A multiple pregnancy is when a woman is pregnant with 2 or more fetuses. Twins are the most common type of multiple pregnancy. So-called “higher-order” pregnancies (when a woman is carrying triplets, quadruplets, quintuplets, or more) are less common.

The risk for certain complications during and after pregnancy is higher in multiple pregnancies. To lessen these risks, your doctor will see you more often than a woman carrying 1 baby.

Twins in Utero
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Multiple pregnancies occur when a single fertilized egg divides and develops into 2 or more fetuses (identical twins) or when more than 1 egg is fertilized by a different sperm (fraternal twins). Triplets, quadruplets, and quintuplets can be identical, fraternal, or a combination of both.

Risk Factors

Multiple pregnancy is more common in women of African ancestry. It is also more common in women over 30.

Factors that may increase your changes of having a multiple pregnancy include:

  • Use of fertility treatments
  • A previous multiple pregnancy
  • A family history of multiple births
  • More than 1 previous pregnancy


Symptoms include the following:

  • More rapid weight gain than expected in the first trimester
  • Larger than expected uterus
  • Severe morning sickness
  • More fetal movement than with a singleton pregnancy


You will be asked about your symptoms and medical history. A physical exam will be done. Your doctor may refer you to a healthcare professional who has experience with multiple pregnancies.

Most multiple pregnancies are discovered during an ultrasound examination. An ultrasound examination is a test that uses sound waves to see how the fetus is developing.

Other tests that may detect a multiple pregnancy include:

  • A higher result on certain blood tests done near the 16th week of pregnancy
  • Hearing more than 1 heart beat during a routine examination


Multiple pregnancies have a greater risk for certain complications. If you experience any of these conditions, your doctor will discuss the best treatment plan for you.

Preterm Labor

Most multiple births are preterm (before the end of 37 weeks of pregnancy). Babies born preterm have a higher risk for many health problems. To delay preterm birth, your doctor may suggest bed rest at home or in a hospital or prescribe certain medications. If labor threatens to occur before 34 weeks of pregnancy, you may be given steroid medication to help your babies’ lungs mature.

Gestational Diabetes

Gestational diabetes is a disorder in which the body becomes less sensitive to insulin resulting in high blood sugar levels. Gestational diabetes treatment aims to return blood sugar levels to normal through diet, exercise, blood sugar level testing, and sometimes insulin shots.


Preeclampsia is a condition occurring during pregnancy when a woman has high blood pressure and more than normal amounts of protein in her urine. Treatment may include drugs, rest, and early delivery of the babies.

Abnormal Fetal Position (Breech or Transverse)

More than 1 fetus in the uterus increases the chance that 1 of them will be unable to turn head down. A breech or transverse presentation increases the chance of needing a cesarean delivery.

Twin Twin Transfusion Syndrome (TTTS)

Twins sometimes share vessels in the placenta. If this sharing is unequal, this syndrome can develop. In TTTS, 1 twin transfuses (donates blood) to the other. The donor twin becomes anemic and the receiving twin develops problems of having too much blood and fluid in the body.

Postpartum Hemorrhage

More than 1 fetus in the uterus increases the chance of postpartum hemorrhage. This is heavy blood loss in the mother after delivering the babies.


To help reduce your chance of having health problems during a multiple pregnancy, take the following steps:

  • Get early and regular prenatal care so your doctor can closely monitor your pregnancy.
  • Follow general pregnancy nutrition advice, including getting more calcium, folic acid, protein, and iron in your diet.
  • Gain the appropriate amount of weight, especially in the first 20-24 weeks of pregnancy.

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