MULTIPLE GESTATION When more than one fetus simultaneouslydevelops in the uterus,it is called multiple pregnancy.Simultaneous development of two fetuses(twins) isthe commonest; although rare,development of more thantwo may also occur. 3 fetuses : triplets 4 fetuses : quadruplets 5 fetuses : quintuplets 6 fetuses : sextuplets
TWINS Dizygotic(2/3 rds) Monozygotic(1/3 rd) Results from fertilization Resultsfromfertilization of two ova of a single ovum
out come of twinning process depends on when division occurs: with in 72hrs after fertilization (prior to morula stage) diamniotic-dichorionic twins. B/W 4th&8th day:after formation of inner cell mass & when chorion already devoleped-diamniotic monochorionic twins After 8th day-monoamniotic monochorionic twins. If the division is intiated later,i.e after the embrionic disc has formed, cleavage is incomplete - conjoined twins.
INCIDENCE Monozygotic twins : one in 250 births Dizygotic twins : ranges from 1:20 to 1:200 In india it is 1:80 Hellin’s rule : twins 1:80 triplets 1:80 ² quadruplets 1:80³
PREVALENCE AND CAUSES Monozygotic twinning is independent of race, heredity,age & Parity. A.race : whites 1:100 blacks 1 :80 Nigerians 1:20 B. Heredity
C. Maternal age & parity : 0 @ puberty ,peak @ 37 yrs frequency of multiple gestation in first pregnancy was 1.3% compared with 2.7% in fourth pregnancy Twinning increased from 1:50 during first pregnancy to 1:15 in sixth. D. Nutritional : E. Role of gonadotrophins
F. Infertility therapy Incidence- With conventional gonadotrophin therapy-16to40% (75% twins) With hMG it is 25 – 30% Ovulation induction increases both dizygotic & monozygotic twinning
G.ART Typically , pts undergo super ovulation if vitro fertization is attempted in all retrieved ova,& 2to4 embryos are transferred to uterus In general, the greater the no. of embryos that are transfered , The greater the risk of twins & of higher order multiple gestation
Diagnosis History Older maternal age (at peak of ovulation 38yrs) Previous history of twinning; high parity History of use of ovulation induction drug or pregnancy following assisted reproductive technique Good maternal nutrition Family history of twinning
CLINICALLY A. Symptoms and Signs All of the common annoyances of pregnancy are more troublesome in multiple pregnancy. The effects of multiple pregnancy on the patient include earlier and more severe pressure in the pelvis, nausea, backache, varicosities, constipation, hemorrhoids, abdominal distention, and difficulty in breathing. A “large pregnancy” may be indicative of twinning (distended uterus). Fetal activity is greater and more persistent in twinning than in singleton pregnancy.
(1) Uterus larger than expected (> 4 cm) for dates. (2) Excessive maternal weight gain that is not explained by edema or obesity. (3) Polyhydramnios, manifested by uterine size out of proportion to the calculated duration of gestation, is almost 10 times more common in multiple pregnancy. (4) History of assisted reproduction.
(5) Elevated MSAFP [maternal serum alpha- fetoprotein]values (6) Outline or ballottement of more than one fetus.palpation of 2 fetal heads/presence of three fetal poles. (7) Multiplicity of small parts. (8) Simultaneous recording of different fetal heart rates, each asynchronous with the mother’s pulse and with each other and varying by at least 8 beats per minute. (The fetal heart rate may be accelerated by pressure or displacement.) (9) Palpation of one or more fetuses in the fundus after delivery of one infant.
INVESTIGATIONS1. Biochemical tests: a- chorionic gonadotropin in plasma and in urine. b- alpha fetoprotein level (alone is not diagnostic).
USG 1st trimester – Dating scan - No of gestational sacs - Chorionicity 2nd Trimester - To rule out anomalies - No of fetuses 3rd Trimester - For fetal growth - For amniotic fluid index every 15 days – To detect any growth difference (TTTS / Growth discordance)
ULTRASONOGRAPHIC FINDINGS Chorionicity can be identified by USG as early as the first trimester Presence of two separate placentas and a thick – generally 2mm or greater dividing membrane supports the presumption of the diagnosis of dichorionicity Fetuses of opposite gender are always dizygotic “Twin – Peak” sign – Confirms dichorinic twinning 97% Sensitivity & 100 % specificity for dichorionicity
Maternal risks Fetal risks Nausea,vomiting, mechani Abortion cal distress Vanishing twin/fetal Anemia papyraceous PIH/Preeclampsia Preterm labour Poly/oligohydramnios Fetal anomalies Preterm labour Discordant growth Malpresentation Death of one fetus APH Twin to twin transfusion Prolonged labour syndrome Operative interference Cord prolapse PPH Locked twins
RISKS MATERNAL Increased symptoms of early pregnancy like nausea& vomiting Increased risk of miscarriage ---- rate of missed abortion is twice as high as the 2% rate seen in singletons @10-14 wks vanishing twin syndrome minor disorders of preg.--- backache,breathlesness,varicose veins anaemia Preterm labour & delivery Hypertension (Cont………)
Antepartum haemorrhage as result of placenta previa& placental abruption• Hydramnios• single fetal death• increased risk of an operative vaginal birth• increased likely hood of cesarean birth• post partum haemorrhage• Maternal mortality
FETAL RISKS Still birth (or) neonatal death - 10% of perinatal mortality rate PNMR in twins is up to 10times that in singletons Single fetal death in twins Preterm labour and delivery - rate 30% to 50% in twins 80 % in triplets IUGR – 25% to 33% Congential anomalies
Twin reversed arterial perfusion sequence Conjoined twins - 1 in 200 monozygotic twins Cord accident - due to preterm birth, PROM, hydramnios Mal position & mal presentation Zygosity Mono amniotic twins Hydramnios
Twin - twin transfusion syndromeRisk of asphyxia - 4 to 5 times that of a singletonOperative vaginal birth, especially for the second twinTwin entrapment – rare, 1 in 817 twin pregnancies,associated with mono amniotic twinsCerebral palsy – prevalence in twins is 8 times that insingletons, and in triplets it is 47 times that in singletons
Twin – to – twin Transfusion syndrome It is a complication unique to monochorionic multiple pregnancies Hypovalemia, oliguria, and oligohydramnios develop in the donor twin, producing “ Stuck twin” phenomena Hypervolemia, polyuria and hydramnios evolve in the recipient twin, who can develop circulatory over load and hydrops TTTS usually occurs b/w 15 & 26 wks
Fetal risks In untreated TTTS – mortality rate is nearly 100% In advanced neonatal care - 63% mortality Spontaneous abortion & extreme preterm delivery are associated with hydramnios Fetal death due to cardiac failure in the recipient or poor perfusion in donor
Acardiac twins (Reversed-Arterial Perfusion TRAP). * rare 1:3500 births. * large A-A placental shunt between umbilical arteries in early embryogenesis, 75% monochorionic, diamniotic. 25% monochorionic monoamniotic
ANTEPARTUM MANAGEMENT OF TWINPREGNANCY To reduce perinatal mortality and morbidity in pregnancies complicated by twins, it is imperative that: 1. Delivery of markedly preterm infants be prevented. 2. Failure of one or both fetuses to thrive be identified and fetuses so afflicted be delivered before they become moribund. 3. Fetal trauma during labor and delivery be avoided. 4. Expert neonatal care be available.
Ante partum management Early diagnosis (mainly by ultra sound) Regular antenatal check up , supplementation of folic acid & iron Screening for maternal Hyper tension gestational diabetes mellitus & their treatment Serial USG – Chorionicity, fetal No. anomalies, fetal health ,onset of preterm labour
DIET- Caloric consumption increased by 300 kcal/day 60 to 100 mg/day of iron 1 mg of folic acid is recommended. Bed Rest-Limited physical activity, helps in reducing preterm births in women with multiple fetuses Interval of antenatal visit should be more frequent to detect at he earliest,the evidences of anemia,preterm labour or pre-eclampsia.
ANTEPARTUM SURVEILLANCE Tests of Fetal Well-Being- serial sonography at every 3-4 weeks interval. Assessment of fetal growth,amniotic fliud volume and AFI, non-stress test and doppler velocimetry are carried out.
PRETERM LABOUR PREDICTION Cervical length and fetal fibronectin levels predicted preterm birth. 24 wks-Cx length- < 25mm –before 32 wks 28 wks- fetal fibronectin is predictive Tocolytic Therapy Corticosteroids for Lung Maturation Cerclage Women with multifetal gestation at 24 wks >closed internal os on digital Cx ex >normal cervical length by USG ex >negative fetal fibronectin testLow risk to deliver before 32 wks
PRETERM MEMBRANE RUPTURE DELAYED DELIVERY OF SECOND TWIN Expectant management for ruptured membranes Asynchronous birth of attempted, mother to be evaluated and counseled for risks1. Infection2. Abruption3. Congenital anomalies
Indication for induction of labour in multifetal gestation:1. Severe pregnancy induced hypertension2. Fetal distress3. Discordant growth with fetal distress near term
DURATION OF GESTATION. As the number of fetuses increases, the duration of gestation decreases.The mean gestational age at delivery was 35 weeks. PROLONGED PREGNANCY. A twin pregnancy of 40 weeks or more should be considered postterm. At and beyond 39 weeks, the risk of subsequent stillbirth was greater than the risk of neonatal mortality. PULMONARY MATURATION-ratio usually exceeds 2 by 36 weeks in singleton pregnancies, it often does so by about 32 weeks in multifetal pregnancy.
IN LABOUR MANAGEMENT Trained obstetrical attendant. Blood should always be made available. I.V line. CTG monitoring. Anesthetist C-S Pediatrician for each fetus. Mode of delivery depend on presentation.
DELIVERY OF TWIN FETUSES LABOUR-preterm labour, uterine contractile dysfunction, abnormal presentation, prolapse of the umbilical cord, premature separation of the placenta, and immediate postpartum hemorrhage are more common
PRESENTATION AND POSITION Most common presentations at admission for delivery are cephalic-cephalic, cephalic-breech, and cephalic- transverse Importantly, these presentations, especially those other than cephalic-cephalic, are unstable before and during labor and delivery. Compound, face, brow, and footling breech presentations are relatively common, especially when the fetuses are small, amnionic fluid is excessive, or maternal parity is high Prolapse of the cord
VAGINAL DELIVERY The presenting twin typically bears the major force of dilating the cervix and the remaining soft tissues of the birth canal. When the first twin is cephalic, delivery can usually be accomplished spontaneously or with forceps.
LOCKED TWINS The phenomenon of locked twins is rare For twins to lock, the first fetus must present breech and the second cephalic. With descent of the breech through the birth canal, the chin of the first fetus locks between the neck and chin of the second, cephalic fetus. Cesarean delivery is recommended when the potential for locking is identified. Planned cesarean delivery does not improve neonatal outcome when both twins are cephalic..
WHEN 1ST TWIN IS BREECH When the first twin is breech, most physicians plan a cesarean delivery cesarean delivery is the method of choice when the first twin is noncephalic Except when fetuses are so immature that their survival is of doubt, breech delivery may be conducted > First fetus presents as a breech, major problems are most likely to develop if: 1. The fetus is unusually large and the aftercoming head is larger than the capacity of the birth canal. 2. The umbilical cord prolapses.
VAGINAL DELIVERY OF THE SECONDTWIN As soon as the presenting twin has been delivered, the presenting part of the second twin, its size, and its relationship to the birth canal should be quickly and carefully ascertained by combined abdominal, vaginal, and at times intrauterine examination
INTERNAL PODALIC VERSION With this maneuver, the fetus is turned to a breech presentation by the operators hand placed into the uterus.The obstetrician grasps the fetal feet to then effect delivery by breech extraction.
INTERVAL BETWEEN FIRST AND SECONDTWINS In the past, the safest interval between delivery of the first and second twins was commonly cited as less than 30 minutes If continuous fetal monitoring is used, a good outcome is achieved even when this interval is longer. As interval prolongs maternal & fetal morbidity increases (Living stone & collogues 2004 )
ACTIVE MANAGEMENT OF 3RD STAGE Risk of PPH can be minimised- 0.2mg methergin i.v with delivery of the anterior shoulder of the 2nd baby. Placenta delivered by controlled cord traction Oxytocin drip for atleast one hour followinfg delivery of the second baby
ANALGESIA & ANAESTHESIA1. For vaginal delivery Epidural analgesia is preferred ,As it possible to extended it up for purpose of Em .LSCS (Koffel 1999) For Internal podalic version Prefered to done under balanced epidural G.A 3. For cesarean section Spinal anaesthesia after adequatly preloading the circulation (to prevent hypotension) 4. For C.S performed for 2nd twin spinal anaesthesia / under balanced general aneasthesia
Cesarean delivery Indications1. First twin non cephalic presentation2. Both twins non cephalic presentation3. Fetal distress4. Antepartum haemorrhage5. Second fetus larger6. When cervix promptly contracts & and thickens after delivery of first infant & does not dilate subsequently