Can twins be detected early in pregnancy?

This is the 3206th article of Da Yi Xiao Hu

Sometimes in the clinic, we meet some expectant mothers who have particularly severe early pregnancy reactions, nausea, vomiting, and in severe cases, they cannot eat normally, and even have ketoacidosis and need to be hospitalized for fluid rehydration treatment. When this type of patients come to see a doctor, they usually ask me: "Doctor, my pregnancy reaction is so severe, am I pregnant with twins?" I can only tell her truthfully that a mild early pregnancy reaction does not mean a single pregnancy. Similarly, a severe early pregnancy reaction does not mean a twin pregnancy. Once, a pregnant woman who was more than 2 months pregnant looked like she was more than 4 months pregnant. She told me complacently that everyone around her thought she was pregnant with twins. After the prenatal examination, the expectant mother was confirmed by ultrasound to be a single pregnancy in the uterus. I was angry and told her with a smile: "This is because she is too fat, that is, she eats too much, which causes the abdomen to bulge, that is, the belly. It's not twins!".

Then, some readers are very curious, can twins be seen in the early stages of pregnancy? First of all, twins cannot be seen with the naked eye in the early stages of pregnancy! From an anatomical point of view, when the pregnancy is one month, that is, when the menstruation is just overdue, the size and shape of the pregnant woman's uterus basically do not change, such as the size of an egg. When the pregnancy is two months, the uterine wall of the pregnant woman becomes very soft and the cervix becomes thicker. After three months of pregnancy, the size of the uterus is about the size of the pregnant woman's fist. The doctor can touch the bottom of the uterus with his hand about 2-3 horizontal fingers above the female pubic symphysis. Therefore, most pregnant women cannot see an enlarged abdomen from the appearance within 12 weeks of pregnancy. In the early stages of pregnancy, due to the small fetus, even experienced obstetricians can hardly judge the size of the uterus by the naked eye before the 12th week of pregnancy, or judge single or multiple pregnancies by abdominal examination. The pregnancy test stick in the early stages of pregnancy cannot detect twins. In the clinic, some patients will ask: "Doctor, I took a blood test to check the HCG value is very high, much higher than other pregnant women with the same gestational age as me. Can this mean that it is twins?" This is also unfounded. Blood HCG is a glycoprotein secreted by the placental trophoblast cells in pregnant women. The high or low blood HCG value in early pregnancy only indicates that the activity of the chorionic villi is strong, and does not directly indicate a twin pregnancy.

It is recommended to do a vaginal B-ultrasound examination as soon as possible. It is recommended that pregnant mothers who are known to be pregnant should do a vaginal B-ultrasound at 6+ weeks of pregnancy. On the one hand, it can determine whether the location of the gestational sac is in the uterine cavity and exclude ectopic pregnancy in time. On the other hand, it can determine the actual gestational age. At the same time, it can also be understood whether it is a twin pregnancy. In the case of twins, the ultrasound will indicate two embryos, and both can see the fetal heartbeat. It is very meaningful to make a diagnosis of twin pregnancy in early pregnancy, which can give pregnant women enough time to consider whether to perform fetal reduction surgery and retain a single fetus. Because the number of fetuses is also proportional to the risk during pregnancy, if the pregnant mother is pregnant with twins, it means that the risk factor of the fetus in the mother is also significantly higher than that of a single fetus. Especially for pregnant women who had a cesarean section and a scarred uterus before, the risk is higher and there is a risk of rupture of the scarred uterus. It is very difficult for pregnant mothers to be pregnant, so pregnant mothers must not ignore prenatal examinations, and they must have regular prenatal examinations to know the situation of themselves and their children in time!

Author: Reproductive Medicine Center, Affiliated Hospital of Guangdong Medical University

Zou Lin, Chief Physician, Master Supervisor