Multiple Pregnancy Flashcards
Locked twins
occur when the after-coming head of the first breech fetus is locked with the head of the second cephalic fetus.
Di-chorionic twins US F/U:
US should be done at 24, 28, 32 and 36 wks
Mono-chorionic twins US follow-up:
US should be done every 2 wks until delivery at 16, 20, 22 and 24.
Complications which occur only in monochorionic twin pregnancy include
TTTS, TAPS, TRAP sequence, monoamniotic pregnancy and conjoined twinning.
Percentage of monochorionic among twin pregnancies
One third
TTTS earliest sign:
The ‘donor’ twin has a DVP of < 2 cm (oligohydramnios) and the ‘recipient’ twin has a DVP > 8 cm (polyhydramnios).
the diagnosis of polyhydramnios is made when DVP ≥ 8 cm at ≤ 20 weeks and ≥ 10 cm after 20 weeks’ gestation.
TTTS percentage
TTTS affects 10 – 15% of monochorionic twin pregnancies and is associated with increased perinatal mortality and morbidity; if untreated, it leads to fetal demise in up to 90% of cases, with morbidity rates in survivors of over 50%
The success rate of TTTS Management:
fetoscopic laser ablation, which significantly improves the prognosis. Laser treatment in these pregnancies results in 60–70% double survival and.
In monochorionic twin pregnancy, screening for TTTS should start at
16 weeks, with scans repeated every 2 weeks thereafter
Quintero staging
I Polyhydramnios-oligohydramnios sequence: DVP>8cm in recipient twin and DVP<2cm in donor twin
II Bladder in donor twin not visible on ultrasound
III Absent or reversed umbilical artery diastolic flow, reversed ductus venosus a-wave flow, pulsatile umbilical venous flow in either twin.
IV Hydrops in one or both twins
V Death of one or both twins
Treatment of TTTS
• Laser ablation is the treatment of choice for TTTS at Quintero stages II and above (GRADE OF RECOM- MENDATION: A).
• Conservative management with close surveillance or laser ablation can be considered for Quintero stage I (GRADE OF RECOMMENDATION: B).
• When laser treatment is not available, serial amnioreduction is an acceptable alternative after 26 weeks’ gestation (GRADE OF RECOMMENDATION: A).
If conservative management is chosen for Quintero stage I, worsening poly- hydramnios, maternal discomfort and shortening of the cervical length are considered ‘rescue’ criteria signalling a need to proceed with fetoscopic laser treatment.
In a systematic review of the management of Stage 1 TTTS pregnancy, overall survival appeared to be similar for those undergoing laser therapy or conservative management (85% and 86%, respectively), but was somewhat lower for those undergoing amnioreduction (77%)
The risk of recurrence of TTTS and occurrence of TAPS is reduced by use of the Solomon technique (equatorial laser dichorionization) compared with the highly-selective technique
A common practice is weekly ultrasound assessment for the first 2 weeks after treatment, reducing to alternate weeks following clinical evidence of resolution
The prenatal diagnosis of TAPS is based on
the finding of discordant MCA Doppler abnormalities
The incidence of TAPS occurring spontaneously in MCDA twins is up to
5%
However, it may complicate
96 up to 13% of cases of TTTS following laser ablation
The criteria for TAPS diagnosis postnatal:
include a difference in hemoglobin concentration between the twins of more than 8 g/dL and at least one of either reticulocyte count ratio greater than 1.7 or small vascular anastomoses (< 1 mm in diameter) in the placenta
The prenatal diagnosis of TAPS is based on
the finding of discordant MCA Doppler abnormalities, including MCA-PSV > 1.5 multiples of the median (MoM) in the donor, suggesting fetal anemia, and MCA-PSV < 1.0 MoM in the recipient, suggesting polycythemia.
The polycythemic twin might have a ‘starry sky’ appearance of the liver pattern due to diminished echogenicity of the liver parenchyma and increased brightness of the portal venule walls.
Additional ultrasound findings in TAPS include differences in placental echogenicity and thickness, with a bright, thickened section associated with the donor and an echolucent thin section associ- ated with the recipient.
Antenatal and postnatal staging of twin anemia– polycythemia sequence (TAPS)
Stage Antenatal staging
1 Donor MCA-PSV > 1.5 MoM and recipient MCA-PSV < 1.0 MoM,
without other signs of fetal
compromise / Hb diff (g/dL)
> 8.0
2 Donor MCA-PSV > 1.7 MoM and
recipient MCA-PSV < 0.8 MoM, without other signs of fetal compromise / > 11.0
3 Stage 1 or 2 and cardiac compromise in donor (UA-AREDF, UV
pulsatile flow, or DV increased or
reversed flow)
4 Hydrops of donor twin
5 Death of one or both fetuses, preceded by TAPS
Postnatal staging: intertwin
> 14.0
17.0 > 20.0
TAPS screening and management
to screen for TAPS, the MCA-PSV should be measured from 20 weeks onwards in both fetuses, and during the follow-up of cases treated for TTTS. Prevention of TAPS by modifica- tion of the fetoscopic laser ablation technique remains the best way to prevent morbidity
Treatment options for Twin reversed arterial perfusion (TRAP)
• The chances of survival of the pump twin are increased by the use of minimally invasive techniques (e.g. cord coagulation, cord ligation and photocoagulation of the anastomoses, as well as intrafetal methods), preferably before 16 weeks of gestation
Percentage of TRAP
is a rare complication of mono-
chorionic twin pregnancy (1% of monochorionic twin
pregnancies and 1 in 35000 pregnancies overall).
Monochorionic pregnancy optimum US follow up
Fetal ultrasound assessment should take place every 2 weeks in uncomplicated monochorionic pregnancies from 16+0 weeks onwards until delivery
(RCOG)
• Incase of demise of one fetus of twins in MCDA or MCMA what steps should be taken ?
Esp.(post-laser),brainimaging of the surviving cotwin should be considered 4–6 weeks later, and neurodevelopmental assessment should take place at 2 years of age
The outcome of the monozygotic twinning process depends on when division occurs if zygote divide
*Within 72 hrs after fertilization: two embryos (di-di) morula stage
* If happen btw 4-8 days: diamniotic monochorionic twin blastocyst stage
*btw 8-12 days: mono-mono at implanted blastocyst
* more than 13 days: conjoined twins at formed embryonic cyst
The incidence of pregnancy-related hypertension in women with twins is
20%
Recipient twin complications in TTTS:
- circulatory overload and heart failure
- hypervolemia and hyperviscosity and occlusive thrombosis
- polycythemia that may leads to severe hyperbillirubinemia and kernicterus.
The prevalence of TTTS approximates
1-3 cases per 10000 births (SMFM,2013)
The two diagnostic criteria of TTTS diagnosis:
1- monochorionic diamnionic pregnancy
2- hydramnios defined by a largest vertical pocket >8 cm in one sac and oligohydramnios defined by largest vertical pocket < 2 cm in the other twin.
Spontaneous TAPS usually occurs after — wks GA, and iatrogenic TAPS develops within — wks of laser photocoagulation procedure
Spontaneous TAPS usually occurs after 26 wks GA, and iatrogenic TAPS develops within 5 wks of laser photocoagulation procedure
Possible complications of expectant management of hydatidiform mole with coexisting normal fetus
Vaginal bleeding
Hyperemesis gravidarum
Thyrotoxicosis
Early-onset preeclampsia
Complications of multiple pregnancy
- monochorionic related complications
- selective fetal growth restrictions
- fetal demise
When discordant growth is identified before 20 wks of one of twins, fetal death occurs in approximately
20% of growth restricted foetuses.
Complications associated with twin growth discordancy
Within range of 15-40 %: incidence of RDS, IVH, seizure, periventricular leukomalacia, sepsis, NEC rose directly with growth discrepancy degree.
If discrepancy >30% fetal death RR increased to 5.6, if discrepancy> 40% increased to 18.9
Women with monochorionic diamnionic twins, who lost one twin were — times more likely to experience death of the cotwin than women with dichorionic twins who lost one twin.
Women with monochorionic diamnionic twins, who lost one twin were 16 times more likely to experience death of the cotwin than women with dichorionic twins who lost one twin.
The most common complication of multiple pregnancy
Preterm labor
15%
15 % of TTTS risk in mono
15% risk of demise or neurological deficit if one of the twins death
Membrane thickness of di di
2 mm
All mono mono delivered by
CS irrespective to twin presentation
Rate of PPROM in twins, triplets, quadruplets, and higher order multiples.
twins 17%
triplets 20%
quadruplets 20%
higher order multiples 100%
Timing of delivery in dichorionic diamniotic and monochorionic diamniotic and monoamniotic:
ACOG recommends for:
-uncomplicated dichorionic twin pregnancies delivery at 38 wks.
- uncomplicated monochorionic diamniotic btw 34 and 37+6.
- monoamnionic at 32 to 34 wks.
Unless another obstetrical indication develops.
Specific risks of selective termination or reduction are:
(1) abortion of the remaining fetus
(2) abortion or retention of the wrong fetus
(3) damage without death to a fetus.
(4) preterm labor
(5) discordant or growth-restricted foetuses (6) maternal complications: infection, hge, DIC
The risk of neurological deficit if the co twin die
18 % in mono
1% in di di
The risk of fetal demise if the co twin die
15% in mono
3% in di di
Important statistics in TTTS
When expectantly managed, stage I twin–twin transfusion syndrome is associated with progression to a higher stage in 15% of cases. For untreated severe twin–twin transfusion syndrome in stages III–V, perinatal mortality is reported to be 70–100%.
TIMING OF DELIVERY of Dichorionic twins
38 weeks
TIMING OF
DELIVERY of monochorionic twins
36 wks
Conjoined twins incidence
Conjoined twins are a rare type of monoamniotic twins, estimated to occur in 1.5 per 100,000 births worldwide
multifetal pregnancies, increase the risks for
preeclampsia, postpartum hemorrhage, and maternal death were twofold higher than these rates in singleton gestations, Rates of placenta previa and placenta accreta spectrum are increased.
If zygotes divide within the first – hours after fertilization, two embryos, two amnions, and two chorions develop, and a monozygotic, dichorionic, diamnionic twin gestation evolves. Two distinct placentas or a single, fused placenta may develop. If division occurs between days – through –, a monozygotic, monochorionic, diamnionic twin pregnancy results. By – days, the chorion and the amnion have already differentiated, and division results in two embryos within a common amnionic sac, which is a monozygotic, monochorionic, monoamnionic twin gestation. Conjoined twins result if division initiates later after day –.
If zygotes divide within the first 72 hours after fertilization, two embryos, two amnions, and two chorions develop, and a monozygotic, dichorionic, diamnionic twin gestation evolves. Two distinct placentas or a single, fused placenta may develop. If division occurs between days 4 through 8, a monozygotic, monochorionic, diamnionic twin pregnancy results. By 8 days, the chorion and the amnion have already differentiated, and division results in two embryos within a common amnionic sac, which is a monozygotic, monochorionic, monoamnionic twin gestation. Conjoined twins result if division initiates later after day 13.
Superfecundation is
fertilization of two ova within the same menstrual cycle but not at the same coitus nor necessarily by sperm from the same male.
superfetation
an interval as long as or longer than a menstrual cycle intervenes between fertilizations. Superfetation is not known to occur spontaneously and is likely due to ART. Pseudosuperfetation often results from markedly unequal growth of twins with the same gestational age.
To confirm suitable growth in dichorionic pairs, we perform sonography every - weeks, starting at – to – weeks. Monochorionic twins are imaged every – weeks for twin-twin transfusion syndrome.
To confirm suitable growth in dichorionic pairs, we perform sonography every 4 weeks, starting at 16 to 20 weeks. Monochorionic twins are imaged every 2 weeks for twin-twin transfusion syndrome.
– percent of parturients with twins developed a hypertensive disorder of pregnancy
14 percent of parturients with twins developed a hypertensive disorder of pregnancy
Congenital anomaly rates in monoamnionic twins reach – to – percent
Congenital anomaly rates in monoamnionic twins reach 18 to 28 percent
The frequency of conjoined twins has a prevalence of — in 100,000 births, and ———– is the most common type
The frequency of conjoined twins has a prevalence of 1.5 in 100,000 births, and thoracopagus is the most common type
Spontaneous TAPS can develop at any gestational age and complicates – to – percent of monochorionic twins
Spontaneous TAPS can develop at any gestational age and complicates 1 to 6 percent of monochorionic twins
Iatrogenic TAPS develops in up to – percent of pregnancies after ————- of the placenta and usually develops within 5 weeks of a procedure
Iatrogenic TAPS develops in up to 13 percent of pregnancies after laser ablation of the placenta and usually develops within 5 weeks of a procedure, In iatrogenic TAPS, the former TTTS recipient twin usually becomes anemic, whereas the former donor becomes polycythemic (Tollenaar, 2016)
Antenatally, TAPS is diagnosed by discordant MCA peak systolic velocity (PSV) values between twins. Specifically, an MCA-PSV value that is >— multiples of the median (MoM) in the donor twin and <– MoM in the recipient twin (Society for Maternal-Fetal Medicine, 2013).
Antenatally, TAPS is diagnosed by discordant MCA peak systolic velocity (PSV) values between twins. Specifically, an MCA-PSV value that is >1.5 multiples of the median (MoM) in the donor twin and <1.0 MoM in the recipient twin (Society for Maternal-Fetal Medicine, 2013).
Hydatidiform Mole with Coexisting Normal Fetus Managment
The live birth rate from one review was 50 percent (Zilberman, 2020). The risk of gestational trophoblastic neoplasia (GTN), which is a malignant sequelae of hydatidiform mole, is similar whether the pregnancy is terminated or not (Massardier, 2009; Sebire, 2002). Given the limited number of cases, robust data for firm recommendations are lacking.
complications of expectant management in case of Hydatidiform Mole with Coexisting Normal Fetus include
vaginal bleeding, hyperemesis gravidarum, thyrotoxicosis, and early-onset preeclampsia. Many of these complications result in preterm birth with its attendant adverse perinatal outcomes. Logically, close antepartum and postpartum surveillance is needed for those continuing the pregnancy. Postpartum GTN surveillance is essential
DISCORDANT GROWTH in monochorionic twin Percent discordancy is then calculated formula ??. The American College of Obstetricians and Gynecologists (2021b) defines discordance as an estimated fetal weight difference >– percent.
Percent discordancy is then calculated as the weight of the larger twin minus the weight of the smaller twin, divided by the weight of the larger twin. The American College of Obstetricians and Gynecologists (2021b) defines discordance as an estimated fetal weight difference >20 percent.
DISCORDANT GROWTH complications in monochorionic twins
The incidence of respiratory distress syndrome, intraventricular hemorrhage, seizures, periventricular leukomalacia, sepsis, and necrotizing enterocolitis rose directly with the percentage of weight discordancy. Rates of these conditions grew substantially if discordancy exceeded 25 percent. The relative risk of fetal death increased significantly to 5.6 if weight discordancy was >30 percent and rose to 18.9 if >40 percent.
Management of monochorionic twins with growth discordance?
Nonstress testing and biophysical profile assessment have all been recommended in management of twin growth discordancy. If significant discordancy is identified in a monochorionic twin pair, umbilical artery Doppler studies in the smaller fetus may help guide management (Gratacós, 2007).
How to diagnose Restricted growth of one twin fetus is termed selective fetal-growth restriction (sFGR) and usually develops late in the second and early third trimester.
Some diagnose sFGR if the abdominal circumference (AC) measurement difference exceeds 20 mm or if fetal-growth discordance is >20 percent (Khalil, 2019).
If sFGR is diagnosed, what is the management and plan of follow-up?
weekly testing of fetal wellbeing, evaluation of amnionic fluid volume, and umbilical artery Doppler velocimetry are undertaken.
Investigators have correlated Doppler results with placental findings and with the degree of sFGR to predict fetal outcome (Gratacós, 2012). These correlations have yielded categories of sFGR.
• Type I shows positive end-diastolic flow, a smaller degree of weight discordance, and a relatively benign clinical course. • Type II displays persistently absent end-diastolic flow in the smaller twin and carries a high risk of deterioration and demise. • Type III has intermittently absent or reversed end-diastolic flow. Because of large artery-to-artery anastomoses associated with the placentas in this last category, type III is associated with a lower risk of deterioration than type II. In all evaluated cases, unequally shared placenta was noted to some degree.
The Institute of Medicine (IOM) (2009) recommends a — to —lb weight gain for women with twins and a normal body mass index. The daily recommended augmented caloric intake for women with twins is – to – kcal/kg/d. Diets contain 20 percent protein, 40 percent carbohydrate, and 40 percent fat divided into three meals and three snacks daily.
The Institute of Medicine (IOM) (2009) recommends a 37- to 54-lb weight gain for women with twins and a normal body mass index. The daily recommended augmented caloric intake for women with twins is 40 to 45 kcal/kg/d. Diets contain 20 percent protein, 40 percent carbohydrate, and 40 percent fat divided into three meals and three snacks daily.
Weekly antenatal surveillance is undertaken at – weeks’ gestation for uncomplicated dichorionic pregnancies and at — weeks’ gestation or uncomplicated monochorionic gestations (American College of Obstetricians and Gynecologists, 2021a).
Weekly antenatal surveillance is undertaken at 36 weeks’ gestation for uncomplicated dichorionic pregnancies and at 32 weeks’ gestation or uncomplicated monochorionic gestations (American College of Obstetricians and Gynecologists, 2021a).
The American College of Obstetricians and Gynecologists (2021b) recommends delivery at — to – weeks’ gestation for uncomplicated dichorionic diamnionic twin pregnancies.
The American College of Obstetricians and Gynecologists (2021b) recommends delivery at 38 0/7 to 38 6/7 weeks’ gestation for uncomplicated dichorionic diamnionic twin pregnancies.
The American College of Obstetricians and Gynecologists (2021b) recommends for Uncomplicated monochorionic diamnionic twin pregnancies can be delivered between — and – weeks.
Uncomplicated monochorionic diamnionic twin pregnancies can be delivered between 34 0/7 and 37 6/7 weeks.
The American College of Obstetricians and Gynecologists (2021b) recommends for monochorionic monoamnionic twin pregnancies, delivery is recommended at – to – weeks.
For monochorionic monoamnionic twin pregnancies, delivery is recommended at 32 0/7 to 34 0/7 weeks.
Complications of selective reduction procedures
specific risks include (1) loss of all remaining fetuses, (2) abortion or retention of the wrong fetus, (3) damage without death to a fetus, (4) preterm labor, (5) fetuses with discordant or growth restriction, and (6) maternal complications. With reduction procedures, uncommon potential complications are infection, hemorrhage, or disseminated intravascular coagulopathy because of retained products of conception.
In monochorionic diamniotic pregnancy with single twin demise
What is the percentage of other twin demise ? What is the percentage of neurological damage ?
- 15%
- 18% neurological damage in mono di while 1% in di-di
