Caesarean Section: The last resort for the pelvic floor -

Caesarean Section: The last resort for the pelvic floor -

Changes to thefemale pelviswith Pregnancyand childbirthPhilip Toozs-HobsonConsultant UrogynaecologistBWH

Introduction• Urinary incontinence estimated to affect2.5 million women in the UKMORI poll 1991• Childbirth an important aetiological factorin the development of stress incontinenceThomas et al 1980• 11% lifetime risk of surgery for prolapseOlsen et al

• “Most published studies have evaluatedanatomical & neurological aspects ofthe pelvic floor function after childbirthwhich permits the assumption thatlabour & delivery cause pelvic floordamage. However data for this arescarce and variable”Morakinjo & Spencer 2001

Background data

What Is normal?• >400 “normal” women• Stage 0 6.7%• Stage 1 43.3%• Stage 2 47.7%• Stage 3 2.7%• Risks• Parity• Vaginal delivery• Macrosomia• Age• Hysterectomy• Menopause statusSwift et al 2006

ProLong data13000 women 54% return Mean age 42• Urinary symptomsBaseline 336 year 44%13 year 50%•

Postnatal urinary incontinenceAuthor year incidence follow upWilson „96 35% 3/12Meyer „98 21-36% 9/52Groutz „99 1.6% 12/12

Epidemiology• Length of second stage• Head circumference• Birth weight• EpisiotomyNo obstetric factor significant 1/12 afterdeliveryViktrup et al 1992

Onset of incontinence• 8.5% onset prior to pregnancy• 23% permanent onset during pregnancy• 50% temporary during pregnancy• 19% onset postnatallyIosif et al 1981

Prevalence of stressincontinence• Pre-pregnancy nulliparous 0%multipara 10%• 38 weeks nullipara 39%multipara 42%• Postpartum primipara 6%multipara 11%Stanton et al 1980

Pregnancy or delivery• AN stress 6.4 OR (4.1-9.9)• Prepreg BMI 1.07/unit BMI• LSCS 0.27 OR (0.27-0.5)• Weight, episiotomy, length of labour NSEason et al 2004

Self reported risk factors• parous women >nulliparous women> Men• Pregnancy of any sort increased risk ofpelvic floor dysfunction– Difference for LSCS and forceps significant– Parity• LSCS does not confer any long termbenefit over vaginal deliveryMcClenon et al 2000

Antenatal markersBladder neck movement• Increased rotation and descentKing & Freeman 1996• Antenatal stress incontinenceToozs-Hobson 1997

Incidence of urinaryincontinence• 1 normal delivery 24.6%• 1 Caesarean section 5-11%• 3 Caesarean sections 35%Wilson et al 1996

Post natal Stress incontinenceAetiology• denervation of the pelvic floor muscles inwomen with stress incontinenceSmith et al 1989• Partial denervation and re-inervation in80% of women undergoing their 1stvaginal deliveryAllen et al 1990

Longer term follow up• Antenatal symptoms highest prevalence• 2/3 had symptoms at 7-15 years• Doubles risk of incontinence at 7-15 yrs• Pelvic floor re innervation appeared toprogress longer term not an adequatemarker therefore of uncertain significanceDolan et al 2003

Faecal incontinenceArthur year incidence follow upWilson „96 4.9% 3/12MacArthur „97 4% 10/12Meyer „98 4-5% 9/52Groutz „99 2.6% 12/12Zetterstrom „99 1.2% 5-9/12

Incidence of trauma to analsphincter• 35% of primiparous women haveevidence of occult damage• Subsequent damage 4-6%• Associated with instrumental deliverySultan et al 1994

Anal incontinence risk factors• Large baby (>4 kg)• Instrumental deliveryHojberg 1999Tetzchner 1997

Does mode of delivery predisposeto anal incontinence?• 18 studies• 12000 subjects• Forceps vs LSCS OR 2.01 (1.47-2.74)• NVD vs LSCS OR 1.32 (1.02-1.64)• Forceps vs NVD OR 1.47 (1.22-1.78)Pretlove et al 2008

Changes associated with childbirth

Normal nulliparous pelvis• “angel” sign• Smooth levatorcomplex• Symmetricalappearance• Supported anteriorsulci

Changes to pelvic floorVaginal delivery• Increased levator hiatus• Increased displacement of vaginal sulciCaesarean section• Decreased levator hiatusToozs-Hobson et al 1998

Measurement of paravaginaldefects

Changes to levator hiatusVaginal deliveryCaesarean sectionPre del Post del Pre del Post delLevator ani 14.9 cm 3 16.3* cm 3 14.2 cm 3 12.7* cm 3Vaginal sulciDown (R) 6.8cm 7.0 cm 6.7 cm 5.4 cmLat (R)11.4 cm 12.8* cm 12.3 cm 12.5 cmDown (L) 7.2 cm 9.6* cm 7.0 cm 8.3 cmLat (L)12.8 cm 14.2* cm 13.3 cm 11.9 cm

Levator Hiatus changes

3D USS of Urethral sphincter

Effect of vaginal delivery• Reduction in MUCP and FUL• Development of urinary symptomsassociated with decrease in MUCP & FULIosif et al 1981Van Gleelen et al 1982Toozs-Hobson et al 1997

Vaginal delivery• Decrease in urethral sphincter volumein women with stress incontinenceToozs-Hobson 1997• Decrease in striated muscle with ageand parityPerucchini et al 1997

Urethral sphincter volumesPre del vol Post del volSigVag del 0.98 cm 3 0.84 cm 3 0.001LSCS 1.03 cm 3 0.98 cm 3 n.s.Asymptomatic 1.02 cm 3 0.97 cm 3 n.s.Symptomatic 0.96 cm 3 0.84 cm 3 0.02

Pelvic floor distortion associatedwith pelvic floor prolapse• Aim to assess architectural distortion withprolapse• Women with both levator defects andarchitectural defects have highest rate ofprolapse (78%)Huebner et al 2008

Pelvic floor distortion with childbirth

Pelvic floor distortion with childbirth• MRI of nulliparous women– Stretch ratio of 3.5 on posteriomedialpuborectalis• Mechanical modelHoyte 2008– Distortion 0.66 for vertical displacementParente 2008

Pelvic Floor StrengthEffect of vaginal delivery:• Decrease in strength• Decrease in EMG• Decrease in periometer readingSampselle 1990Marshall et al 1996

Neurophysiological investigations• Functional asymmetry– May contribute to severity of symptomsEnck et al 2004• Pudendal nerve stretch up to 35%– MRI simulations on cadavarsLien et al 2003• Need to standardise concentric needleEMGVodusek 2006

Collagen metabolism• Reduced in GSI• Deficient in prolapse• Increased with HRTKeene et al 1993Jackson et al 1995• Decreased fascial strength in pregnancyLandon et al 1990

Collagen changes• Joint hypermobility is associated withstress incontinence• Pregnancy results in collagenremodellingNorton et al 1988Lavine 1998• No relationship between stressincontinence & joint hypermobility inpregnancyChaliha 1999

Obstetric risk factors• 3.3 RR women with 4 children vs womenwith 1 child• Tearing or episiotomy associated withsymptomatic POP• No association with instrumental deliveryor length of labour• Abdominal delivery halved risk vs vaginaldeliveryTegerstedt et al 2003

Effect of delivery on the pelvic floor• Larger hiatus and Bladder neck mobilitywith vaginal delivery• However greater distensibility in womenwho achieved vaginal deliveryToozs-Hobson et al 2007

Conclusions• Lots of studies little conclusive data• Parity definitely a factor• Genetics contributing• Anatomical factors– Asymmetry of anatomy– Physical characteristics may dictate obstetricperformance

Causation Vs association• Powerlabour• Passage delivery typecollagen/CT• Passenger SizeParity• Practice/prejudices

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