Multiple Births and LBW


Preterm and Low Birth Weight and Multiple Births: An Information Guide for Parents

What is a multiple birth pregnancy?

A multiple birth pregnancy is when a woman is pregnant with twins, triplets or more. The terms "at risk" or "high risk" may be used to describe multiple birth pregnancies. This does not necessarily mean that the mother or babies will have problems but they will be closely watched as the pregnancy continues. Women expecting twins or more will require special health care during their pregnancy to prevent or manage any problems. Potential risks increase with each additional baby within the multiple birth pregnancy.

Did You Know...

  • 3% of births in Canada are multiples?
  • Over 55% of multiple births are low birth-weight? (A baby born with low birth weight weighs less than 2,500 grams (5-1/2 pounds)
  • The average length of a multiple pregnancy is:
    • 36 weeks for twins
    • 33 weeks for triplets
    • 31 weeks for quadruplets


What are the increased risks of a multiple birth pregnancy?

For the mother:

  • Extreme nausea and vomiting (can cause dehydration)
  • Pregnancy Induced Hypertension (PIH) (high blood pressure in pregnant mothers)
  • Diabetes during pregnancy (gestational diabetes)

For the babies:

  • Low birth weight
  • The average weight for each multiple birth baby is:
    • Twins = 2,500 grams (5-l/2 pounds)
    • Triplets = 1,800 grams (4 pounds)
    • Quadruplets = 1,400 grams (3 pounds
  • One baby doesn't grow as well as the other(s)
  • Being born too soon (preterm birth)
  • Twin-to-twin transfusion syndrome (TTTS)*. See the definition at the end of this article.

Why can preterm birth and/or low birth weight be a problem?

  • Babies born a couple of weeks early usually have few, if any, long term health problems; however, they may require specialized newborn care.
  • Babies born very early (preterm) need a lot of medical and nursing care in the early weeks or months of their lives.
  • A few of these babies may have lasting problems or disabilities.
  • Not all cases of preterm and low birth weight can be prevented.

What can a woman pregnant with twins, triplets or more do to help reduce the risks of preterm birth?

Early Prenatal Care

  • Find out as soon as possible if you are expecting more than one baby.
  • It is recommended for women expecting multiples to be seen by an obstetrician (a doctor who specializes in delivering babies).
  • A maternal-fetal specialist (called a perinatologist) will provide care to women expecting triplets and more and/or when there are health concerns for women expecting twins.
  • Find out, through testing, if the babies are dizygotic (fraternal) or monozygotic (identical).
  • Some monozygotic twins have a greater chance of having additional health risks such as twin-to-twin transfusion syndrome (TTTS).
  • TTTS can also occur within monozygotic babies in a triplet or more pregnancy.
  • Women expecting multiples may have contact with many different types of health providers such as physicians, registered nurses, midwives, ultrasound technicians, laboratory technicians, nutritionists/dieticians, physiotherapists, and childbirth educators to name a few.

Healthy Eating

  • Women expecting two or more babies need to eat more and have a higher weight gain than a woman expecting one baby.
  • Research tells us that weight gain in the first 28 weeks is important for the babies' health. A rough weight gain guide for a twin pregnancy is:
    • 9 kilograms (20 pounds) by 20 weeks
    • 14 kilograms (30 pounds) by 28 weeks, and
    • 18 kilograms (40 pounds) by 36-38 weeks.
    • For triplets or more, weight gain should be even higher.
  • Discuss weight gain with your doctor at each prenatal visit.

Staying Healthy

  • Make and keep regular appointments with your doctor.
  • Become informed about multiple birth pregnancy and what to expect.
  • Multiple Birth Canada's site at contains a lot of information. They can provide you with contact information for your local multiple birth support chapter.
  • Expect extra appointments for ultrasounds, lab work, and visits with obstetricians and perinatologists.
  • Attend multiple birth prenatal classes if they are locally available.
  • If you are a smoker, try to stop or reduce smoking.
  • Stay away from people who smoke (second hand smoke). Second hand smoke is harmful for mother or babies.
  • Try to reduce stress in your life.


  • Rest when tired. Take time to sit and relax. Cleaning the house can wait.
  • Try to get some extra child care help for other children.
  • It isn't unusual to be put on bedrest or reduced activity for some part of a multiple birth pregnancy.
  • While resting, avoid lying on your back. Lay on your left side to increase the blood flow to heart, womb and babies.

What other information do pregnant mothers of multiples need to know about the birth?
It is important to know the warning signs of preterm labour.
Report these signs to your doctor immediately.
It may be possible to delay preterm labour by a few days or more if it'is detected early.


Warning Signs of Early Labour

  • Increased pelvic pressure (like the babies are pushing down)
  • Feeling of fullness or heaviness
  • Pain or pressure in the lower back or a change in the type of lower backache
  • Loss of fluid from the vagina, either as a sudden 'gush' or a slow 'leak'
  • Bleeding from the vagina
  • Thick mucous discharge from the vagina. This can be normal in pregnancy but may be a symptom of an opening birth canal (cervix). Tell your doctor immediately if this is happening.
  • Cramps (such as when you are having your period), or stomach pains with or without diarrhea
  • Contractions
  • Some women can just feel 'different'.
  • Women carrying triplets or more may go through silent labour, which is painless and free of cramping or contractions.
  • Fever, chills, dizziness, vomiting, bad headache, sudden or severe swelling of feet, hands or face. These are also signs of pregnancy induced hypertension (PIH). If this is happening, tell your doctor immediately.
  • Each additional day the babies can spend inside the mother's womb increases their chances of survival. The lungs are the last organs to mature before the babies are born. Lung maturity can be improved by giving a steroid injection to the mother prior to delivery.
  • If you are having triplets or more, expect to deliver the babies in a hospital that can care for several premature newborns all at once.
  • A caesarean section is often needed for twin pregnancies and is expected for delivery of triplets or more.

If you think there might be a problem or you are not sure of what is happening, go directly to the hospital, preferably to the hospital where you had planned to give birth or call 911.

If you are a husband/partner:

  • Share this information with your wife/partner.
  • Work together as a team.
  • Attend doctors' appointments and ultrasounds with your wife/partner
  • Try to take over most of the housework (especially heavy tasks), grocery shopping, laundry, vacuuming or arrange for someone to do it.
  • If there are other children, help with the childrearing.
  • Encourage your wife/partner to rest and eat healthy foods.
  • Learn about preterm labour.
  • Learn more about multiple pregnancy and birth.
  • Do not smoke around your wife/partner. Second hand smoke hurts both the mother and the babies.

If you think there might be a problem with the pregnancy or are not sure of what is happening to your wife/partner, go directly to the hospital, preferably to the one where you had planned to give birth, or call 911.


If you are a friend or colleague:

  • Share this information with the expectant mother and father.
  • Offer to help with housework, grocery shopping, cooking a meal or laundry.
  • Let the family know you want to help.
  • Offer to take care of the other children.
  • Do not smoke around a pregnant woman. Second hand smoke hurts both the mother and the babies.

*Twin-to-Twin-Transfusion Syndrome (TTTS) - a condition in which blood from one monozygotic twin fetus transfuses into the other fetus via blood vessels in the placenta. It can also occur between monozygotic multiples in a triplet or more pregnancy.

For more information about multiple births contact:
Multiple Births/Naissances multiples Canada
Toll-Free (in Canada): 1-866-228-8824
Telephone: 705-429-0901; Fax: 705-429-9809 Email:

Multiple Birth: Prenatal Education & Bereavement Support -

For more information about preterm birth and low birth weight: Talk to your health care provider.


Low birth weight means being born at less than 4 lbs.
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© 2019 Ottawa Coalition for the Prevention of Low Birth Weight
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