Research Updates 2001–2005

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The staff of Danc­ing Thru Preg­nan­cy® (DTP) reg­u­lar­ly mon­i­tors research and applies find­ings to the devel­op­ment of best prac­tices, in order to keep our pro­grams and edu­ca­tion­al sem­i­nars safe, effec­tive, and up-to-date.

Sum­mer 2005 — mod­er­ate exer­cise and breast milk; adverse effects of sta­t­ic stretch­ing dur­ing warm-up activ­i­ty; phys­i­cal activ­i­ty, cop­ing mech­a­nisms, and women’s expe­ri­ence of birth; the effec­tive­ness of strength­en­ing exer­cis­es for post­par­tum pelvic gir­dle pain

Win­ter 2005 — poten­tial mech­a­nism where­by exer­cise may reduce the risk of preeclamp­sia; pre­na­tal activ­i­ty ques­tion­naire; and, exer­cise and post­par­tum well-being

Win­ter 2004 — pre­na­tal aer­o­bic activ­i­ty reduces risk of preeclamp­sia and low birth weight, and improves tol­er­ance for labor; post­par­tum group exer­cise may ben­e­fit mom

Fall 2003 — mater­nal exer­cise and its impact on fetal oxy­gen, sub­strate deliv­ery, hor­mone response

Sum­mer 2002 — mater­nal exer­cise, oxida­tive stress and long term car­dio­vas­cu­lar impact on off­spring health

Spring 2002 — review of research find­ings on exer­cise in preg­nan­cy and the ear­ly post­par­tum peri­od

Sum­mer 2001- mater­nal aer­o­bics and birth out­comes in first time moth­ers, por­tal vein flow, and meta­bol­ic mark­ers; strength train­ing in late ges­ta­tion

For research on nutri­tion, go to Nutri­tion in the sec­tion under Tips/Classes.

For research on menopause, hor­mone replace­ment and exer­cise, go to Menopause below.

Sum­mer 2005

A study on breast milk in exer­cis­ing moms con­clud­ed that moms who are breast­feed­ing can exer­cise mod­er­ate­ly with­out dimin­ish­ing the amount of vital fat­ty acids in their breast milk. In fact, the con­cen­tra­tion of cer­tain fats involved in infant growth and devel­op­ment may tem­porar­i­ly increase right after a bout of mod­er­ate activ­i­ty. The authors sug­gest that exer­cise could ben­e­fit breast­feed­ing moth­ers and babies.

Source: Bopp M; Love­la­dy C; Hunter C; Kin­sel­la T. (2005). Mater­nal diet and exer­cise: Effects on long-chain polyun­sat­u­rat­ed fat­ty acid con­cen­tra­tions in breast milk. J Am Diet Assoc, 105(7):1098–1103.

Researchers found that stretch­ing to the point of dis­com­fort can adverse­ly affect per­for­mance tests of sta­t­ic bal­ance and move­ment and reac­tion times in healthy males. Fur­ther­more, insert­ing a stretch­ing rou­tine with­in a rest peri­od of a warm-up nul­li­fies a small ben­e­fit in move­ment and reac­tion times and bal­ance per­for­mance. These find­ings sup­port DTP’s long-stand­ing rec­om­men­da­tion that range of motion (ROM) activ­i­ties and games be employed, rather than sta­t­ic stretch­ing, in the lead up to aer­o­bic activ­i­ty.

Source: Behm DG; Bam­bury A; Cahill F; Pow­er K. (2004). Effect of acute sta­t­ic stretch­ing on force, bal­ance, reac­tion time, and move­ment time. Med Sci Sport Ex, 36(8):1397–402.

The fol­low­ing arti­cle lends sup­port to the idea that phys­i­cal activ­i­ty that includes cop­ing tech­niques for labor may well con­tribute to a woman’s sat­is­fac­tion with her expe­ri­ence of birth.

The pain expe­ri­ences of cul­tur­al­ly diverse child­bear­ing women are described based on a sec­ondary analy­sis of nar­ra­tive data from phe­nom­e­no­log­ic stud­ies of the mean­ing of child­birth. Find­ings by Cal­lis­ter, et al. indi­cate that under­stand­ing the mean­ing of pain, women’s per­cep­tions of pain, and cul­tur­al­ly bound pain behav­iors is fun­da­men­tal in order for nurs­es to facil­i­tate sat­is­fy­ing birth expe­ri­ences for cul­tur­al­ly diverse women. Study par­tic­i­pants were inter­viewed in the hos­pi­tal after giv­ing birth or in their homes with­in the first weeks after hav­ing a baby. Tran­scripts of inter­views with child­bear­ing women who lived in North and Cen­tral Amer­i­ca, Scan­di­navia, the Mid­dle East, the People’s Repub­lic of Chi­na, and Ton­ga were ana­lyzed. Par­tic­i­pants described their atti­tudes toward, per­cep­tions of, and the mean­ing of child­birth pain. Cul­tur­al­ly bound behav­ior in response to child­birth pain was also artic­u­lat­ed. A vari­ety of cop­ing mech­a­nisms were used by women to deal with the pain.

Source: Cal­lis­ter, et al. (2003). The pain of child­birth: Per­cep­tions of cul­tur­al­ly diverse women. Pain Man­ag Nurs, 4(4):145–154.

Exer­cis­es designed to strength­en the mus­cles that sup­port that pelvic gir­dle can ease post­par­tum pelvic gir­dle pain. After treat­ment and at one year post­par­tum, women who per­formed sta­bi­liz­ing exer­cis­es report­ed reduced pain inten­si­ty and dis­abil­i­ty, and improved qual­i­ty of life. Accord­ing to researchers, an indi­vid­u­al­ized treat­ment approach with spe­cif­ic sta­bi­liz­ing exer­cis­es appears to be more effec­tive than phys­i­cal ther­a­py with­out spe­cif­ic sta­bi­liz­ing exer­cis­es for women with pelvic gir­dle pain after preg­nan­cy.

Source: Stuge B; Laerum E; Kirkeso­la G; Vollestad N. (2004). The effi­ca­cy of a treat­ment pro­gram focus­ing on spe­cif­ic sta­bi­liz­ing exer­cis­es for pelvic gir­dle pain after preg­nan­cy: a ran­dom­ized con­trolled tri­al. Spine, 29(4):351–9.

Win­ter 2005

Based on the epi­demi­o­log­i­cal find­ings of Soren­son et al (see Win­ter 2004 update) and oth­ers, the the­o­ry has been pro­posed that there are three mech­a­nisms that might account for the reduced lev­el of preeclamp­sia found in phys­i­cal­ly fit preg­nant women. These are 1) stim­u­la­tion of pla­cen­tal growth and vas­cu­lar­i­ty, 2) reduc­tion of oxida­tive stress, and 3) exer­cise-induced rever­sal of mater­nal endothe­lial dys­func­tion. The authors rec­om­mend future research include prospec­tive epi­demi­o­log­ic case-con­trol stud­ies that accu­rate­ly mea­sure occu­pa­tion­al and recre­ation­al phys­i­cal activ­i­ty dur­ing preg­nan­cy, as well as con­trolled ran­dom­ized clin­i­cal tri­als that look at the effect of mater­nal exer­cise on bio­chem­i­cal mark­ers for endothe­lial dys­func­tion, pla­cen­tal dys­func­tion and oxida­tive stress.

Source: Weiss­ger­ber, TL, Wolfe , LA , and Davies, GAL. The Role of Reg­u­lar Phys­i­cal Activ­i­ty in Preeclamp­sia Pre­ven­tion. Med­i­cine and Sci­ence in Sports and Exer­cise 36(12):2024–2031, 2004 Dec.

Researchers devel­oped and test­ed a preg­nan­cy phys­i­cal activ­i­ty ques­tion­naire (PPAQ) to ascer­tain the type, dura­tion, and fre­quen­cy of phys­i­cal activ­i­ties per­formed by preg­nant women in household/caregiving, occu­pa­tion­al, sports/exercise, trans­porta­tion and inac­tiv­i­ty. The authors con­clude that their research indi­cates the PPAQ is a reli­able and rea­son­ably accu­rate mea­sure of a broad range of phys­i­cal activ­i­ties dur­ing preg­nan­cy.

Source: Chasan-Taber, L, Schmidt , MD , Roberts, DE, Hos­mer, D, Marken­son, G, Freed­son, PS. Devel­op­ment and Val­i­da­tion of a Preg­nan­cy Phys­i­cal Actvi­ty Que­sionnnaire. Med­i­cine and Sci­ence in Sports and Exer­cise 36(10):1750–1760, 2004 Oct.

In a study that exam­ined mater­nal well-being in post­par­tum sub­jects on the basis of sport/exercise (SE) activ­i­ty prepreg­nan­cy to post­par­tum, researchers found that post­par­tum SE, edu­ca­tion and socioe­co­nom­ic sta­tus were pre­dic­tors of mater­nal well-being and that fam­i­ly and social sup­port were sig­nif­i­cant fac­tors in main­tain­ing or increas­ing SE. These find­ings sup­port the find­ings of Sampselle et al (see Spring 2002 update, ref­er­ence 12).

Source: Blum, JW, Beau­doin, CM, Caton-Lemos, L. Phys­i­cal activ­i­ty pat­terns and mater­nal well-being in post­par­tum women. Mater­nal and Child Health Jour­nal 8(3):163–169, 2004, Sept.

Win­ter 2004

Recre­ation­al aer­o­bic phys­i­cal activ­i­ty in ear­ly preg­nan­cy and/or the year pri­or to preg­nan­cy is asso­ci­at­ed witha a sig­nif­i­cant reduc­tion in the risk of preeclamp­sia. Depend­ing on the inten­si­ty of exer­cise, risk was reduced by 24% to 54%.

Source: Soren­son, TK et al. Recre­ation­al phys­i­cal activ­i­ty dur­ing preg­nan­cy and risk of preeclamp­sia. Hyper­ten­sion. 41(6):1273–80, 2003 Jun.

Recre­ation­al phys­i­cal activ­i­ty reduces the risk of low birth weight infants.

Source: Leifer­man JA. Even­son KR. The effect of reg­u­lar leisure phys­i­cal activ­i­ty on birth out­comes. Mater­nal & Child Health Jour­nal. 7(1):59–64, 2003 Mar.

Women who do aer­o­bic exer­cise through the entire preg­nan­cy tol­er­ate labor bet­ter phys­i­cal­ly than those who do not. Reg­u­lar mater­nal exer­cise may reduce labor-induced lipid per­ox­i­da­tion by improv­ing the defense capa­bil­i­ties against free rad­i­cal gen­er­a­tion.

Source: Kobe H. Nakai A. Koshi­no T. Ara­ki T. Effect of reg­u­lar mater­nal exer­cise on lipid per­ox­i­da­tion lev­els and antiox­i­dant enzy­mat­ic activ­i­ties before and after deliv­ery. Jour­nal of Nip­pon Med­ical School . 69(6):542–8, 2002 Dec.

There is increas­ing evi­dence that women who pur­sue group exer­cise in the post­par­tum peri­od are at reduced risk for post­par­tum depres­sion. This study sug­gest addi­tion­al stud­ies are need­ed.

Source: Cur­rie J. Pramwalk­ing as post­na­tal exer­cise and sup­port. Aus­tralian Jour­nal of Midwifery14(2):21–5, 2001 Jun.

Fall 2003

Sus­tained bouts of mater­nal exer­cise dur­ing preg­nan­cy cause an acute reduc­tion in oxy­gen and nutri­ent deliv­ery to the pla­cen­tal site. The decreased flow also ini­ti­ates a slight fall in inter­vil­lous and fetal pO2 which ini­ti­ates a fetal sym­pa­thet­ic response. This, cou­pled with hemo­con­cen­tra­tion and improved pla­cen­tal per­fu­sion bal­ance, main­tains fetal tis­sue per­fu­sion and oxy­gen uptake. Exer­cise train­ing dur­ing preg­nan­cy (reg­u­lar bouts of sus­tained exer­cise) increas­es rest­ing mater­nal (and per­haps fetal) plas­ma vol­ume, inter­vil­lous space blood vol­ume, car­diac out­put and pla­cen­tal func­tion. These changes buffer the acute reduc­tions in oxy­gen and nutri­ent deliv­ery dur­ing exer­cise and prob­a­bly increase 24 h nutri­ent deliv­ery to the pla­cen­tal site. Thus, the effect of any giv­en exer­cise reg­i­men on fetal growth and size at birth is depen­dent on the type, fre­quen­cy, inten­si­ty and dura­tion of the exer­cise as well as the time point in the preg­nan­cy when the exer­cise is per­formed. Mater­nal car­bo­hy­drate intake is yet anoth­er mod­i­fy­ing fac­tor. Begin­ning a mod­er­ate exer­cise reg­i­men increas­es both anatom­ic mark­ers of pla­cen­tal func­tion and size at birth while main­tain­ing a rig­or­ous exer­cise reg­i­men through­out preg­nan­cy selec­tive­ly reduces growth of the fetal fat organ and size at birth. Like­wise, decreas­ing exer­cise per­for­mance in late-preg­nan­cy increas­es size at birth while increas­ing exer­cise per­for­mance decreas­es it. Final­ly, the infants born of exer­cis­ing women who eat car­bo­hy­drates which ele­vate 24 h blood glu­cose lev­els are large at birth irre­spec­tive of exer­cise per­for­mance.

Source: Clapp JF 3rd. The effects of mater­nal exer­cise on fetal oxy­gena­tion and feto-pla­cen­tal growth. Euro­pean Jour­nal of Obstet­rics, Gyne­col­o­gy, & Repro­duc­tive Biol­o­gy. 110 Sup­pl 1:S80-5, 2003 Sep­tem­ber 22.

Exam­in­ing the effects of mater­nal exer­cise on sub­strate uti­liza­tion and hor­mone respons­es, Bessinger et al found no sig­nif­i­cant dif­fer­ences between exer­cise tri­als in oxy­gen uptake, res­pi­ra­to­ry exchange ratio, or heart rate. Preg­nan­cy ele­vat­ed rest­ing triglyc­eride lev­els but low­ered plas­ma glu­cose lev­els. Exer­cise dur­ing preg­nan­cy caused a reduc­tion in plas­ma glu­cose lev­els but ele­vat­ed cir­cu­lat­ing triglyc­eride lev­els (P <.05). Rest­ing lev­els of cor­ti­sol, growth hor­mone, and insulin were ele­vat­ed dur­ing preg­nan­cy com­pared with after deliv­ery, but rest­ing glucagon lev­els were not affect­ed bypreg­nan­cy. Exer­cise caused cir­cu­lat­ing lev­els of cor­ti­sol, growth hor­mone, and glucagon to increase (P <.05). The exer­cise-induced change in the cor­ti­sol lev­el was greater dur­ing preg­nan­cy than that after deliv­ery. The exer­cise-induced changes in growth hor­mone and glucagon lev­els were great­est after deliv­ery com­pared with those dur­ing preg­nan­cy (P <.05). Exer­cise reduced insulin lev­els (P <.05), with the great­est reduc­tion at 33 weeks’ ges­ta­tion. There were no sig­nif­i­cant dif­fer­ences in urine urea nitro­gen excre­tion as a result of exer­cise. The authors con­clud­ed that pro­tein appears to be a rel­a­tive­ly unim­por­tant fuel dur­ing a 30-minute bout of mod­er­ate inten­si­ty exer­cise in this group of women eval­u­at­ed dur­ing preg­nan­cy and after deliv­ery. Fur­ther­more, a 30-minute bout of mod­er­ate inten­si­ty exer­cise would not be expect­ed to com­pro­mise fetal amino acid avail­abil­i­ty.

Source: Bessinger RC. McMur­ray RG. Hack­ney AC. Sub­strate uti­liza­tion and hor­mon­al respons­es to mod­er­ate inten­si­ty exer­cise dur­ing preg­nan­cy and after deliv­ery. Amer­i­can Jour­nal of Obstet­rics & Gyne­col­o­gy. 186(4):757–64, 2002 Apr.

Sum­mer 2002

The fol­low­ing excerpt from a recent review on the mech­a­nisms of car­dio­vas­cu­lar dis­eases does a good job of elu­ci­dat­ing one of the rea­sons preg­nant women should be exer­cis­ing. Per­sons wish­ing to read the entire arti­cle and exam­ine the ref­er­ences (num­bers includ­ed with­in the text below), should refer to Med­Line or the ACOG web­site.

Source: Napoli , Clau­dio MD, PhD; Ler­man, Lilach O. MD, PhD

Involve­ment of Oxi­da­tion-Sen­si­tive Mech­a­nisms in the Car­dio­vas­cu­lar Effects of Hyper­c­ho­les­terolemia [Review]. Mayo Clin­ic Pro­ceed­ings 76(6):619–631, 2001

Excerpt:

EFFECTS OF HYPERCHOLESTEROLEMIA AND INCREASED OXIDATION ON EARLY ATHEROGENESIS IN HUMANS

Until recent­ly, athero­ge­n­e­sis was thought to begin dur­ing late child­hood, although fat­ty streaks had occa­sion­al­ly been observed in younger children.163,164 How­ev­er, a sys­tem­at­ic mor­pho­me­t­ric analy­sis of the entire aor­ta of pre­ma­ture human fetus­es demon­strat­ed that for­ma­tion of fat­ty streaks, the pre­cur­sors of more advanced ath­er­o­scle­rot­ic lesions, is preva­lent in all fetal aor­tas and that their num­ber and size are marked­ly increased in fetus­es whose moth­ers had hyper­c­ho­les­terolemia dur­ing pregnancy.138 Fetal lesions con­tained typ­i­cal com­po­nents of ear­ly ath­er­o­scle­rot­ic lesions, such as native and oxi­dized LDL and macrophages, and their dis­tri­b­u­tion reflect­ed that of more advanced ath­er­o­scle­ro­sis seen in adults, ie, most exten­sive in the abdom­i­nal aor­ta, fol­lowed by the aor­tic arch. This sug­gests that, dur­ing the ear­li­er stages of preg­nan­cy, mater­nal hyper­c­ho­les­terolemia may pro­mote ear­ly athero­ge­n­e­sis in the fetus.165,166 The assump­tion that LDL oxi­da­tion is a con­trib­u­tor to athero­ge­n­e­sis in fetal arter­ies was also sup­port­ed by a lat­er study 167 in which the mid­dle cere­bral and basi­lar arter­ies of fetus­es con­tained sig­nif­i­cant­ly small­er lesions than the aor­ta and com­mon carotid arter­ies. Deter­mi­na­tions of the arte­r­i­al activ­i­ties of oxy­gen-rad­i­cal scav­engers, such as man­ganese super­ox­ide dis­mu­tase, cata­lase, and glu­tathione per­ox­i­dase, indi­cat­ed that over­all intracra­nial arter­ies of human fetus­es were bet­ter pro­tect­ed against oxi­da­tion than extracra­nial arteries.167 These results are con­sis­tent with the assump­tion that bet­ter pro­tec­tion against free rad­i­cal-medi­at­ed oxi­da­tion may con­tribute to the greater resis­tance of intracra­nial arter­ies to hyper­c­ho­les­terolemia-induced athero­ge­n­e­sis and vas­cu­lar dysfunction.168

To inves­ti­gate whether fetal lesions regress and/or whether they influ­ence athero­ge­n­e­sis dur­ing child­hood and ado­les­cence, the Fate of Ear­ly Lesions in Chil­dren (FELIC) study was designed.139 Ath­er­o­scle­ro­sis was estab­lished by com­put­er-assist­ed image analy­sis in nor­mo­c­ho­les­terolemic chil­dren and was found to progress much faster in chil­dren whose moth­ers had hyper­c­ho­les­terolemia dur­ing preg­nan­cy than in chil­dren of nor­mo­c­ho­les­terolemic moth­ers, despite nor­mal lipid pro­files in both groups of chil­dren. None of the risk fac­tors of athero­ge­n­e­sis assessed in these chil­dren could account for the faster athero­ge­n­e­sis in chil­dren of hyper­c­ho­les­terolemic moth­ers. Although parental genet­ic dif­fer­ences are like­ly to con­tribute to the dif­fer­ent sus­cep­ti­bil­i­ty of chil­dren to the dis­ease, we pos­tu­lat­ed that mater­nal-fetal hyper­c­ho­les­terolemia induced con­sti­tu­tive changes in gene expres­sion in arte­r­i­al cells, which were asso­ci­at­ed with a greater sus­cep­ti­bil­i­ty to the dis­ease lat­er in life.165,166 A recent study demon­strat­ed that fetal lesions in the rab­bit can be reduced with vit­a­min E or cholestyra­mine treat­ment of the hyper­c­ho­les­terolemic moth­ers dur­ing pregnancy.169

Mater­nal hyper­c­ho­les­terolemia dur­ing ges­ta­tion should there­fore be added to the list of risk fac­tors deter­min­ing the need for mon­i­tor­ing and for pre­ven­tive therapy.170 Cur­rent clin­i­cal guide­lines place great empha­sis on ear­ly detec­tion of hypercholesterolemia,171 although such screen­ing would not detect an increased risk asso­ci­at­ed with mater­nal hyper­c­ho­les­terolemia in nor­mo­c­ho­les­terolemic sub­jects. An intense lipid-low­er­ing inter­ven­tion may be a ther­a­peu­tic option for chil­dren with sev­er­al risk fac­tors. As indi­cat­ed by a recent meta-analy­sis of stud­ies on the devel­op­ment of coro­nary artery dis­ease in chil­dren and adolescents,172 an aver­age reduc­tion of LDL cho­les­terol by 25% can be obtained with statins in com­bi­na­tion with a lipid-low­er­ing diet. Statins are gen­er­al­ly well tol­er­at­ed in chil­dren and ado­les­cents, and cur­rent data do not indi­cate adverse effects on growth and sex­u­al devel­op­ment in male ado­les­cents. In high-risk chil­dren, fol­low-up may need to include an attempt for an ear­li­er than usu­al non­in­va­sive diag­no­sis of ath­er­o­scle­ro­sis. Poten­tial approach­es include mea­sure­ment of coro­nary flow veloc­i­ty in the dis­tal left ante­ri­or descend­ing ( LAD ) coro­nary artery with transtho­racic Doppler echocardiography,173 deter­mi­na­tion of the degree of steno­sis in the prox­i­mal LAD coro­nary artery by trans­esophageal Doppler study 174 or mag­net­ic res­o­nance imaging,175 mea­sure­ment of coro­nary flow reserve in the LAD coro­nary artery by con­trast-enhanced transtho­racic sec­ond har­mon­ic echocardiography/Doppler study,176 or quan­tifi­ca­tion of coro­nary cal­ci­fi­ca­tions by elec­tron beam com­put­ed tomography.177–179

Anoth­er clin­i­cal sce­nario that may involve dys­lipi­demia and oxida­tive stress is the preg­nan­cy-relat­ed preeclamp­sia syn­drome, the eti­ol­o­gy and patho­gen­e­sis of which remain poor­ly understood.180 Recent evi­dence points to a pro-oxi­dant shift in preeclamp­sia, and ROS and/or their metabo­lites have been hypoth­e­sized to ulti­mate­ly com­pro­mise the vasodila­to­ry, anti­ag­gre­ga­to­ry, and bar­ri­er defense func­tions of the endothe­li­um. Fail­ure of flow-induced shear stress may con­tribute to the ges­ta­tion­al hyper­ten­sion of preeclampsia.181 Mater­nal dys­lipi­demia and altered iron kinet­ics in preeclamp­sia may poten­tial­ly affect dis­ease progression.180 Oxida­tive stress as a result of inter­ac­tion of feto­pla­cen­tal and mater­nal fac­tors and autoim­mune reac­tion may lead to the man­i­fes­ta­tions of preeclamp­sia. For exam­ple, inter­ac­tion of mater­nal neu­trophils and oxi­dized lipids with pla­cen­tal cells and pla­cen­ta-derived fac­tors can engen­der a vicious cycle of oxida­tive stress that may ulti­mate­ly cause wide­spread endothe­lial cell dys­func­tion and phys­i­o­log­i­cal per­tur­ba­tions down­stream of cel­lu­lar sig­nal­ing. A ran­dom­ized con­trolled tri­al recent­ly showed that vit­a­min C and E sup­ple­men­ta­tion may be ben­e­fi­cial in women with or at increased risk for preeclampsia,182 sug­gest­ing that the “pri­mum movent” of the dis­ease was increased lipid oxi­da­tion dur­ing preg­nan­cy.

CONCLUSIONS

Hyper­c­ho­les­terolemia is a com­mon clin­i­cal dis­or­der that may begin ear­ly in life in humans, and it sub­se­quent­ly pro­motes athero­ge­n­e­sis by injur­ing the vas­cu­lar wall, there­by impair­ing a mul­ti­tude of func­tions and sig­nal­ing path­ways that it con­trols and lead­ing to devel­op­ment of athero­ma­tous plaques. The under­ly­ing mech­a­nisms respon­si­ble for these abnor­mal­i­ties may emanate from acti­va­tion of oxi­da­tion-sen­si­tive mech­a­nisms, increased oxi­da­tion of LDL cho­les­terol, and quench­ing of NO. This cas­cade of events can begin as ear­ly as dur­ing preg­nan­cy, alter­ing the com­plex frame­work of sig­nal­ing net­work in the arte­r­i­al wall. Nov­el treat­ment strate­gies* that attempt to decrease oxi­da­tion and restore bioavail­abil­i­ty of NO have the poten­tial to decrease mor­pho­log­ic and func­tion­al arte­r­i­al dam­age and improve car­dio­vas­cu­lar out­comes in patients with hyper­c­ho­les­terolemia.

* Ann’s note: “Nov­el treat­ment strate­gies” refers to exer­cise, among oth­er things.

Spring 2002

Review of Research Find­ings on Exer­cise in Preg­nan­cy

Note: Since the orig­i­nal post­ing of this update, Kramer, in his Cochrane review, raised doubts about the incon­sis­ten­cy and low num­bers in the method­ol­o­gy of research con­clud­ing that fit­ness impacts labor, birth or fetal out­comes, although he does con­clude that mater­nal exer­cise does lead to phys­i­cal fit­ness, and improved self-image and con­fi­dence in one’s body. None-the-less, on the basis of sub­se­quent research and a re-review of research pre­vi­ous­ly exam­ined, DTP holds to the view that fit­ness improves labor and birth out­comes, and may well be a fac­tor in reduc­ing the need for med­ical inter­ven­tion in labor. How­ev­er, because of the grow­ing need for obste­tri­cians and mid­wives to prac­tice defen­sive med­i­cine in the cur­rent legal cli­mate, it may be doubt­ful that this out­come can be clean­ly assessed.

For the last fif­teen years, it has been well under­stood that women who are fit may have short­er active labors with a sig­nif­i­cant­ly low­er rate of cesare­an births [1,2]. More recent evi­dence is show­ing that women who begin reg­u­lar, mod­er­ate exer­cise in the first trimester, and con­tin­ue through their preg­nan­cy, also ben­e­fit. One study has shown that first time moth­ers who do not exer­cise are 4.5 times as like­ly to require a cesare­an birth than women who begin exer­cise in the first trimester [3].

Reg­u­lar, mod­er­ate phys­i­cal activ­i­ty begun in ear­ly preg­nan­cy is healthy for both moth­er and baby. One of the major rea­sons the baby ben­e­fits is that the placenta–the organ of cir­cu­la­tion bring­ing nutri­ents and oxy­gen to the umbil­i­cal cord for deliv­ery to the fetus–is larg­er and more exten­sive­ly devel­oped in exer­cis­ing moth­ers [4–6]. In addi­tion, blood flow to the uterus, or womb, is greater in exer­cis­ing women [7]. As long as there are no med­ical prob­lems, healthy women should be encour­aged to par­tic­i­pate in reg­u­lar, mod­er­ate exer­cise once they have been screened by the obste­tri­cian or nurse-mid­wife and giv­en the okay to par­tic­i­pate.

A rea­son exer­cise is ben­e­fi­cial for the mom is its abil­i­ty to reduce dis­com­fort. A well-designed pre­na­tal reg­i­men will help with a num­ber of preg­nan­cy-relat­ed phys­i­cal prob­lems [8–11]. In addi­tion, a group class has many ben­e­fits. Research stud­ies on var­i­ous peri­ods in women’s lives tell us that when under­go­ing major life changes, there are ben­e­fits from being with oth­er sim­i­lar women. In addi­tion, women who return to vig­or­ous activ­ty pri­or to six weeks post­par­tum have less weight to lose, score bet­ter on mater­nal adap­ta­tion tests, and are in a hap­pi­er mood than seden­tary women [12]

1. Clapp, JF 3rd and Dick­stein, S. 1984. Endurance exer­cise and preg­nan­cy out­come, Med Sci Sports Exerc 16(6): 556–62.

2. Hall , DC and Kauf­mann, DA. 1987. Effects of aer­o­bic and strength con­di­tion­ing on preg­nan­cy out­comes, Am J Ob /Gyn, 157(5): 1199–1203.

3. Bungum, TJ, Peaslee, DL, Jack­son , AW and Perez , MA . 2000. Exer­cise dur­ing preg­nan­cy and type of deliv­ery in nul­li­parae, JOGNN 29(3): 258–64.

4. Clapp, JF, et al. 2000. Begin­ning reg­u­lar exer­cise in ear­ly preg­nan­cy: effect on feto­pla­cen­tal growth, Am J Ob Gyn 183: 1484–8.

5. Clapp, JF 3rd and Rizk, K. 1992. Effect of recre­ation­al exer­cise on midtrimester pla­cen­tal growth, Am J Ob Gyn 167(6): 1518–21.

6. Jack­son, MR, Gott, P, Lyle, SF, Ritchie, JW and Clapp, JF 3rd. 1995. The effects of mater­nal aer­o­bic exer­cise on human pla­cen­tal devel­op­ment: pla­cen­tal vol­u­met­ric com­po­si­tion and sur­face areas, Pla­cen­ta 16(2): 179–91.

7. Clapp, JF, Step­an­chak, W, Tomasel­li, J, Kor­tan, M and Fanes­low, S. 2000. Por­tal vein blood flow–effects of preg­nan­cy, grav­i­ty and exer­cise, Am J Ob Gyn 183(1): 167–72.

8. Ost­gaard, HC, Zether­strom, G, Roos-Hans­son, E, Svan­berg, B. 1994. Reduc­tion of back and pos­te­ri­or pelvic pain in preg­nan­cy, Spine 19(8): 894–900.

9. McIn­tyre , IN and Broad­hurst, NA. 1996. Effec­tive treat­ment of low back pain in preg­nan­cy, Aust Fam Prac 25(9 Sup­pl 2): S65-67.

10. Andrews, CM and O’Neil, LM. 1994. Use of pelvic tilt exer­cise for lig­a­ment pain relief, J Nurse Mid­wif 39(6): 370.

11. Sampselle, CM, Miller, JM, Mims, BL, DeLancey, JO, Ash­ton-Miller, JA and Anton­akos, CL. 1998. Effect of pelvic mus­cle exer­cise on tran­sient incon­ti­nence dur­ing preg­nan­cy and after birth, Ob Gyn 91(3): 406–12.

12. Sampselle, CM, Seng, J, Yeo, SA, Kil­lion, C and Oak­ley, D. 1999. Phys­i­cal activ­i­ty and post­par­tum well-being, JOGNN 28(1): 41–9.

Sum­mer 2001

Researchers assessed the asso­ci­a­tion between par­tic­i­pa­tion in aer­o­bic exer­cise dur­ing the first two trimesters of preg­nan­cy and type of deliv­ery in nul­li­parous women. They con­clud­ed that reg­u­lar par­tic­i­pa­tion in phys­i­cal activ­i­ty dur­ing the firt two trimer­sters of preg­nan­cy may be asso­ci­at­ed with reduced risk for cesare­an deliv­ery in nul­li­parous women.

Source: Bungum TJ. Peaslee DL, Jack­son AW, Perez MA- Exer­cise dur­ing preg­nan­cy and type of deliv­ery in nul­li­parae. Jour­nal of Obstet­ric, Gyne­co­log­ic, & Neona­tal Nurs­ing 29(3):258:64, 2000, May-Jun.

Researchers test­ed the hypoth­e­sis that preg­nan­cy increas­es por­tal vein blood flow and that reg­u­lar exer­cise train­ing dur­ing preg­nan­cy lim­its the flow redis­tri­b­u­tion away from the splanch­nic and uter­ine cir­cu­la­tions in response to either grav­i­ta­tion­al or exer­cise-induced hemo­dy­nam­ic stress. Con­clu­sions: Por­tal vein blood flow ris­es sig­nif­i­cant­ly dur­ing preg­nan­cy, and flow redis­tri­b­u­tion away from the splanch­nic and uter­ine cir­cu­la­tions in response to severe hemo­dy­nam­ic stress is reduced by exer­cise train­ing in mid and late preg­nan­cy.

Source: Clapp JF 3rd, Step­an­chak W., Tomasel­li J., Kor­tan M, Fanes­low S.- Por­tal vein blood flow-effects of preg­nan­cy, grav­i­ty, and exer­cise. Amer­i­can Jour­nal of Obstet­rics & Gyne­col­o­gy. 183(1):167–72, 2000 Jul.

This study detect­ed a strong trend that 10 weeks of mod­er­ate exer­cise (3 times a week, 30 min­utes at RPE of 13, dur­ing weeks of 18–28) low­ered the dias­tolic blood pres­sure among preg­nant women at risk of hyper­ten­sive dis­or­ders. The reduc­tions were prob­a­bly due to the effect of exer­cise itself, not to weight or over­all dai­ly phys­i­cal activ­i­ty lev­els.

Source: Yeo S, Steele NM , Chang MC, Leclaire SM, Ronis DL, Hayashi R

Effect of exer­cise on blood pres­sure in preg­nant women with a high risk of ges­ta­tion­al hyper­ten­sive dis­or­ders. Jour­nal of Repro­duc­tive Med­i­cine. 45(4):293–8, 2000 Apr.

Preg­nan­cy and exer­cise have oppo­site effects on fat mass and insulin resis­tance. This study test­ed the hypothe­ses that exer­cise dur­ing preg­nan­cy alters the preg­nan­cy-asso­ci­at­ed increas­es in the lev­els of tumor necro­sis fac­tor alpha and lep­tin, and that the changes in tumor necro­sis fac­tor alpha and lep­tin con­cen­tra­tions dur­ing preg­nany con­tin­ue to reflect changes in fat mass­es.

Con­clu­sions: Reg­u­lar weight-bear­ing exer­cise dur­ing preg­nan­cy sup­press­es the preg­nan­cy-asso­ci­at­ed changes nor­mal­ly seen in both tumor necro­sis fac­tor alpha and lep­tin. The decrease in lep­tin reflects decreased fat accre­tion, and researchers spec­u­late that the changes in tumor necro­sis fac­tor alpha may reflect a change in insulin resis­tance.

Source: Clapp JR 3rd, Kiess W. Effects of preg­nan­cy and exer­cise on con­cen­tra­tions of the meta­bol­ic mark­ers tumor necro­sis fac­tor alpha and lep­tin. Amer­i­can Jour­nal of Obstet­rics & Gyne­col­o­gy. 182(2):300–6, 2000 Feb.

This study exam­ines car­dio­vas­cu­lar respons­es to strength con­di­tion­ing exer­cis­es. Mater­nal heart rate and blood pres­sure and fetal heart rat (FHR) respons­es were mea­sured in both the supine (30 degrees tilt) and seat­ed pos­tures dur­ing hand­grip (HG), sin­gle-leg exten­sion (SL), and dou­ble-leg exten­sion (DL) exer­cise. Preg­nant sub­jects exhib­it­ed high­er heart rates but sim­i­lar blood pres­sure respons­es to con­trol sub­jects under all exper­i­men­tal con­di­tions. Sig­nif­i­cant increas­es were observed for the fre­quen­cy of FHR accel­er­a­tions (0.10 to 0.27/min) from rest to DL in the sit­ting pos­ture at 90% RM. Mod­er­ate fetal brady­car­dia was observed occa­sion­al­ly in the tilt­ed supine pos­ture at rest and both dur­ing (SL, DL) and fol­low­ing (HG, SL, DL) exer­cise, sug­gest­ing that this pos­ture should be avoid­ed in late ges­ta­tion.

Source: Avery ND, Stock­ing KD, Tran­mer JE, Davies GA , Wolfe LA. Fetal respons­es to mater­nal strength con­di­tion­ing exer­cis­es in late ges­ta­tion. Cana­di­an Jour­nal of Applied Phys­i­ol­o­gy. 24(4):362–76, 1999 Aug.

Researchers from the Depart­ment of Ob/Gyn, Uni­ver­si­ty of Syd­ney , New South Wales , Aus­tralia , exam­ined [mater­nal] post­na­tal dis­tress, eat­ing, exer­cise, and vom­it­ing before and dur­ing preg­nan­cy. They found that post­na­tal dis­tress was asso­ci­at­ed with body weight and shape con­cerns, dis­or­dered eat­ing before and dur­ing preg­nan­cy, and with vom­it­ing dur­ing preg­nan­cy. Low inten­si­ty exer­cise duirng ear­ly preg­nan­cy played a pro­tec­tive role. The authors rec­om­mend that women with eat­ing dis­or­ders should be con­sid­ered at risk for post­na­tal prob­lems. The authors found four vari­ables that were asso­ci­at­ed with greater dis­tress: fear of weight gain before and dur­ing preg­nan­cy, being dis­tract­ed by thoughts of food dur­ing preg­nan­cy, being afraid of gain­ing more weight than the preg­nan­cy would explain, and vom­it­ing more fre­quent­ly dur­ing the first 3–4 months of preg­nan­cy. Par­tic­i­pat­ing in low-inten­si­ty exer­cise for rea­sons of shape and weight dur­ing months 3–4 of preg­nan­cy account­ed for less dis­tress. The most dis­tressed moth­ers were suf­fer­ing from an eat­ing dis­or­der at the time of preg­nan­cy. The binge and/or purge type of eat­ing dis­or­der was asso­ci­at­ed with more dis­tress than a food restric­tion type of dis­or­der.

Source: Abra­ham S. Tay­lor A. Con­ti J. Post­na­tal depres­sion, eat­ing, exer­cise, and vom­it­ing before and dur­ing preg­nan­cy. Inter­na­tion­al Jour­nal of Eat­ing Dis­or­ders. 29(4):482–7, 2001 May.

Menopause

Exer­cise in Midlife and Old­er Women

This stud­ied exam­ined the rela­tion­ship of changes in phys­i­cal activ­i­ty and mor­tal­i­ty among old­er women (65 and old­er at base­line). 9518 com­mu­ni­ty-dwelling white women where assessed at base­line; 7553 assessed at fol­low-up, medi­an 5.7 years lat­er. Walk­ing and oth­er phys­i­cal activ­i­ties; cause of death tracked for up to 12.5 years after base­line (6.7 years after fol­low up).

Com­pared with con­tin­u­al­ly seden­tary women, those who increased phys­i­cal activ­i­ty lev­els between base­line and fol­low-up had low­er mor­tal­i­ty from all caus­es, car­dio­vas­cu­lar dis­ease and can­cer, inde­pen­dent of age, smok­ing, body mass index, comor­bid con­di­tions and base­line physcial activ­i­ty. Asso­ci­a­tions between changes in phys­i­cal activ­i­ty and reduced mor­tal­i­ty were sim­i­lar in women with and with­out chron­ic dieseases but tend­ed to be weak­er among women aged at least 75 years and those in poor health. Women who were phys­i­cal­ly active at both vis­its also had low­er all-cause mor­tal­i­ty and car­dio­vas­cu­lar mor­tal­i­ty than seden­tary women.

Source: Gregg, EW, Cauley, JA, Stone, K, et al. Rela­tion­ship of Changes in Phys­i­cal Activ­i­ty and Mor­tal­i­ty Among Old­er Women. JAMA, 289(18):2379–2386.

2002 Annouce­ments by the Women’s Health Ini­tia­tive Writ­ing Group

Risks and Ben­e­fits of Estro­gen and Prog­estin in Healthy Post­menopausal Women. JAMA, 288(3):321–333, 2002 July 17.

The release of find­ings from the Women’s Health Ini­tia­tive study on HRT has been a bomb­shell for many women tak­ing hor­mone place­ment under the assump­tion that it pro­vid­ed pro­tec­tion again heart dis­ease. While we have known for some time that cer­tain can­cers are linked to HRT , espe­cial­ly long-dura­tion dosage, the dis­ap­pear­ance of the mirage of pro­tec­tion of HRT against heart dis­ease was a schock. But, the whole sto­ry is com­plex. There are both risks and ben­e­fits. The per­cent­age of change in risk is great, but the num­bers are very small. Per 10,000 per­son-years, there were 7 more CHD events, 8 more strokes, 8 more pul­mi­nary embolisms, 8 more inva­sive breast can­cer cas­es, 6 few­er col­orec­tal can­cers and 5 few­er hip frac­tures.

It is help­ful to review the descrip­tion of the find­ings as pub­lished in the July 2002 press release from the Nation­al Heart, Lung, and Blood Insti­tute (NHLBI) of the NIH:

41% increase in stroke

29% increase in heart attack

100% increase in venous throm­boem­bolism

22% increase in CVD

26% increase in breast can­cer

37% decrease in col­orec­tal can­cer

33% decrease in hip frac­ture

24% decrease in total frac­tures

No dif­fer­ence in total mor­tal­i­ty (all cause mor­tal­i­ty)

Relat­ed arti­cles that may be of inter­est include:

Lacey, JV, Jr, Mink, PJ, Lubin, JH, et al. Menopausal Hor­mone Replace­ment Ther­a­py and Risk of Ovar­i­an Can­cer. JAMA 288(3):334–341.

Chle­bows­ki, RT, Hen­drix, SL, Langer, RD, et al. Influ­ence of Estro­gen Plus Prog­estin on Breast Can­cer and Mam­mog­ra­phy in Healthy Post­menopausal Women: The Women’s Health Ini­tia­tive Ran­dom­ized Tri­al. JAMA 289(24):3243–3253.

Li, CI, Mal­one, KE, Porter, NS, et al. Rela­tion­ship Between Long Dura­tions and Dif­fer­ent Reg­i­mens of Hor­mone Ther­a­py and Rist of Breast Can­cer. JAMA 289(24):3254–3263.

Menopause Fit­ness: Brain, Mind, Mood and Exer­cise

The impact of exer­cise on mood in midlife is pro­found. Both chron­ic and acute exer­cise can have a pos­i­tive effect on mood and reduce the lev­el of somat­ic and vaso­mo­tor symp­toms com­pared with non-exer­cis­ers, regard­less of menopause sta­tus or whether or not a woman is tak­ing hor­mone replace­ment [321]. In one study, the degree of a woman’s psy­cho­so­mat­ic symp­toms in per­i­menopause was found inverse­ly relat­ed to the degree of exer­cise from her thir­ties on (less exer­cise pro­duced greater feel­ings of “weak­ness”) and from her for­ties on (“ner­vous­ness” and “melan­cho­lia”) [2]. The researchers con­clud­ed that the greater the degree of exer­cise from her for­ties on, the less­er the degree of her symp­toms after menopause, and that exer­cis­ing mod­er­ate­ly from the sub­jec­tive point of view in the per­i­menopausal peri­od may alle­vi­ate symp­toms [2].

Hot flash­es (vaso­mo­tor symp­toms) are expe­ri­enced at some point by per­haps 80 or 90% of women with a chang­ing gyne­co­log­i­cal sta­tus in West­ern nations [3,4,5]. Tem­per­a­ture reg­u­la­tion requires inte­gra­tion of auto­nom­ic, endocrine and skele­to­mo­tor respons­es in the hypo­thal­a­mus [6]. With estro­gen at a low ebb, mal­func­tions in the body’s ther­mo­stat occur. The sen­sa­tion of being over­heat­ed is relat­ed to the metab­o­lism of the neu­ro­trans­mit­ter nor­ep­i­neph­rine, which is medi­at­ed by estro­gen in the hypo­thal­a­mus. The con­di­tion is aggra­vat­ed by stress, which results in increased nor­ep­i­neph­rine, but gen­er­al­ly lessens post­menopausal­ly. In addi­tion, the increas­ing lev­els of FSH caus­es altered sig­nals con­cern­ing the inter­nal tem­per­a­ture set-point. The abil­i­ty of exer­cise to con­tribute to stress man­age­ment may well be a fac­tor for reduc­tion of vaso­mo­tor symp­toms.

It is like­ly that ade­quate lev­els of estro­gen in the female brain are nec­es­sary for mem­o­ry stor­age and learn­ing new tasks [7]. The pari­etal (frontal) lobes of the cere­bral cor­tex are impor­tant for orga­ni­za­tion­al think­ing and are affect­ed in ear­ly menopause by a chang­ing estro­gen con­cen­tra­tion. This prob­a­bly accounts for the reports of “fuzzy think­ing” by midlife women. Alzheimer’s dis­ease (AD), while relat­ed to estro­gen lev­els, has many more dimen­sions than fuzzy think­ing.

1. Slaven, L and Lee, C. 1997. Mood and symp­tom report­ing among mid­dle-aged women: the rela­tion­ship between menopausal sta­tus, hor­mone replace­ment ther­a­py, and exer­cise par­tic­i­pa­tion, Health Psy­chol 16(3): 203–8.

2. Ueda, M and Toku­na­ga, M. 2000. Effects of exer­cise expe­ri­enced in the life stages on cli­mac­teric symp­toms for females, J Phys­i­ol Anthro Appl Human Sci 19(4): 181–9.

3. Northrup, C. 1994. Women’s Bod­ies, Women’s Wis­dom. NY: Ban­tam.

4. Kro­nen­berg, F. 1990. Hot flash­es: Epi­demi­ol­o­gy and phys­i­ol­o­gy, Ann NY Acad Sci 592: 52–86.

5. McKin­lay, SM and Jef­fer­ys, M. 1974. The menopausal syn­drome, Brit J Preent Soc Med 28(2): 108.

6. Kan­del, ER, Schwartz, JH and Jes­sell, TM. 1991. Prin­ci­ples of Neur­al Sci­ence, 3rd ed. Nor­walk , CT : Apple­ton & Lange, pp. 752–53.

7. Bari­na­ga, M. 1994. Watch­ing the brain remake itself, Sci­ence (Dec. 2): 1475–76.