How do you calculate 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 does discordance mean in twins?

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 causes twin 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 Stage 3 twin-to-twin transfusion syndrome?

Stage 3: The imbalance of blood flow starts to affect the heart function in one or both babies. This is seen in abnormal blood flow in the umbilical cords or hearts of the twins.

What is twin twin transfusion syndrome?

Twin-to-twin transfusion syndrome (TTTS) is a rare pregnancy condition affecting identical twins or other multiples. TTTS occurs in pregnancies where twins share one placenta (afterbirth) and a network of blood vessels that supply oxygen and nutrients essential for development in the womb.

What is discordance rate?

Discordance rate is the ratio between total number of discordant subjects to the total number of subjects assessed. As can be seen in Figure 1, the discordant rate is calculated by adding the off-diagonal counts and dividing by the total number of subjects assessed.

What is concordance and discordance?

7. 3. A pair of observations is concordant if the subject who is higher on one variable is also higher on the other variable. A pair of observations is discordant if the subject who is higher on one variable is lower on the other variable.

What does it mean to have twin growth discordance?

Twin growth discordance. 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 10 th centile.

How to calculate birth weight discordance for twins?

Calculation of Twin Birth Weight Discordance Birth weight discordance = (larger twin weight−smaller twin weight) / larger twin weight×100.

What is the definition of birth weight discordance?

Birth weight discordance = (larger twin weight−smaller twin weight) / larger twin weight×100. 1. Breathnach FM, etal., Perinatal Ireland Research Consortium. Definition of intertwin birth weight discordance. Obstet Gynecol. 2011 Jul;118 (1):94-103.PMID: 21691168 All calculations must be confirmed before use.