s c i r t e t s b O After delivery: urinary retention and headache (esp. after dural puncture). Epidural anesth esia for those having heparin thromboprophylaxis: When low molecular weight heparin (LMWH) is used, wait 12h after heparin dose be- fore inserting block or removing catheter (24h if on therapeutic rather than prophylactic dose of heparin). \200\22552 Wait at least 4h afte r block siting before next dose of LMWH. Aim to give LMWH at 18.00h each day. Beware use of other anti- coagulants or non-steroidal anti-in \202 ammatory drugs. Inductions may need to be timed around heparin doses. Heparin use can preclude use of regional an- aesthesia (e g in spontaneous labor). All patients must be extremely vigilantly monitored to detect new numbness; weakness; bowel or bladder dysfunction. Any neurological problem must be investig ated as an emergency. Combined spinal epidural (CSE) anesthesia gives quicker pain relief, with little or no moto r blockade in most mothers, allowing standing, walking, sit- ting, and voiding urine. A lar ge-bore needle is put into the epidural space, and a \201 ne-bore needle put through that to puncture the subdural space. (Cerebro- spinal \202 uid can be aspirated via the spina l needle to con \201 rm placement.) A small dose of opiate (eg fentanyl) and anesthetic is used intrathecally to give pain relief during the 1st stage. An epidural catheter threaded into the epidural space allows top up with anesthetic to give more profound analgesia for 2nd stage. The patient can control the dose, and this leads to a dose reduction of 35%, and reduces motor blockade. Women should inform their midwife if they notice light-headedness, nausea, or weak legs. Spontaneous delivery rates are not better than with traditional epid ural. Systematic review (n=2658) found that apart from quicker onset of action there was no diff erence when com- pared to low-dose epidural in terms of mobilization in labor, modes of birth, maternal satisfaction, post dural puncture headache, blood patch, or maternal hyp otension. 137 \200\207Skilled anesthetic help is vital. 67 s c i r t e t s b O Multiple pregnancy 68 \200 Incidenceuk Twins: 3 : 200 pregnancies; triplets: 1 : 10,000. Predisposing factors Previous twins; FH of twins (dizygotic only); \200\200 maternal age (<20yrs 6.4 : 1000, >25yrs 16. 8 : 1000); induced ovulation and IVF (1% of all UK pregnancies of which 25% are \211 twins ); race origin (1 : 150 pregnancies for Japa- nese, 1 : 23 in Nigerian Yoruba women). The w orldwide rate for monozygotic (of which 75% monochorionic ie shared placenta) twins is cons tant at 4 : 1000. Features Early pregnancy: uterus large for dates; hyperemesis. Later the re may be polyhydramnios. The signs are: >2 poles felt; a multiplicity of fetal parts felt; 2 fetal heart rates heard (reliable if rates diff er by >10 beats/min). Ultrasound con \201 rms diagnosis (at 11+0 \200\22313+6 weeks distinguishes monochorionic from di- chorion ic twins by placental masses, lambda or T sign, membrane thickness). Complications during p regnancy \200 Polyhydramnios \200 Pre-eclampsia (10% in singleton pregnancies; 30% in t wins) \200 Anemia commoner (iron and folate requirements increased) \200 APH incidence rises (6% for twins vs 4.7% for single- tons) from both abruption and placenta praevia (lar ge placenta). Fetal complications Perinatal mortality \200\200 (8 : 1000 singletons; 36.7 : 1000 for twins; 73 : 1000 for triplets; 204 : 1000 for higher multiples). The main proble m is pre- maturity. Mean gestation for twins is 37 weeks, for triplets 33 weeks. Growth res triction (p52) is commoner (growth rate=singletons until 24 weeks, may slow thereafter). Ma lformation rates \200\200 \211\2102 \200\2234, especially if monozygotic. Severe disabili ty rate 1.5% for singletons, 3.4% for twins. Ultrasound is the main diag- nostic test. Sele ctive feticide (eg with intracardiac potassium chloride)1 is best used before 20 weeks in t he rare instances where it is indicated. With mono- chorionic pregnancies, placental vascul ar anastomoses may result in disparate twin size and one being born plethoric (so jaundiced later), the other anemic ie twin-twin (feto \200\223fetal) transfusion (FFT). Placental an astomosis laser coagu- lation can treat. Rarely, a fetus dying in utero shrinks and mummi \201 es (fetus papyraceous) which may be aborted later or delivered prematurely. Complicati ons of labor PPH (4 \200\2236% in singletons, 10% in twins). Malpresen- tation is common (c ephalic (Ce)/Ce 40%, Ce/breech (Br) 40%, Br/Br 10%, Ce/ transverse (Tr) 5%, Br/Tr 4%, Tr/Tr 1%). Vasa praevia rupture; cord prolapse (0.6% singleton, 2.3% twins); premature placental separation and cord entan- glement (especially monoamniotic). Undiagnosed twins with synto metrine use. Management \200 Ultrasound at 11+0 \200\22313+6 weeks for viability, chorio nicity, nuchal translucency, malformation: monthly from 20wks (2-weekly if monochorionic: m embrane folding suggests FFT). 138 Check fetal growth using 2 biometric variables. Name twi ns eg left, right. Discordant growth of \211 25% indicates growth restriction and tertiar y center referral. Refer also if FFT; fetal anomaly; monochorionic (MC) +monoamniotic; or M C+diamniotic (triplets); discordant death. \200 Check FBC at 20 \200\22324 weeks. Give as pirin >12wks if risks indicate (p48). \200 More antenatal visits, eg weekly from 30 weeks (risk of eclampsia \200\200). \200 Tell the mother how to identify preterm labor, and w hat to do. \200 Off er elective birth at 37+0 wks for uncomplicated dichorionic twins; at 36+0 wks (+steroids p51), for uncomplicated monochorionic twins; at 35+0 weeks (+steroids) for uncomplicated triplets. \200 42 Use IV access in labor and anaes- thetist availabilit y at delivery. Have pediatricians (one per baby) present at delivery in case resuscitation needed (2nd twins have a higher risk of as- phyxia). Most women spontaneously deliver befor e these dates. s c i r t e t s b O Terminology: Monochorionic twins or triplets share the placenta. If Monoam- niotic they sha re one amniotic sac; if di-amniotic there are 2 sacs, triamniotic, there are 3. One placent a risks fetofetal transfusion, 1 sac risks entanglements. 1 In monochorionic twins, total c ord coagulation is required to avoid hemorrhage from the co-twin into the dying fetus. Pota ssium is CI (could pass to other twin).139 Ethical and legal considerations are complex. 69 IVF babies, \200\225140 and psychological consequence of triplets With >4 million IVF babi es born worldwide 141 since 1978 it is apparent that there are increased problems for pregn ancy and off spring, not merely those of multiple pregnancy. These are: \200 Multiple bir th: aff ects 1 in 4 IVF pregnancies. Monozygotic twins are also commoner. The rate of tripl ets was 5 \211\210 pre-IVF rates by 1998 but are now only twice, as only 2 eggs are implant ed into women <40 years old. Meta- analysis shows that 1 fresh embryo transfer with a froze n embryo months later if unsuccessful gives as good results as 2 embryos transfer. 142 \200 Older mother eff ects: so more pre-eclampsia, pregnancy induced hyper- tension, cesar ean section delivery, and diabetes in the mothers (all of which have implications for off s pring). s c i r t e t s b O Donor egg problems: pregnancy-induced hypertension is 7.1 times more common if nulliparous women receive donated eggs than for standard IVF. \200 Genetic defects: Beckwith \200\223 Wiedemann syndrome is 6 times commoner in IVF babies and there is concern that intracytopla smic sperm injection (ICSI) techniques could encourage chromosomal abnormalities or cystic \201 - brosis in off spring of men with azoospermia or oligospermia, so screening of thes e men for cystic \201 brosis carrier status and chromosomal abnormali- ties before perfor ming ICSI is recommended. Low birthweight is 1.75 times commoner for singleton IVF babies com- pared to naturally con ceived babies (and very low birthweight 2.7 \200\2233 times commoner). Part of this is due to prematurity, part to growth restriction. Interestingly low birthweight is particularly c orrelated to the number of gestation sacs at earliest scan, even if a baby ends up as a sin gleton. IVF twins are less commonly low birthweight compared to naturally conceived twins. \200 Vasa praevia (p14) rates increased, possibly up to 1 : 300. 143 \200 Prematurity i s twice as common in IVF singleton babies compared to those naturally conceived, 3 times mo re common for prematurity <32 weeks. Again it is commoner if there was originally >1 gestat ion sac. There is less diff erence between IVF and naturally conceived twins. \200 Perina tal mortality is \200\200 60% in IVF conceived singletons (but natural con- ception after delay \200\200 mortality \211\2103 compared to quick conception). \200 Abnormality rate s are slightly increased (in singletons too). Bringing up one child is diffi cult: twins ar e often very very diffi cult \200\224but triplets is more than very very very diffi cult \200\224and are frequently a source of signi \201 cant psychopathology. Even 4 years after their birth, all mothers in one triplets study 144 suff ered from exhaustion and emotional distress. The relationship with the children was often diffi cult (aggression and con \202 icts). One-third of mothers had suffi cient depression to require psychotropic medi- c ation, and one-third spontaneously expressed regrets about having triplets. If triplets are reduced to twins in utero, subsequently one-third of mothers will suff er emotional proble ms (persistent sadness and guilt) up to 1 year. However, adjustment had occurred in 90% by 2 years after birth. 145 Legislation in most developed countries is trying to limit the numbers of embryos that may be implanted at in vitro fertilization in order to reduce higher-order pregnancies (already there has been a reduction by 25% since 1998). The UK current practice is to implant only 2 embryos in mothers <40yrs; though 3 may be implanted if she is >40 yrs. 146 Breech (ie buttock) presentations 70 \200 \200 Breech presentation The commonest malpresentation: 40% of babies are breech at 20 weeks, 20 % at 28 weeks, but only 3% at term. In pregnancy it is normal for the buttocks to come to l ie in the fundus. Conditions predisposing to breech presentation: \200 Contracted pelvis \200 Bicornuate uterus \200 Fibroid uter- us \200 Placenta praevia \200 Oligohydram nios \200 Spina bi \201 da \200 Hydrocephalic fetus. Ultrasound may show the cause and in \202 uence the management. Extended breech presentation is commonest \200\224ie \202 exed at the hips but ex- tended at the knees. Flexed breeches sit with hips and knees both \202 exed so that the presenting part is a mixture of buttocks, external genitalia, and feet. Footling breeches are the least common. The feet are the presenting part and this typ e has the greatest risk (5 \200\22320%) of cord prolapse. Diagnosis of breech presentation Diagnose antenatally. The mother may complain of pain under the ribs. On palpation the lie is longitudinal, no head is felt in the pelvis, and in the fundus there is a smooth round m ass (the head) which can be ballotted, a sensation akin to quickly sinking an apple in wate r. External cephalic version (ECV) \200\225147 \200\224turning the breech by maneuvering i t through a (usually forward), somersault. Turn the baby only if vaginal deliv- ery planned . Version at 36 weeks is recommended for primips, 37 weeks for multips. Success rate 40% pr imips (67% if spinal block used), 148 60% multips. Tocolysis can \200\200 success rates. V ersion contraindications: \200 Placenta praevia \200 Multiple pregnancy (except deliver y of 2nd twin) \200 APH in last 7 days \200 Ruptured membranes \200 Growth restricted babies \200 Abnormal cardiotocography \200 Mothers with uterine scars, uterine abnorma lity \200 Fetal abnormality \200 Pre-eclampsia, or hypertension (risk of abruption is i ncreased) \200 Unstable lie. Monitor CTG (p44). Give anti-D (500U) to rhesus -ve patients . Emergency cesarean rate after ECV is 0.43%. 149 Mode of delivery Planned cesarean section may provide better outcome for the fetus vs vaginal delivery. A large multicentre trial (n = 2088) pub- lished in 2000 suggested it is. 151 Re-analysis and later data questions that conclusion. 152 Others sug- gest that with careful selection vaginal delivery remains a sa fe option. 153 Evidence is less clear for pre-term singletons and twins. (RCOG recommends c esarean if 1st twin breech; vaginal delivery if 2nd twin breech.) If vaginal delivery occur s, attend- ants experienced at breech delivery should be pre- sent. These are becoming hard er to \201 nd. Assisted breech delivery The breech engages in the pelvis with the bitro- chanteric diameter (9.5cm) transverse. With further descent through the pel- vis, rotation occurs so the bitrochanteric diameter lies anteroposteriorly as it emerges from the birth c anal, being born by lateral \202 exion of the trunk. External rotation then occurs so tha t this diameter is again transverse. The shoulders enter the pelvis with the bisacromial di ameter transverse and ro- tate through 90 emerging in the AP diameter. The head enters th e pelvis with the sagittal suture transverse and rotates 90 . When the body is completely born it is allowed to hang for about 1 \200\2232 mins until the nape of the neck is well se en. The body is then lifted above the vulva by an assistant, the head being delivered with forceps. \200\207Check baby for hip dislocation ( \200\200 incidence): also, if vaginal de livery, for Klumpke \200\231s paralysis (p764) and signs of CNS injury. s c i r t e t s b O CI to vaginal route \200\225150 \200 Inadequate pelvis \200 Footling breech \200 Kne eling breech \200 Baby >3800 or <2000g \200 Previous cesarean \200 Hyperextended neck \200 Lack of clinician experienced in breech delivery Concomitant condition. CI vaginal delivery 71 Other malpresentations Occipitoposterior presentation (OP) In 50% of patients the mothers h ave a long \200\230anthropoid \200\231 pelvis. Diagnosis may be made antenatally by palpat ion (p40). On vaginal examination the posterior fontanelle will be found to lie in the post erior quadrant of the pelvis. Labor tends to be prolonged because of the degree of rotation needed, so adequate hydration and analgesia (consider epidural) are important. During labo r 65% rotate 130 so that the head is occipitoanterior at the time of birth, 20% rotate to the transverse and then arrest ( \200\230deep transverse arrest \200\231), 15% rotate so t hat the occiput lies truly pos- terior and birth is by \202 exion of the head from the pe rineum. Although in 73% delivery will be a spontaneous vaginal delivery, 22% will require f orceps and 5% a cesarean section. Face presentation Incidence 1 : 994. 15% are due to conge nital abnormality such as anencephaly, tumor of or shortened fetal neck muscles. Most occur by chance as the head extends rather than \202 exes as it engages. Antenatal diagnosis: the fetal spine feels S-shaped, the uterus is ovoid without fullness in the \202 anks and there is a deep groove between the occiput and the back. On early vaginal examination, the nose and eyes may be felt but later this will not be possible because of oedema. Most enga ge in the transverse (mentobreg- matic diameter \211\2109.5cm). 90% rotate so that the chi n lies behind the symphysis (mentoanterior) and the head can be born by \202 exion. If th e chin rotates to the sacrum (mentoposterior), cesarean section is indicated. Brow presenta tion This occurs in 1 : 755 deliveries and is often associated with a contracted pelvis or a very large fetus. Antenatal diagnosis: the head does not engage (mentovertical diameter \211\21013cm) and a sulcus may be felt be- tween the occiput and the back. On vaginal exami nation the anterior fonta- nelle and supraorbital ridges may be felt. Deliver by cesarean s ection. Transverse lie (compound shoulder presentation) This occurs in 1 in 400 deliveries and is usually in mul- tiparous women (see MINIBOX). Antenatal diagnosis: ovoid uterus wide r at the sides, the lower pole is emp- ty, the head lies in one \202 ank, the fetal heart is heard in variable positions. On vaginal examination with mem- branes intact no distingu ishing features may be felt, but if ruptured and the cervix dilated, ribs, shoulder, or a p rolapsed hand may be felt. The risk of cord prolapse is high. External cephalic version (p7 0) may be attempted from 32 weeks. If malpresentation persists or recurs cesarean section w ill be necessary. Those with persistent instability of lie need hospital admission from 37 weeks (to prevent cord prolapse at home when the membranes rupture) and decision as to elec tive cesarean section. \200 s c i r t e t s b O Typical causes \200 Multiparity \200 Multiple pregnancy \200 Polyhydramnios \200 Pl acenta praevia \200 Arcuate/septate uterus Contracted pelvis \200 \200 Prolapsed cord 72 \200 This is descent of the cord through the cervix, either alongside (occulta) or in front of t he next presenting part (overt) in the presence of ruptured membranes. It is an emergency b ecause cord compression causes fetal asphyxia. Cord pro- lapse is the wildcard that makes e very home delivery a gamble with death. 154 But with speedy intervention, neonatal deaths m ay be kept to <10%. 155 Incidence 0.1 \200\2230.6%; \200\200 if: 2nd twin, footling breech , shoulder presentation, polyhy- dramnios, unengaged head, transverse or unstable lie, male . If cord presentation is noted prior to membrane rupture, carry out cesarean section. When ever you rupture membranes, remember that cord prolapse is possible, eg if the present- ing part is poorly applied. External cephalic version is also a risk. Presentation The problem is obvious if the cord is at the introitus. But the only sign may be fetal bradycardia or variable fetal heart decelerations: al- ways do a vaginal exam in this context to exclude p rolapsed cord. Action Get help. Activate alarms. Tell labor ward. Keep cord in vagina (mini mal handling prevents spasm). Stop the presenting part from occluding the cord: \200 Displ ace the presenting part by putting a hand in the vagina; push it back up (towards mother \200\231s head) during contractions. NB: there is little evidence that replacing the cord a bove the presenting part helps (not recommended). \200\225156 \200 Use gravity, either pl ace the woman head down (left-lateral position) or get s c i r t e t s b O her into knee \200\223elbow position (kneeling so rump higher than head). \200 Infuse 500mL saline into bladder via an IVI giving set taped to a catheter(16G). Reme mber to empty the bladder before any attempt at delivery/extraction. \200 Tocolysis (terbu taline 0.25mg sc) reduces contractions and helps bradycardia. In general, if the fetus is a live, immediate cesarean is best. If cervix fully di- lated and the presenting part is low in pelvis, delivery by forceps (if cephalic) or by breech extraction (by an experienced obs tetrician) is best if it leads to birth in <15min. The pediatrician will take paired cord b lood samples for pH and base excess (if normal, intrapartum hypoxic brain injury is \200 \230excluded \200\231). \200 Impacted shoulders (shoulder dystocia) \200\225157 This is i nability to deliver the shoulders after the head has been delivered. RCOG de \201 nition: a delivery requiring additional obstetric maneuvers to re- lease the shoulders after gentle downward traction has failed. The incidence is 0.6% deliveries (UK and USA). There can be high rate of fetal mortality and morbidity. Postpartum hemorrhage occurs in 11% of mothers and 3.8% get 4th degree perineal tears whether or not maneuvers are used. Brachial plex- us injuries occur in 4 \200\22316% (1 : 2300 live births UK) of which 10% are left with perma nent disability. A common cause of litigation: note which shoulder is anterior as posterior shoulder injuries are not considered due to accoucheur (maternal propulsive forces may con tribute to injuries). Associations: \200 Large/postmature fetus (but most babies >4800g d o not de- velop it and 48% that do weigh <4000g), eg maternal BMI >30kg/m2 \200 Induced o r oxytocin augmented labors \200 Prolonged 1st or 2nd stage or secondary arrest \200 As sisted vaginal delivery \200 Previous shoulder dystocia (1 \200\22316%). Most occur in wo men with no risk factors. \200\207Suggest cesarean birth to diabetic mothers with macrosom ic fetuses; discuss it if previous shoulder dystocia. Management The danger is death from a sphyxia. \200 Speed is vital as the cord is usually squashed at the pelvic inlet. \200 U se the McRoberts (hyper \202 exed lithotomy) position. It is successful in 90%. Abduct, ro tate outwards, and \202 ex maternal femora so each thigh touches the abdomen (1 assistant to hold each leg). This straightens the sacrum rela- tive to the lumbar spine and rotates the symphysis superiorly helping the impacted shoulder to enter the pelvis without manipula ting the fetus. \200 73 Apply suprapubic pressure for 30sec: with \202 at of hand laterally in the direc- tion ba by is facing, and towards mother \200\231s sacrum. Apply steady traction to the fetal head towards the \202 oor. This aims to displace the anterior shoulder allowing it to enter th e pelvis. If this fails, check anterior shoulder is under the symphysis (here the diam- eter of the outlet is widest); if not rotate it to be so and repeat traction. If this fails, rotation by 180 so posterior shoulder now lies anteriorly may work, as may delivery of the posterior arm. Episiotomy helps rotations/arm delivery. \200 If these ha ve failed, alternatives now include getting the mother into \200\230all fours position \200\231; maternal symphisiotomy; or replacement of the fetal head by \201 rm pressure of the hand to reverse the movements of labor and return the head to the \202 exed occipito -anterior position and cesarean delivery. The baby is likely to be severely acidotic at thi s stage. s c i r t e t s b O If the baby dies prior to delivery, cutting through both clavicles (cleidotomy) with strong scissors assists delivery. Check the baby for damage, eg Erb \200\231s palsy ( \201 g 1, p77) or fractured clavicle. \200 Beware PPH or 4th degree vaginal tears in the mother. In the notes, record time of d elivery of head; direction head faced after restitu- tion; maneuvers (timing & sequence); t ime of delivery of body; who and when present; Apgar of baby at birth; umbilical cord blood acid \200\223base measurement. Meconium-stained liquor In late pregnancy, it is normal for some babies to pass meconium (b owel con- tents), which stains the amniotic \202 uid a dull green. This is not signi \201 cant. Dur- ing labor, fresh meconium, which is dark green, sticky, and lumpy, may be p assed. This may be a response to the stress of a normal labor, or a sign of distress, so tr ansfer to a consultant unit and commence continuous fetal heart rate monitoring (p44). Aspi ration of fresh meconium can cause severe pneumonitis. Routine suction of nasopharynx and o ropharynx prior to birth is not recommended. Only suction airway if there is thick/tenaciou s meconium in oropharynx. Have a healthcare professional trained in advanced neonatal suppo rt in attendance (p107) to suck out pharynx and trachea under direct vision using a laryngo scope if the baby has depressed vital signs. Observe ba- bies after light staining present for 2 hours; if more signi \201 cant staining, for 12 hours. \200 109 \200 Meconium aspiration in some countries has been reducing. This is, in part, thought due to a reduction in births of babies >41 weeks \200\231 gestation. 158 Sur- factant may reduce th e need for extracorporeal oxygenation. 159 Team-work, obstetric emergencies, and debrie \201 ng There is no \201 ner example of int erdisciplinary working than when midwife, obstetrician, and pediatrician (with porters, lab staff , and others) unite to achieve optimal outcomes in diffi cult obstetric practice. Bu t outcomes are frequently not optimal, and the reason is usually poor team-work \200\224not al- ways because of overwork: 25% of obstetricians and 58% of midwives freely admit goals are not shared between professions. 160 One way forward is regular meetings, agreement on spheres of leadership, auditable standard s, simulations, and debrie \201 ng after emergencies, empha- sizing that we cannot control the ever-present threat of disasters, and that when these occur it is structures not indiv iduals that need interrogating. 161 We should also debrief patients after disasters and near-misses. This can help avoid post-traumatic stress disorder and fear of future births. 156 Dystocia Dystocia is diffi culty in labor, implying problems with one or more of the \200 \2303 P \200\231s: 1 Passages \200\224there may be soft tissue (eg \201 broid or cervical dystocia after 74 \200 cervical biopsy or genital mutilation, p247) or bony obstruction. 2 Passenger \200\224owing to a large baby; see also impacted shoulders/shoulder dystocia (p72) or an abnormal presentation. 3 Propulsion \200\224thanks to the uterine powe rs. Cephalopelvic disproportion is the appropriate label if diameters are unfav- ourable (p 42) and/or the head is big; but see the box for a critique of this idea. The pelvis The ide al pelvis has a round (gynaecoid) brim, but 15% of women have a long oval (anthropoid) brim . A very \202 at brim (platypelloid \201 g 1) is less favorable; it occurs in 5% of wom en over 152cm (5ft), but in 30% of women <152cm. Kyphosis, scoliosis, sacralization of the L5 vertebra, spondylolisthesis and pel- vic fract ures all aff ect pelvic anatomy. Rickets and polio were important causes of pelvic problems . Suspect pelvic contraction if the head is not engaged by 37 weeks in a Caucasian primip ( do ultrasound to exclude placenta praevia). Presentation & lie Cephalic presentations are l ess favorable the less \202 exed the head is. Transverse lie and brow presentations alway s need cesarean sec- tion: face and OP (p71) presentations may deliver vaginally but are mo re likely to fail to progress. Breech presentation is most unfavorable if the fetus >3.5kg. The uterine powers Contractions start in the fundus and propagate down- wards. The intensi ty and duration of contractions are greatest at the fundus, but the contraction reaches its peak in all parts of the uterus simultaneously. Normal contractions occur at a rate of 3 p er 10min, they should last up to 75sec. The contraction peak usually measures 30 \200\22360 mmHg, and the resting uterine tone between them should be 10 \200\22315mmHg. Uterine muscle has the property of retraction: this shortening of the muscle \201 bres encourages cervi cal dilatation. Uterine dysfunction/functional dystocia is easily diagnosed in labor by lac k of cervical dilatation over 2h associated with weak contractions. 161 (If con- tractions are good, failure to progress is usually due to cephalo-pelvic dispro- portion.) Contractio ns may be hypotonic ( \200\201resting tone, low contraction peaks) or they may be normotoni c but too infrequent, or they may be coupled (2 con- tractions coupled too close together a re ineffi cient). 162 s c i r t e t s b O If membranes are intact, amniotomy may be tried. If cervical dilatation <1cm/h, oxytocin ma y help (p64). Whenever oxytocin is used, discuss with a senior obstetrician and limit geome tric dose increase to nullips (multips may be very sensitive to oxytocin). 40min may be nee ded for assessing dose changes (don \200\231t expect progress to be as fast as with normal labor: median rate =1.4cm/h for nullips and 1.8cm/hour for multips). 163 Despite oxytocin, \200\230failure to progress \200\231 is the major problem for many women in the 1st stage of labor. Pain and fear cause release of catecholamines which can inhibit uterine activ- ity. So adequate analgesia is needed (p66) and may speed labor \200\231s progress. Conseque nces of prolonged labor Neonatal mortality rises as does mater- nal morbidity (especially f rom infection). NB! \200\207Modern management of labor entails careful monitoring of progr ess (p64) to diagnose and treat delay promptly. \200\207When there is dystocia, ask \200\234is safe vaginal delivery possible? \200\235 75 Most women have an abnormal pelvis! The ideal pelvis, just like the ideal woman, is a male construct that does not exist. Reducing the pelvis to a few dimensions belies its complexit y, and this reductionism is one reason why pelvimetry (bedside, ultrasound, or MRI) is disa ppointing and leads to unnecessary cesarean sections. \200\207The only valid test of labor is labor itself. Another reason is that pelvimetry perpetuates the myth that bones are sta tic. There is a dialog between the baby and the pelvis: the baby \200\231s skull molds to i ts shape (p90) and the pelvis responds to pregnancy-associated hormones (eg relaxin). These induce resorption of the symphyseal margins (symphyseolysis) and change the \201 brocart ilaginous disc, increasing symphyseal width (eg by 100%) and mobility. 164 \200\223166 s c i r t e t s b O Fig 1. This platypelloid pelvis is inviting engagement of the head in the transverse positi on. Because the pelvis is so \202 at, deep transverse arrest is a particular risk. Redrawn from L pez-Zeno, J, Glob. libr. women \200\231s med with permission from Sapiens G lobal Library, Ltd. Operative vaginal delivery (forceps/ventouse) \200\225167 Operative delivery 10 \200\22313 % of births UK. A companion in labor; an upright or lateral position for delivery; avoidanc e of epidural or delay in pushing with epidural, reduce the need for operative deliveries. Conditions of use The head must be engaged, the membranes ruptured, the position of the hea d known and the presentation suitable, ie vertex or face (mentoanterior); cephalo \200\223p elvic disproportion must be absent (molding not excessive); the cervix must be fully dilate d; the uterus contracting; and analge- sia adequate (epidural or perineal in \201 ltration if episiotomy); pudendal blocks may be suffi cient for mid-cavity forceps and ventouse del iveries but not for Kielland \200\231s. The bladder must be empty. A neonatal resuscitator should attend. Forceps These are designed with a cephalic curve, which \201 ts around the fetal head, and a pelvic curve which \201 ts the pelvis. Short-shanked (eg Wrigley \200 \231s) forceps are used for \200\230lift out \200\231 deliveries, when the head is on the perineum; long-shanked (eg Neville Barnes) for higher deliveries, when the sagittal su- tur e lies in the AP diameter. Kielland \200\231s forceps have a reduced pelvic curve, making t hem suitable for rotation (only in experienced hands). Indications for use Forceps may be u sed when there is delay in the second stage: this is frequently due to failure of maternal eff ort (uterine inertia or just tiredness), epidural analgesia, or malpositions of the fet al head. They may be used when there is fetal distress or a prolapsed cord, or eclampsia \200\224all occur- ring only in the second stage. They are also used to prevent undue mater nal eff ort, eg in cardiac disease, respiratory disease, pre-eclampsia. They are used for t he after-coming head in breech deliveries. See BOX, OPPOSITE. Technique Learn from demonstr ation. The following is an aide-m moire for non-rotational forceps. Place the mother in li thotomy position with her bot- tom just over the edge of the delivery bed. Use sterilizing \202 uid to clean the vulva and perineum; catheterize; check the position of the head. In sert pu- dendal block, in \201 ltrate episiotomy site (not necessary if she has an epidura l). Assemble the blades to check they \201 t, with the pelvic curve pointing upwards. The handle which lies in the left hand is the left blade and is inserted \201 rst (to the mo ther \200\231s left side) and then the right: the handles should lock easily. Trac- tion mu st not be excessive (the end of bed is not for leverage!). Synchronize traction with contra ctions, guiding the head downwards initially. Episiotomy may be needed when the head is at the vulva. Change the direction of traction to up and out as the occiput clears the symphys is pubis. If baby needs resusci- tation, give to resuscitator. Forceps complications: Mater nal: Trauma (commoner than with ventouse). Fetal: facial bruising, VII paralysis (usually r esolves); brachial plexus injury. Ventouse The ventouse, (vacuum extractor), causes less ma ternal trauma than forceps (but still aff ects 11%). It is preferred worldwide (but not in the UK). It may be used in preference to rotational forceps. As traction is applied, with the cup over the posterior fontanelle, rotation during delivery occurs. It should not be us ed if the head is above the ischial spines. It is contraindicated for face presentations an d for babies <34+0 wks; caution if 34+1 \200\22336+0 wks. A cup is applied with a suction f orce of 0.8kg/cm2. The baby \200\231s scalp is sucked up to form a \200\230chi- gnon \200 \231, which resolves in 2 days. There is increased rate of fetal cephalhaema- toma (p90), f ailed delivery, fetal retinal hemorrhages compared to forceps. After delivery Give vitamin K (p120). Give regular analgesia. Document time and volume of 1st void urine (catheterize f or 12h if epidural). Pass catheter if re- sidual suspected. Is thromboprophylaxis needed (p 16)? Arrange physiotherapy to reduce incontinence. Discuss future delivery; >80% will be va ginal but indi- vidual plan if 3rd or 4th degree tear with this delivery. 76 \200 s c i r t e t s b O 77 Indications for operative delivery Relative indications (cesarean an alternative) \200 De lay or maternal exhaustion in second stage. \200 Dense epidural block with diminished urg e to push. \200 Rotational instrumental delivery needed for malposition of head. \200 S uspected fetal distress. Speci \201 c indications for forceps (forceps delivery is usually superior to ventouse or cesarean in these circumstances) \200 Assisted breech delivery, forceps to deliver head. \200 Assisted delivery of preterm infant <34 weeks \200\231 gest ation. \200 Controlled delivery of head at cesarean section. \200 Assisted delivery wit h face presentation. \200 Assisted delivery with suspected coagulopathy or thrombocytopen ia in s c i r t e t s b O fetus (but note coagulopathy is a relative CI to forceps). Instrumental delivery where maternal condition precludes pushing (eg cardiac disease, respiratory disease). \200 Cord prolapse in second stage of labor. \200 Instrumental delivery under GA. Operative delivery likely to fail (Consider delivery in t heater) \200 Maternal BMI >30 \200 Big baby (estimated weight >4kg) \200 OP presentat ion (p71) \200 Midcavity if >1/5 head palpable per abdomen \200\207Abandon operative vag inal delivery if no progression with each pull and delivery not imminent with 3 pulls by ex perienced operator. Obstetric brachial plexus injury (OBPI) OBPI complicates <0.5% of live births. factors: Lar ge birthweight; Risk shoulder dystocia with prolonged 2nd stage of labor; forceps delivery; vacuum extraction; diabetes mellitus; breech presentation. Formerly, the cause of OBPI was excessive lateral traction applied to the fetal head at delivery, in association with ante rior shoulder dystocia. Instrumental-associated OBPI may arise because of nerve stretch injuries after rotations of >90 or from direct compression of the forceps blade in the fetal neck. 168 Not all cases of bra- chial plexus palsy are attributable to traction. Intrauterine factors may play som e role. 169 Management: 10 \200\22320% need surgical intervention for optimal results. 170 Some injuries will be permanent. 171 See p764 for orthopedic insights. Fig 1. Brachial plexus injury. Cesarean section (CS) 78 \200 \200\207If previous section, localize placenta by ultrasound to see if praevia. If color \202 ow Doppler suggests accreta/percreta (p14), off er MRI to clarify invasion. \200 37. 2 Incidence WHO says to aim for <15%. It is \200\20624% of UK labors (30% in the USA) 9 \200\22316% are pre-labor. 172 Maternal mortality: 1 per 100,000. Morbidity is high- er \200\224eg infection, ileus, and thromboembolism. For 1st operations 25% are due to failure to progress, 28% for fetal distress, 14% for breech; of 2nd cesareans 44% have had previou s section. Use of support in labor, induction at 41 weeks, consultant involvement in decisi on to section, fetal blood sampling when fetal monitoring is used, and use of a 4 hour part ogram with action line all help re- duce incidence of cesarean sections. 9 : 1000 will requ ire ITU care. Lower uterine segment incision Joel Cohen incision (straight incision 3cm abo ve symphysis pubis) with blunt dissection thereafter is recommended (re- duces blood loss). Fetal laceration rate is 2%. Classical cesarean section (vertical incision) Rarely used. I ndications: \200 Very premature fetus, lower segment poorly formed \200 Fetus lies tran sverse, with ruptured membranes and liquor draining \200 Structural abnormality makes low er segment use impossible \200 Constriction ring present \200 Fibroids (some) \200 So me anterior placenta praevia when lower segment abnormally vascular \200 Mother dead and rapid birth desired. Before an emergency section \200\207Explain to the mother what is to happen. \200 Activate the anesthetist, theater staff , porters, and pediatrician. \200 Have the mother breathe 100% O2 if there is fetal distress. \200 Neutralize gastric conte nts with 20mL of 0.3 molar sodium citrate, and pro- mote gastric emptying with metocloprami de 10mg IV. (NB: there is no time for H2 agonists to work; ranitidine is kept for elective sections, eg 150mg Po 2h before surgery.) Consider pre-operative emptying of stomach (eg if prolonged labor or opiate given). The stomach should be routinely emptied prior to extubat ion to minimize risk of post-operative aspiration. See Men- delson \200\231s syndrome, p80. s c i r t e t s b O Take to theater (awake); set up IVI. Take blood for crossmatch, eg 2U; if for abrup- tion ( 6U and 2 IVIs if previous section and anterior placenta praevia \200\224see below).