What is a multiple pregnancy?

A multiple pregnancy is a pregnancy with two or more babies. In some multiple pregnancies, the babies develop from different eggs (fraternal); in others, they develop from the same egg (identical). When the babies are fraternal, each has a separate placenta (whose fetal part is called the chorion) and separate amniotic sacs. These are known as dichorionic-diamniotic twins. The babies may be boys, girls, or a combination of both. Like siblings born from different pregnancies, these babies may (or may not) look very similar to each other. Depending on when the fertilized egg splits, identical twins may also be dichorionic-diamniotic. Usually, however, the babies share a placenta and have separate sacs. These are known as monochorionic-diamniotic twins. About 75 percent of all identical twins fall into this category. In rare cases, identical babies share both a single placenta and a single amniotic sac. These are known as monochorionic-monoamniotic twins. Because all identical babies share the same genetic material, they will be of the same gender and look alike, although they will have different personalities.

If you are pregnant with more than one baby, you are more likely to have health complications. When the pregnancy involves identical babies, the health risks for the babies increase as well. For this reason, you’ll be seeing your doctor more often during the pregnancy and may need extra medical care during labor and delivery. In the United States, 32 of every 1,000 births involve twins, and 93 out of every 100,000 births involve “higher order” multiples—pregnancies with triplets or more. We’ll be focusing on twin pregnancies here, but the information applies to higher-order pregnancies as well.

Who will be on my care team?

At the Midwest Fetal Care Center, a collaboration between Children’s Minnesota and Allina Health, we specialize in individual attention that starts with you having your own personal care coordinator to help you navigate your babies’ treatment process. We use a comprehensive team approach to multiple pregnancies and any associated conditions. That way, you are assured of getting the best possible information by some of the most experienced physicians in the country. For a multiple pregnancy, your care team will include a maternal-fetal specialist, a pediatric cardiologist, a neonatologist, a geneticist, a nurse specialist care coordinator, a fetal care clinical social worker, and several other technical specialists. This entire team will follow you and your babies closely through the evaluation process, and will be responsible for designing and carrying out your complete care plan.


Meet the team

What causes multiple pregnancy?

Multiple pregnancies involving identical babies appear to occur by chance. If, for example, you come from a family with identical twins, you are not more likely to have identical twins yourself. You are, however, more likely to give birth to identical twins if your pregnancy involved an assisted reproductive technology, such as in vitro fertilization. Several factors raise the odds of having fraternal (non-identical) twins. All these factors increase the likelihood that a woman will release (ovulate) two or more eggs at the same time. If more than one of those eggs become fertilized, then a fraternal multiple pregnancy may occur. Here are those factors:


  • The mother’s family has a history of fraternal twins. Some families have certain genetic variations that make it more likely that women will ovulate more than one egg per menstrual cycle.
  • The mother is over the age of 35. The chances of releasing two or more eggs during a single menstrual cycle increases with age.
  • Fertility drugs were used for pregnancy. These drugs often cause more than one egg to be released at the same time.
  • The pregnancy occurred using in vitro fertilization. The procedure may have involved more than one embryo being implanted in the uterus.

How is multiple pregnancy diagnosed?

The main way to confirm a multiple pregnancy is by ultrasound. This confirmation can be made during the first trimester of the pregnancy—as early as six weeks of gestation. Early ultrasound examinations are routinely performed during pregnancy as they are the most accurate way to date a pregnancy. Tests taken of the mother’s blood can sometimes suggest the presence of more than one baby. One of these tests, which can be done quite early in pregnancy, is able to identify exceptionally high levels of human chorionic gonadotropin (HCG), a hormone produced by the cells around an embryo. When there is more than one embryo, levels of this hormone become very elevated in the mother’s blood. This early blood check is usually done, however, only with women who are undergoing fertility treatment. The results of another maternal blood test, which is done routinely during the 15th to 20th week of pregnancy to identify the possibility of certain birth defects, may also suggest a multiple pregnancy. This test looks for high levels in the mother’s blood of alpha-fetoprotein, a protein released by the developing baby’s liver. The presence of two (or more) babies results in more of the protein being released. If you have not already had an ultrasound, your doctor will schedule one if blood tests suggest the presence of more than one baby.

How is a multiple pregnancy managed before birth?

Women who are carrying two or more babies are monitored by their doctor more frequently during pregnancy because of an increased risk of complications.

One of the most significant risks for the babies is an early (premature) birth. Six in 10 twins and almost all higher-order multiples are born prematurely (before 37 weeks of gestation). Babies born prematurely are at greater risk than full-term babies of having long-term health problems and may also require hospital care. If the babies are monochorionic (sharing the same placenta), they are also at increased risk of sharing abnormalities like twin-to-twin transfusion syndrome (TTTS), a potentially life-threatening condition in which blood flows unevenly between the babies while they are in the womb. A multiple pregnancy also raises health risks for the mother, including anemia (low levels of red blood cells), preeclampsia (a high blood pressure disorder), gestational diabetes (high blood sugar levels), and postpartum hemorrhage (abnormal blood loss after giving birth). Your pregnancy care will be determined by the type of multiple pregnancy you have (dichorionic-diamniotic, monochorionic-diamniotic, or monochorionic-monoamniotic), the number of babies you are carrying, your overall health, your medical history, and your expectations for your pregnancy and delivery. This care will include more frequent prenatal visits and, starting in the second trimester, more frequent ultrasounds—every two to four weeks, depending on the type of multiple pregnancy. You will also be referred to a maternal-fetal specialist, who may recommend special testing and who will coordinate your medical care for possible complications. In addition, you’ll receive special nutritional counseling. Women who are carrying more than one baby need extra calories, protein, and other nutrients. If TTTS has been diagnosed, a prenatal laser surgery procedure may be recommended to ensure a healthy flow of blood to both of the babies.


How is a multiple pregnancy treated after birth?

Our goal will be to have your babies delivered as close to your due date as possible. Because the placenta in twin pregnancies is under added stress, dichorionic twins are usually delivered by 38 weeks gestation and monochorionic twins by 37 weeks gestation. With twins, a vaginal delivery may be feasible, depending on the position, weight, and health of your babies. Triplets and other higher-order multiples are usually born by cesarean section. Because twins and higher-order babies are more likely to be born prematurely and require special care after birth, we may recommend that your babies be delivered at one of our specialized mother-baby centers. Children’s Minnesota is one of only a few centers nationwide with the birth center located within the hospital complex. This means that your babies will be born just a few feet down the hall from our newborn intensive care unit (NICU). If necessary, many of the physicians you have already met may be present during or immediately after your babies’ birth so we can care for them right away.


What is the long-term prognosis for my babies?

The long-term prognosis for twins and higher-order multiples is excellent, but it is heavily dependent on the babies’ gestational age at birth.


Will my babies need long-term follow-up care?

Your babies will not need any long-term follow-up care, although such care may be required for other conditions associated with premature birth.


Contact us

Need a referral or more information? You or your provider can reach the Midwest Fetal Care Center at 855-693-3815.