multifetal gestation
DESCRIPTION
Multifetal Gestation. Xiong yu Obstetric & Gynecology Hospital , Fudan University. Incidence. twins : 1:100 。 triplets : 1:10,000 。 quadruplets : 1:1,000,000 。 quintuplets : 1:100,000,000 。. Incidence. Between 1980 and 2005,the number of live births from twin deliveries rose - PowerPoint PPT PresentationTRANSCRIPT
Multifetal Gestation
Xiong yu
Obstetric & Gynecology Hospital, Fudan University
Incidence
twins : 1:100。 triplets : 1:10,000。 quadruplets : 1:1,000,000。 quintuplets : 1:100,000,000。
Incidence
Between 1980 and 2005,the number of live births from twin deliveries rose nearly 50 percent, and the number of higher-order multifetal births increased more than 400 percent. However, changing infertility therapy has led to slight decreases in rates of higher- order multifetal births.
Factors that Influence Twinning Race Heredity Maternal Age and Parity Nutritional Factors Pituitary Gonadotropin Infertility Therapy Assisted Reproductive Technology (ART)
Factors that Influence Twinning Dizygotic twins : 2/3 influenced remarkably by race, heredity, maternal age,
parity, and, especially, fertility treatment
monozygotic twins : 1/3 1:250 independent of race, heredity, age, and parity
Dizygotic twins Two ovums, Two sperms。 Different Gene:
1. appearance: different or alike2. gender : same or different
Placenta: two placentas fuse to one placenta, twin peak, no communicated
blood vessel Diamnionic/dichorionic (DA/DC)
Placenta and membrane of dizygotic twins
two placentastwo amnions two chorions
fused placentatwo amnions fused chorion
Monozygotic twins One ovum, One
sperm。 Same Gene:
1. appearance: same
2. gender : same Four types:
1. DCDA
2. MCDA
3. MCMA
4. MCMA conjoined twins
Conjoined twins (1:60,000)
Importance of Chorionicity
Chorionicity determine the outcome of twins, while not zygoticity.
Compare to DCDA, higher incidence of abortion, perinatal mortality, preterm, FGR and morfamation in MC twins.
If one twin died in MC twins, the other twin will be in high risk of sudden death and nervous system effects.
-----Determination of chorionicity correctly is important to predict the prognosis and twin-specific complications.
Outcomes of Different Chorionic Twins
Sonographic Evaluation ( prenatal)--- Dichorionic Diamniotic twins (DCDA)
first trimester ( before 8 weeks):two sacs
after 14 weeks : opposite gender ( dizygotic)
10-14 weeks:1. two separate placentas2. dividing membrane: 2 mm≧
3. one fused placenta, twin peak
Sonographic Evaluation ( prenatal)--- Monochorionic Diamniotic twins (MCDA)
first trimester ( before 8 weeks): one sac
after 14 weeks : same gender
10-14 weeks: dividing membrane: ‹2mm one placenta : none twin peak, T sig
n
divided amnion
no divided amnion
Sonographic Evaluation ( prenatal)--- Monochorionic Monoamniotic twins (MCMA)
Determination of Chorionicity (postnatal)
Gender1. Opposite: DC2. Same: DC or MC
Placenta: two placentas : DC one placenta: number of membrane
partition that separated twin fetuses 1. 0 : MCMA2. 2 : MCDA3. 3 or 4 : DCDA
Complications(maternal) Anemia: 74.6%
Preeclampsia: 30%
Postpartum hemorrhage: 2 times (average blood loss with vaginal delivery of twins is 1000 mL)
Higher rate of CS: 53.3%
Emergent peripartum hysterectomy: 3 times (twins), 24 times (triplets of quadruplets)
Heart failure
Depressive symptoms : 50%
Maternal death
Complications (fetal)
Abotion (3 times in twins, MC:DC 18:1) Malformations Placental vascular anastomosis (twin-twin transfusion
syndrome, TTTS) Fetal-growth restriction Preterm delivery (60% twins, 93% triplets) Perinatal mortality
Outcomes in twins
Twin-specific ComplicationsTwin pregnancy
Dizygotic twins Monozygotic twins
DCDADCDA MCDA MCMA
TTTS TAPS TRAPConjoined Twins
70% 30%
35% 65% <1%
Discordant Twins (one IUGR)
Discordant Twins (sIUGR)
1. 1. Twin-Twin Transfusion Syndrome (TTTS)Twin-Twin Transfusion Syndrome (TTTS)Definition blood is transfused from a donor twin to its recipient sibling. the donor becomes anemic and its growth may be restricted. the recipient becomes polycythemic and may develop circulatory overload
manifest as hydrops. donor twin is pale, and its recipient sibling is plethoric.
Vascular Anastomoses With rare exceptions, vascular anastomoses between twin
s are present only in monochorionic twin placentas.
Three types:
Arterio-Arterial(A-A): most common, 75% monochorionic twin placentas.
Venous –Venous(V-V): 50%
Arterio-Venous(A-V): 50%
Vascular Anastomoses in TTTS Pure superficial vascular anastomoses occur TTTS
rarely.
Pure deep anastomosis almost occurr TTTS.
Superficial and deep anastomosis result to 79% T
TTS.
Functional arterial anastomosis with compensation
for twins bloodstream, there is a lower incidence of
TTTS in arterial anastomosis.
No A-A anastomosis, 61% twins will occur TTTS.
A-A anastomosis, 15% twins will occur TTTS.
Fetal Brain Damage
Quarello (2007): 315 liveborn fetuses with TTTS
Cerebral abnormalities: 8%
Cerebral palsy, microcephaly, porencephaly, and multicystic encephalomalacia
Donor: ischemia results from hypotension, anemia, or both.
Recipient: ischemia develops from blood pressure instability and episodes of severe hypotension
Fetal Brain Damage (one twin demise)
Pharoah and Adi (2000): 348 survivors whose twin sibling
had died in utero.
The prevalence of cerebral palsy was 83 per 1000 live bi
rths–--a 40-fold increased risk over baseline.
Even with delivery immediately after the co-twin demise is
recognized, the hypotension that occurs at the moment of d
eath has likely already caused irreversible damage.
Diagnosis (Prenatal)1. monochorionicity2. same-sex gender 3. hydramnios defined if the largest vertical pocket is > 8 cm i
n one twin and oligohydramnios defined if the largest vertical pocket is < 2 cm in the other twin
4. umbilical cord size discrepancy5. cardiac dysfunction in the recipient twin with hydramnios 6. abnormal umbilical vessel or ductus venosus Doppler veloc
imetry 7. significant growth discordance
Quintero staging systemQuintero staging system
Stage I: polyhydramnios(>8cm) in recipient / aligodramnios(<2cm) in donor, but urine still visible sonographically within the donor twin's but urine still visible sonographically within the donor twin's bladder bladder
Stage II: criteria of stage I, but urine is not visible within the donor's criteria of stage I, but urine is not visible within the donor's bladder bladder
Stage III: criteria of stage II and abnormal Doppler studies of the criteria of stage II and abnormal Doppler studies of the umbilical artery, ductus venosus, or umbilical vein. umbilical artery, ductus venosus, or umbilical vein.
Such as Such as AEDV or AEDF in donor, ductus venosusductus venosus regurgitation or Umbilical vein pulsatility in recipient.
Stage IV: ascites or frank hydrops in either twinascites or frank hydrops in either twin
Stage V: demise of either fetus demise of either fetus
Diagnosis (Postnatal) MCDA:
1. number of placenta, chorionic membrane, amniotic membrane
2.2. same-sex gendersame-sex gender
Examination in neonate:1.1. discordancediscordance in hemoglobin: ≥5g/l
2.2. discordancediscordance in red blood cell: ≥ 109
3.3. ddiscordance in iscordance in body weight : ≥15-20%
Treatment 1
Conservative treatment:Observation and RestDrug:
---Indomethacin: reduced the volume of amniotic fluid ---Digoxin: acting on donor, increase cardiac output and relieve symptoms
----Not the main method, may be useful to one fetal but have adverse effects on the other twin.
Treatment 2 Invasive treatment
Amnioreduction
Septostomy (intentional creation of a communication in the
dividing amnionic membrane)
Fetoscopic Laser Occlusion of Chorioangiopagous Vessels (FLOC)
Selective feticide
RFA( Radio Frequency Ablation ) Umbilical cord ligation
Monopolar or Bipolar coagulation
2.TRAP (Twin Reversed Arterial Perfusion) Sequence Incidence: rare, about 1 in 35,000 births Definition : one twin has an absent, rudimentary, or nonfunctioning
heart (acardiac twin) , the other twin is normal (pump twin). TRAP sequence has been associated with adverse perinatal outcomes.
Placentation: majority of acradic twins is monochorionic diamniotic. vascular anastomoses: arterial-to-arterial (A-A)
Diagnosis
The diagnosis is made with ultrasound.
The features useful in the diagnosis of acardia include absence of normal cardiac structure and cardiac movement and variable structural abnormalities.
Malformations of Acardia Four groups: acardius acephalus, acardius amorphus or anideus, acardius aco
rmus, and acardius anceps or paracephalus.
Management The pump twin is usually morphologically normal, and the risk of aneuploidy is
9%. The goal of antepartum management of a pregnancy complicated by the TRAP s
equence is to maximize outcome for the structurally normal pump twin. Expectant management: serial sonographic evaluation
Selective feticide: radiofrequency ablation (RFA) of the cord of the acardius, 95% pump twin survival.
Criteria: twin weight ratio >0.70 elevated combined ventricular output elevated cardiothoracic ratio
congestive cardiac failure polyhydramnios
3. Discordant Twins (Diagnosis)
Weight Discordancy(%) =weight (large)-weight (small)/ weight (large) Diagnosis:
Weight Discordancy ≥ 25%Simple: abdominal circumferences difference ≥ 20 mm
Hollier (1999): 1370 twin pairs Weight discordancy ≥ 25%: predicts an adverse perinatal outcome. Weight discordancy ≥ 30%: relative risk of fetal death is 5.6.Weight discordancy ≥ 40%: relative risk of fetal death is 18.9.
Discordant Twins (sIUGR, MCDA)
Distinguish with TTTS
One small , the other normal.
One oligohydramnios , the other normal volum of amniotic fluid .
Management: Discordant Twins in DC
Before 28 weeks: follow up, ultrasound weekly.
After 28 weeks: intensive care
surveillance: daily nonstress testing (NST)terminate in time if abnormal apperance.
Management: Discordant Twins in MC
10-20% IUGR fetus will die and result in the bad outcome of nervous system in 20% survival fetus.
Treatment Protocols ( before 26 weeks):1. Expect treatment
1. close ongoing surveillance2. terminate in time if abnormal ultrasonic apperance
2. Termination of pregnancy : abortion3. Laser4. Selective feticide (sIUGR fetus)
4.Monoamnionic Twins 1% monozygotic twins high perinatal mortality: 17%
cord entanglement (>50%)congenital anomalypreterm birthFGRvascular anastomoses
Management problematic
unpredictability of fetal death resulting from cord entanglement
lack of an effective means of monitoring 26-28 weeks: elective hospitalization
daily: nonstress testing (NST)corticosteroids for lung maturation: betamethasone
32-34 weeks: Elective deliverya second course of betamethasone34 weeks: cesarean delivery
Delivery
When How Evaluation
Time of Delivery
According to the Chorionicity
No obvious complications: DCDA : 37-38 weeks
MCDA: 34-36 weeks
MCMA: 32-34 weeks
Mode of Delivery 1
cephalic-cephalic: 42% Generally advocated vaginal delivery
If a first twin is cephalic, delivery can usually be accomplished spontaneously or with forceps.
Hogle (2003) perfomed an extensive literature review and concluded that planned cesarean delivery does not improve neonatal outcome when both twins are cephalic.
Muleba (2005) identified increased rates of respiratory distress in the second twin of preterm pairs regardless of the mode of delivery or corticosteroid use.
Mode of Delivery 2cephalic–noncephalic : 45% , cephalic-breech, and cephalic-transverse:
The optimal delivery route for cephalic–noncephalic twins is controversial.
A randomized study found that cesarean section and vaginal delivery were no differences in neonatal outcomes.
Prerequisite for vaginal delivery is the obstetrician's technology and experience.
As the number of trained doctors with experiences of assisted breech delivery and internal podalic version were reduced quickly, patients faced with two options: cesarean section or external podalic version on the second fetal.
Mode of Delivery 3Breech presentation:13% As in singletons, if a first fetus presents as a breech, major problems
may develop if:The fetus is unusually large, and the aftercoming head is larger
than the birth canalThe fetus is sufficiently small. The extremities and trunk may
deliver through an inadequately effaced and dilated cervix, but the head may become trapped above the cervix
The umbilical cord prolapses. Therefore, cesarean section is always recommended.
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