Multiple Gestations Flashcards
Risk factors of multiple gestations
IVF
Maternal age
Family History
Black race
Classifying multiple pregnancies is based on…
of fetus
# of fertilized eggs (Zygosity)
# of placenta (chorionicity)
# of amniotic cavities (amniocity)
Fraternal twins (non-identical)
Dizygotic
Dichorionic
Diamniotic
Monozygotic twins (Identical)
Monozygotic
Same-sex
Mono/Di chorionic
Mono/Di amniotic
Etiology of dizygotic twins
IVF
Induction
Familial
Racial
Types of monozygotic depends on
when split occurs
If monozygotic split occurs within 3 days of conception
Pregnancy will be
Dichorionic
Diamniotic
If monozygotic split occurs within 4-8 days, pregnancy will be
monochorionic
diamniotic
Maternal and fetal effects of multiple gestation
Maternal: physio changes are exaggerated
Fetal: monochorionic placenta has unique ability to develop vascular connection btwn fetal circulations (increases complications)
Complications of multiple gestation
- Miscarriage + Severe preterm
- Increased Perinatal mortality
- Increased stillbirths in monochorionic pregnancies
- Death of one fetus
The avg Gestational age @ delivery for multi-preg
37 wks
Percentage of twins born preterm
50%
Percentage of babies requiring NICU in twin pregnancy
20-25%
Perinatal mortality is how many times higher in multiple gestation
5.5 times higher than singleton
The intrauterine death of one twin in the first trimester increases the chance of
poor outcome for co-twin and complications (DIC)
Mono/ DI chorionic differences in death of one fetus
Dichorionic: death of one twin in 2nd or 3rd tri. associated with onset of labour
Monochorionic: death of one twin leads to complications , death and/or brain damage in survivor twin (30%)
Mono/Di chorionic differences in FGR multiple pregnancies
Dichorionic : x2 the risk of low fetal birth weight. avoid delivery before 28-30 wks.
Monochorionic: death of one twin results in handicap or death of co twin due to secondary hypotenstion to placental anastamoses.
Prolong delivery without risk to co-twin
Di/Mono chorionic differences in Fetal anomalies
Dichorionic: x2 risk of structural anomalies like spina bfida
Monochorionic: x4 risk of anomalies
Management of Multi pregnancy where one fetus has anomaly
Monitor and manage accordingly or fetocide given in lethal conditions where healthy twin is @ risk (ex: Anacephaly causing polyhydramnios and preterm labour of both)
Chromosomal anomalies in monozygotic twins
Anomaly will effect both or neither due to identical genetic make up
Complication of Monochorionic pregnancy
Placental vascular anastomoses allows communication between to feto-placental circulations.
Imbalance of bloodflow leads to Twin to Twin Transfusion Syndrome
Twin to Twin transfusion syndrome
One twin is overperfused and other is under-perfused
What happens to underperfused twin in TTTS
hypovolemic, oliguric, oligohydramnios
What happens to overperfused twin in TTTS
hypervolemic, polyuria, polyhydramnios, myocardial damage, high output cardiac failure
Diagnosing TTTS
via U/S in 2nd trimester. Over perfused baby will have increased abdominal girth
Treatment of TTTS
Amniocentesis every 1-2 wks prolongs pregnancy and increases survival
Fetoscopal laser coagulation to disrupt communication
Complication of monoamniotic
Increase in cord accidents.
Opt for CS @ 32-34 wks
Differential Diagnosis of Multi Preg
Any large for date preg
Polyhydramnios
Uterine fibroids
Urinary retention
Ovarian masses
Antenatal Managment of multi preg
Routine care: HTN + Gestational DM more likely in multiple pregnancy
ROutine supplementation of iron and folic acid due to increase in demand
When and how to determine chorionicity
via U/S in late first trimester (10-12wks).
Dichorionic= V shaped extension of placentaltissue into base of inter-twin membrane (lambda or twin peak)
Monochorionic : T shape
Test for fetal abnormalities
Trisomy 21 @ 12 wks
Rest optimally @ 20wks
Monitoring of fetal growth + wellbeing done via
U/S including fetal measurement, activity, lies and amniotic fluid volume
Signs of TTTS via U/S
Difference in
1. fetal size
2. fetal activity
3. bladder volumes
4. amniotic fluid
5. cardiac size
Threatened preterm labour
Maternal steroid therapy (fetal lung)
Educate on signs of preterm labour
Advanced planning
Screen for strep B
Diagnosing preterm labour via
Transvaginal/Cervical U/S most promising predictor
Intrapartum prep
Twin CTG
portable U/S for delivery
Standard oxytocin IV for 2nd twin
Second higher oxytocin dose in case of PPH
2 neonatal resucitation sets
2obstetricians + 2 paediatricians
Analgesic given in Multi-preg labour
Epidural recommended, kept running through second stage of labour
Fetal well-being during labour
Monitor FHR continuously
abnormal HR assessed via scalp sampling.
Abnormal HR in 2nd baby-> CS (watch for cord prolapse or placenta separation)
Vertex-Vertex Delivery how to assess lie of 2nd baby
via abdominal palpation and U/S
If lie is cephalic (vertex-vertex)
wait for descent of head then amniosotomy w/ contractions
When to give oxytocin in vertex vertex delivery
If no contractions after 1st baby for 5-10 mins
If 1st baby cephalic, 2nd breech
Breech extraction can be performed
If 2nd baby is transverse
Perform ECV
if fails
internal podalic can take place, rupture membrane as late as possible
Non vertex 1st twin
ELective CS
Requirements of twin delivery
Large room
Operating theatre ready
Anaesthesiologist present
Senior Obs
2 midwives
Twin resucitation
Forceps at hand
Blood
IV access
Neonatologists
Oxytocin infusions
Postpartum Haemorrhage
Increased risk in multi pregnancies. High dose of oxytocin given after delivery as prophylaxis
Higher multiples (3+ babies)
IVF main cause
Increased risks
Median G.A= 33wks
CS usually
