Transcript 슬라이드 1 - 부산 백병원 산부인과

Management of
Multiple Pregnancy
부산백병원 산부인과
김영남
Ref.
•Evidence-based care of women with a multiple pregnancy
Dodd JM, Best Pract Res Clin Obstet Gynaecol. 2005
•Management of Multiple pregnancy: Prenatal care-Part I
•Management of Multiple pregnancy: Prenatal care-Part II
•Management of Multiple pregnancy: Labor and Delivery
Ayres A, Obstet Gynecol Surv. 2005
•Chapter 39 Multiple gestation, Williams obstetrics,22nd ed.
Incidence
• More than 3 % in US
Martin and colleques, 2002
• 1.4 per 100 birth in Korea
Korean birth certificate,
1996
• In Our Hospital (1997 – 2004)
M ultiple pregnancy rates
5.0%
4.0%
3.0%
2.1%
2.4%
2.3%
3.7%
3.9%
2002
2003
4.3%
2.4%
1.9%
2.0%
1.0%
0.0%
1997
1998
1999 2000
2001
2004
2007
• Twining rates per 1000 births (1986)
Country
Nigeria
Monozygotic
Dizygotic
Total
5.0
49
54
Black
4.7
11.1
15.8
White
4.2
7.1
11.3
India
3.3
8.1
11.4
Japan
3.0
1.3
4.3
US
•
Trend of Increasing rates of multiple pregnancy (between 1980 and 2001, in
US)
– 77 percent rise in twin deliveries
– 459 percent rise in high-order multiple births
Types and Genesis of Twining
Dizygotic
Monozygotic
By timing of division
< 3 day
Dichorionic
Diamnionic
Dichorionic
Diamnionic
4- 8 day
> 8 day
Monochorionic Monochorionic
Diamnionic
Monoamnionic
> 12 day
Conjoined
Management in Pre-Pregnancy
•Risks associated with assisted reproductive techniques
•Ovulation induction; 20-40% increase the risk of Multiple pregnancy
 Clomiphen; 1.83% – 17%
 hMG-hCG; 18% - 53.5%
•Number of embryos or zygotes transferred following ART
 risk of multiple pregmancy; 1.4% - single embryo transfer with IVF
 17.9% - two embryo transfer
 24.1% - four embryo transfer
 RCTs comparing single-embryo transfer with double-embryo transfer
; single transfer women – less likely to become pregnant (RR 0.69, 95% CI 0.51 – 0.93)
but, reduced risk of a twin pregnancy (RR 0.12, 95% CI 0.03 – 0.48) & low infant birthweight
(RR 0.17, 95% CI 0.04 – 0.79)
•Infertility treatment increase both dizygotic and monozygotic (but, more dizygotic)
Management in Pre-Pregnancy
•Women who are offered ART should be provided with adequate counseling
about the increased risk of multiple pregnancy and the potential
complication
•All pregnant women should be advised to take periconceptual folate
supplementation to reduce the risk of fetal neural tube defects
Antepartum Management
다태임신의 예후
1. 일반적인 예후
1) 자연유산 ↑
2) 주산기 사망률 ↑
3) 선천성 기형 ↑(특히 일란성)
; 쌍둥이 형성 자체의 결과, 혈관연결에 의한 혈류교환의 결과, 자궁 내 밀집현상의 결과
4) 출생 체중:
; 저체중아----태아발육부전 및 조산 때문
; 체중 간 불일치----이란성; 태반의 불균형, 유전적 성향, 제대이상, 태아기형 등
일란성; 할구의 불균등 분배, 태반 내 혈관연결, 기형 등
5) 재태기간 감소: 태아수 증가함에 따라 제태기간은 감소
; 쌍태임신의 1/2에서 조산경험
; 평균 제태기간- 쌍태임신; 35주, 세쌍둥이; 32주, 네쌍둥이 30주, 다섯쌍둥이 29주
6) 조산
; 조산으로 인한 신생아 사망 및 이환율 증가
; 태아성장의 불일치가 있는 경우, 심각한 주산기 사망 및 이환율 보임
7) 지연임신(prolonged pregnancy): 쌍태임신의 경우, 임신 40주가 경과 시 지연임신으로 간주
Perinatal mortality
• Multiple births contribute up to 10% of all perinatal mortality rate
- 10 greater than singleton
- At all weeks of gestation, associated with an increase in the risk of both stillbirth
and neonatal death
• Increased mortality associated with monochorionic twin compared with
dichorionic twin
- A review of 1051 twin pair
;monochorionicity (OR 2.0; 95%CI 1.2-3.4) & discordant birth weight (OR 4.3;
95%CI 2.5-7.3) as factors associated with twin dying in utero.
Antepartum Management
Ultimate goals
–
–
–
–
–
to
to
to
to
to
prevent the delivery of markedly preterm fetuses
identify growth restriction in 1 or both fetuses
expedite their delivery before they become moribund
deliver the fetuses atraumatically
have expert anesthesia and neonatal care available
Antepartum Management
Determination of chorionicity
Best performed in the first trimester with Ultrasound
1. Numbers of G-sac
2. Detection of the ‘lambda sign’ or ‘twin peak’
; best seen between 10-14 weeks, disappear after 20 weeks
3. Measurement of membrane thickness, using a cut-off value of 2 mm
Describe as DCDA / MCDA / MCMA twin
Antepartum Management
Nutrition and Weight Gain
•Increased requirements for calories, protein, minerals, and vitamins
35- to 40-lb total weight gain is recommended
additional 150 kcal/day above the level for singleton pregnancy
take 60 - 100 mg of iron and 300 ㎍ of folate after the 12th week of gestation
Antepartum Management
Antenatal screening
• Increased hypertensive disorders in pregnancy
– 5 times greater in primigravid women
– 10 times greater in multiparous women than singleton pregnancy
-> frequent antenatal attendance allows the early detection of hypertension
• Gestational diabetes screening; conflicting evidence to support the practice
• Increased risk of antepartum hemorrhage from both placenta previa and
abruption
Antepartum Management
Nuchal translucency screening
•No RCT about NT in multiple pregnancy
• Reports from a study of 448 women with a twin pregnancy
; NT + maternal age
=> yield similar sensitivity & false-positive rates for women with a dichorionic
pregnancy as those for women with a singleton pregnancy.
Sebire N, British Journal of Obstetrics and Gynaecology, 1996
•The false-positive rate of screening is higher in women with a
monochorionic twin pregnancy than in singleton pregnancies, with discordance
for nuchal translucency measures a possible indicator of early onset twin–twin
transfusion syndrome.
Nicolaides K, 1999
Antepartum Management
Routine fetal anomaly ultrasound at 18–20 weeks
•Twins have an increased risk of congenital abnormalities
->midtrimester ultrasound examination between 18 and 20 weeks gestation.
; A retrospective review of 245 women with a twin pregnancy
-> congenital malformation in 4.9% of cases
Edwards M, Ultrasound in Obstetrics and Gynecology, 1995
Antepartum Management
Preterm labor
•Higher risk of preterm birth
; rates varying from 30 to 50%.
•Trend to increasing preterm birth ; from 40.9% (1981) to 55.0% (1996), in US
•Greater risk of preterm birth
 for monochorionic twin than dichorionic twins
(9.2% of monochorionic vs. 5.5% of dichorionic twins, before 32 weeks)
 for higher-order multiple pregnancies (up to 80% in triplet gestations)
•In our hospital
Twin 중 preterm birth rate
100%
69%
80%
60%
52%
76%
52%
47%
55%
61%
71%
40%
20%
0%
1997
1998
1999
2000
2001
2002
2003
2004
Antepartum Management
Preterm labor
1. Cervical assessment
• Cervical length of less than 25 mm at 24 weeks in twins;
; predictor of spontaneous preterm birth at < 32 weeks (OR 6.9), < 35 weeks
(OR 3.2), and < 37 weeks (OR 2.8)
; its clinical usefulness as a routine evaluation is questionable because of
the lack of proven treatments affecting outcome
2. Fetal fibronectin
•The presence of fetal fibronectin in cervical secretions ;
; positive test at 28 weeks to predict preterm birth before 35 weeks
=> 50% sensitivity, 92% specificity, 62.5% positive predictive value, 87.3% negative
predictive value
•it is unclear if this knowledge can result in effective interventions that could
reduce preterm labor and birth
Antepartum Management
Preterm labor
3. Cervical cerclage
• Prophylactic cervical cerclage in preventing preterm birth in multiple
pregnancies
; no benefit
; the routine use of cerclage cannot be recommended.
4. Prophylactic tocolytic agents
• The use of prophylactic beta-mimetic agents to prevent preterm birth
; no benefit in reducing the incidence of preterm labor and birth
; their use is not advocated
• Complications occur more often with the use of tocolytic therapy in multiple
gestations than in singletons
; cardiovascular complications (34.4% vs. 4.0%)
; the result of a greater increase in plasma volume and cardiac output
Antepartum Management
Preterm labor
5. Prenatal corticosteroids
The use of corticosteroids ( < 34 weeks) is recommended
Fetal Lung Maturation
•Pulmonary maturation is synchronous in twin gestations, measured by L/S ratio
•The data concerning acceleration of fetal lung maturation in twin pregnancies is conflicting.
 At each biweekly interval from 31 to 36 weeks, twin L/S ratios were significantly greater
than those of singletons
No significant difference in the incidence of RDS (38% vs. 35%) or in the use of
mechanical ventilation (41% vs. 39%) between groups
Antepartum Management
Fetal growth
The growth of twin
< 28 to 30 weeks ; similar to singletons
> 30 weeks; starts to lag behind the growth of singletons
By 36 weeks, the mean birth weight of twins is 2500 g (2800 g for singletons)
•The birth weight discordance calculation
; Bwt (large) – Bwt(small)
Bwt (large)
• Perinatal morbidity and mortality in twin pregnancies is related to intrapair birth
weight discordance
As the weight discordance increase, the perinatal mortality increase
Labor and Delivery
Timing of birth
• The lowest risk of perinatal mortality and morbidity; between 36 and 38 weeks
 After 38 weeks gestation, the perinatal death rate and intrauterine growth
restriction of twin pregnancies increase substantially
In a single RCT from Japan, Women were randomised at 37 weeks
gestation either to induction of labor or to continued expectant management
; No statistically significant differences
• The ideal time of delivery for an uncomplicated twin pregnancy is still uncertain.
However, the literature appears to support delivery by 38 weeks of gestation
Antepartum Management
Mode of birth
•Women with a twin pregnancy are more likely to give birth by caesarean, with
gestational age and fetal presentation influencing this decision
•First twin vertex/second twin vertex
•the most common presentation of twins
•the general recommendation is for vaginal birth, even for infants of estimated very low
birthweight (less than 1500 g)
•First twin vertex/second twin non-vertex
•no consensus as to the most appropriate mode of birth
•The only small RCT, planned vaginal or planned caesarean birth showed no
differences in neonatal outcome
•For the second non-vertex twin of birthweight less than 1500 g, some reports
recommend caesarean birth to reduce the risk of birth trauma
•First twin non-vertex
• Caesarean section is often performed
Antepartum Management
General care in labor
1. Monitored continuously by an external monitor, a trained obstetric attendant should be
present with the patient throughout the labor.
2. Blood and blood component products should be immediately available.
3. An intravenous access with a large-bore catheter should be in place during the labor
and delivery process.
4. An appropriate intravenous antibiotic should be administered for group B Streptococcus
prophylaxis if indicated.
5. Delivery of the multiple gestation should be in an operating room or in a delivery room
6. Ultrasound should be in the delivery room to determine the lie, presentation, and
position of the second twin after the delivery of the first fetus.
7. An experienced anesthesiologist/anesthetist
8. a trained pediatrician or neonatologist skilled in neonatal resuscitation
9. an obstetrician who is skilled in evaluating the presentation and position of the second
twin and also in intrauterine manipulation to expedite the delivery of the second twin
should attend the delivery.
Antepartum Management
General care in labor
•
•
•
•
Intrapartum blood loss and postpartum haemorrhage
; intravenous access with blood available for cross-matching
When the plan is for vaginal birth, continuous electronic fetal monitoring is recommended
Epidural analgesia is widely available
Experienced obstetrician, with the availability of a paediatrician, neonatal nurse and
anaesthetist
• After the birth of the first twin, the lie of the second twin should be assessed and, if not
longitudinal, converted to such by internal podalic version or external cephalic version
followed by amniotomy.
• An infusion of Syntocin should be available in the event of uterine inertia.
• Active management of the third stage of labor with an oxytocic agent is advocated after the
birth of the second twin
TIME INTERVAL BETWEEN DELIVERIES
• If there is continuous fetal and uterine monitoring, a time restriction for the delivery
interval between the first and second twins is not necessary
•However, the cesarean section rate was higher in the group in which the interval was
15 minutes compared with the group with the interval 15 minutes (18% vs. 3%)
다태임신의 특이한 합병증
1) 단일양막성 쌍둥이(monoamnionic twins)
- 일란성 쌍태아의 약 1%
- 매우 높은 태아 사망률, 제대간의 꼬임현상이 주된 사망원인
2) 결합쌍둥이(conjoined twins)
- 일명 샴쌍둥이(Siamese twins)
(1) 앞 쪽: 가슴붙은 쌍둥이(thoracopagus)
(2) 뒤 쪽: 엉덩붙은 쌍둥이(pygopagus)
(3) 둔부: 머리붙은 쌍둥이(craniopagus)
(4) 미부: 좌골붙은 쌍둥이(ischiopagus)
3) 쌍둥이간 수혈증후군(twin-to-twin transfusion syndrome)
4) 무심장 쌍둥이(acardiac twin); Twin reversed-arterial-perfusion(TRAP) sequence
5) 불일치 쌍둥이(discordant twin)
6) 일측태아의 사망
Congenital Anomaly of One Twin
• Occur more frequently than single pregnancy
in particular neural tube defects, bowel atresia, and cardiac anomalies,
chromosomal anomalies
Major malformations - 2.12%(twin) Vs 1.05% (single)
Minor malformations - 4.13% (twin) vs 2.45% (single)
Higher in monozygotic than dizygotic (3.1% vs 1.9%)
•Option of management
continuation of the entire pregnancy
termination of the entire pregnancy
selective termination of the anomalous fetus
 For women with a monochorionic twin, selective termination carries
an additional risk of pregnancy loss when compared with dichorionic
twin pregnancy
Monoamniotic Twins
•less than 2% of monozygotic
•risk of cord entanglement, subsequent perinatal mortality (half of the cases)
; unpredictable, no effective monitoring method
• Current care
; based on cases, with no RCTs to inform practice.
; Frequent monitoring will not prevent sudden fetal death
; No consensus of the optimal timing and mode of birth
; Prophylactic preterm birth may not be indicated
Twin–Twin Transfusion Syndrome (TTTS)
Incidence; 4 - 35% of monochorionic twin
Mechanism
; Vascular anastomosis (usually deep arteriovenous anastomosis)
; unidirectional blood flow in anastomosis (imbalanced blood flow)
; resulting in discordance in fetal size and amniotic fluid volume
-> donor twin – oligohydramnios, recipient twin – polyhydramnios
; in severe oligo-polyhydramnios syndrome,
Stuck twin (oligo-); pulmonary hypoplasia, growth restriction, contracture
Poly-; PROM, fetal hydrops
TWIN–TWIN TRANSFUSION SYNDROME (TTTS)
Diagnosis
• monochorionic twin gestation with placental vascular anastomoses
• same-sex fetuses
• intertwin birth weight difference 20%
• polyhydramnios of the larger twin, oligohydramnios of the smaller twin
• hemoglobin difference of 5 g/dL
Perinatal outcome
• The overall perinatal survival rate; 21% - 65%
• Affecting factors; gestational age at diagnosis, the gestational age at
delivery, the severity of the disease, ie, presence of hydrops fetalis.
TWIN–TWIN TRANSFUSION SYNDROME (TTTS)
Management
•Serial amnioreduction
•Laser photocoagulation
•Septotomy
•Selective fetocide
 Expectant vs. serial amnioreduction
; higher survival rate in amnioreduction group (69% vs. 20%)
 Serial amniocentsis vs. laser photocoagulation
; In non-RCT studies, laser coagulation is associated with increased rates of
successful pregnancy and intact neurodevelopmental survival.
 Longer-term f/u of children wiith laser coagulation
; median age of 21 months
; minor neurological deficiencies - 11%
major neurological deficiencies in a further 11% of children studied
TWIN REVERSED ARTERIAL PERFUSION (TRAP)
SEQUENCE ; Acardiac twin
•Mechanism;
; direct arterial–arterial communications
; when the arterial pressure in one twin exceeds the other, there is a reversal of
blood flow in the ‘perfused twin’ and the cotwin as the pump twin
; The perfused twin is designated as the acardiac twin
secondary to the perfusion of ‘used’ deoxygenated blood from the donor or pump
twin to the hypoxaemic perfused twin
TWIN REVERSED ARTERIAL PERFUSION (TRAP) SEQUENCE
• Mortality
; perfused twin – 100%
; donor twin – 50-70 %
- with development of hydramnios and hydrops secondary to high output cardiac failure
•Management
; no RCTs to inform optimal clinical management of the TRAP sequence
; Case series recommend fetal surveillance,
- Control of polyhydramnios or hydrops; serial amniocentesis
; Occulusions of the circulation of the acardiac twin
; Mid trimester hysterotomy and selective delivery of acadiac twin
Discordant Twin
 Weight discordance usually apparent in the late second or early third trimester
In monochorionic twins
; placental vascular anastomoses -> an imbalance in blood flow between the fetuses
In dichorionic twin
; genetically different, in utero crowding
Discordant Twin
Diagnosis
The weight discordance that is clinically significant has not been well stablished.
As the weight discordance increase, the perinatal mortality increase
the risk of fetal death increased progressively when the weight discordance
exceeded 25%
; the relative risk of 2.9 at 26% to 30% discordance
5.6 at 31% to 40% discordance
; an intrapair weight discordance of 20% to 25% is associated with a significant
risk of an adverse perinatal outcome.
Single Fetal Death
In 1 trimester
‘vanishing twin’
; Clinically - vaginal bleeding
; The prognosis for the remaining fetus - generally good
After 1 trimester
• Incidence of fetal demise; 0.5 - 6.8%
• Morbidity
maternal DIC; 25% or much less
risk of death in the remaining twin; 20–25%
preterm birth
development of renal and cerebral cystic lesions in the survivor
Single Fetal Death
 Single fetal death & Monochorionic
; Single fetal death in utero is more frequent in monochorionic twin
; Morbidity in surviving monochorionic cotwin
- 10 times greater than for dichorionic twin
- In review of 481 twin,
; monochorionic – 30% neonatal death, 10% cerebral palsy
dichorionic – benign except anomaly cases
- In review of 92 twin
; intrauterine death (26% vs. 2.4%), anemia (51.4% vs. 0%), intracranial
lesion at birth (46% vs. 0%) – greater in the monochorionic twin
Specific problems; microcephaly, hydrocephaly, porencephaly, cerebral atrophy,
cerebral palsy, limb reduction, intestinal atresia, renal necrosis, and pulmonary,
hepatic or splenic infarction
Proposed mechanism in monochorionic twin (esp. CNS abnormalties)
; the massive blood loss that occurs from the survivor into the more relaxed
circulation of the dead twin through vascular anastomoses
Single Fetal Death
 Management
• Optimal care for the surviving monochorionic co-twin is uncertain.
• Expectant management with close maternal and fetal surveillance
• Monochorionic; immediate delivery of the surviving twin does not prevent the
occurrence of central nervous system ischemic complications
• Dichorionic; the outcome of the surviving twin is usually benign.
 Longer-term childhood follow-up;
; the risk of handicap or cerebral impairment in surviving co-twin
- up to 20%
Conclusions
• Pre-pregnancy care should focus on avoiding multiple pregnancy
• Early prenatal care centres on determining chorionicity and screening for
fetal anomalies,
• Later care focusing on the presentation, prediction and management of
preterm birth, and intrauterine growth restriction.
•
•The optimal timing and mode of birth are the focus of current multicentred
RCTs.