Being pregnant with twins, triplets and other multiples


  • You and your babies are more likely to have health complications than if you’re pregnant with one baby (also called a singleton).  

  • You may need to go to extra prenatal care checkups so your health care provider can check you and your babies closely for complications.  

  • Premature birth (birth before 37 weeks of pregnancy) is the most common complication of being pregnant with multiples.  

  • If you’re pregnant with multiples, you’re 6 times more likely to have your babies early than if you’re pregnant with one baby. 

What does being pregnant with multiples mean?

Being pregnant with multiples means being pregnant with twins, triplets or more. More than 3 in 100 women (3 percent) are pregnant with multiples each year. 

Most women with multiples are pregnant with twins. But some women get pregnant with three (triplets), four (quadruplets) or more babies. These are called higher-order multiples.

How do you know if you’re pregnant with multiples? 

You may be pregnant with multiples if: 

  • Your breasts are very sore.
  • You’re very hungry or you gain weight quickly in the first trimester.
  • You feel movement in different parts of your belly at the same time. 
  • You have severe morning sickness. Morning sickness is nausea (feeling sick to your stomach) and vomiting that happens in the first few months of pregnancy, usually in the first few months. It’s sometimes called nausea and vomiting of pregnancy or NVP.
  • Your provider hears more than one heartbeat or finds that your uterus (womb) is larger than usual.
  • You have high levels of human chorionic gonadotrophin (also called hCG) or alpha-fetoprotein in your blood. HCG is a hormone a woman’s body makes during pregnancy. Alpha-fetoprotein is a protein a developing baby makes during pregnancy. 

Your health care provider uses ultrasound to find out for sure if you’re pregnant with multiples. Ultrasound uses sound waves and a computer screen to show a picture of a baby in the womb.

What kind of prenatal care do you need if you’re pregnant with multiples?

You may need special medical care during your pregnancy, labor and birth. You may need to go to extra prenatal care checkups so your provider can check for pregnancy complications. You also may need more prenatal tests (like ultrasounds) to check on your growing babies throughout your pregnancy. 

If you’ve had pregnancy complications in the past or if you have health conditions that put you at risk for pregnancy complications, your provider may refer you to a maternal-fetal medicine specialist. This is an obstetrician (also called OB) with special education and training to take care of women who have high-risk pregnancies. If you’re referred to a specialist, it doesn’t mean you’ll have problems during pregnancy. It just means the specialist can check you and your babies closely to help prevent or treat any conditions that may happen.  

Do you need to eat a special diet if you’re pregnant with multiples? 

No. But you do need more of certain nutrients, like folic acid, protein, iron and calcium when you’re pregnant with more than one baby. You can get the right amounts of these nutrients by eating healthy foods and taking your prenatal vitamin every day. Prenatal vitamins are multivitamins made just for pregnant women. Compared to a regular multivitamin, they have more of some nutrients that you need during pregnancy. Your provider can prescribe a prenatal vitamin for you at your first prenatal care checkup. Even when you’re pregnant with multiples, you only need to take one prenatal vitamin each day. 

How much weight should you gain if you’re pregnant with multiples?

You need to gain more weight than if you were pregnant one baby. The amount of weight to gain depends on your pre-pregnancy weight and how many babies you’re carrying. Talk to your provider about the right amount of weight gain for you. 

Here are some weight-gain guidelines if you’re pregnant with twins: 

  • If you were at a healthy weight before pregnancy, you want to gain about 37 to 54 pounds during pregnancy. 
  • If you were overweight before pregnancy, you want to gain about 31 to 50 pounds during pregnancy. 
  • If you were obese before pregnancy, you want to gain about 25 to 42 pounds during pregnancy. 

Do you need to limit exercise and other activities if you’re pregnant with multiples?

Talk to your provider before you start any exercise program. Ask about what kind of activities are safe for you to do. You may need to avoid high-impact activities, like aerobics or jogging, that involve jumping or putting stress on joints. But you may be able to do some activities, like swimming, prenatal yoga or walking. 

You may need to limit your activity later in pregnancy. This may include doing less physical activity, travel or work. Many women pregnant with multiples go on bed rest. Bed rest means reducing your activities while you’re pregnant. Bed rest may mean staying in bed all day or just resting a few times each day.  

How can a multiple pregnancy affect your health?

If you’re pregnant with multiples, you’re more likely to have complications, including:

  • Preterm labor. Preterm labor is labor that happens too early, before 37 weeks of pregnancy. Preterm labor can lead to premature birth. 
  • Anemia. Anemia is when you don’t have enough healthy red blood cells to carry oxygen to the rest of your body. You may have anemia if your body isn’t getting enough iron. Iron-deficiency anemia is common in multiple pregnancies and can increase your chances of having giving birth early. Your provider may prescribe an iron supplement for you to make sure you’re getting enough iron. 
  • Gestational diabetes. This is a kind of diabetes that can happen during pregnancy. If untreated, it can cause serious health problems for you and your babies. 
  • Gestational hypertension or preeclampsia. These are types of high blood pressure that only pregnant women can get.                                        
  • Hyperemesis gravidarum. This is a severe kind of morning sickness or nausea and vomiting of pregnancy (also called NVP).
  • Polyhydramnios. This is when you have too much amniotic fluid. Amniotic fluid is the fluid that surrounds your baby in your uterus (womb). 
  • Miscarriage and stillbirth. Miscarriage is when a baby dies in the womb before 20 weeks of pregnancy. Stillbirth is when a baby dies in the womb after 20 weeks of pregnancy. Some women pregnant with multiples have a condition called vanishing twin syndrome. This is when one or more babies die in the womb, but one baby survives. 

You’re more likely to have these complications after giving birth to multiples than if you’re pregnant with one baby: 

  • Postpartum depression (also called PPD). This is a kind of depression that some women get after having a baby. PPD is strong feelings of sadness that last for a long time. These feelings can make it hard for you to take care of your baby. 
  • Postpartum hemorrhage. This is when a woman has heavy bleeding after giving birth. It’s a serious but rare condition. 

How can being pregnant with multiples affect your babies’ health?

If you’re pregnant with multiples, your babies are more likely to have health complications including: 

  • Complications from premature birth. Premature babies may have more health problems or need to stay in the hospital longer than babies born later. They also may have long-term health problems that can affect their whole lives. More than half of twins and nearly all triplets and other higher-order multiples are born prematurely. The earlier in pregnancy your babies are born, the more likely they are to have health problems. Some premature babies have to spend time in a hospital’s neonatal intensive care unit (also called NICU). This is the part of a hospital that takes care of sick newborns. 
  • Birth defects. Multiples are about twice as likely to have birth defects than singleton babies, including neural tube defects (like spina bifida), cerebral palsy, congenital heart defects and birth defects that affect the digestive system. Birth defects are health conditions that are present at birth. They change the shape or function of one or more parts of the body. Birth defects can cause problems in overall health, how the body develops or how the body works.
  • Growth problems. Multiples are usually smaller than singleton babies. Your provider can use ultrasound to check your babies’ growth at prenatal care checkups. When one twin is much smaller than the other, they’re called discordant twins. Discordant twins are more likely to have health problems during pregnancy and after birth. 
  • Low birthweight (also called LBW). This is when a baby is born weighing less than 5 pounds, 8 ounces. These babies are more likely than babies born at a normal weight to have certain health problems as newborns, like retinopathy of prematurity, and other health problems later in life, like high blood pressure. More than half of twins and nearly all higher order multiples are born with LBW.
  • Twin-twin transfusion syndrome (also called TTTS). This condition happens when identical twins share a placenta and one baby gets too much blood flow, while the other baby doesn’t get enough. The placenta grows in your uterus (womb) and supplies your babies with food and oxygen through the umbilical cord. TTTS can be treated with laser surgery to seal off the connection between the babies’ blood vessels and amniocentesis (also called amnio) to drain off extra fluid. 
  • Neonatal death.  This is when a baby dies in the first 28 days of life. Premature birth is the most common cause of neonatal death

How are multiples born?

If you’re pregnant with multiples, you’re more likely to have a cesarean birth (also called c-section) than if you’re pregnant with one baby. A c-section is surgery in which your baby is born through a cut that your doctor makes in your belly and uterus. Most triplets and higher-order multiples are born by c-section.

If you’re pregnant with twins, you may be able to have a vaginal birth if both babies are in the head-down position and you have no other complications, or if the lower twin is in the head-down position but the higher twin isn’t. You may need a c-section if neither baby is in the head-down position or there are other complications. 

Are some women more likely to get pregnant with multiples?

Yes. You may be more likely than others to get pregnant with more than one baby if:

  • You have fertility treatment. Fertility treatment is a special medical treatment to help women get pregnant. 
  • You’re in your 30s, especially your late 30s. If you’re 30 or older, you’re more likely than younger women to get pregnant with multiples because you may release more than one egg during a menstrual cycle (also called your period).
  • You have a family history of multiples. If you or other women in your family have had fraternal (non-identical twins), you may be more likely to have twins, too. You’re also more likely to have multiples if you’ve been pregnant before, especially if you’ve been pregnant with multiples.   
  • You’re obese. Obese means you have an excess amount of body fat. 
  • You’re black or Caucasian. Black women are more likely to have twins than other women. Caucasian women, especially those older than 35 years old, are most likely to have higher-order multiples. 

What causes you to get pregnant with multiples?

A multiple pregnancy usually happens when more than one egg is fertilized. But it also can happen when one egg is fertilized and then splits into two or more embryos. 

More women are pregnant with multiples now than in the past. This is mostly because more women are having babies later in life (you’re more likely to have multiples if you’re older than 30) and more women are using fertility treatment to get pregnant. 

What are identical and fraternal twins?

Identical twins happen when one fertilized egg splits into two. Identical twins look almost exactly alike and share the exact same genes. Fraternal twins happen when two separate eggs are fertilized by two separate sperm. Fraternal twins don’t share the exact same genes. They are no more alike than they are to any brothers and sisters from different pregnancies with the same mother and father.

More information

Centers for Disease Control and Prevention (CDC)

Last reviewed: June, 2015