Twins Flashcards
When there is 1 “placental mass” on US, with an upward or downward projection of placental tissue into the area where the amnion and chorion interface between 2 amniotic sac is suggestive of what chorinonicity?
Dichorionic
Referred to as “Lambda Sign” or “Twin Peak Sign”
When the dividing membrane between two amniotic sacs is > 2 mm thick suggests what chorionicity?
Dichorionic
Cleavage 3 days after fertilization
Dichorionic Diamniotic
Cleavage 4-8 days after fertilization
Mono Di
Cleavage 9-12 days after fertilization
Mono-Mono
Cleavage >/= 13 days after fertilization
Conjoined Twins
Dividing membrane is thin (< 2 mm) and membrane insertion to the placenta is at a right angle (T sign)
Monochorionic
How much folate should a mom with twins take?
1 mg folate daily
What staging system is used to diagnosis Twin-twin transfusion syndrome?
Quintero Staging
Quintero Stage 1
MVP < 2 cm in donor sac
MVP > 8 in recipient sac
Quintero Stage 2
Non visualization of fetal bladder in donor twin over 60 minutes of observation
Quintero Stage 3
Absent or reversed UAD
Quintero Stage 4
Hydrops in 1 or both twins
Quintero Stage 5
Fetal demise in 1 or both twins
In Monochorionic twins, when should surveillance for TTTS start?
16 weeks, Q2 weeks
For Monochroinic twins- with the death of 1 twin, what is the risk of a neurologic abnormality in the surviving twin
18% chance if co-twin dies in utero after 14 weeks gestation
**the death of one twin causes hypotension in the other twin because of the placental anastomoses and causes neuro injury
For Monochroinic twins- with the death of 1 twin, what is the risk of a death in the surviving twin
15% risk of death
For Dichorinoic twins- with the death of 1 twin what is the risk of neurologic abnormality in the surviving twin?
1% risk of neuro injury if co-twin dies after 14 weeks
For Dichorinoic twins- with the death of 1 twin what is the risk of death in the surviving twin?
3% risk of death in the surviving twin
What is the incidence of preterm birth in twins in the US?
59% before 37 weeks
11% before 32 weeks
Recommended delivery for Di-Di twins
38 weeks
*Vaginal delivery after 32 weeks if presenting twin is cephalic
Recommended delivery for Mono-Di Twins
34w0d-37w6d
Recommended delivery for Mono-Mono twins
32 to 34 weeks
C-SECTION
*Up to 80% perinatal mortality primarily secondary to cord entanglement
General twin management
Add 300 kcals to diet
1 mg Folate
Supplement with Oral Fe
US at 11-14 wks to determine chorionicity
Labmda sign = dichorionic
T sign = monochorionic
Offer Genetic counseling/aneuploidy screening
Twins at increased risks of anomalies
(especially monochorionic)
NIPT not as accurate, NT is accurate
Di-Di:
Anatomy scan
Serial growth US
Antenatal testing at 36 wks if uncomplicated
Monochorionic:
MFM consult
Screening US starting at 16 wks Q2 weeks to assess for TTTS
Detailed anatomy
Fetal ECHO. Increased risk of CHD
Mono-mono:
Inpatient at 24-28 wks
Antenatal surviellance, serially growth
Delivery at 32-34w by CS
Mono-di:
Antental surviellence outpatient at 32w
Delivery 34-38w
Maternal Risks w/ Twins?
Hyperemesis
GDM
Pre E
Acute Fatty liver of pregnancy
Anemia/PPH
C/S
Postpartum Depression
Fetal Risks of twinning
Increased risk of aneuploidy compared to singletons
- NIPT is less sensitive, cannot specify affected twin, and has a higher rate of test failure
- Recommend NT (not affected by twinning)
Increased risk of congenital malformations
- Increase folic acid to 1 mg
- Anatomy scan 18-20
- If monochorionic will need fetal ECHO
Preterm birth and resultant infant morbidity + mortality
- Intraventricular hemhorrage
- Periventricular leukomalacia/Cerebral palsy
- NEC
- Neec for respiratory support
Requirements for vaginal deliveries of twins?
NOT mono-mono
Twin A is vertex
GA > 32 weeks
EFW > 1,500 g
Less than 20% growth discordance
Delivery in OR, w/ ability to convert to CS
