What causes twin growth discordance?
The causes of twin growth discordance are often unknown. The most important is considered to be monochorionicity, mainly because of unequal sharing, or of velamentous cord insertions in the IUGR twin [20]. Other possible causes are “intrauterine crowding” and the presence of malformations [21-23].
What is normal discordance in twins?
About 75% of twins exhibit < 15% discordance (concordant), 20% are 15-25% (mildly) discordant, and about 5% are more than 25% (severely) discordant. Higher frequencies and increased severity are seen among triplets.
How do you calculate growth discordance with twins?
Calculation of Twin Birth Weight Discordance. A difference of 18% or greater in birth weight should prompt more intensive fetal monitoring [1]. Birth weight discordance =(larger twin weight−smaller twin weight) / larger twin weight×100.
What is fetal discordance?
Birth weight discordance was defined as a difference of 20% or more of the weight of the heavier twin, associated with an intra-uterine growth restriction (10(th) percentile) of at least one twin. Ultrasound discordance was defined as a difference of estimated fetal weight>20%.
What is the ultrasound criteria for discordant growth in monochorionic twinning?
Discordant growth in twin gestations, usually defined as a difference of >20% or 25%, has been found in 7% to 15% of MCDA twin pregnancies3, 4 and contributes to neonatal mortality and morbidity.
What does EFW discordance mean?
Twin growth discordance is a term used in obstetric imaging to describe a significant size or weight difference between the two fetuses of a twin pregnancy. To be classified as a growth discordance, some consider that the estimated fetal weight (EFW) of the smaller twin should fall under the 10th centile.
What is a discordance?
1 : lack of agreement or harmony : the state or an instance of being discordant. 2 music : dissonance.
How is EFW calculated?
log10(Fetal weight) = 1.3596 – (0.00386 * AC * FL) + (0.0064 * HC) + (0.00061 * BPD * AC) + (0.0424 * AC) + (0.174 * FL) , where: Fetal weight is given in grams (g); AC means the Abdominal Circumference and is given in centimeters (cm);
Is normal delivery possible for MCDA twins?
MCDA twins are best born between 36 and 37 weeks. Moreover, 60% of twin pregnancies deliver spontaneously before 37 weeks. After 37 weeks, the risks of shared circulation outweigh the neonatal risks.
How is discordance of twins best measured?
The standard diagnostic test for growth discordance is ultrasound. Growth discordance can be estimated by measuring crown rump length (CRL: the distance measured from the top of the head to the bottom of the buttocks) at or before 12 weeks of gestation (Tai 2007).
How often do identical twins have growth discordance?
Twin Growth Discordance may happen in 25% of twin pregnancies. When you hear the term discordant twins, this means that the twins at birth show a distinct difference in size. Usually, the other twin’s weight is greater than 10%. This condition is common in identical twins but may also happen in fraternal twins.
What does it mean when your twins are discordant?
When you hear the term discordant twins, this means that the twins at birth show a distinct difference in size. Usually, the other twin’s weight is greater than 10%. This condition is common in identical twins but may also happen in fraternal twins.
What causes weight discordance in twin pregnancies?
Twin growth discordance may happen in about 25% of twin pregnancies and can either be a weight discordance or size discordance. Weight discordance is a weight incongruence of more than 25% and is possibly associated with intrauterine growth restriction (IUGR) in the smaller twin.
Can a transfusion cause twin growth discordance?
Size discordance, on the other hand, is usually associated with anemia or can be a result of a twin-twin transfusion. Twin Growth Discordance may happen in 25% of twin pregnancies.