda dized sco es [( alue–mean)/ s anda d de ia ion] o body s eng h (mean o uppe and lowe - body s eng h s anda dized alues), lexibili y and CRF a he 16 h week o p egnancy (Fig 2A) and he 34 h week o p egnancy (Fig 2B). Bo h clus e ed g oups we e compa ed by caesa ean o aginal deli e y wi h an ANCOVA analysis. We adjus ed he analysis o ma e nal age, pa i y, ma e nal BMI a he 16 h ges a ional week, exe cise in e en ion and bi h place (public o p i a e hospi al). The s a is ical analyses we e conduc ed wi h he S a is ical Package o Social Sciences (IBM SPSS S a is ics o Windows, Ve sion 20.0. A monk, NY: IBM Co p). The s a is ical signi i- cance was se a p<0.05. Resul s O all he 159 pa icipan s, 158 had comple e sociodemog aphic da a (Fig 1). The inal sample size was composed o 158 Caucasian p egnan women (age 32.9±4.6 yea s, BMI 24.9±4.1 kg/ m 2 ) wi h alid da a o he p esen analyses. A he 16 h and 34 h weeks o p egnancy, 156 and Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 5 / 18 Fig 1. Flowcha in he selec ion o s udy pa icipan s o speci ic s udy aims. h ps://doi.o g/10.1371/jou nal.pone.0229079.g001 Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 6 / 18 124 women pa icipa ed in he physical i ness es s (Fig 1). A o al o 18 pa og ams we e no ound in he in o ma ic sys em (n = 9) o could no be collec ed as some pa icipan s deli e ed in a p i a e hospi al no associa ed wi h he s udy (n = 9) and pa og ams could no be accessed, nei he could he samples o placen a be collec ed. Howe e , he ype o deli e y was eco ded o he deli e ies in p i a e hospi als. Hence, a o al o 141 women had comple e alid da a o bi h ou comes. The sociodemog aphic and clinical cha ac e is ics o he s udy pa icipan s a e shown in Table 1. Mos o he pa icipan s li ed wi h hei pa ne and mo e han hal had Uni e si y educa ion and wo ked ull ime. App oxima ely 61% o he sample we e nullipa ous and 75.6% had aginal bi hs. Bi hs ook place a ound 39.5±1.3 weeks o ges a ion, wi h a mean neona e body weigh o 3305±480.6 g ams. A he 16 h and 34 h ges a ional weeks, mean alues we e simila in uppe -body s eng h (Hand g ip); lowe -body s eng h (Chai s and); and 4.1 ±6.2 cm and 3.9±6 cm in lexibili y es (Back Sc a ch) (all, p>0.05), bu dec eased in CRF 22.1 ±5.5 ml/Kg/min and 17.9±4.9 ml/Kg/min (p<0.001) (Modi ied B uce eadmill es ). All umbilical co d blood gas mean alues we e wi hin no mal anges. Pea son’s pa ial co ela ions o physical i ness le els a he 16 h and he 34 h ges a ional weeks wi h ma e nal and neona al ou comes a e shown in Table 2.Rega ding he ma e nal ou comes, physical i ness le els we e no associa ed wi h hese measu es. In ela ion o neona al ou comes, uppe -body muscle s eng h a he 16 h week o ges a ion was associa ed wi h highe bi h weigh ( = 0.191, p<0.05). Lowe -body muscle s eng h was no associa ed wi h any ma e nal and neo- na al ou come (p>0.05). G ea e ma e nal lexibili y a he 16 h week was associa ed wi h a mo e alkaline pH ( = 0.220, p<0.05), highe PO 2 ( = 0.237, p<0.05), highe a e ial oxygen sa u a ion ( = 0.242, p<0.05), and lowe PCO 2 ( = -0.331, p<0.01) in a e ial umbilical co d blood. Ma e - nal CRF a he 16 h week was ela ed o highe PO 2 ( = 0.267, p<0.05) and highe oxygen sa u a- ion ( = 0.375, p<0.01) in a e ial umbilical co d blood. Physical i ness le els a he 34 h week o p egnancy we e no associa ed wi h any ma e nal and neona al bi h ou comes (all, p>0.05). S2 Table, compa ing he i ness le els a he 16 h and he 34 h weeks o ges a ion, he e we e no di e ences in lexibili y, uppe - o lowe -body s eng h be ween he di e en ime poin s. CRF dec eased by 4.14 (5.07) ml/kg/min om he 16 h o he 34 h weeks o ges a ion (95% CI: 3.01, 5.27; p<0.001). The associa ions o he changes in CRF wi h bi h ou comes a e shown in Table 3. A e ial co d blood PO 2 and O 2 sa u a ion we e in e sely associa ed wi h he CRF change (B = -0.603; 95% CI: -1.101, -0.105; p = 0.019, and B = -1.544; 95% CI: -2.720, -0.368; p = 0.011, espec i ely), wi h simila esul s in he model adjus ed o baseline CRF, age, pa i y, weigh change and exe cise in e en ion. The model adjus ed only o baseline alues o CRF showed an in e se associa ion be ween CRF change and a e ial co d blood PO 2 (B = -0.622; 95% CI: -1.221, -0.023; p = 0.042). Di e ences in physical i ness le els a he 16 h and 34 h ges a ional weeks by bi h ype ( aginal o caesa ean sec ion) a e shown in Table 4. A he 16 h week o p egnancy, no signi i- can di e ences we e ound in uppe - and lowe -body muscle s eng h be ween women who had aginal bi hs compa ed wi h women who had caesa ean sec ions (bo h, p>0.05). The mean o lexibili y le els was +2.4 (4.7) cm in he Back Sc a ch es in women who had caesa - ean sec ions compa ed wi h +5.0 (6.2) cm in women who had aginal bi hs (95% CI -0.027, -0.020; p= 0.027). Finally, women who had caesa ean sec ions had a mean o CRF o 18.4 (4.2) ml/kg/min in he Modi ied B uce es compa ed wi h women wi h a aginal bi h who had 23.3 (5.7) ml/kg/min in CRF (95% CI: -0.035, -0.009; p = 0.001). Fo physical i ness a he 34 h week o ges a ion, lexibili y was highe in women who had aginal bi hs wi h 4.9 (6.0) cm, han in women wi h caesa ean sec ion, 1.0 (5.8) cm (95% CI: 0.027, 0.001; p = 0.033). Fig 2A and Fig 2B show he clus e ed o e all physical i ness a he 16 h and 34 h weeks o ges a ion, espec i ely. Rela i e o women who had aginal bi hs, women who had caesa ean Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 7 / 18 Fig 2. h ps://doi.o g/10.1371/jou nal.pone.0229079.g002 Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 8 / 18 Table 1. Sociodemog aphic and clinical cha ac e is ics o he s udy sample (n = 158). Ma e nal cha ac e is ics n Mean (SD) Age, yea s 158 32.9 (4.6) Body mass index a he 16 h ges a ional week, Kg/m 2 158 24.9 (4.1) Body mass index a he 34 h ges a ional week, Kg/m 2 158 27.8 (4.1) Weigh a he 16 h ges a ional week, Kg 157 67.04 (11.8) Weigh a he 34 h ges a ional week, Kg 123 74.57 (10.8) Weigh change ( om he 16 h o he 34 h ges a ional weeks) 121 8.7 (3.4) E hnici y (Caucasian) 158 158 (100) n (%) Li ing wi h a pa ne , 154 (97.5) Educa ional s a us 158 P ima y o high-school 37 (23.4) Specialized aining 27 (17.1) Uni e si y deg ee 94 (59.5) Wo king s a us 158 Homewo k/unemployed 48 (30.4) Pa ial- ime employed/s uden 41 (25.9) Full- ime employed 69 (43.7) Type o bi h 143 Spon aneous 83 (58) Ins umen al acuum/ o ceps 24 (16.8) Caesa ean sec ion 36 (25.5) Planned ( ee o bu ocks coming i s ) 7 (27.5) Bi h place 147 Public Hospi al 138 (93.9) P i a e Hospi al 8 (5.4) Home 1 (0.7) Pa i y 158 Nullipa ous 96 (60.8) Mul ipa ous 62 (39.2) Physical i ness a he 16 h ges a ional week Mean (SD) Uppe -body s eng h (Hand g ip),mean (Kg) 156 27.2 (4.2) Lowe -body s eng h (Chai s and),numbe o epe i ions 93 15.7 (2.4) Flexibili y (Back Sc a ch),mean (cm) 156 4.1 (6.2) CRF (Modi ied B uce es ),VO 2max 127 22.2 (5.5) Physical i ness a he 34 h ges a ional week Uppe -body s eng h (Hand g ip),mean (Kg) 124 27.2 (4.4) Lowe -body s eng h (Chai s and),numbe o epe i ions 65 15.9 (2.5) Flexibili y (Back Sc a ch),mean (cm) 123 3.9 (6) CRF (Modi ied B uce es ),VO 2max 97 17.9 (4.9) Neona al ou comes Sex ( emale, n (%)) 141 72 (51.4) Ges a ional age a bi h, wk 141 39.5 (1.3) Bi h weigh , g ams 141 3305 (480.6) Placen al weigh , g ams 106 573.7 (102.6) Apga sco e 1 minu e 138 8.6 (1) Apga sco e 5 minu es 138 9.6 (0.7) Umbilical Co d blood Gas (Con inued) Associa ion o physical i ness and ma e nal and neona al bi h ou comes PLOS ONE | h ps://doi.o g/10.1371/jou nal.pone.0229079 Feb ua y 18, 2020 9 / 18 8. 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