Definition: Any Pregnancy in which 2 or moreembryos or fetuses occupy the uterussimultaneously Increased incidence (assisted reproductivetechnology) Twins account for about 1% of pregnancies Hellins law (80 n-1)- Twins → 1 in 80- Triplets → 1 in 802- Quadruplets → 1 in 803
↑maternal age and parityAssisted reproduction techniques- Ovulation induction agents(gonadotropins)- In-vitro fertilization (IVF)Family history
Monozygotic twins (identical) Originate by fertilization ofsingle ovum by single sperm. The twinning may occur atdifferent periods afterfertilization and this influencesthe process of implantation andthe formation of the fetalmembranes.
Monozygotic/identical/uniovular(1 zygote divide into 2)~33%DichorionicDiamniotic(cleavage ofembryonic egg<3days )~30%MONOchorionicDiamniotic(4-8days)~69%MONOchorionicMONOamniotic(9-12days)~1%
Dizygotic twins(non-identical ) Results fromfertilisation oftwo ova by twosperms. Dichorionic anddiamniotic twins.
A. History Taking Family history of multiplepregnancy Recent infertility treatment Excessive nausea and vomiting Excessive lower limb swellingand varicosities Excessive fetal movement andabdomen overdistension Extremely fatigue
B. Physical Examination Anaemia & oedema Raised BP Uterus larger than dates Polyhydramnios (> in monozygotictwins) Multiple fetal parts & poles > 1 heart sound with different rates Abnormal weight gain
Zygosity Ultrasound-=> Gender discordance = dizygotic DNA fingerprinting, from amniotic fluid sample(amniocentesis), placental tissue (chorionicvilli sampling) and fetal blood (cordocentesis) Chorionicity Characteristic of membrane(US)-
Why so important todifferentiate???Prenatal diagnosis of chorionicity is important asmonochorionic pregnancies have increased rates andseverity of all types of obstetric complications whencompared with dichorionic pregnancies.
Maternal• ↑ Sx of early pregnancy (↑HCG)• Miscarriage• Anaemia (↑ Fe,folate & B12 )• Polyhydramnios (uniovular twins)• PIH (↑3-5x)• APH (placenta praevia)• PPH (uterine atony d2 overstretching)• GDM (↑diabetogenic placentalhormones)• Ineffective labour (malpresentation)• Thromboembolic ds (↑pelvic veincompression)Fetal• Single fetal death• Preterm labour (d2overdistended uterus, polyH,intrauterine infection)• IUGR (discordant growth)• Stillbirth• Congenital abnormality• Twin to twin transfusionsyndrome• Asphyxia (cord entanglement)• Intrauterine death
TTTS is found in MCMA as well as MCDApregnancies. TTTS is more common in MCDA pregnancies thanMCMA pregnancies, possibly reflecting that thereare more protective artery–artery anastomoses inthe latter. Rarely (in approximately 5% of cases), thetransfusion may reverse during pregnancy, with thedonor fetus demonstrating features of a recipientfetus and vice versa Unequal placental sharing and peripheral,‘velamentous’ cord insertions are common in TTTS
Affects 10-15% of monochorionic twinpregnancies. Pathophysiology: Result of transfusion of blood from donor torecipient twin through abnormal artery-to-vein anastomoses in the placenta The donor suffers hypovolaemia and hypoxia →IUGR, smaller in size, oligohydramnios & highoutput cardiac failure The recipient fetus exhibit hypervolemia →large size, polyhydramnios, cardiomegaly, CCF
More than 90% ends in miscarriage/severe pretermdelivery To monitor: US doppler 2 weekly Management:I. Laser coagulation – occlude the vascularanastomosis between twins (presenting prior to26weeks of gestation)II. Amnioreduction every 1 - 2/52, drain amnioticfluid from recipient sacIII. Septotomy (cord entanglement risk)IV. Anticipate preterm delivery – corticosteroid(promote fetal lung maturity
Occur in monochorionic twin Fetal demise <14weeks-not increase risk onthe survivor twin Confers risk to survivor twin if fetaldemise after 14 weeks. Dt transfer of thromboplastin from deadtwin > produce thrombotic arterial occlusion> occlusions of ant & mid cerebral arteries >multicystic encephalomalacia & neurologicdamage. Induce consumptive coagulopathy in mother.
• All women with a multiple pregnancy should beoffered an ultrasound examination at 10–13weeksof gestation to assess:I. viabilityII. chorionicityIII. major congenital malformationIV. nuchal translucency for designation of risk ofaneuploidy and twin-to-twin transfusionsyndrome.
1. Ultrasound at 10–13 weeks: (a) viability; (b)chorionicity; (c) NT: aneuploidy2. Structural anomaly scan at 20–22 weeks.3. Serial fetal growth scans e.g 24, 28, 32 and thentwo- to four-weekly.4. BP monitoring and urinalysis at 20, 24, 28 andthen two-weekly.5. 34–36 weeks: discussion of mode of delivery andintrapartum care.6. Elective delivery at 37–38 completed weeks.7. Postnatal advice and support (hospital- andcommunity-based) to include breastfeeding andcontraceptive advice
1. Ultrasound at 10–13 weeks: (a) viability; (b)chorionicity; (c) NT: aneuploidy/TTTS2. Ultrasound surveillance for TTTS and discordantgrowth: at 16 weeks and then two-weekly.3. Structural anomaly scan at 20–22 weeks (includingfetal ECHO).4. Fetal growth scans at two-weekly intervals untildelivery.5. BP monitoring and urinalysis at 20, 24, 28 and thentwo-weekly.6. 32–34 weeks: discussion of mode of delivery andintrapartum care.7. Elective delivery at 36–37 completed weeks (ifuncomplicated).8. Postnatal advice and support (hospital- andcommunity-based) to include breastfeeding andcontraceptive advice.
Dietary advice: adequate caloric intake to meetincreased demands, supplement of iron (60-80mg /day), folic acid, calcium, vitamins Monitor for infection, anaemia, PIH, pretermlabour & malpresentation Corticosteroid if strong possibility of pretermlabour (for lung maturity)
INTRAPARTUM MANAGEMENT OF TWINSCriteria for vaginal delivery fulfilledDeliver the 1st twinClamp and cut the cordNote lie of 2nd twinTransverse lie Longitudinal lieAttempt External CephalicVersion and vaginal deliveryunder GAIf unsuccessful C-sectionAmniotomy with controlled oxytocininfusion if there is uterine inertiaNote presentationVertex BreechVaginal delivery or optionallyoutlet forceps or ventouseBreech extractionor assisted breechdelivery
In PIH and cardiac disease: give oxytocin 10unit i.mSyntometrine 1 ml (5 unit oxytocin and 500mcg ergometrine i.m) with delivery of anteriorshoulder of 2nd babyPlacenta delivered with controlled cord tractionIn high risk of uterine atony and PPH, i.vinfusion 40 units oxytocin over 6 hours afterdelivery)Episiotomy/perineal repair if needed