Potential Complication: IUGR with Twins

Intrauterine growth restriction (IUGR) is a condition in which one or both twins don't grow well. A baby with IUGR is much, much smaller than other babies of the same gestational age.

IUGR affects up to 25% of twin pregnancies. If severe, it can pose big risks to twins. Fortunately, with regular prenatal checkups, your doctor can spot this problem if it occurs and you can take steps to reduce the impact on your twins. You can't always prevent IUGR. But a healthy lifestyle will go a long way toward reducing your risks.

How Can It Affect My Babies and Me?

Mild growth restriction may not cause any health problems. But if severe, IUGR can seriously harm twins before and after birth. The extent of the health problems depends upon the cause and severity of the growth restriction. It also depends upon how far along you are in the pregnancy when it develops.

With IUGR, twins are more likely to have:

  • Trouble handling the stress of vaginal delivery
  • A premature birth and low birth weight
  • A cesarean delivery
  • Meconium aspiration, a condition in which a baby inhales meconium (baby's first stool in the womb)
  • Low blood sugar
  • Less resistance to infection
  • Poor control of body temperature after birth
  • Long-term developmental and physical disabilities problems

Although rare, some babies with severe IUGR die before delivery.

Who Is at Risk for IUGR?

Because you are carrying twins, it is likely your babies will be smaller than usual. In fact, being pregnant with more than one baby is a risk factor for IUGR.

Other twin risks. Twins who share a placenta may also:

  • Have unequal distribution of blood and nutrients between them. As a result, one twin may be much smaller. This is called selective intrauterine growth restriction.
  • Also share blood vessels. They may develop a serious condition called twin-twin transfusion syndrome ( TTTS ). When this happens, there is an unequal exchange of blood between the twins, putting them both at risk.
  • Share the same amniotic sac. Then the umbilical cords may become tangled, restricting blood flow to one or both twins.

Other risk factors. Other factors that may influence babies' growth include:


Screening for IUGR

Your doctor will check the size and health of your twins with an ultrasound exam. This exam allows your doctor to:

  • See your babies inside your uterus
  • Measure your babies' body parts
  • See if your twins share a placenta

With Doppler studies, it is possible to check blood flow through the umbilical cord.

If the Diagnosis Is IUGR

If your twins have IUGR, you will undergo more exams to monitor their health. You may have weekly ultrasound exams to check:

  • Your twins' movement and breathing
  • Placental blood flow
  • Amount of amniotic fluid

You may also need:

  • Non- stress testing to evaluate the twins' heartbeats and well being
  • Doppler flow studies to test blood flow through the umbilical cord and in the vessels of the babies' brains
  • Amniocentesis (amnio) to check for infection or chromosomal abnormalities
  • Blood tests to check for infections or other health problems

You can help monitor the health of your babies by paying close attention to your twins' movement. If you feel them moving around a lot, they are probably doing fine.

However, tell your doctor right away if:

  • You notice a lack of movement
  • Your babies become less active than normal

If your doctor decides that your twins have stopped growing or their lives are at risk, you may need to deliver them early. The twins will need to stay in the hospital until they can breathe and feed normally, and are able to regulate their body temperature.

If you develop TTTS, the condition may resolve on its own. If it becomes severe, though, your doctor may recommend intrauterine surgery.

WebMD Medical Reference Reviewed by Nivin Todd, MD on January 13, 2019



The American College of Obstetricians and Gynecologists: "Having Twins."

The Institute for Maternal Fetal Health: "SIUGR."

The Society of Fetal-Maternal Medicine: "High-Risk Pregnancy Care, Research, and Education for Over 35 Years."

American Academy of Family Physicians: "Intrauterine Growth Restriction" and "Intrauterine Growth Retardation."

Children's Hospital of Pittsburgh of UPMC: "Intrauterine Growth Restriction (IUGR)."

Interview with Laura E. Riley, MD, Medical Director Labor and Delivery, Massachusetts General Hospital, author of You and Your Baby: Pregnancy , member of the communications committee for Society of Maternal and Fetal Medicine.

© 2019 WebMD, LLC. All rights reserved.


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