Twin gestation Flashcards
Causes of large for dates on examination
- Wrong dates
- Multiples
- Molar
- Uterine pathology
- Polyhydramnios
Which has worse outcomes- monozygotic or dizygotic twins
Monozygotic
+pregnancy loss
Preterm delivery
Perinatal morbidity and mortality
Screening tests in twin pregnancy- accuracy differences
- Fetal nuchal translucency performed with good accuracy, however the CFTS and biomarkers have less accurate risk stratification for twins.
- Risks for down syndrome based on age also less accurate
- Amniocentesis at 15-16 weeks, CVS can also be done->has +risk of spontaneous abortion
- 18 week morphology scan
Information to provide for early pregnancy
- Generally everything that happens in single pregnancy is more pronounced in twins
- Consider stopping work at 28-30 weeks
- If at 8 weeks 2 fetal hearts visible, likely to continue, miscarriage unlikely at that stage
- Vaginal birth good possibility, although increased risk of C section in some.
- Morning sickness should improve after 12 weeks. Eat small regular meals
- Take iron and folate
Finishing the initial consult
- Order normal pregnancy investigations
- Information about support groups
- Considerations for ongoing family planning
- Review when results are back
- Referral to hospital/midwife care- whichever is decided
Multiple gestation complications->mneumonic
The Ps of Multiple Gestation Complications Increased rates of: Puking Pallor (anemia) Preeclampsia/PIH Pressure (compressive symptoms) PTL/PROM/PPROM Polyhydramnios Placenta previa/abruptio PPH/APH Prolonged labour Cord Prolapse Prematurity Mal Presentation Perinatal morbidity and mortality Parental distress Postpartum depression
Maternal complications
Hyperemesis gravidarum GDM Gestational HTN Anemia \++Physiological stress Compressive C/S
Utero-placental complications
PROM/PTL PolyH PP PL Abruption PPH (atony) Umbilical cord prolapse Cord anomalies
Fetal complications
Prematurity IUGR Malpresentation Congenital anomalies TTT Increased perinatal morbidity/mortality Twin interlocking (breech + vertex) Single fetal demise
Increased antenatal screening
USS every 2-3 weeks from 28 weeks to assess growth, may be further ++ if MCDA, MCMA
Vaginal vs C/S
Can attempt vaginal delivery if first twin is vertex, however often second twin will need to be delivered as C/S
Types of twin
Dichorionic, diamniotic
Dichorionic, monoamniotic
Monochorionic, diamniotic
Monochorionic, monoamniotic
Risk factors for dizygotic
Drugs Race Advanced maternal age Parity "Fraternal"
Frequency of maternal twins, monozygotic
Occurs in 1 in 250
Timing of divisions in monozygotic->amnionicity and chorionicity
- Division of the ovum between days 0 and 3: Dichorionic, diamniotic monozygotic twins.
- Division between 4 and 8 days: Monochorionic, diamniotic monozygotic twins
- Division between 9 and 12 days: Monochorionic, monoamniotic monozygotic twins.
- Division after 13 days: Conjoined twins.
Preferred first trimester screening marker
Nuchal translucency
What is twin-twin transfusion
Complication of monochorionic multifetal gestation in blood/IV volume shunted from one twin to another
Complications of TTT
Single fetal demise
One twin develops complication due to underperfusion, the other due to overperfusion
Etiology of TTT
Arterial blood from one passes through placenta to vein of the other
Clinical features of TTT
- Donor twin: IUGR, hypovolemia, hypotension, anemia, oligohydramnios
- Recipient: hypervolemia, HTN, CHF, polycythemia, edema, polyH, kernicterus in neonatal period
Ix in TTT
USS detection
Doppler flow analysis
Management of TTT
- Therapeutic serial amniocentesis to decompress polyH of recipient and decrease pressure
- IU blood transfusion to donor if necessary
- Laparoscopic occlusion of placental vessels
