Congenital abnormalities and teratology Flashcards
Incidence of twin pregnancy
per 1000
2-7 far east
9-20 europe
20-45 nigeria
Multiple pregnancy aetiology
Ethnicity
Increasing maternal age
Increasing parity
Family history
Fertility treatment
Monozygous
1 egg
Identical
Dizygous
2 eggs
Non identical
Separate amnions, chorions and placenta
Monozygotic split at 2 cell stage
1 egg splits to 2 inner cell masses
Progresses to 2 babies
2 completely separate amnions, chorions and placentae
Still identical
Monozygotic split at early blastocyst stage
2 inner cell masses
Common chorion, separate amnion
Joined placentae
Identical
Later stage split
Later splitting yields 2 embryos from one inner cell mass
Common chorion, amnion and joined placentae
Twin pregnancy diagnosis- dichorionic
All dizygous twins are dichorionic
Dichorionic twins must be diamniotic
Twin pregnancy diagnosis- monochorionic
Monozygous twins may be monochorionic or dichorionic
MC have vascularly joined placentae
MC twins have 3x increased loss rate
MC twins usually diamniotic
Lamda sign in pregnancy
Shows dichoriotic
T sign
Monochorionic
Complications of multiple pregnancy
Symptoms of pregnancy
Anaemia
Hypertension
Intrauterine growth restriction
Pre-term labour
Delivery problems
Perinatal mortality
Twin pregnancy mortality
Stillbirth- after 24 weeks
Early neonatal- first 7 days
Neonatal- in first 28 days
Perinatal- SB and early neonatal
Infanat- first year
Rates are per 1000 birth
First trimester management of twin pregnancy
Discuss screening for chromosomal anomalies
Determine chorionicity
Discuss fetal reduction if triplets or more
Second trimester management of twin pregnancy
Detection of fetal abnormality
Serial scans for growth for all
- DC monthly 24 weeks
Serial scans for TTTS if MC twins
- 2 weekly 16-28 weeks then monthly
Maternal complications
