How early can a doctor detect twins by ultrasound?
I think it might depend on if they are fraternal twins or identical twins. If identical, they divide from one egg & sperm, and separate out some time during their development. If fraternal twins, they can come from two different sperm and two eggs, developing separately, and not together, so they should be able to be spotted by ultrasound earlier. Here is some information: An ultrasound can often tell you whether your babies are fraternal or identical, based on whether there are one or two placentas and whether the babies are the same gender. An experienced technician performing a trans-vaginal ultrasound between 9 and 14 weeks can determine with nearly 100 percent certainty whether your babies share a single placenta. (The accuracy rate drops to about 90 percent in the second trimester as the womb becomes more crowded.) If your babies share a placenta, they’re identical. If there are two placentas, your twins may be fraternal or identical.
