The growth of double chorionic twins is inconsistent.
At present, the diagnostic criteria for twin growth inconsistency are not uniform, American College of Obstetricians and Gynecologists ( ACOG) It is recommended that the difference in birth weight between the two fetuses is 15% ~ 25% are twin growth inconsistencies. Canadian College of Obstetricians and Gynecologists ( SOGC) The view is that the difference between the abdominal circumference of the two fetuses is more than 20 mm or the difference between the estimated weight of the fetus is more than 20%, which means the growth of the twins is inconsistent. Royal College of Obstetricians and Gynecologists ( RCOG) defines the range of twin growth inconsistency as the difference between the estimated weight of the two fetuses is greater than 25%. Most fetal medical centers in China recommend that the difference between the estimated weight of the two fetuses is ≥ 25% as the diagnostic standard. At present, there is no widely accepted growth curve for the estimated weight of normal twins. SOGC and ACOG believe that the growth curve of normal singleton can be used instead of twins.
The reasons for the growth inconsistency between the two fetuses of double chorionic twins may be related to the different genetic potential of the two fetuses, the structural abnormality of one fetus, chromosome abnormality or the abnormality of placenta occupied by small fetus. Placental factors such as placental weight, placental area ratio, abnormal umbilical cord insertion (racket or sail attachment) are obviously related to the growth inconsistency of twins.
It is suggested that pregnant women with inconsistent twin growth should be transferred to an experienced prenatal diagnosis center for detailed fetal structure screening, and consultation should be conducted to decide whether fetal genetic examination is needed. Care should be strengthened in the third trimester of pregnancy, and the timing of delivery should be determined by comprehensively considering fetal estimated weight, gestational age, maternal condition, etc.
Intrauterine death of one fetus in double chorionic twin pregnancy (IUFD)
Because there is no anastomotic blood vessel between placentas in double chorionic twins, The death of one fetus generally does not affect the other. The risk of simultaneous death of the surviving fetus is 4%, and the risk of neurological sequelae is 1%. The main risk is premature delivery. If the surviving fetus does not have high-risk factors or the gestational age is far away from full term, the pregnancy is usually expected, and most outcomes are good.
One of the abnormalities of double chorionic twins
For one of the two chorionic twins with fetal abnormalities (including structural abnormalities and chromosomal abnormalities), The severity of fetal abnormalities, the influence on the mother and healthy fetus, the risk of fetal reduction surgery should be comprehensively considered, and an individualized treatment plan should be formulated in combination with patients’ wishes, ethics and social factors. For serious fetal abnormalities, fetal reduction surgery is feasible. At present, the more commonly used technology is potassium chloride intracardiac injection guided by abdominal ultrasound.
Author: Duan Tao
The article was reprinted by Clove Garden authorized by the author.