Multiple pregnancy

Visiting the Clinic

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Each stage of your pregnancy will bring new, exciting and potentially confusing elements into your life. We’re here to help you at each step. 

Your obstetric care provider has referred you to our specialized clinic due to the nature of your pregnancy.

Not all expectant mothers carrying twins are referred to us. Some unique risks arise only in certain multiple pregnancies, depending on how they were conceived, i.e. by fertilization of just one egg (monozygotic twins) or two (dizygotic twins) or three, as in the case of triplets. This distinction occurs right at conception, long before pregnancy is detected, and is not under anyone’s control. Even doctors cannot determine what kind of twins you are carrying until the first ultrasound in the first trimester. The majority of twins we care for arise from just one fertilized egg.

One of our primary care objectives is to screen throughout pregnancy for any unique twin conditions that can arise in this type of multiple pregnancy. We also care for twins arising from fertilization of two separate eggs, dizygotic twins if there are any maternal or fetal problems. Finally, we also care for all multiple pregnancies with three or more babies expected.

Your first visit

When you are referred to us, your doctor sends some information about your pregnancy to our Nurse Coordinator, including your Ontario Antenatal Record, which chronicles information regarding pregnancy dating (last period, any previous ultrasounds, your medical, surgical and family history) and results of your routine screening bloodwork. Once your information is reviewed with a physician, we schedule you for an appointment at the Multiples Clinic on a Wednesday. 

On the day of your visit, you will usually have an ultrasound just prior to your appointment. This serves to provide the physician with up-to-date information on the size and general health of your babies before meeting with you.  

When you arrive, a nurse will go over your history, and enquire about general questions you might have. The nurse is a tremendous teaching resource and can provide a lot of valuable information about pregnancy. She will conduct a preliminary assessment of your blood pressure and weight and test your urine. 

In the examination room, you will be seen by a resident.  Residents are on the journey to become doctors, specialists or sub-specialists. The resident will identify themselves and their level of training. A resident’s job is to learn about multiple pregnancy from you, and residents highly value their interaction with our patients.  

As with all of our care providers, they will treat you with respect and confidentiality. They will communicate any concerns you raise to the attending physician, who will then come to see you. 

Your first visit with us is likely to be the longest, to ensure that we take the time to address your concerns and counsel you appropriately. Our job is to ensure you are well informed and have a good sense of what to expect in terms of the frequency and nature of clinic visits, ultrasounds and decision points.

First trimester

Generally, it is preferable for us to see multiple pregnancies in the first trimester. This is the best time to date the pregnancy, determine the type of multiple pregnancy, and screen for relatively common genetic conditions.  

All pregnant women in Ontario are offered first-trimester screening for aneuploidy, genetic conditions affecting chromosome number such as Down syndrome (Trisomy 21) and Trisomy 18 (Edward’s syndrome). The test includes two serum markers (a maternal blood test) and ultrasound measurement of nuchal translucency (NT), which can be done as early as 11 weeks of gestation. This screening test is also available for twin pregnancies, for which the results are a little more challenging to interpret.

The result determines risk for the whole pregnancy. Specifically, for monochorionic twins, it is the risk that both twins are affected. For dichorionic twins, it is the risk that one or both twins are affected. Learn more about FTS screening in Ontario, or discuss it with your physician. 

Non-invasive prenatal testing is a screening test for certain chromosomal abnormalities. It assesses the presence of circulating fetal DNA not attached to any cell (cell-free DNA) in maternal blood. While it can be performed for twin pregnancies, results are harder to analyze. For example, in twin pregnancy, if the NIPT suggests possible Down Syndrome, it can be difficult to know which fetus is affected. Therefore, further discussion with your physician would be indicated and we could suggest invasive testing (i.e. amniocentesis). If results are normal, this is very reassuring to future parents. NIPT cannot be performed for triplets or higher order multiples.

Second trimester

During the second trimester, your doctor will order a routine ultrasound to assess the structure of your babies between 18 and 22-weeks’ gestation, which is standard for all pregnancies. The sonographer performing the scan obtains multiple images to screen for major structural differences in the anatomy of your babies. This is a lengthy exam when more than one fetus needs to be examined.  

Often in multiple pregnancies, all views of all structures cannot be obtained during a single visit and you may be asked to return. This does not mean there is any problem with the structure of your baby or babies. Most likely, it’s simply that the position or crowding of your babies at the moment made it impossible to obtain all required views. 

If you are expecting monochorionic twins, you will be booked for a more detailed review of fetal anatomy, a Level II ultrasound examination. The sonographer will obtain additional views of the heart of each baby and measure all their long bones. This exam is required because structural differences are much more likely to occur when multiples arise from the splitting of one fertilized egg. In addition, ultrasound is key to screen for special twin conditions that can develop in monochorionic twins. The sonographer will be looking closely for any signs of these conditions starting as early as 16 weeks.

With multiple pregnancies, you can expect more frequent ultrasound visits than for a singleton.

Generally, for uncomplicated dichorionic twins, once normal structure has been confirmed, ultrasound exams are done every four weeks during the second trimester to assess fetus growth. In uncomplicated monochorionic twins, the fetuses are surveyed with ultrasound every two weeks for growth and screening for special twin conditions. For both types of twins, your doctor may also ask to assess your cervical length by transvaginal ultrasound to look for warning signs of impending preterm birth. 

The second trimester is also when all pregnant women are offered screening for gestational diabetes. This is usually done between week 24 and 28. This first involves a trip to the lab where you will be offered a 50-gm sweet glucose drink. You will have a blood test one hour later to assess your blood sugar. You do not have to fast (stop eating) for this test.

Should the glucose test be positive (blood sugar 7.8 or higher), we will offer you a confirmatory diagnostic test called a glucose tolerance test. This is a two-hour test where we measure your fasting glucose. You drink a sweet glucose liquid, and then we take your blood one and two hours later. If your results are abnormal, we will refer you to receive teaching about diabetes and to consult with diabetic specialists to help you manage your blood sugar. This may involve following a special diet, frequent monitoring of your blood sugar by finger pricks or taking insulin if your blood sugar cannot be controlled by diet alone.

Third trimester

The third trimester is a time of rapid growth and development of your babies and a rise in the risk of maternal conditions, such as hypertension or diabetes.  

Generally, the frequency of your clinical assessments and ultrasound surveillance also increases in the last trimester, and later in the pregnancy your doctor may request weekly or biweekly visits.  

The third trimester is also when fetuses have a good chance of surviving if born prematurely. You will perceive active fetal movements daily, which is an important sign that your babies are doing well. Your doctor will discuss how important it is for you to be aware of fetal movement.  

You must report any perceived change from normal movement to your doctor, as it means you need further fetal testing. 

At approximately 36 weeks, your doctor will request a rectovaginal swab for Group B Streptococcus, which you can do yourself. This is a pathogen that a baby can acquire during its transit through the birth canal. Premature babies are more susceptible to this organism, which can lead to pneumonia or meningitis.

If the swab is positive and you are planning a vaginal delivery, you will be offered antibiotic during labour to decrease the risk that your babies become infected. 

Your doctor will begin planning your delivery with you and will explain special considerations for delivery of multiple babies.