Preconception is the time before a woman becomes pregnant – the best time for a woman to prepare her body for a baby. This is a time when a woman can address any possible risk factors that may affect the baby’s health and development throughout the pregnancy. There are many controllable risk factors in the preconception period that can be addressed to ensure the mother and baby are as healthy as possible. Optimizing health before becoming pregnant can help to create an ideal environment for the developing baby, especially in the first few critical weeks of pregnancy, before many women even know that they are pregnant.

The timing of pregnancy has a significant impact on preconception health. Although it is ideal to make health changes prior to conception, many times a pregnancy is not planned. It is therefore important for all women of childbearing age to know how to reduce the risks of potential health problems should they become pregnant.

Pre-Existing Conditions

Although certain pre-existing conditions do not preclude women from having a healthy pregnancy, it is important for women with these conditions to take certain precautions and measures to ensure the healthiest outcome for their baby.

Meeting with a doctor before becoming pregnant is very important. Certain pre-existing conditions that require medications may harm the developing baby. Pre-existing conditions may also require special maintenance during pregnancy due to the changes in a woman’s body.

A woman and her doctor can determine the best way to manage any conditions that existed prior to or during the pregnancy. A doctor can recommend medications and treatment options that are safer for the developing baby while still managing the mother’s condition (e.g. diabetes, high blood pressure, epilepsy, chlamydia, HIV, etc.). It is advisable to talk to a doctor about the best labour and delivery options, as certain conditions can create difficulties.

Pre-Existing Diabetes and Pregnancy

If a woman has diabetes, it is important for her to talk to her doctor before becoming pregnant to discuss how to manage her diabetes during pregnancy. Achieving and maintaining proper control over insulin is important in the prevention of poor outcomes for the baby.

During pregnancy, the baby will use some of the mother’s glucose, and so glucose levels may need to be adjusted. Pregnant women should be prepared for low blood sugar reactions by monitoring their insulin, meals and exercise closely to ensure their insulin requirements are being met.

Blood sugar control is extremely important before and throughout pregnancy. It decreases the chance of certain birth defects (e.g., heart, neuraltube, genital and/or urinary system defects). During labour and delivery, blood sugar levels should be monitored and maintained to ensure the healthiest outcomes for the mother and child.

If any of the following symptoms occur, contact a health care provider immediately:
  • High or low blood glucose levels
  • High HbA1c levels
  • Positive urineketones
  • Any symptoms of a bladder infection (e.g., frequent urination, pain or burning when urinating)
  • Unable to eat due to nausea or vomiting
  • A decrease in the baby’s movements
  • A decrease of more than 5-10% in insulin requirements after 32 weeks 

Hepatitis B and C

Hepatitis B (HBV) and Hepatitis C (HCV) are viruses that cause serious liver disease. Both forms of the virus can be passed to a baby during pregnancy. It is therefore important to be tested prior to pregnancy as a woman may not even realize she has the virus.

If Hepatitis B is detected before pregnancy, a woman can be treated to prevent her baby from being infected. If the virus is detected during pregnancy, treatment should begin for both the woman and her developing baby. If a woman is not treated for Hepatitis B, there is an increased risk of her to passing the virus onto her baby.

There is no vaccine for Hepatitis C. However, a newborn baby can be vaccinated with the Hepatitis A and Hepatitis B vaccines to provide some protection from the Hepatitis C virus.

HIV and Pregnancy

HIV is the acronym for Human Immunodeficiency Virus. This name highlights the fact that HIV can only be transmitted from one human to another human, and that it is a virus that causes a deficiency in the immune system. Once a person becomes infected with HIV, the virus begins destroying the cells that are responsible for the human immune system, making it difficult for the body to fight off infections and diseases.

HIV is a progressive disease that continually causes changes and damage to an individual’s immune system. When a person’s immune system becomes damaged and they contract one or more opportunistic infections (i.e., infections that individuals with HIV are particularly susceptible to such as a respiratory, fungal and various forms of cancer), they are said to have AIDS (Acquired Immune Deficiency Syndrome).

HIV can only be transmitted when there is a direct exchange of specific bodily fluids between two humans. The five fluids capable of transmitting HIV are blood, semen and pre-cum, vaginal and anal fluid, and breast milk. HIV can also be transmitted from mother to child during pregnancy and/or delivery. Although there is no cure for HIV or AIDS, with appropriate care and treatment the risk of transmission from mother to infant can be reduced to less than 2%. Without treatment, the risk of transmission from mother to infant is approximately 25%: A woman may not know that she has been exposed to the HIV virus and therefore a doctor will advise women who are pregnant or thinking of becoming pregnant to be tested for HIV.


Sexually Transmitted Infections and Pregnancy

Sexually Transmitted Infections (STIs) are spread through unprotected sexual contact. Many people who have STIs do not know that they are infected because many STIs do not produce visible symptoms. Testing for STIs during pregnancy is very important, as some STIs can be passed on to the developing baby prenatally, during delivery, or during breastfeeding.

There are many different STIs, such as syphilis, chlamydia, gonorrhoea, nongonococcal urethritis, trichomoniasis, hepatitis B, hepatitis C, human papilloma virus, and genital herpes. Certain STIs can cause very serious damage to a baby. For example, untreated syphilis can cause brain damage, blindness, deafness or even death in the developing baby. Many STIs can be treated during pregnancy (e.g., chlamydia, gonorrhoea, syphilis). There are others that cannot be treated (e.g., genital herpes), but knowing a woman’s status presents the opportunity to reduce the risk of transmitting the infection to the baby. For this reason, testing for STIs informs health professionals of the woman’s condition and can help to prevent her baby from becoming infected.

To download a fact sheet on Sexually Transmitted Infections and Your Pregnancy, click here.

Folic Acid

Folic acid is important in the prevention of neural tube defects. Neural tube defects are very serious and can be immediately fatal or result in conditions such as spina bifida or anencephaly. The neural tube is the embryonic structure that develops into the brain and spinal cord and normally closes by the 29th day of pregnancy. If a neural tube defect occurs, the backbone and spinal cord never closes completely.

Taking 0.4 mg of folic acid supplement before and during pregnancy can decrease the risk of having a baby with a neural tube defect by 50% in most women. Women affected by diabetes, obesity or epilepsy can reduce the risk by up to 70% and will likely be prescribed a larger doe of folic acid to help reduce their risk. It is therefore very important that all women of childbearing age take folic acid supplements, even if they are not planning a pregnancy, as neural tube defects can occur before a woman even knows that she is pregnant.


Healthy Lifestyles

The lifestyle choices a woman makes prior to becoming pregnant and in the first few weeks of pregnancy can affect her health and the health of her baby. What a woman eats, drinks, or ingests can affect her unborn baby. Women should avoid smoking, drinking alcohol and using street drugs. They need to check with their physician regarding prescription drugs and whether over-the-counter medications are safe to take during pregnancy. Women also need to maintain a healthy weight and stay active while eating a nutritional diet. If a woman is in an unhealthy relationship she may need to seek help as domestic violence may begin or intensify during pregnancy.

If a women is not sure of the safety of her medications and finds it difficult to abstain from smoking, drinking and taking drugs or, if she is in an abusive relationship she should seek help and guidance from a physician, a trusted health professional, a councilor or close friend to discuss her options.


Alcohol Use and Pregnancy

When a pregnant woman drinks alcohol, there is a chance that her baby will be born with Fetal Alcohol Spectrum Disorder (FASD). FASD describes the range of disabilities that can occur when the unborn baby is prenatally exposed to alcohol. Prenatal alcohol exposure primarily affects the central nervous system (the brain), and can affect physical, behavioural, learning, social, and adaptive domains. It is also strongly associated with mental illness. Because the damage to the fetus affects the developing brain, FASD is lifelong and is not something that can be “cured”. However, with support, individuals with FASD can lead fulfilling and productive lives.

FASD is a preventable disability … if a woman does not drink during pregnancy there is no chance that her child would be born with FASD. There is no known safe time, kind, or amount of alcohol to drink while pregnant. Binge drinking and heavy drinking have been found to be especially damaging to the developing baby.


Pregnancy and Physical Activity

Pregnancy does not have to stop women from being active. Exercise can be safe and enjoyable during pregnancy. In fact, healthy pregnant women should participate in regular physical activity. It’s good for both women and their unborn children.

During pregnancy, women who exercise may benefit from:
  • fewer musculoskeletal problems, including less back and pelvic pain
  • increased maternal cardiovascular fitness
  • lowered risk of gestational (pregnancy-related) diabetes
  • increased management of pre-existing diabetes
  • increase in maternal positive body image, well-being and self-esteem
Things to remember
  • Every pregnancy is different. Women should consult their health care provider before beginning or changing their physical activity program.
  • If a woman has been active (3x a week for 30 minutes) before becoming pregnant and has her pregnancy care provider’s approval, she can safely continue to exercise during her pregnancy.
  • If a woman did not exercise prior to becoming pregnant, it is safest to begin a new fitness program during the second trimester. She should slowly increase the length of aerobic activity from 15 to a maximum of 30 minutes per session, for a maximum of four sessions per week.
  • Pregnant women can safely perform strength training activities two or three times per week. For muscles to recover, one day of rest should be allowed between sessions. High repetitions (12 to 15) and low weight are recommended.
  • During pregnancy, it is important to consider aerobic activities where the body is supported, such as swimming or cycling. Some other safe activities may include walking, low-impact aerobics, and stair climbing.
  • Pregnant women should include stretches as part of their warm up and cool down.
  • Drinking water before, during, and after activities to replace lost body fluids is important.
  • Pregnant women should be advised to breathe normally throughout activities and never hold their breath.
  • If a separation of the abdominal muscles has occurred, women should not perform abdominal exercises as this might make the condition worse.
  • Women should consult their physician before continuing any physical activity program after birth.
Cautions for physically active pregnant women
  • Avoid activities that require sudden starts or stops, jumping, or rapid changes in direction.
  • Avoid being active in warm, humid weather, especially during the first trimester or during illness.
  • Check the temperature of a heated pool before swimming. The recommended water temperature for pregnancy is 83-85° F/28.3-29.4° C.
  • Avoid hot tubs and whirlpools.
  • After the 16th week (fourth month) of pregnancy, avoid exercises that require lying on the back.
  • Avoid lifting heavy weights. Light hand weights or elastic resistance bands are recommended to build or maintain upper and lower body strength and improve posture.
  • Some yoga positions are not safe during pregnancy. Please go to Prenatal Yoga for more information.
PARmed-X for Pregnancy is a medical tool for screening pregnant women who are interested in starting an exercise program or who wish to continue being active. Please follow PARmed-X for PREGNANCY to find a copy of this tool. This will help guide discussions with your patient.
  • Davies, G. A., Wolfe, L. A., Mottola, M. F., MacKinnon, C. (2003). Joint SOGC/CSEP Clinical Practice Guideline: Exercise in Pregnancy and the Postpartum Period. Canadian Journal of Applied Physiology, 28(3), 329-341. Retrieved from
  • Ferraro, Z. M., Gaudet, L., Adamo, K. B. (2012). The Potential Impact of Physical Activity During Pregnancy on Maternal and Neonatal Outcomes. Obstetrics and Gynecology Survey, 67(2), 99-110. Retrieved from

Prescription Drugs, Over-the-Counter Drugs, Supplements, Illicit Drugs, and Pregnancy

During pregnancy, a woman’s body needs certain nutrients and supplements to give her baby what it needs for proper development. However, there are medications, supplements and drugs that can be detrimental to the developing baby. During pregnancy, an unborn baby is nourished through the mother’s placenta, and this connection allows many substances, including the by-products of many drugs, to pass from the mother to the fetus.

Some prescription medications are teratogenic (chemicals that affect how the fetus grows at different developmental stages) and can adversely affect how the baby develops. It is important for a woman to see her doctor or health care professional, to discuss her options for managing her condition while pregnant. In some cases the risk to mother, by not taking the medication, may outweigh the risks to the fetus, in which case a doctor will recommend continuing therapeutic use of the medication.

Over-the-counter medications such as cough syrups, painkillers, antacids, nose drops, laxatives, sedatives, diuretics, and vitamin supplements are drugs that should be used carefully and only on the advice of a doctor. Even if a medication has been found to be safe during pregnancy, it is important that women adhere to the recommended doses that have been tested for safety.

Illicit or street drugs can have harmful effects on the developing baby and expectant mother. Some drugs are associated with risk of congenital defects, miscarriage, preterm birth and low birth weight as well as possible withdrawal in the newborn. Drugs may also be passed through the mother’s breast milk and can have varying effects on the infant. If a woman has difficulty stopping her drug use, she should seek assistance from a trusted health care professional or councillor.

Any woman who is planning to become pregnant, or suspects she may already be pregnant, should tell a health care professional so that she receives the appropriate care and advice.


Smoking and Pregnancy

Smoking has a negative effect on a woman’s health before she becomes pregnant and can be very harmful to both a woman and her baby during and after pregnancy. Any exposure to cigarette smoke can affect a woman’s reproductive, maternal and physical health. Exposure to tobacco smoke can also harm an unborn baby. Chemicals from tobacco smoke, such as carbon monoxide and nicotine, can cross the placenta to affect the unborn baby. Babies born to mothers who smoke have a greater risk of preterm birth and low birth weight, as well as low oxygen levels, developmental and learning problems, visual and respiratory problems, bleeding in the brain and jaundice. Pregnant women who smoke or who are exposed to second-hand smoke have a higher risk of pregnancy complications such as miscarriage, ectopic pregnancy or gestational hypertension.

Environmental tobacco smoke (ETS), also known as second-hand and third-hand smoke can also cause health problems for children after birth. The harmful products in tobacco smoke can also be passed to the infant in breast milk. When children breathe in ETS, they are passively smoking, which can cause ear, throat and/or lung infections, asthma, allergies, coughing and wheezing and may lead to SIDS (Sudden Infant Death Syndrome). The effects of ETS will continue to harm the health of children and their mothers until smoking is completely removed from their environment.

Third-hand smoke, the chemicals from smoke that remain even after the smoke is gone, is also dangerous. Third-hand smoke can get trapped in hair, skin, fabric, carpet, furniture and dust, and buildings over time. These chemicals pollute the air and can therefore adversely affect people’s health. Infants are especially susceptible to third-hand smoke because they breathe more quickly and spend more time on the floor where there is a build up of chemicals.

It is important for both the woman’s health and the health of her baby to have a smoke-free environment. For more specific information on tobacco use and pregnancy, see the resources below:

  • Newland, J. (2009). Do your patients know about third-hand smoke? The Nurse Practitioner, 2, 5.