First Trimester

Bleeding & Cramping


Bleeding in Pregnancy


What are the possible causes of bleeding or spotting?



  • Cervical friability (i.e. cervix that bleeds easily for benign reasons)

  • Growth spurt (common around 12 weeks, again around 20 weeks–often with cramping) Irritation or trauma, especially if infection, cervical cyst or polyp present

  • Hemorrhoids

  • Unknown causes



  • Implantation spotting (i.e. as the fertilized egg attaches itself to the uterus it may cause some irritation and bleeding)

  • Ectopic pregnancy (i.e. the embryo is growing outside the uterus)

  • Subchorionic hematoma

  • Miscarriage



  • Placenta Previa

  • Abruption

  • Cervical dilation

  • Early labor 

  • “show” (a sign of cervical dilation starting to happen)


When should I worry about miscarriage?


Obviously miscarriage is what everyone worries about whenever they see spotting.



One in three pregnant people experience spotting or bleeding in pregnancy. Only 50% of these go on to have miscarriages, the majority in the first trimester. While 40% of pregnancies end up in miscarriage, most of these are before 4 weeks of pregnancy (i.e. 2 weeks post conception, when you would miss your period). After 4 weeks, the miscarriage rate goes down to 15%. In addition, once your baby’s heartbeat has been heard, the chance of miscarriage goes down to 5%. Part of the reason that so many pregnant people experience spotting is that there is a tremendous increase in blood volume, which means that capillaries in the cervix are easily disturbed causing bleeding. This is the equivalent of having your gums bleed after brushing or starting a nosebleed by blowing your nose – both things that many pregnant people also experience for the same reason. An average non-pregnant person has about 4 litres of blood. The same people when pregnant will increase their blood volume to over 6 litres! With this large increase, some of it may “leak” out sometimes.



Miscarriage cannot be predicted, only diagnosed. If you are having signs of a threatened miscarriage, your midwife may be able to send you for some testing:


  • Ultrasound will be able to determine if the embryo is implanted inside the uterus, and once you are past 6-7 weeks, if there is a heartbeat.

  • Early in the first trimester, bloodwork that is repeated every 48 hours will be able to demonstrate whether your pregnancy hormones are increasing at an expected rate.

  • If you are beyond 10-12 weeks gestation, your midwife may be able to find your baby’s heartbeat in the clinic with a Doppler.


In any case, by the time the bloodwork results are returned or an ultrasound appointment can be made, the situation will often have made itself obvious (i.e. either the bleeding stops, or becomes heavier and clearly a miscarriage). 


What can I expect if I do have a miscarriage?


What to expect depends on how far along you are, and how the miscarriage is diagnosed. Generally, the later your gestation is, the more physically intense the experience. Typically, the first sign may be spotting that progresses from brown to red over a few hours or days, then has a few hours of very intense cramping and heavy bleeding, subsiding into regular bleeding like a normal period. You may pass some clots or tissue. Or the (impending) miscarriage may be diagnosed during an ultrasound. If this is the case, you have two options:



i.e. waiting for your body to complete the miscarriage on its own. Sometimes this happens immediately. Sometimes it takes days to weeks.



i.e. inducing the miscarriage. A medically-induced miscarriage may include using medication to cause the uterus to contract and expel its contents.



i.e. a D+C This means dilating your cervix and evacuating the uterus with instruments, under either local or general anesthetic. This latter procedure is occasionally necessary when miscarriages don’t complete on their own.


What if I am past the first trimester?

Once you are past the first trimester, it is unlikely you are losing the pregnancy. As in the first trimester, most causes of second and third trimester bleeding are benign, but at the same time should still be monitored.



Genetic Screening


Genetic screening involves family history, demographic data (such as age), and often also includes testing to identify risk of conditions that may affect the baby.


Some conditions run in families, such as cystic fibrosis, thalassemia, sickle cell and others may relate to processes that occur during a particular pregnancy (trisomy 21, 18, 13), others may be a particular birth defect that runs in the family, e.g. heart defects, cleft palate.


As part of prenatal care, obtaining a full history is important and any conditions or situations that may have a genetic component are identified and a genetic consult will be offered. Prenatal screening is offered to all clients in early pregnancy. Accessing this information is a choice you make. Many clients opt out of genetic screening test and many use it. It is very individual and can affect how you view your pregnancy, and your baby. We respect your choices but want to ensure you have access to all the information about this testing to decide if this will be useful for you.


Prenatal screening options include services covered through OHIP as well as private pay options.


For a detailed guide on options available through our health care system please visit the Prenatal Screening Ontario website at


Private pay options include the Non-Invasive Prenatal Test or NIPT. Sometimes this is referred to as the Harmony Test or the Panorama Test. These are brand names of the test by private companies.


This is a blood test that looks at fetal DNA in the pregnant person's blood. The benefits of this test are that the false positive and false negative rates are low. That is, it is considered to be 99% accurate is assessing trisomies such as Down’s Syndrome.  It also gives a result earlier than the OHIP covered options. The cost of this test is several hundred dollars. OHIP will pay for this test in certain situations, e.g., if an amniocentesis is being offered to you because of your age or because of positive results on other tests.  You can choose to have this test and pay for it yourself. 





Herpes in Pregnancy


What is herpes?

The Herpes Simplex Virus (HSV) is one of the most common human viruses. There are two types of HSV, Type 1 (HSV-1) and Type 2 (HSV-2). HSV is a recurrent viral infection, which means that once acquired, a person will always carry the virus. Usually the virus will remain dormant, but occasionally the virus will reactivate and cause an outbreak. During this time, a person is contagious.


How is herpes transmitted?

HSV prefers mucous membranes, but it can affect any area of the body. Infections of the mouth, lip or face (e.g. cold sores) are usually, although not always, caused by Type 1. Genital infections are usually, although not always, caused by Type 2. HSV can only be spread by direct contact with an infectious person. They may have visible sores, sores in difficult to see places (e.g. on the cervix), or not have sores but be “shedding” cells that contain the virus.


It is estimated that up to 30% of North Americans have genital herpes, and about 80% will suffer from a cold sore sometime in their life. As many as 80% of infected adults do not know they carry HSV, either because they never had overt symptoms or because they didn’t recognize their symptoms. 


How can Herpes Affect Me?


True primary episode

The initial infection with HSV of any type is referred to as a true primary episode. A primary outbreak is usually worse than a recurrent episode; people often report serious symptoms, such as pain, tingling, tenderness, and flu-like symptoms (such as fever, chills, headache, fatigue, muscle and joint aches). Depending on whether they now have oral or genital herpes, they will usually have swollen lymph glands around the neck or groin respectively. 


Lesions usually appear on the infected area 2-14 days after being exposed to the virus. The lesions from a primary outbreak are generally larger, more numerous and last longer than those from a recurrent infection. The lesions may last for three weeks if no therapy is initiated. There is an increased risk of transmission of the virus due to viral shedding for up to three months after the lesions from a primary infection have healed. Symptoms may or may not be present during this period. 


Recommendations for Primary HSV Outbreaks in Pregnancy

Treatment at the end of the pregnancy with the anti-viral drug Acyclovir. If the outbreak is in the third trimester, it is recommended to birth by cesarean section due to high chance of viral shedding and therefore transmission to baby during vaginal birth.


Non-primary, first episode

If someone with HSV-1 is then infected with HSV-2 (or vice versa), this referred to as a non-primary, first episode. This is not a true primary episode, because the HSV-1 antibodies moderate the effects of the HSV-2 infection (or vice versa). These episodes are usually worse than recurrent infections, but less than true primary infections.


Recurrent episodes

A recurrent episode is a repeat outbreak triggered by an event that causes the virus to reactivate. Most people will have at least a few. Usually recurrences get milder and less frequent with time. Sometimes the onset of an outbreak is preceded by symptom s such as tingling, pain, itching, burning, fatigue, fever and/or tenderness. Usually people with a history of herpes become aware of what their initial or prodromal symptoms are, as well as what can trigger outbreaks.


Sometimes the virus is present without any noticeable symptoms or lesions. This is called viral shedding.


How can Herpes Affect my Baby?

Neonatal herpes infection occurs in 1 of every 2000-10,000 births. The most common time of transmission is as the baby passes through the birth canal, but it can also happen in the uterus or after the birth.


Almost all neonatal herpes infections occur as a result of true primary episode genital infect ion during late pregnancy when birth occurs before the development of protective maternal antibodies. Having a primary outbreak poses a higher risk to

the newborn than a recurrent outbreak (up to 50% vs. 5%).


Neonatal herpes infection can be a variety of symptoms, ranging from an isolated sore to brain infection and, in rare cases, death. Neonatal herpes can be diagnosed only if it is looked for. The problem with treatment is less the difficulty of findi

ng a useful drug and more the delay that often occurs before the diagnosis is made. If the pregnant person has herpes, the pediatrician needs to know in order to consider the possibility of neonatal herpes when seeing a sick baby.


Recommendations for Herpes Outbreak in Labour

If you are in labour and you have herpes lesions around your cervix, vagina, labia, vulva, or anywhere where the baby might come in contact during the birth, it is recommended that you have a cesarean to avoid transmitting the virus to your baby. If the lesions are not in an area where the newborn can come in immediate contact, we can cover these lesions with sterile tape and plan for a vagina l birth.


What are my options for testing?

You may already know you have HSV because your infection symptoms were obvious. It is possible have a blood test to see if you carry antibodies to HSV-1 and/or HSV-2, which would indicate a past or present infection. This test will not tell us where on your body you were infected.


If you have an outbreak, a swab can be taken directly from the sores and used to verify that it is HSV, as well as determine which type.


Recommendation for HSV testing in pregnancy

If you have any lesions that could be HSV, it is recommended to do both a swab and a blood test. If you have no history of HSV infection but your partner does, you may be at risk of having a primary outbreak. In this case, it is recommended that you have a blood test to see if you have HSV antibodies, and then practice safe sex for the rest of the pregnancy.


What are my options for treatment?


Prevention of infection

The number one preventative against genital herpes is safe-sex, such as using condoms and other barrier methods. If your partner has a history of genital herpes but you have never had an outbreak (confirmed by a blood test), it may be recommended that your partner take Acyclovir for the duration of the pregnancy to prevent transmission If either you or your partner is experiencing any prodromal symptoms, it is best to refrain from any intimate contact, wash hands frequently and not share eating utensils, lip balms, etc.


It is also important not to participate in kissing or oral sex if you or your partner has a cold sore.


Prevention of recurrence

















HSV is often triggered by stress–emotional stress, illness, inadequate diet, lack of sleep, hormone surges, allergies, etc. It can also be triggered by certain foods that are very acidic, spicy and/or high in a protein called arginine. Pregnancy is a state of lowered immunity and high hormones, as well as having other unique stresses; therefore some people find they experience more frequent outbreaks during this time. Prevention centres around stress reduction–exercise, massage, meditation, and diets low in fat, sugar, and processed foods also contribute to lowered stress levels. For those with severe or frequent outbreaks, diet modification to decrease high arginine foods, and increase high lysine foods can help, as well as supporting the immune system with supplements of vitamins, homeopathics, etc. 













There are numerous ways to deal with an HSV outbreak, depending on its severity and location. Acyclovir is an antiviral drug that is commonly prescribed for people experiencing a primary HSV infection during pregnancy because of the increased risk of transmission to the fetus. This therapy is also an option for people experiencing frequent and/or severe recurrent outbreaks during pregnancy. 


The current standard is to recommend Acyclovir to people with a history of genital herpes, to be taken from 36 weeks till the birth. The aim is to minimize the chance of an outbreak or viral shedding at the time of birth when it is most dangerous to the baby.


It must be understood, however, that Acyclovir, while it is given to many pregnant people in North America every year and there have not been any confirmed risks to the baby, long-term studies continue to be needed. Recommendation for HSV treatment in pregnancy Acyclovir should be offered to anyone having a primary HSV outbreak Acyclovir should also be offered to anyone who is experiencing or at high risk of experiencing severe and/or frequent recurrent HSV outbreaks Acyclovir should be offered at 36 weeks of pregnancy to people with known genital herpes, in order to prevent an outbreak or viral shedding during birth.


If there is any suspicion of neonatal infection, the baby should receive immediate treatment with intravenous Acyclovir.



What is anemia?


Anemia is not a disease; it a symptom of either a reduction of the number of red blood cells in the bloodstream or not enough hemoglobin in each red blood cell. Since hemoglobin combines with and transports oxygen to the body cells for nourishment as well as collecting carbon dioxide for transport to the lungs, any condition that reduces the number of red blood cells or decreases the hemoglobin concentration also lowers the amount of oxygen getting to the rest of the body.










Being anemic does not predispose you to postpartum hemorrhage, but it can worsen its impact. People who are anemic take longer to recover postpartum, and experience more difficulties coping due to excessive tiredness and weakness. Ideally, the aim in pregnancy should not only be to avoid anemia, but to reach optimal hemoglobin levels so that your postpartum transition is as easy as possible.


How can anemia affect my baby?

During the last six weeks of pregnancy, the baby stores iron in its liver to supplement its needs for the first three to six months of life. Like with other nutrients, the pregnant person's body prioritizes the baby’s needs over their own, thus it is rare that the baby will develop iron-deficiency anemia unless the pregnant person is severely iron deficient. 


What causes iron-deficiency anemia?

The cause of anemia in the large majority of cases is nutritional deficiency. Anemia may also occur as a result of illness, or blood loss such as can occur at birth.


Iron depletion is common among  people with a uterus because they lose blood every month. It is estimated that one third to one half of pregnant people begin their pregnancies with low iron, and about 1 in 10 of these people are already anemic. Growing a healthy baby increases a person’s iron requirements. In addition, in mid-pregnancy the amount of blood volume increases rapidly, peaking around 28-32 weeks. Because the blood plasma increases before the blood hemoglobin, this causes the relative concentration of hemoglobin to drop temporarily. This is normal and is referred to as hemodilution.


How is anemia diagnosed?


Iron-deficiency anemia is the most common problem of pregnancy. It is recommended that all clients be tested for anemia at their first prenatal visit, and then again around 28 -32 weeks or as symptoms arise. A simple blood draw will check the hemoglobin concentration in the blood, as well as the amount of iron stored in the liver as ferritin (think of this as “backup”). If diagnosed with nutritional anemia, it is recommended to have follow-up testing after 3-4 weeks of treatment.


What are my options for treatment?


If you are not anemic, a nutritious diet high in iron-rich foods will help keep you that way. Regular exercise can also help prevent or treat anemia, because it helps increase the body’s oxygen carrying capacity. If you are taking multivitamins, it is important to remember that these should be in addition to, not a substitute for, a nutritious diet. Although multivitamin supplements for pregnant people all contain iron, this iron frequently causes side effects such as nausea, diarrhea, heartburn and/or constipation leading to worse nutrition habits! As well, the iron in multivitamins is usually blocked from being absorbed by the calcium and zinc content. Iron overload can be toxic, causing liver damage. People who are not anemic or who have thalassemia should not take iron supplements. 


Treating Anemia

Treatment depends on how severe your anemia is, what other approaches you may have already tried, and what your body tolerates. For mild anemia, therapies with herbs and nutrition may work well. For others, iron supplements are recommended.

  • Floradix (take double the recommended dose)

  • Feramax

  • Palafer


Iron-rich foods

HEME iron is found only in animal sources and is absorbed more easily than NON-HEME iron, which is found in vegetable sources. Regardless, both types of iron are valuable, and may be absorbed effectively to boost iron levels. 


Increasing iron absorption

  • Do not take calcium or zinc supplements at the same time as iron, since they combine in the intestine and prevent absorption. Consume concentrated sources of calcium at different times than iron sources.

  • Eating foods high in vitamin C with your iron will increase absorption.

  • Cooking in cast-iron will aid in increasing hemoglobin levels.

  • Minimize caffeinated tea and coffee, or drink between meals only – the polyphenols decrease iron absorption

  • Combine heme and non-heme sources of iron in the same meal.















*Due to mercury content, limit certain fish/shellfish to no more than 12 ounces total per week. Pregnant people should not eat liver, as the high vitamin A content can be harmful to the baby.










































* Iron amounts in enriched foods vary; check the label for accurate information. If the iron amount is given as a percentage of the daily value (DV), the standard used is 14 mg (or 7 mg for infant cereals). For example, if a serving of cereal has 25% of the daily value, it has 3.5 mg of iron (0.25 x 14 mg).



Nausea and Vomiting in Pregnancy

Only about 15% of pregnant people don’t suffer from nausea at some time during their pregnancy. More than half will have vomiting. Since each person is different and each pregnancy is different, the severity will vary.


What causes nausea?

No one knows exactly what the cause is. It is believed that it’s a combination of the many physical changes taking place in the body, especially the higher levels of hormones during early pregnancy.


How long will it last?

Nausea usually starts between 5 and 6 weeks of pregnancy. Although common in the morning, “morning sickness” can actually last all day, or even be worse in the evening. For 80% of sufferers, nausea gradually lessens, with more and more nausea-free days, until it ceases completely around the 12th week – although physical or emotional stresses can causes temporary relapses. The other 20% of sufferers will have nausea for a longer period of time, some even until the end of pregnancy.


Is it dangerous to me or my baby?

Nausea, especially if severe, can be emotionally draining. Many pregnant people find that it interferes with usual daily activities, making it necessary to find ways to cope. But the large majority of the time nausea isn’t physically harmful to the childbearing person or baby. If you were healthy before you started pregnancy, your body and your baby will draw on your nutritional reserves. There is even a theory that the minimal nutrition of the first trimester during the stage when the placenta is growing, essentially tricks the body to grow a larger, more efficient placenta.


What if I can’t keep anything down?

About 1% of people suffer from excessive vomiting in pregnancy, a condition called “hyperemesis gravidarum”. In such cases, the lack of food, fluids and nutrients may be harmful to their health and the well-being of their baby, if left untreated. Treatment usually includes IV fluids, as dehydration makes the condition worse, which in turn increases the amount of nausea, vomiting and fluid loss.


Nausea Survival Strategies

Low blood sugar 


  • Having low blood sugar can cause or worsen nausea, so eat small, frequent meals.

  • Carry snacks such as raw almonds (which also minimize heartburn).

  • When you first wake up, eat a snack, and then rest for 15 minutes before getting out of bed.

  • Keep a few crackers or bowl of nuts in the bathroom, so you can keep your blood sugar up by snacking during those middle of the night trips.

  • Until your nausea decreases, eat according to your cravings – better to eat something, than nothing at all


Carbs & Proteins

  • Eat protein for sustained energy. Try some just before bed to avoid morning nausea.

  • Go for complex carbs, as refined carbs can quickly cause a blood sugar low.

  • Some people find carbs (crackers, dry toast, popcorn, granola bars) more relieving, other prefer proteins (nuts, cheese)


Flavors, Smells, Textures

  • People may crave certain flavors: salty, sweet, sour. Find what works for you.

  • Smelling citrus fruit – oranges and lemons – can help. Eating citrus also helps your body to efficiently absorb iron.

  • Keeping the saliva flowing by sucking on something sour can help, but don’t do this on an empty stomach

  • Avoid spicy, fatty and fried foods

  • Try eating food cold, as it may not smell as strong as when hot. Try popsicles.

  • Minimize cooking smells.

  • The smells of coffee and red meat are often triggers.



  • Don’t let dehydration make your nausea worse: drink at least 2 litres a day.

  • Drinks that lessen nausea count towards your 2 litres: ginger tea, ginger ale, anything bubbly like sparkling water or seltzer

  • Caffeine counts against your 2 litres, as it causes more dehydration – drink an extra cup of water for every cup of caffeine or ounce of chocolate



  • Avoid letting your stomach to be fully empty

  • Don’t take supplements on an empty stomach.

  • Try digestive teas if indigestion, constipation or diarrhea is associated with your nausea: fennel, mint, chamomile, etc.

  • Take digestive enzymes at mealtime, such as papain and bromelain.

  • Try activated charcoal for a “sour” stomach, 2 capsules when nauseous, up to twice a day. 



  • Being tired makes nausea worse. In the first trimester it’s normal to need more sleep, so go to bed early.

  • Take naps whenever you can.



  • Emotional and physical stress can make nausea worse. You may need to take some time from work, or adjust your work hours.

  • Avoid warm places as feeling hot can add to nausea.

  • Many complementary therapies can help with nausea by decreasing physical stress: see your chiropractor, have a massage.

  • Try finding relief through counseling and talking with others, to eliminate any psychological component



  • CO2 buildup in the blood contributes to nausea, but can be reduced with cardiovascular activity like walking and swimming.

  • Exercise in fresh air seems to be especially helpful.



  • Try 25mg of Vitamin B6, up to 6 per day.

  • The iron in daily vitamins can make nausea worse. Take vitamins with food or just before bed. If this doesn’t help, then decrease or stop taking daily vitamins until your nausea is gone. Vitamins are supposed to fill the nutrient gaps in your diet– if you eat worse because of increased nausea, then they are not helping. Continue to take folic acid alone on a daily basis.


  • Take 250 mg capsules up to four times a day, or 5-6 cups of fluid per day. Try ginger ale, ginger beer, ginger tea, candied ginger or ginger-lemonade.



  • Research has been shown acupuncture to be effective. Look for a practitioner with experience in treating pregnant people.

  • Try SeaBands, available at drugstores, designed to offset motion sickness by stimulating acupressure points in the wrist.



  • Diclectin is a medication considered safe for treating nausea in pregnancy. It is a combination of Vitamin B6 and an antihistamine. It can have uncomfortable side effects such as dry mouth or sleepiness, so it’s usually only for serious nausea. Ask your midwife for more info and/or a prescription.

  • There are other medications that may be suitable. Speak to your midwife about these options.

Thalassemia & Pregnancy

What is thalassemia?

Thalassemia is the name of a group of inherited blood disorders. There are two main types of thalassemia: alpha and beta, in reference to the alpha and beta proteins that form hemoglobin in the blood. Hemoglobin is the oxygen-carrying component of red blood cells, so if the body doesn’t produce enough of either of these two proteins, the result is anemia that begins in early childhood and lasts throughout life.


What are the effects of thalassemia?

Thalassemia ranges widely in severity. Babies born with thalassemia may have mild to severe anemia, may develop jaundice, organ damage or even die.


How is thalassemia transmitted?

Thalassemia is an inherited disease, i.e. it is passed on by parents who have the thalassemia gene.


Because the gene is recessive, both parents must each pass on the thalassemia gene in order for the baby to have the full disease.


If the baby only inherits one gene, they will become a carrier but not express the full disease. Sometimes this carrier state is referred to as “thalassemia trait”.  Most carriers lead normal, healthy lives. They may not even realize that they carry this gene.


When both parents are carriers:

  • 1 in 4 chance that their child will inherit 2 thalassemia genes and have severe outcomes of the disease = Thalassemia major

  • 2 in 4 chance that the child will inherit the thalassemia trait, i.e. become a carrier = Thalassemia minor

  • 1 in 4 chance that the child will inherit 2 normal genes


How is thalassemia diagnosed?

When you do your routine blood test at the beginning of your pregnancy, one result we review is the Mean Corpuscular Volume, or MCV. The MCV reading determines the size of your red blood cells. For adults, if the MCV reading is less than 75 you may be a trait carrier. If your MCV reading indicates that you may have the thalassemia trait, additional blood tests can be performed to make sure.


Genetic counseling can also aid in identifying if you should have this blood test. Because thalassemia occurs most commonly among Mediterranean, Middle-Eastern, Asian, and African people, if you and the other genetic contributer are from any of these groups, you may want to consider genetic counseling and/or further testing. 


During pregnancy, chorionic villus sampling (CVS) or amniocentesis can detect or rule out thalassemia in the fetus. Early diagnosis is important so that treatment can prevent complications.


What is the treatment for thalassemia?

The use of frequent blood transfusions and antibiotics has greatly improved the outlook for children born with thalassemia. Still, there is a chance that these babies will be born with major organ damage and may not live a full life span.

Ultrasound in Pregnancy 

What is ultrasound?

During an ultrasound scan, very high frequency sound waves are produced by a transducer (the part of the machine which is placed on the body). The sound waves are passed into the body where they encounter structures (such as the fetus). When this happens, the waves reflect back, and the sound (or echo) is detected electronically and transmitted onto a screen as a dot. This results in a picture being formed, with strong echoes creating white dots (representative of bone), weaker echoes creating grey dots (tissue) and no reflection creating black dots (fluid).


Can ultrasound confirm that my baby is “normal”?

Ultrasound has been used for many years to gain information about developing babies.  Ultrasound in many situations is considered a screening test rather than a diagnostic test.  This means that there may be a small chance of false positives or false negatives when ultrasound is used as a diagnostic tool in pregnancy.  However, ultrasound remains the method of choice for confirming the diagnosis of some conditions (i.e. spina bifida), and is considered a valuable tool to gain information about the developing fetus.  The accuracy of an ultrasound is directly related to the skill of the technician performing the scan, and the quality of the equipment used and the cooperation of the baby!


At what point in pregnancy will I be offered an ultrasound?

  • An ultrasound may be offered in the first trimester if there is any difficulty predicting a due date for the pregnancy (see below).

  • For people interested in the Early First Trimester Screen (eFTS), an ultrasound is performed between 11 weeks and 13 weeks and 6 days. The ultrasound component of eFTS measures the nuchal translucency (NT), a fold at the back of the neck, which may give information about an increased probability of Down syndrome. Please see the section on genetic screening for more information about this test.

  • All people in pregnancy are offered an anatomy ultrasound at 18-21 weeks. At this point, a scan is used to identify that the baby is developing and growing normally.

  • An ultrasound may be offered at other points in pregnancy for any of the following reasons: concern that the baby is not growing as expected, to investigate the source of vaginal bleeding, to diagnose cervical changes in cases of suspected preterm labour, to identify the position of the baby if not certain the head is presenting first, to follow up previously discovered concerns, to monitor a pregnancy that extends far past the due date, or as a visual aid during invasive procedures such as amniocentesis or external cephalic version.


What are the benefits of having an ultrasound in pregnancy? 

Dating:  When performed in early pregnancy, ultrasound is considered a reliable method of predicting the estimated due date, especially for people who have irregular menstrual cycles, or are uncertain of when their last period was.  Dating ultrasounds have been shown to reduce the number of pregnancies considered to be “post-term” and to decrease the rate of inductions for pregnancies extending far past the due date.


Fetuses:  Ultrasound can detect multiple (i.e. twin) pregnancies early on, which allows people access to specialized care sooner, as well as to identify which type, identical (monozygotic) or fraternal (dizygotic). Multiple pregnancies can be associated with a higher rate of complications and the type of twining is an important factor in the risk of multiple pregnancies.  Early detection also allows more time to prepare physically and psychologically for the birth of multiples.


Malformations of the Fetus:  Approximately 35–50% of serious defects are diagnosed during a detailed ultrasound at 18-21 weeks.  Ultrasound may also detect “soft markers”— characteristics of the fetal anatomy which are in themselves normal but can be associated with an increased chance of genetic anomalies.  Detection of several soft markers or true abnormalities allows people the chance to consider options to further diagnosis such as amniocentesis, as well as the opportunity to consider termination of the pregnancy or the ability to engage resources/prepare for the birth of a special needs baby.


Uterine formation:   Although rare, some people have a uniquely shaped uterus that increases the likelihood of complications such postpartum hemorrhage. More commonly, many people (30% over the age of 30) have uterine fibroids; in rare cases, they are large enough and low enough in the pelvis to make vaginal birth difficult or impossible. Detection by ultrasound may aid clients and their caregivers in making birth plans, e.g. hospital instead of home.


Placental Location:   Ultrasound can rule out placenta previa (a condition affecting 0.5% of the population where the placenta grows over top of the cervix; cesarean birth is indicated).  For the small number of people affected by placenta previa, early detection may result in healthier moms and babies. The placenta being near the cervix or even partly covering it is a common finding around 18-20 weeks, but usually it moves as the uterus grows. In these circumstances, a follow up ultrasound to confirm that the placenta is clear of the cervix is offered.


Parents’ Experience of Ultrasound:  Many parents say that they are happy to see their baby. While the pregnant person has often being feeling the baby move for a few weeks, a number of partners report that this is the first time the baby seems “real” and that this allows them to feel “more connected” to the pregnancy. What are the limitations of ultrasound in pregnancy?


Dating:  While some research shows ultrasound to be more effective in determining a due date than simply calculating based on a person’s last menstrual cycle, the difference detected in mostcases would be unimportant and not impact the outcome for the pregnant person or baby.  (The exception to this would be in cases of preterm/post-term pregnancies). 


Placental Location:  There is no evidence that routine screening ultrasounds at 18-21 weeks improve outcomes for the pregnant person or baby in the case of placenta previa. There are frequently false positives for previa and low lying placentas that necessitate a follow up ultrasound.


Malformations of the Fetus:  At least 50% of fetal malformations will not be detected via ultrasound. Additionally, some malformations will be “diagnosed,” but in reality not be present, causing undue stress to expectant parents.  Approximately 4 -17% of people who are told that their fetus has “soft markers” associated with an increased chance of Down syndrome will actually be not be carrying a baby with Down syndrome.  Many clients given this type of information consider proceeding to diagnostic testing (e.g. amniocentesis), which carries a degree of risk (1 in 200 chance of miscarriage following the procedure).


Estimated fetal size:  Ultrasound only gives a rough estimate of fetal size. It is especially difficult to accurately estimate the size of very large or very small babies at term, when the margin of error is +/- 1lb. Therefore, ultrasound is only one tool of many that are used to estimate fetal size (and whether it will fit through a person’s pelvis).


Parents’ Experience of Ultrasound:  While an ultrasound has the potential to be a happy experience, real or mistaken diagnosis of abnormalities of the fetus can be very upsetting for parents. If soft markers are noted, some parents have a hard accepting even after further testing shows these markers are variations of normal, that their pregnancy or their baby is not abnormal. Some pregnant people also say it leaves them feeling “less connected” to their pregnancy to use external technology to view what they feel happening inside their bodies. As well, while most ultrasound technicians are warm and welcoming, the occasional one who is not may cause the parents to wrongly fear that something is wrong. (Any problems will be immediately addressed by the radiologist who supervises the technicians.)


Like choosing any test, families choosing ultrasound screening should consider the positive, negative or equivocal findings that could be revealed so as to be prepared for unexpected results, and the potential for further testing options to be offered.


Is ultrasound safe?

The effects of ultrasound are difficult if impossible to study, due to the many variables including age of the exposed fetus, different levels of exposure by different machines and different technicians, frequency of exposure, inherent genetic differences between fetuses, and a large variety of measurable outcomes. We can say, however, that so far there has been no well designed study to date linking ultrasound to adverse outcomes for the pregnant person or baby. As well, ultrasound has been used on millions of pregnant people for more than 30 years without any clear adverse effects. Recent literature may show a potential link between ultrasound exposure in pregnancy and subsequent left-handedness, especially in boys, but the significance of this, if any, is unknown.


At the same time, because there have never been any long term, scientific studies on ultrasound, most experts agree that ultrasound exposure should be minimized and only be used during pregnancy for medical indications. 

Private ultrasound clinics offering 3-D images or videos have become very popular among expecting families.  In 2004, the FDA (Food and Drug Administration in the USA) put out a caution discouraging people from obtaining “keepsake” ultrasounds during pregnancy.  Their rationale for this cites studies that acknowledge ultrasound as a form of energy that can raise the temperature of tissue.  While there is no evidence that this could harm a fetus, the FDA says that there is a potential that ultrasounds in pregnancy aren’t entirely innocuous.


Is there an alternative to having an ultrasound in pregnancy?

While it is considered the standard of care for pregnant people to be offered a detailed scan from 18-21 weeks in pregnancy, some debate exists about whether or not routine ultrasound is necessary in normal pregnancies. The main alternative to having a routine ultrasound is simply to not have one.  People choosing to decline a scan in pregnancy ideally are aware of the benefits and limitations of ultrasound, as well as potential information that could be gained solely via this method of prenatal screening.


Can I find out the sex of my baby?

Oftentimes, it is possible to identify the genitals of the baby using ultrasound, but sometimes it is difficult due to fetal position. As this is not one of the requirements of the fetal screening that is being performed, so the technician will not deliberately be looking for genital confirmation as part of the anatomy scan. It is wise to inform the ultrasound technician your preference in regards to knowing about the fetal genitalia.


What about Doppler use in the clinic?

The Doppler that midwives in clinic settings use to verify the fetal heart rate, is a form of ultrasound. If you wish to minimize ultrasound exposure, your midwife can (occasionally or always) use a specially designed stethoscope called a fetoscope or pinard horn to listen to the heartbeat.


The limitations of using the fetoscope include:

  • having to wait until the fetus is large enough to hear (usually after 20-24 weeks)

  • sometimes it’s hard for parents to hear without a trained ear

  • it is impractical to use during labour as the person needs to be lying flat


The advantages of using the fetoscope, besides minimizing ultrasound exposure, include:

  • there is something magical about hearing the actual heartbeat of your baby, not an electronic representation produced by the Doppler technology

  • helping to verify the position of the baby