Being pregnant with twins, triplets and other multiples

KEY POINTS

  • If you’re pregnant with multiples, you and your babies are more likely to have health complications than if you’re pregnant with one baby.

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

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

What causes you to get pregnant with multiples?

A multiple pregnancy (being pregnant with multiples) means you’re pregnant with more than one baby. If you’re pregnant with higher-order multiples, it means you’re pregnant with three or more babies. 

Multiple pregnancy usually happens when more than one egg is fertilized by a man’s sperm. But it also can happen when one egg is fertilized and then splits into two or more embryos that grow into two or more babies. 

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

Most babies are singleton babies. This means you’re pregnant with just one baby. But more women are getting pregnant with multiples now than in the past. This is mostly because more women are having babies later in life, and you’re more likely to have multiples if you’re older than 30. Also, more women are using fertility treatment to get pregnant. Fertility treatment is medical treatment to help women get pregnant.

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 health care provider hears more than one heartbeat or finds that your uterus (womb) is larger than usual. The uterus is the place inside you where your baby grows. 
  • You have high levels of a hormone called human chorionic gonadotrophin (also called hCG) or a protein called alpha-fetoprotein in your blood. HCG is a hormone your body makes during pregnancy. Alpha-fetoprotein is a protein that a developing baby makes during pregnancy. 

Your 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?

If you’re pregnant with multiples, you may need extra medical care during pregnancy, labor and birth. You may need to go to extra prenatal care checkups so your provider can watch you and your babies for problems. 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 a doctor with education and training to take care of women who have high-risk pregnancies. High-risk means you’re more likely than most pregnant women to have problems with your pregnancy. If you’re referred to this kind of doctor, it doesn’t mean you’ll have problems during pregnancy. It just means he can check you and your babies closely to help prevent or treat any conditions that may happen.  

How can a multiple pregnancy affect your health?

If you’re pregnant with multiples, you’re more likely than if you were pregnant with one baby to have complications, including:

  • Preterm labor. This is labor that happens too early, before 37 weeks of pregnancy. Preterm labor can lead to premature birth (birth before 37 weeks of pregnancy).
  • 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. A condition called iron-deficiency anemia is common in multiple pregnancies and can increase your chances of premature birth. 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 only pregnant women can get. If untreated, it can cause serious health problems for you and your babies. Diabetes is when you have too much sugar (called blood sugar or glucose) in your blood.
  • Gestational hypertension or preeclampsia. These are types of high blood pressure that only pregnant women can get. High blood pressure is when the force of blood against the walls of your blood vessels is too high. It can cause problems during pregnancy. Preeclampsia is a condition that can happen after the 20th week of pregnancy or right after pregnancy. It’s when a pregnant woman has high blood pressure and signs that some of her organs, like her kidneys and liver, may not be working properly.
  • 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 or 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 who are 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. 

If you’re having multiples, you’re more likely to have these complications after giving birth: 

  • 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 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: 

  • Premature birth. Premature babies (born before 37 weeks of pregnancy) may have more health problems or need to stay in the hospital longer than babies born later. Some may spend time in a hospital’s newborn intensive care unit (also called NICU). This is the part of a hospital that takes care of sick babies. Premature babies 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. 
  • Birth defects. 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. Multiples are about twice as likely as singleton babies to have birth defects, including neural tube defects (like spina bifida), cerebral palsy, congenital heart defects and birth defects that affect the digestive system. The digestive system helps your baby’s body process food.  
  • 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 your baby is born weighing less than 5 pounds, 8 ounces. Babies with LBW are more likely than babies born at a normal weight to have certain health problems, like retinopathy of prematurity. They’re also more likely to have 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.

Are you more likely than other women to get pregnant with multiples?

You may be more likely than other women to get pregnant with more than one baby if:

  • You have fertility treatment. If you’re having fertility treatment, it’s important to try to get pregnant with just one baby. For example, if you’re having a treatment called in vitro fertilization (also called IVF), you can have just one embryo placed in your uterus. This is called single embryo transfer (also called SET). In IVF, an egg and sperm are combined in a lab to create an embryo (fertilized egg) which is then put into your uterus. If you’re having any kind of fertility treatment, talk to your provider about ways to help lower your chances of getting pregnant with multiples. 
  • You’re in your 30s, especially your late 30s. If you’re 30 or older, you’re more likely than younger women to release more than one egg during a menstrual cycle (also called your period).
  • You have a family history of multiples. Family history is a record of health conditions and treatments that you, your partner and everyone in your families has had. If you or other women in your family have had fraternal 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. If you're obese, you have an excess amount of body fat and your body mass index (also called BMI) is 30 or higher. To find out your BMI, go to cdc.gov/bmi.
  • 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. 

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 need a c-section if neither baby is in the head-down position or if you have other complications. You may be able to have a vaginal birth if:

  • Both babies are in the head-down position and you have no other complications
  • The lower twin is in the head-down position but the higher twin isn’t. 

Vaginal birth is the way most babies are born. During vaginal birth, the uterus (womb) contracts to help push the baby out through the vagina.

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

No. But you do need more of certain nutrients, like folic acid, protein, iron and calcium. You can get the right amount 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?

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 weight before pregnancy and how many babies you have. Talk to your provider about how much weight to gain.  

Here’s what you should know about gaining weight 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 physical activity if you’re pregnant with multiples?

Talk to your provider about what kind of activities are safe for you to do. You may need to cut out any high-impact activities, like aerobics or jogging, that make you jump or put stress on your joints. But you may be able to do some activities, like swimming, prenatal yoga or walking. 

You may need to limit physical activity later in pregnancy, including travel and 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.  

More information

Last reviewed: March, 2017