Five weeks pregnant is often the week everything becomes real. For many people, this is the week the pregnancy test turns positive — or the week a faint line from last week becomes unmistakably dark. Your baby is the size of a sesame seed. You may feel completely normal, or you may already feel like your body has been taken over by something with very specific and non-negotiable opinions about what you eat, smell, and do.
Both are normal. Five weeks is early. And early pregnancy comes with a specific set of questions that nobody fully prepares you for.
This guide covers what is actually happening at five weeks, what is safe, what is not, and what warrants a call to your care provider.
What Is Happening at 5 Weeks
At five weeks, your embryo is undergoing one of the most significant developmental events of the entire pregnancy — the formation of the neural tube. The neural tube is the structure that will become your baby’s brain and spinal cord. It forms and closes between approximately days 17 and 30 after conception — which means at five weeks, this process is either underway or just completing.
This is why folic acid matters so much before and during early pregnancy. Neural tube defects — including spina bifida and anencephaly — occur when the tube fails to close properly, and adequate folate intake in the weeks surrounding conception significantly reduces this risk. If you are not already taking a prenatal vitamin with at least 0.4 mg of folic acid daily, start now. If you have a personal or family history of neural tube defects, speak to your care provider — you may need a higher dose.
Beyond the neural tube, at five weeks your embryo is developing the foundations of the heart, which begins beating between five and six weeks. A rudimentary circulatory system, the placenta, and the yolk sac — which provides nutrition until the placenta takes over — are all forming simultaneously.
Health Canada’s pregnancy nutrition and supplementation guidelines outline the specific recommendations for folic acid, vitamin D, and iron supplementation during pregnancy. These are worth reviewing at this stage.
What You Might Be Feeling at 5 Weeks
Symptoms at five weeks vary enormously from person to person and pregnancy to pregnancy. Some people feel nothing at all. Others feel everything at once.
Common symptoms at five weeks:
- Nausea — often called morning sickness, though it can occur at any time of day or persist around the clock. It is caused by rising hCG levels and typically peaks between weeks eight and ten before easing.
- Breast tenderness — often the first symptom people notice. The breasts may feel heavy, sore, or unusually sensitive.
- Fatigue — profound, unlike ordinary tiredness. Your body is building a placenta and an embryo simultaneously. The energy expenditure is significant even when nothing is visibly happening.
- Frequent urination — begins earlier than most people expect, caused by increased blood volume and the kidneys processing more fluid.
- Mild cramping — light cramping as the uterus begins to grow and adjust is common and generally not a cause for concern. It typically feels like mild period cramps.
- Light spotting — implantation bleeding can occur around this time and is generally light, brief, and pink or brown rather than red.
- Heightened sense of smell — an early pregnancy hallmark caused by hormonal changes. Smells that were previously neutral or pleasant can become overwhelming or nauseating.
- No symptoms at all — also entirely normal. The absence of symptoms does not indicate a problem.
What Is Safe at 5 Weeks
Exercise
For most people with uncomplicated pregnancies, continuing your existing exercise routine at five weeks is safe. This is not the time to start a new high-intensity program, but walking, swimming, yoga, cycling, and moderate strength training are all generally appropriate.
The Society of Obstetricians and Gynaecologists of Canada recommends that pregnant people without contraindications aim for at least 150 minutes of moderate-intensity exercise per week across pregnancy. Exercise in pregnancy is associated with reduced risk of gestational diabetes, preeclampsia, excessive weight gain, and cesarean delivery.
What to avoid: activities with a high risk of falling or abdominal impact — contact sports, horseback riding, skiing, cycling on uneven terrain. These are not categorically prohibited but warrant discussion with your care provider given your specific situation.
If you experience any of the following during exercise, stop and contact your care provider: chest pain, shortness of breath disproportionate to the activity, dizziness, heavy bleeding, or painful contractions.
Sex
Sexual intercourse is safe in an uncomplicated pregnancy at five weeks. The embryo is protected by the amniotic sac, the uterine wall, and the cervical mucus plug that forms in early pregnancy. Penetration does not reach or harm the embryo.
Some people experience spotting after sex in early pregnancy due to increased cervical sensitivity — this is generally harmless but worth mentioning to your care provider if it occurs regularly.
Sex during pregnancy is not safe if you have been advised otherwise by your care provider — in cases of placenta previa, preterm labour risk, or certain cervical conditions, restrictions may apply.
Travel
Travel at five weeks is generally safe for uncomplicated pregnancies. If you are flying, stay hydrated, move regularly to reduce the risk of blood clots, and wear compression socks on longer flights. Blood clot risk is elevated during pregnancy — this is worth taking seriously even at this early stage.
Road travel is safe with standard precautions — wear your seatbelt correctly, with the lap belt below the bump and the shoulder belt between the breasts.
International travel at five weeks requires consideration of destination-specific health risks — certain vaccines are contraindicated in pregnancy, and Zika virus remains a concern in some regions. Consult your care provider before international travel.
Work
Most work is safe to continue at five weeks. If your work involves exposure to chemicals, radiation, heavy lifting, or prolonged standing, discuss this with your care provider and your employer. In Canada, pregnant employees have the right to request workplace accommodation — your employer cannot legally require you to work in conditions that pose a risk to your pregnancy.
Skincare and Personal Care Products
This is an area where the guidance is more nuanced than most people realize.
Safe: Fragrance-free moisturizers, gentle cleansers, physical sunscreens containing zinc oxide or titanium dioxide, hyaluronic acid, niacinamide, azelaic acid, vitamin C.
Avoid or limit:
- Retinoids — including retinol, tretinoin, and adapalene — are associated with birth defects and should be discontinued immediately if you were using them.
- Salicylic acid in high concentrations — low concentrations in rinse-off products are generally considered low-risk, but high-dose leave-on formulations are best avoided.
- Hydroquinone — a skin-lightening ingredient with high absorption rates; avoid during pregnancy.
- Formaldehyde — found in some nail polishes and hair-straightening treatments; avoid.
- Chemical sunscreens containing oxybenzone — some evidence of hormonal disruption; switch to a physical sunscreen as a precaution.
- Essential oils in high concentrations — many essential oils are not studied for pregnancy safety; use caution with anything applied topically or inhaled intensively.
When in doubt about a specific ingredient, the Motherisk program — formerly based at Hospital for Sick Children in Toronto and now available through provincial health lines — provides evidence-based guidance on medication and product safety during pregnancy.
What Is Not Safe at 5 Weeks
Alcohol
There is no established safe level of alcohol consumption during pregnancy. The recommendation from Health Canada and every major Canadian medical authority is to avoid alcohol entirely throughout pregnancy.
Alcohol crosses the placenta freely. At five weeks — when the neural tube, heart, and foundational organ systems are forming — the embryo is at a particularly vulnerable stage of development. Fetal alcohol spectrum disorder is entirely preventable, and complete abstinence is the only approach that eliminates the risk.
Smoking and Vaping
Smoking during pregnancy is associated with increased risk of miscarriage, ectopic pregnancy, placental abruption, preterm birth, low birth weight, and sudden infant death. If you smoke, stopping now is one of the most impactful things you can do for this pregnancy.
Vaping is not a safe alternative during pregnancy. The long-term effects are not fully understood, but the nicotine in most vaping products is associated with the same risks as smoking. Cannabis use during pregnancy is also not recommended — THC crosses the placenta and is associated with adverse fetal neurodevelopmental outcomes.
Speak to your care provider about cessation support. Nicotine replacement therapy in some forms may be recommended as a safer alternative to continued smoking — this is a conversation worth having.
Certain Medications
Many over-the-counter and prescription medications are not safe during pregnancy. Five weeks is early enough that some people do not yet know they are pregnant when they take medications — if this applies to you, speak to your care provider rather than assuming the worst.
Medications to avoid without confirmed medical guidance:
- Ibuprofen and other NSAIDs — not recommended in pregnancy, particularly in the first and third trimesters. Acetaminophen is the recommended pain reliever during pregnancy, used at the lowest effective dose for the shortest necessary time.
- Certain antibiotics — some are safe, some are not. Never self-prescribe antibiotics during pregnancy.
- Acne medications — isotretinoin (Accutane) is severely teratogenic and must be discontinued before conception. If you were on isotretinoin and did not know you were pregnant, contact your care provider immediately.
- Some antidepressants and psychiatric medications — do not stop any medication without speaking to your prescribing physician first. Untreated mental health conditions carry their own risks during pregnancy. This requires a nuanced conversation, not an abrupt discontinuation.
The NRC’s Drug Safety in Pregnancy resource and your pharmacist are both accessible first references for medication questions.
Raw and High-Risk Foods
The dietary restrictions relevant at five weeks are the same as throughout pregnancy — and they matter most in the first trimester when the embryo is most vulnerable. Our What Not to Eat During Pregnancy guide covers the full list with the reasoning behind each restriction.
The headline items: raw fish and shellfish, unpasteurized dairy and soft cheeses, undercooked meat and deli meats unless heated until steaming, raw eggs, unwashed produce, and raw sprouts.
Hot Tubs and Saunas
Elevated core body temperature in the first trimester is associated with neural tube defects and other developmental complications. Hot tubs, saunas, and very hot baths that raise your core temperature above approximately 38.9°C should be avoided — particularly in the first trimester when organogenesis is underway.
Warm baths are fine. The distinction is temperature, not the act of bathing.
When to Call Your Care Provider
At five weeks, contact your midwife, OB, or family doctor for:
- Heavy vaginal bleeding — particularly if accompanied by cramping. Light spotting can be normal; heavy bleeding is not.
- Severe one-sided abdominal pain — a potential sign of ectopic pregnancy, which requires immediate assessment. If you have sharp one-sided pain and a positive pregnancy test, do not wait.
- Nausea so severe you cannot keep water down — this may indicate hyperemesis gravidarum, which requires medical management. Pushing through severe dehydration is not appropriate.
- Fever above 38°C — any fever in pregnancy warrants contact with your care provider.
- Concerns about medication exposure — anything you took before knowing you were pregnant that you are now worried about.
Go to the emergency department for severe one-sided abdominal pain, heavy bleeding with significant cramping, or shoulder pain alongside a positive pregnancy test — these are potential signs of ectopic pregnancy rupture, which is a medical emergency.
Your First Prenatal Appointment
If you have not yet contacted a care provider, five weeks is a good time to do so. In Canada, most care providers schedule the first prenatal appointment between eight and twelve weeks — but registering now ensures you get into the system and allows time to ask about any early concerns.
At your first appointment you can expect:
- Confirmation of pregnancy and estimated due date
- Blood work — blood type and Rh factor, complete blood count, rubella immunity, STI screening, and thyroid function among others
- Discussion of prenatal vitamin supplementation
- Review of your medical history and any risk factors
- Information about first trimester screening options — including NIPT (non-invasive prenatal testing) and nuchal translucency ultrasound, typically offered between 11 and 14 weeks
If you are in Ontario, the OHIP-funded prenatal care pathway covers the standard appointments and blood work. Other provinces have similar coverage — your care provider can walk you through what is covered in your region.
The First Trimester as a Whole
Five weeks is the very beginning of a first trimester that most people find the most privately difficult part of pregnancy. The symptoms are significant, the risk of miscarriage is at its highest, and most people have not yet told anyone. You are navigating something enormous without the support structure that comes later.
A few things worth knowing: the risk of miscarriage drops significantly after a heartbeat is detected, typically around six to seven weeks. Most first trimester symptoms ease considerably by weeks 12 to 14. And the work your body is doing right now — invisible, exhausting, and extraordinary — is among the most complex biological activity that occurs in human development.
As you move through the first trimester and begin thinking about what lies ahead, our 10 Serious Pregnancy Complications guide gives you the plain-language information on what to watch for across pregnancy. And when the time comes to start thinking about birth preparation, our Hospital Bag Checklist is a useful reference to bookmark now and return to later.
→ Read our What Not to Eat During Pregnancy guide — the foods to avoid and why, for Canadian moms.
→ Read our 10 Serious Pregnancy Complications guide — what to watch for across pregnancy and when to seek help.
→ Read our Hospital Bag Checklist — bookmark it now, come back to it at 35 weeks.
→ Shop the Cradle Song Co collection — curated essentials for pregnancy, postpartum, and baby’s first year.
