When a woman becomes pregnant with more than one fetus, it is called multiple pregnancy (twins). Multiple pregnancy occurs in about 1.5 to 2% of all births in the United States. The frequency of multiple pregnancies is increasing as the success of infertility and in-vitro conception is increasing. The most common type of multiple pregnancy is twins, when the uterus contains two fetuses. Twins occur naturally in about 1 of every 90 births. Identical twins are the result of one fertilized egg or ovum dividing, whereas fraternal twins are the result of two separate and different fertilized eggs implanting in the uterus. Fraternal twins are more common than identical twins and occur most often in persons with a family history of twins, black women, and women with a greater number of children.


Early diagnosis of twins is essential in ensuring a healthy pregnancy. If your care provider suspects by your history or the size of your uterus that you may have a multiple pregnancy, he/she will order an ultrasound examination. Ultrasound examination will be able to verify the presence of more than one fetus.

Special Considerations

The risks of certain complications is higher in a multiple pregnancy, and they are more likely to occur in identical twins than fraternal. The greater the number of fetuses in a pregnancy, the greater the likelihood of complications. The most frequently encountered problem in multiple pregnancies is preterm labor and/or birth.

Preterm is considered birth prior to 37 weeks of completed pregnancy. This may cause problems because the organ systems, such as lungs, are often not ready to support life without the help of technical intervention provided by a Neonatal Intensive Care Unit. Preterm labor can be treated and stopped in many instances if diagnosed and treated early.

Pre-eclampsia is a condition in which the mother’s blood pressure increases during pregnancy. This condition is also more frequently encountered in multiple pregnancies. Your care providers will be careful monitoring your babies growth.

Once it is established that you have a multiple pregnancy, your care provider will schedule more frequent prenatal visits (starting in the late second trimester).The care provider will be able to monitor your babies growth,your blood pressure, and other parameters to ensure a healthy pregnancy. Ultrasounds will be ordered more often during your pregnancy, to monitor each baby’s growth. Your care provider may also have you visit a nutritionist/dietician to help you plan your diet since multiple pregnancies require more calories and nutrients per day. Changes in activities and exercises may be needed and are determined on an individual basis as by your physician.

Growth restriction may also occur in multiple gestations. This occurs when the fetus does not grow at the expected rate.

Labor and Delivery

Delivery of a multiple pregnancy often happens at less than 40 weeks. The labor can spontaneously begin at less than 40 weeks or your physician may elect to induce your labor due to medical necessity (pre-eclampsia, etc.) or to control the environment (have all the necessary personnel available) since birth of more than one baby takes more nurses and equipment at the birth.

The method of delivery for your babies will depend on many factors that will need to be dicussed with your doctor toward the last trimester of your pregnancy. Factors that will be taken into account include the positions, the number of fetuses, how many weeks they are at delivery and the health and safety of the mother.

Multiple pregnancies are exciting and challenging not only for the parents, but also for the care providers. Many of the complications encountered in these pregnancies can be avoided and successfully treated if all the people involved work together in a team effort.

Resources for multiple birth patients


  • Having twins by Elizabeth Noble, 1991.
  • The Joy of Twins by Pamela Patrick, 1988.
  • Mothering Twins by Linda Albi, 1993.
  • The Long Awaited Stork, A Guide to Parenting after infertility by Glazer, 1990.
  • Parenting Your Premature Baby by Janine Mason, M.D. 1989.
  • Your Premature Baby by Frank Manginello, M.D. 1991.
  • What to Expect When Your Expecting by Eisenberg, Murkoff & Hathaway 1986.
  • Coping with Bedrest by Jaime Bolane.
  • Bedrest before Baby by Patricia Leanock.
  • All about Twins by Dr. Liegh, 1983.
  • Care of Twin Children: A Common Sense Guide for Parents by R. Thoreoux, 1984.
  • Make Room for Twins by Terry Pink, 1987.
  • A Parents Guide to Raising Twins by E. Friedrich, 1983.
  • The Psychology of Twins by H. Collier, 1974.
  • The Twin Book by Honor Walters, 1983.
  • The Twins Sourcebook by Twins magazine.
  • Multiple Pregnancy Source Book by Nancy Bowers.
  • When Your Expecting Twins, Triplets and More by Barbara Luke.


TWINS 1-800-821-5533
M.O.M.S. 1-800-MOM-SMAG


La Leche League: call & visit a support group before you deliver.
Call lactation support services at NSMC 303-457-6757.


Twin Services P.O. Box 10066, Berkeley , CA. 94709.
International Twin Association, Inc. 6898 Channel Rd. Minneapolis, MN. 55432
The National Organization of Mothers of Twins Clubs, Inc. P.O. Box 23188 Alburguerque, NM 87192-1188

INTERNET: Multiple sites available- search twin babies, multiple birth, identical twins and parenting twins.