Multiple birth Flashcards
What is the difference between monozygotic twins and dizygotic twins
Monozygotic twins - Identical twins. Ova splits. The two fetuses share a placenta.
Dizygotic twins - Fraternal twins. 2 eggs are fertilised and implant. Each fetus has it’s own placenta.
What is twin to twin transfusion?
A risk factor of monozygotic twins. One twin receives more nutrients than the other. Resulting in both baby’s not being well. One fetus is IUGR.
What are the influencing factors for dizygotic twins?
- Maternal age (35-39yrs)
- Higher parity
- Tall stature
- Family hx of twins
How is a twin pregnancy diagnosed?
Ultrasound and abdominal examination (inspection, palpation, auscultation)
What is monochorionicity?
When there the twins share a placenta.
What are the ultrasound schedule for twins?
First trimester scan, 4 weekly for fraternal and 2 weekly for identical.
What are the risks of multiple pregnancy?
- congenital abnormalities
- minor disorders
- anaemia
- polyhydramnios
- miscarriage
- extreme preterm birth and mortality
- pregnancy-induced HTN
- pre-eclampsia
- twin to twin transfusion
- IUGR
- antepartum haemorrhage
- umbilical cord entanglement
- threatened preterm labour
- C/S
Twins have a ____ risk of congenital abnormalities than singleton pregnancies.
higher.
Dichorionic - twice the risk. monochorionic - four times the risk.
How is one baby with an anomaly managed?
Expectantly or selective fetocide of affected twin.
What is polyhydramnios?
Excess amniotic fluid in uterine cavity. Can be indicative of fetal abnormality and is associated with monochorionic twin pregnancy.
Acute polyhydramnios in the second trimester can lead to ……….
miscarriage or preterm birth.
What is amnioreduction?
Removal of excess fluid by aminocentesis.
What is the average gestation at birth for spontaneous birth of twins?
37 weeks
What does pregnancy-induced HTN increase the rate of?
PIH, severe pre-eclampsia and clotting disorders due to increased hormone production.
What issues do Donor baby’s have vs recipient babys in twin-to-twin transfusion?
Donor - Anaemia due to hypovolaemia, growth restriction, oliguria
Recipient - Hypervolemia, polyuria, polycythaemia.
What signs does the woman have of twin-to-twin transfusion?
Sudden increase in abdominal size and extreme discomfort.
What is the treatment for twin-to-twin transfusion?
Amniocentesis (every 1-2 weeks and draining amniotic fluid)
Prolong pregnancy to improve outcomes.
Fetal surgery to separate placental blood vessels connecting babies’ circulation.
What are the influences that can cause IUGR?
PIH, smoking, diet, infection, fetal abnormality (twin-to-twin transfusion).
Antepartum haemorrhage can occur in multiple pregnancy for what reasons?
- Larger placental size.
- Occurrence of placenta praevia and placental abruption.
- Increase chance of placenta in lower uterine segment.
- The uterus size is larger (increases chance of abruption - SROM and PIH)
What can occur with umbilical cord entanglement?
Blood supply to one fetus is compromised.
Can those with umbilical cord entanglement have a vaginal birth?
No
When there is a threatened preterm labour what needs to be considered?
- screening for bacterial vaginosis
- GBS screening
- maternal steroid therapy
When is IOL organised for twins?
38 weeks
What are some of the various combinations of presentation for twins?
- vertex and vertex
- vertex and breech
- breech and vertex
- breech and breech
- vertex and transverse
- breech and transverse
How can contractions be different in a multiple pregnancy than to a singleton?
Uterine dysfunction due to distention of the uterus. Accurate monitoring of contraction pattern is needed and a synto infusion may be required.
After the birth of twin 1 what must be done regarding twin 2?
- lie, presentation and position established by abdominal palpation.
- FHR
- Maternal BP and HR
- ECV if necessary (C/S if baby does not turn from transverse)
What do you do if twin 2 is not engaged in the pelvis?
apply fundal pressure before ARM to reduce risk of cord prolapse.
How long should it take after twin 1’s birth for contractions to start?
5 mins. If not start an oxytocin infusion.
If there are no signs of distress how long should be allowed between babies’ births?
30-45 mins
What needs to be done regarding the placenta and cords after delivery?
Examine and look at the number of amnions and chorions. Send to pathology to determine zygosity.
What are some of the complications associated with labour and birth?
- malpresentations
- PROM
- Cord prolapse
- prolonged labour
- locked twins
- delayed birth of twin 2
- premature expulsion of the placenta
What is locked twins?
A rare occurrence where the twins heads are ‘locked’ together preventing vaginal delivery.
What can be the risks of delayed birth of twin 2?
- intrauterine hypoxia
- birth asphyxia (due to premature separation of placenta)
- sepsis from ascending infection of twin 1’s umbilical cord
- delay in re-formation of lower uterine segment (needed for cervical dilation to be reached again)
What can speed up the birth of twin 2?
Putting twin 1 at the breast helps stimulate the release of oxytocin from maternal pituitary gland.
What is the danger of premature expulsion of the placenta?
Asphyxia and death of twin 2 can occur. If twin 2’s birth is delayed can increase the risk of intrapartum haemorrhage.
How does the risk of cerebral palsy increase with multiples?
- twins x4 increase
- triplets x20 increase
- If one twin develops CP than the other twin has a 12% chance.
- When twin increases the other twins risk of developing CP by 5%.
Higher risk in identical twins.
Why do conjoined twins occur?
Abnormal or incomplete division of zygote. It can only occur in monozygotic twins.
What is Acardiac twins?
One twin is dependant on the other twin’s cardiovascular system.
Why is there an increasing incidence of mutliples?
- IVF transfer of multiple embryos
- Ovulation induction can cause more than 1 egg to be released
