A twin pregnancy means there are two fetuses in the uterus. This is a rare occurrence that can be due to family history, fertility treatments or other factors. Healthcare providers can detect twins early using ultrasound. A twin pregnancy raises the risk of complications for the pregnant person and fetuses, which is why more frequent prenatal care is necessary.
Twin pregnancies occur when there are two fetuses in your uterus at one time.
The chances of conceiving twins, a type of multiple pregnancy, are low. Twins occur naturally in 1 out of every 250 pregnancies.
Certain circumstances are consistent with carrying more than one fetus. But experiencing the signs of a twin pregnancy doesn’t always mean a person is carrying two fetuses.
These signs, some of which occur in the early weeks of pregnancy, include:
Twin pregnancy symptoms are similar to those of a single fetus (singleton) pregnancy but may be more intense.
You may experience:
The most reliable method of confirming a twin pregnancy is prenatal ultrasound. This test uses sound waves to produce images of your uterus. Ultrasound makes it possible to see whether there are two fetuses.
With a twin pregnancy belly, your bump will show early on. You may need maternity clothes shortly after finding out you are pregnant. Your expanding bump may also cause you to outgrow clothes quickly because of extra weight gain. It’s common to put on around 50 lbs. during a twin pregnancy, compared to 30 lbs. for a singleton baby.
Twins are either fraternal or identical.
Conjoined twins are extremely rare and occur when an identical twin embryo does not fully divide. The babies’ bodies are fused and may share vital organs. Common points of fusion are the chest or abdomen. This can result in a shared liver or heart.
Circumstances that increase your chances of having twins include:
Fertility treatments can lead to a twin pregnancy:
A full-term pregnancy is 37 weeks. Twin pregnancies rarely last this long, with the typical twin pregnancy lasting 35 to 36 weeks. Many people go into labor sooner.
Few treatments are available to prevent preterm labor, and they're not always successful. Once you go into active labor, there's no way to stop labor from progressing.
With twin pregnancies, both the pregnant person and twins face a higher risk of complications. Prenatal checkups occur more frequently with twin pregnancies, making it possible to detect issues in earlier stages.
Twin pregnancies are high risk because there are many potential complications. Many people receive prenatal care from maternal-fetal medicine experts. These obstetricians specialize in preventing, detecting and caring for complications of high-risk pregnancies.
Twin pregnancy complications include:
Premature twins are at risk for additional complications, which may include:
A cesarean birth (c-section) is likely with twin pregnancies. If you're pregnant with twins and not having complications, it's possible to try for a vaginal delivery.
A note from Cleveland Clinic
Finding out you're pregnant with twins can be exciting, but you might also feel overwhelmed. A twin pregnancy requires more frequent prenatal visits because there are higher chances of complications. Most people who are pregnant with twins deliver just before they're considered full-term. Though twins are often born via c-section, talk to your provider about the possibility of a vaginal delivery. They're there to help with any questions or concerns you may have.
Last reviewed by a Cleveland Clinic medical professional on 06/01/2022.
Learn more about our editorial process.