51 s c i r t e t s b O Small for gestational age (SGA) 52 \200 \200\207When talking to parents, avoid the term growth retardation as this may imply to th em the inevitability of mental handicap \200\224which is not the case. Distinguish prematur e babies from those who are small-for-gestational age (SGA): they are at risk from diff ere nt problems after birth. Causes of growth restriction (IUGR) Growth restricted neonates are those weighing < the 10th centile for their gestational age (Tables, p129). Maternal facto rs: Multiple pregnancy, malformation, infection, smoking, dia- betes, BP \200\200, Hb \200\201, pre-eclampsia, heart or renal disease, asthma. 10% are to mothers who only ever produce small babies. Asymmetric growth restriction: Where placental insuffi ciency was the cause, head circumference is relatively spared (the baby has been starved). Antenatal diag nosis 50% are undetected before birth, and many babies suspected of IUGR do not have it. Me asuring fundal height progress from the symphysis pubis is recommended by NICE to measure g rowth, (ideally use with centile charts). Oligohydramnios and poor fetal movements are othe r indica- tions of placental insuffi ciency. If growth restriction is suspected, monitor gr owth in utero by serial ultrasounds of head circumference and abdominal circumference. If u mbilical cord Doppler blood \202 ows are normal the outcome of growth restricted pregnanc ies is better (fewer premature births and still- births). Those with abnormal Dopplers may bene \201 t from maternal low-dose aspirin (p47), eg 75mg/24h PO. Biophysical pro \201 le monitoring (p46) and ante- natal cardiotocography (p44) are used to try to detect those ba bies who are becoming hypoxic in utero and who would bene \201 t from delivery to prevent stillbirth. Advise the mother to stop smoking, and to take plenty of rest. Labor and afterc are Growth restricted fetuses are more susceptible to hypoxia, so monitor in labor (p44). I f steroids needed, note later gestation (p51). After birth, temperature regulation may be a problem, so ensure a warm welcome; nurse those <2kg in an incubator. After being relativel y hypoxic in utero the Hb at birth is high, so jaundice is more common. They have little st ored glycogen so are prone to hypoglycaemia. Feed within 2h of birth and measure blood gluc ose before each 3-hourly feed. If hypoglycaemic despite regular feeds, transfer to a specia l care unit. They are more susceptible to infection. Routine induction at 36 weeks does not show bene \201 t over induction if needed. 127 Distinguishing growth restriction from pre maturity Before 34 weeks \200\231 gestation there is no breast bud tissue; from then it dev elops at 1mm diam- eter/week. Ear cartilage develops between 35 and 39 weeks so premature b a- bies \200\231 ears do not spring back when folded. Testes lie in the inguinal canal at 3 5 weeks, in the scrotum from 37. Labia minora are exposed in premature girls. Skin creases on the anterior \205\223 of the foot appear by 35 weeks (on anterior \205\224 by 39, and all over from 39). \200\230Prems \200\231 have red, hairy skin. Vernix is made from 28 wee ks and is maximal at 36 weeks. Prems do not lie with legs \202 exed until 32 weeks. All l imbs are \202 exed from 36 weeks. Eff ects of IUGR in adult life By age 23yrs, milder cog nitive problems have often been overcome 128 \200\224but new problems begin to be manifest: \200 Hypertension \200 Type 2 diabetes mellitus So fetal malnutrition casts a long sha dow. Speci \201 c early de \201 ciencies are im- portant too (eg iodine, iron). s c i r t e t s b O Coronary artery disease \200 Autoimmune thyroid disease. 53 Large for gestational age These are babies above the 90th centile in weight for gestation. Causes: Constitutionally large (usually familial \200\224the largest 10% of the pop- ulatio n); maternal diabetes (p24); hyperinsulinism; Beckwith \200\223Wiedemann syndrome (p638). L abor and aftercare: Large babies risk birth injury (see impacted shoul- der, p72). Large ba bies are prone to immaturity of suckling and swallowing and may need temporary tube feeding . They are prone to hypoglycaemia and hypocalcaemia. Polycythaemia may result in jaundice. They are also prone to left colon syndrome: a self-limiting condition clinically mimicking Hirsch- sprung \200\231s disease (p130) whereby temporary bowel obstruction (possibly also with meconium plug) occurs. Rarely, there is renal vein thrombosis. s c i r t e t s b O Postmaturity (prolonged pregnancy) 54 \200 De \201 nition Prolonged pregnancy is de \201 ned as that exceeding 42 completed weeks of pregnancy (gestation having been assessed by ultrasound at <16 weeks \200\231 gestation). Incidence 5 \200\22310% of pregnancies. Problems \200 Possible placental insuffi ciency \200 Larger fetuses (25% >4000g) \200 Fetal skull more ossi \201 ed so less mouldable \200 Increased meconium passage in labor (25-40%) \200 Increased fetal distress in labor \200 Increased cesarean rates for labors after 41 completed weeks. Management At 38-week visit discuss what is recommended if spontaneous labor does not occur by 41 completed week s, including membrane sweep and induction. Arrange for visit at 41 weeks if not delivered. 1 Membrane sweep. On vaginal examination as much membrane is swept from the lower segment a s possible by a \201 nger inserted through the cervix. It is thought to induce natural pr ostaglandins. This may cause discomfort and a little bleeding but may induce labor \200 \230naturally \200\231. 8 women are mem- brane swept for 1 formal induction avoided. Off er at 40- and 41-week visit in nullips, at 41 weeks in multips. s c i r t e t s b O 2 A policy of induction after 41 completed weeks \200\231 pregnancy does reduce fetal death rate. 129 NICE says to off er induction between 41+0 and 42+O weeks. \200 130 Induction i s with vaginal prostaglandin followed by oxytocin (p62). After induction, monitor the fetus in labor (p44). It is estimated that 500 induc- tions are needed to prevent 1 perinatal de ath. 3 If the woman declines induction then arrange twice weekly cardiotocogra- phy (p44), and u ltrasound estimation of amniotic \202 uid depth to try to detect fetuses who may be becom ing hypoxic. Doppler studies of cord blood \202 ow may be used to look for absent end-dia stolic \202 ow as a predictor of fetal compromise. Interestingly, if one looks at the perinatal mortality \201 gures for England, Wales, and Northern Ireland in 2005, the stillbirth rate was 1 : 1000 total births, and neonatal deat h rate 0.6 : 1000 live births for gestations of 42+ weeks; compared with stillbirth rates o f 2 : 1000 and neonatal deaths of 1 : 1000 for gestations of 37 \200\22341 weeks. 131 NICE warns that their advice may not hold equal weight for all ethnic groups in the UK as Asians have excess fetal mortality, but especially after 37 weeks gestation. \200 130 Signs of p ostmaturity in the baby : Dry, cracked, peeling, loose skin; decreased subcutaneous tissue; meconium staining of nails and cord. \200 Fetal distress Fetal distress signi \201 es hypoxia. Prolonged or repeated hypoxia c auses fetal acidosis. An early sign may be the passage of meconium in labor (p72). Other si gns that the fetus may be hypoxic are a fetal tachycardia persisting above 160 beats/min (t achycardia may also occur if the mother has a high temperature or is dehydrated). Hypoxia m ay also be re \202 ected by loss of variability of the base- line in the fetal heart rate trace and slowing and irregularity of the heart rate (especially late decelerations p45). \200 If the heart rate falls below 100 beats/ min urgent assessment is required. Hypoxia ma y be con \201 rmed by the use of fetal blood sampling (p44). When signi \201 cant hypoxia appears to be present (eg pH <7.24), deliver promptly (by the quickest route available, eg cesarean section or vaginal extraction). In complete anoxia the pH falls by 0.1 unit/min. \200 Obstetric shock Most obstetric shock is associated with severe haem- orrhage (see MIN IBOX). It should be remembered that with placental abruption, actual bleeding may be far in excess of that revealed per vaginam (p56). 55 \200 s c i r t e t s b O Causes \200 Severe hemorrhage \200 Ruptured uterus (p80) \200 Inverted uterus (p86) \200 Amniotic \202 uid embolus Vomiting, diarrhea, and abdominal pain may be signs of genital sepsis. There may be rash (g eneral- ized streptococcal maculopapular). Fever may be absent. Persistent tachycardia, per ipheral vascu- lar shutdown, increased respiratory rate, oliguria, metabolic acidosis, and reduced oxygen saturation indicate critical illness needing urgent management. DIC may deve lop; so may uterine atony with subsequent massive hemorrhage. There may be hypother- mia an d hypotension. Check blood gasses to detect metabolic acidosis. Unfor- tunately young women can maintain blood pressure, appearing deceptively well and talking until sudden cardiovas cular decompensation occurs. Septi- caemia may lack classical signs (eg pyrexia) and must b e considered where profound persisting shock is present, be appropriately investigated (eg blood cultures), and treated immediately suspected, eg cefuroxime 1.5g/8h IV + met- ronidaz ole 500mg/8h IVI + gentamicin 1.5mg/kg/8h IV given over >3min; (do levels, but levels not n eeded acutely, see OHCM p371), without waiting for mi- crobiology results. Liaise with micr obiologists. Nurse on critical care unit with critical care anesthetic help. (p89) Pulmonary embolism \200 Septicaemia \200 Adrenal hemorrhage Prompt resuscitation is required (see individual pages for management). Renal function and urine output should always be measured after shock has occurred (p28). A late complication can be Sheehan \200\231s syndrome (also called Simmonds \200\231 disease) whereby pituitary necrosis leads to lack of thyroid- stimulating hormone, adrenocorticotrophic hormone, and the gonadotrophic hormones, hence leading to hypothyroidism, Addisonian symptoms, and geni- tal atrophy. \200 Anterpartum hemorrhage (APH) 56 \200 Genital tract bleeding from 24+0 wks \200\231 gestation complicates 3 \200\2235% of pregnan - cies. Any bleeding in pregnancy is associated with increased perinatal mortality. Severe bleeds can cause maternal death. Ask about domestic violence. \200\207Avoid vaginal examin ation: placenta praevias may bleed catastrophically. Dangerous causes Abruption, placenta p raevia, vasa praevia (here the baby may bleed to death). Other uterine sources: Circumvalla te placenta, placental sinuses. Lower genital tract sources: Cervical polyps, erosions and carcinoma, cervi- citis, vaginitis, vulval varicosities. Placental abruption ( \200\230acci dental hemorrhage \200\231) Part of the placenta be- comes detached from the uterus. The ou tcome depends on the amount of blood loss and degree of separation. It may recur in subsequ ent pregnancies (4%: 19 \200\22324% if twice). Associations pre-eclampsia, smoking, IUGR (p 52), PROM (p50), multiple pregnancy, polyhydramnios, \200\200 maternal age, thrombophilia, abdo trauma, assisted reproduction, cocaine/amphetamine use, infection, non vertex present ation. Bleeding may be well localized to one placental area and there may be delay before b leeding is revealed. Consequences: Placental insuffi ciency may cause fetal anoxia or death . Com- pression of uterine muscles by blood causes tenderness, and may prevent good contrac tion at all stages of labor, so beware a PPH (which occurs in 25%). Posterior abruptions m ay present with backache. There may be uterine hypercontractility (>7 contractions per 15mi n). Thromboplastin release may cause DIC (10%). Concealed loss may cause maternal shock aft er which be- ware renal failure and Sheehan \200\231s syndrome (p55). Placenta praevia (For terminology and complications, see p14.) The placenta lies in the lower uterine segment. B leeding is always revealed. s c i r t e t s b O Distinguishing Abruption Shock out of keeping with visible loss Pain constant Tender, te nse uterus Normal lie and presentation Fetal heart: absent/distressed Coagulation problems Beware pre-eclampsia, DIC, anuria From Placenta praevia Shock in proportion to visible loss No pain Uterus not tender Both ma y be abnormal Fetal heart usually normal Coagulation problems rare Small bleeds before larg e Note: the risk of PPH is increased in both conditions. The lower segment may not contract w ell after a placenta praevia. Management of APH Always admit. \200 If bleeding is severe c all emergency ambulance, put up IVI, take bloods, and raise legs. Give O2 at 15L/min via ma sk with reservoir. On admission, if shocked give fresh ABO Rh compatible or O Rh \200\223ve blood (eg 6U, 2 IVIs) fast until systolic BP >100mmHg. Send blood for clotting screen. Cat heterize bladder; keep urine output >30mL/h. Call anesthetist to monitor \202 uids (CVP l ines help). Summon expert help urgently. If bleeding is severe, deliver \200\224cesarean se ction for placenta praevia (sometimes for abruption, or induction). Beware PPH (manage 3rd stage with Syntometrine ). For milder bleeding, set up IVI, do Hb, crossmatch, coagulation studies, and U&E. Check pul se, BP, and loss regularly. Establish diagnosis (ultrasound of placenta, speculum examinati on). If placenta praevia is the diagnosis, keep in hospital until delivery (usually by cesa rean section at 37 \200\22338 weeks). If pain and bleeding from a small abruption settles a nd the fetus is not compromised the woman may go home (after anti-D, if indicated; 6-weekly if recurrent bleeds), but then treat as \200\230high-risk \200\231 pregnancy (serial scan s). Arrange follow-up. This page intentionally left blank Normal labor 58 \200 \200\230Labor is one of the shortest yet most hazardous journeys humans make in their life time. \200\231 From the 1st trimester, the uterus has Braxton Hicks contrac- tions (ie non- painful \200\230practice \200\231 contractions, eg to \211 15mmHg pressure; in labor pres sure is 60mmHg). They are commonest after 36 weeks. Normal labor ( \201 g 1) 60% of birt hs are normal and need no intervention (we over-medicalize \200\20620% of labors, interven ing unnecessarily). 132 Normal labor occurs after 37wks \200\231 gestation and results in spontaneous vaginal deliv ery of the baby within 24h of the onset of regular spontaneous con- tractions. It is often heralded by a \200\230show \200\231, ie a plug of cervical mucus and a lit- tle blood as t he membranes strip from the os (membranes may then rupture). The \201 rst stage of labor Latent phase (not necessarily continuous): there are painful contractions, the cervix initi ally effaces (becomes shorter and softer) then dilates to 4cm. Established phase: contracti ons with dilatation from 4cm. A satisfactory rate of dilatation from 4cm is 0.5cm/h. The 1s t stage generally takes 8 \200\22318h in a primip, and 5 \200\22312h in a multip. During th e \201 rst stage check maternal BP, and T 4-hourly, pulse hourly; assess the contractio ns every 30min, their strength (you should not be able to indent the uterus with the \201 n- gers during a contraction) and their frequency (ideally 3 \200\2234 per 10min, lasting up to 1min). Note frequency of bladder emptying. Off er vaginal examination eg every 4h to assess the degree of cervical dilatation, the position and the sta- tion of the head (measu red in cm above the ischial spines) and note the degree of molding (p42). Note the state of the liquor (p73). Auscultate fetal heart rate (if not continuously monitored), by Pinard o r Doppler every 15min, listen- ing for 1min after a contraction. When to use continuous mon itoring? See p44. The second stage Passive stage is complete cervical dilatation (but no de - sire to push. In active stage, the baby can be seen, there is full dilatation with expuls ive contractions and maternal eff ort (using abdominal muscles and the Valsalva maneuver un til the baby is born (see Movement of head in labor, p42). Discourage supine maternal posit ion in 2nd stage. Encourage mother to adopt a comfortable position. Check BP and pulse hour ly, To 4-hourly , assess contractions half-hourly, auscultate for 1min after a contraction every 5 min, off er vaginal examination hourly, and record urination during 2nd stage. If c on- tractions wane, oxytocin augmentation may be needed. s c i r t e t s b O As the head descends, the perineum stretches and the anus gapes. Expect birth within 3h fro m active 2nd stage in primips (refer to obstetrician if not imminent at 2h); expect birth w ithin 2h in a multip (refer if birth not imminent at 1h). Prevent a precipitate delivery (a nd so intracranial bleeding) by pressure over the perineum. 1-min delay in clamping the cor d is recommended in vigor- ous term babies. 123 3-min delay bene \201 ts premature babies ( \200\201 anemia). 133 The third stage is delivery of the placenta. As the uterus contract s to a <24-week size after the baby is born, the placenta separates from the uterus through the spongy layer of the decidua basalis. It then buckles and a small amount of retroplacen tal hemorrhage aids its removal. Signs of separation: Cord lengthening \200\203 rush of bl ood (retroplacental haemor- rhage) per vaginam \200\203 uterus rises \200\203 uterus cont racts in the abdomen (felt with hand as a globular mass). Physiological (natural) 3rd stage takes \211 1h. Use of Syntometrine (ergometrine maleate 500 g IM + oxytocin 5U IM) as the anterior shou lder is born decreases third stage time (to 5min), and de- creases the incidence of PPH, b ut may cause problems for undiagnosed twins. It can precipitate myocardial infarction and i s contraindicated in those with pre-eclampsia, severe hypertension, severe liver or renal i mpairment, severe heart disease and familial hypercholesterolaemia. If BP not measured in l abor give just oxytocin. 134 Examine the placenta to check it is complete. \200\207Is thro mboprophylaxis needed? (p16) 59 s c i r t e t s b O Fig 1. Normal labor Prelabour rupture of membranes at term \200\225109 This is rupture of the membranes prior to the onset of labor in women at or over 37 completed weeks gestation. It occurs in 8 \200 \22310% of pregnancies. Infec- tion of the lower genital tract or amnion is a known aetiolo gical factor. 60 \200 When there is prelabour rupture of membranes risk of serious infection is in- creased (1% v ersus 0.5% for women with intact membranes). 60% of women will go into spontaneous labor wi thin 24 hours. If a woman has prelabour membrane rupture she should be off ered a choice of induction or e xpectant management. If spontaneous labor has not com- menced by 24h then NICE states that it is appropriate to induce labor. \200 130 Vaginal prostaglandin is the preferred method of trying to induce labor. (NICE notes that special product characteristics say use vaginal prostaglandins with caution, or that they should not be used in those with ruptured membra nes but there is over 20 years UK experience with these. So obtain and document informed co nsent with their use.) Until labor is commenced or if expectant management is chosen to con- tinue beyond 24h ask the woman to take her temperature 4-hourly in waking hours and report to hospital immediate ly if she develops fever or if there is change in color or smell of vaginal loss. Bathing a nd showering do not in- crease, but sexual intercourse may increase risk of infection. If t here are signs of infection give a full course if IV antibiotics (p50). s c i r t e t s b O Monitor fetal heart rate at 1st contact and every 24h after membrane rupture whilst the wom an is not in labor. Ask her to report if there are reduced fetal movements. Those giving bi rth after 24h of ruptured membranes should deliver where there are neonatal care facilities , and advise to stay in hospital for 12h after birth. Babies are most susceptible to infection within 12h of birth. Observe at 1h, 2h and then 2- hourly for further 10h. Observations should include, general wellbe- ing, chest movement an d nasal \202 are, capillary re \201 ll, feeding, muscle tone, tem- perature, respiration s and heart rate. If there is any suggestion of sepsis in the baby call a neonatal care spe cialist. Mothers should also be advised to report any health concerns with the baby in the 1st 5 days of life. This page intentionally left blank Induction of labor 62 \200 20% of UK labors are induced arti \201 cially, usually because it has been de- cided that to remain in utero is relatively more risky for the fetus than to be born, but in some it is because of risk to the mother. 75% of inductions are for hypertension, pre-eclampsia, pr olonged pregnancy, or rhesus disease. Other indications are diabetes, previous stillbirth, abruption, fetal death in utero, and placental insuffi ciency. \200\207Inducing mothers at 41+ weeks aims to reduce stillbirth rates. Contraindications Cephalopelvic disproportion w hich is absolute, malpre- sentations other than breech or face presentation, fetal distress , placenta praevia, cord presentation, vasa praevia, pelvic tumor, previous repair to cer- vix. Cone biopsy requires caution. Cervical ripeness When an induction is being planned the state of the cervix will be assessed. In 95% of women at term the cervix is ripe. If primi ps are induced with an unripe cervix (Bishop \200\231s score \211 3, see below) the rates of pro- longed labor, fetal distress, and cesarean section are increased. This is less mark ed in multips. s c i r t e t s b O Modi \201 ed Bishop score Cervical dilation (cm) Length of cervix (cm) Station of head (cm above ischial spines) Cervical consistency Position of cervix 0 0 >2 \200\2233 Firm Posterior Middle 1 1 \200\2232 1 \200\2232 \200\2232 Medium Soft 2 3 \200\2234 <1 \200\2231 Anterior A score of >5 is \200\230ripe \200\231. An unripe cervix may be ripened using prostaglandi n (PGE2) vaginal gel (1mg) the evening before or the morning of induction (use 2mg for unfa vorable primip cervix). If antenatal fetal heart rate monitoring is indicated, this should commence before prostaglandin insertion. If there is failure to ripen (occurs in 12%) PGE2 may be repeated 6 \200\2238h later. If the cervix still remains unripe consider cesarean se ction. PGE2 may stimulate uterine contractions or precipitate labor. Once the cervix is ripe, rupture the membranes (amniotomy) and start intrapartum fetal hear t rate monitoring using a scalp clip or pulse oximetry (less invasive, see OHCM p148). Oxyt ocin is given IV in 5% dextrose using a pump system (eg Ivac ). Infusions start at 1 \200 \2234 milliunits (MU) per min, increasing every 30min until 3 \200\2234 contractions occur every 10min (usually at a rate of 4 \200\22310MU/min: occasionally 20MU/min may be needed); max dose 5U/day. Monitor the fetal heart and stop if distress or uterine hyperstimulation. Beware using large volumes of IV \202 uid (if >4 litres, there is risk of water intoxica tion \200\224ie confusion, convulsions, and coma). Use standard strength solutions as per B NF. When the cervix is 5cm dilated the uterus is more sensitive to oxytocin and 8MU/min may be suffi cient to maintain contractions. Note: the Dublin regimen (p64) results in most wo men going into spontaneous labor. Misoprostol (a prostaglandin E1 analog) PO or PV is as eff ective at cervical ripening and inducing labor as PGE2 and oxytocin. Oral route (eg 50 g 4-hourly) has fewer problems with uterine hyperstimulation. 135 NICE says use only use for labor induction after intrauterin e death. \200 130 Problems of induction \200 Failed induction (15%) \200 Uterine hyper stimulation (1 \200\2235%) \200 Iatrogenic prematurity \200 Infection \200 Bleeding ( vasa praevia) \200 Cord prolapse (eg with a high head at amniotomy) \200 Cesarean secti on (22%) and instrumental delivery rates (15%) are higher \200 Uterine rupture (rare). 63 s c i r t e t s b O Fig 1. Example of a partogram. It has a steep x/y gradient of ratio 1 : 1. Less steep ratio s (eg 2 : 1) may predispose to premature intervention, as does inclusion of the \200\230la tent \200\231 phase on the partogram. Reproduced with permission from the Oxford Handbook of Obstetrics and Gynecology, 2nd editi on. The active management of labor 64 \200 Historically, this emanated from Dublin, a center of excellence for laboring mothers with c oherent labor management plans, and low cesarean section rates (eg 5% vs 24% for other cent ers): forceps rates were 10%. The cardinal features were to have only women in active 1st stage of labor (p58) on labor ward; to assess regularly (eg hourly for 1st 3h, subsequently every 2h) to check that cervical dilatation was progressing well \200\224and to take actio n if not. Mem- branes would be ruptured if no progress after 1h, and labor augmented with o xytocin in primiparous women with single, cephalic presentation babies, if unsatisfactory c ervical dilatation within the next hour (or in subsequent time periods). Satisfactory dilat ation was considered 1cm/h. Mothers had a person- al midwife throughout labor. Women were k ept informed of their progress, given an estimated time of delivery and assured that delive ry should be within 12h of entering the labor ward. Cesarean section would be performed on those for whom delivery not imminent at 12h. The system was very effi cient, with unit deli very costs \205\223 of those of those in the UK at the time. The problem with active manag ement is that it is very medicalized, with amniotomy, frequent examinations, and IVI lines needed. Over time this has been felt to be unacceptable and although amniotomy and augmenta tion have a role in delay in labor; current recommended time scales are slower. Below are t he recommendations of NICE. \200 109 For normal labor see page 58. Delay in 1st stage of l abor This is <2cm/h dilatation in 4h in any woman; or slowing in progress in 2nd or subsequ ent labors. Consider the descent and ro- tation of the fetal head and the strength and freq uency of contractions. When delay is diagnosed off er continuous fetal heart monitoring (p4 4). If delay di- agnosed, off er amniotomy (advise it will <labor by 1h and may \200\200 p ain and contraction strength). Re-examine 2h later; if <1cm progress and amniotomy at 1st d eclined, off er again; if has had; consider oxytocin augmentation; explain- ing that augmen tation increases pain and strength of contractions. Ensure adequate pain relief. Off er epi dural before oxytocin started. Augmentation This recognizes that a primiparous uterus is an ineffi cient organ of birth that is not prone to rupture \200\224but the multiparous uteru s is an effi cient organ that is rupture-prone. Oxytocin may be used to enhance effi ciency in the primiparous uterus without maternal danger. Oxytocin may be dangerous to multips as delay is likely to be from obstructed labor, so a decision to use it must only be made by a senior obstetrician. Continuous fetal heart monitoring should commence when oxytocin used . See p62, p44. Advise examination 4h later: if >2cm dilatation, continue oxytocin, examini ng 4hrly; if <2cm dilatation get obstetric review; cesarean section may be needed. Delay in 2nd stage of labor If delivery not imminent within 1 hour after on- set of active 2nd stag e (p58) in multips; or after 2h in primips call obstetrician experienced in operative deliv ery. Off er amniotomy if membranes not rup- tured. Ensure adequate anesthesia/analgesia. En sure obstetric review every 15 \200\22330mins. If 2nd stage prolonged or fetal compromise c onsider instrumental delivery (p76) with adequate analgesia/anesthesia. Cesarean section (p 78) should be advised if vaginal birth is not possible. Meconium in liquor At amniotomy thi s suggests placental insuffi ciency. Meconium other than light staining in good liquor volu me prompts fetal blood sampling and scalp clip electronic monitoring \200\224or prompt cesa rean section (fetal blood pH low, or very thick meconium). s c i r t e t s b O This page intentionally left blank Pain relief in labor 66 \200 \200\207Pain relief in labor is our greatest gift to womankind; however, in the UK NHS 25% of mothers said they didn \200\231t get the relief they needed. 132 Not everyone wants nat ural birth: don \200\231t make people feel guilty about request- ing pain relief. The ideal analgesia must be harmless to mother and baby, must allow good maternal cooperation, and m ust not aff ect uterine contractility. Education That given by the National Childbirth Trus t meets all these criteria. Education about labor reduces fear; breathing exercises and rel axation tech- niques teach the mother ways to combat pain herself. Waterbirth Laboring in w ater has been shown to reduce need for regional anesthesia. 136 It is recommended by NICE w ith the advice that water tem- perature be checked hourly and kept <37.5o to prevent matern al pyrexia. \200 109 In the \201 rst stage, narcotic injections are often tried, eg pethidine 50 \200\223 150m g IM (not if birth expected in <2 \200\2233h as neonatal respiratory depression may occur, reversible with naloxone 0.1 \200\2230.2mg as a single dose IM). Expect an- algesia by 20mi n and to last 3h. NB: doses frequently produce vomiting, but no relief of pain. Other SE: d isorientation, \200\201 gastric emptying (nausea, vomiting), neonatal respiratory depressi on and drowsiness. CI: mother on MAOIs (p368). Give with antiemetic. Women should not enter water within 2h of injection. \200 109 Nitrous oxide (50% in O2 = Entonox ) can be inhal ed throughout labor and is self-administered using a demand valve. CI: pneumothorax. It can make the woman feel nauseated and light-headed. Pudendal block (sacral nerve roots 2, 3, a nd 4) uses 8 \200\22310mL of 1% lidocaine (= lignocaine) injected 1cm beyond a point just b elow and medial to the ischial spine on each side. It is used with perineal in \201 ltrati on for instrumental deliv- ery, but analgesia is insuffi cient for rotational forceps. Spin al block See p634; used for rotational delivery or cesarean section. Epidural anesthesia Se e p67. Pain relief is by anesthetizing pain \201 bres car- ried by T11 \200\223S5. Epidur als may be started during latent 1st phase of labor \200 109 and continued until placenta delivered, and any perineal repair completed. Set up IVI. Give IV ephedrine and volume prel oad. \200\22552 Check BP, every 5min for 15min, and electronically monitor fetal heart for 30 mins after the epidural is set up, and after top ups. Top-ups are required 2-hourly. R ecall anesthetist if inadequate pain relief within 30mins. Assess level of sensory block ho urly. Epidurals may be helpful for the following: OP position (p71), breech, multi- ple pre gnancy, preterm delivery, pre-eclampsia, forceps delivery, incoordinate uterine contraction s. Problems: For those due to technique, see p635. There may be postural hypotension (IV \202 uids, nurse 15 to left side), urinary retention (catheterize regularly), paralysis ( pelvic \202 oor muscle paralysis reduces rota- tion and voluntary eff ort in 2nd stage, p erhaps increasing need for forceps). Aim for delivery within 4h of full dilatation. Oxytoci n for 2nd stage in primips and delaying pushing until 1 \200\2232h post full dilatation, or strong desire to push, reduces forceps rates. 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.