Pregnancy Guide: Weeks, Trimesters, Nutrition and Tools

Pregnancy at a Glance

Pregnancy is generally measured in gestational weeks and days, usually beginning from the first day of the last menstrual period. A pregnancy due date is estimated at around 40 weeks, although it remains a guide rather than a prediction of the exact day labour or birth will occur.

Pregnancy weeks are commonly grouped into three stages called trimesters. As pregnancy progresses, the developing baby grows and changes, while your body may experience physical, hormonal and emotional changes. Antenatal appointments, tests and scans can also help your maternity-care team monitor your health and the pregnancy.

Understand the trimesters of pregnancy.

Find the Pregnancy Information You Need

Choose the path that best matches your current question.

Pregnancy Calculators and Tools

Pregnancy tools can help you understand pregnancy timing and organise important dates. Their results are estimates and should not replace pregnancy dates recorded by your doctor, midwife or maternity-care professional.

Pregnancy Due Date and Gestational Age Calculator

Estimate your due date and calculate how many weeks and days pregnant you are using:

• The first day of your last menstrual period; or
• A known estimated due date.

Your result can include your gestational age, current pregnancy week, trimester, approximate conception date and time remaining until your estimated due date.

Pregnancy Calendar by Due Date

Create a personalised pregnancy timeline using your estimated due date. Follow your pregnancy weeks and trimester transitions in one place.

Pregnancy Weeks, Due Dates and Gestational Age

Pregnancy dating connects your estimated due date with your current gestational age, pregnancy week and trimester.

The standard last-menstrual-period method estimates the due date at around 40 weeks from the first day of the last period. Its usefulness can be affected by irregular cycles or uncertainty about the date entered.

Follow Pregnancy by Stage

Week- and trimester-based information can help you connect gestational age with fetal development, changes in your body and the care that may be relevant at different stages. Pregnancy, Birth and Baby provides week-by-week information about fetal growth and what may be happening to the pregnant person's body.

Pregnancy Nutrition

A varied diet provides energy, protein, vitamins, minerals and other nutrients during pregnancy. Individual requirements can vary, and a doctor, midwife or dietitian can provide advice based on your diet, health and pregnancy circumstances.

Some nutrients have specific Australian pregnancy guidance. Healthdirect advises discussing supplement needs and dosages with a doctor or midwife rather than assuming every supplement is suitable for everyone.

Start with the pregnancy nutrition guide

Explore dietary foundations, food choices, important nutrients and general supplement considerations.

Popular pregnancy nutrition guides

Key nutrients during pregnancy

Explore educational guides about priority pregnancy nutrients:

Other pregnancy nutrient articles should be accessed through the pregnancy nutrition guide rather than all being promoted as first-level pregnancy destinations.

Antenatal Care and Pregnancy Information

Antenatal care includes appointments, checkups, tests and scans offered during pregnancy. These can provide information about your health and your baby's health and may help identify matters that need further assessment.

Your care will depend on factors such as:

• Your health history
• Your stage of pregnancy
• Whether you are carrying one baby or more
• Results from screening or tests
• Recommendations from your maternity-care team

Speak with your health professional about the appointments, tests and scans appropriate for your pregnancy.

Pregnancy Symptoms and Everyday Safety

Pregnancy experiences vary. Some physical and emotional changes are common, but symptoms can also have causes unrelated to pregnancy.

Seek advice from your health professional when:

• You are concerned about a symptom
• A symptom is severe or sudden
• A symptom continues or becomes worse

Pregnancy Vitamins and Supplements

Food and a varied diet are central to pregnancy nutrition. Supplements may complement dietary intake, but suitability can vary according to your diet, health, medicines and professional recommendations.

Before choosing or combining pregnancy supplements:

• Read the product label and approved directions.
• Consider nutrients already supplied by food and other products.
• Check for overlapping ingredients.
• Speak with your doctor, midwife, pharmacist or dietitian about your individual needs.

The TGA regulates vitamins and other therapeutic goods in Australia, and product advertising must comply with restrictions on health and therapeutic claims.

The information on this page does not determine whether a particular product, ingredient or dosage is appropriate for you.

Before and After Pregnancy

Pregnancy is one stage of a broader reproductive and maternal-health journey.

Information Notice

The information on this page is general and educational. It does not:

• Confirm pregnancy
• Diagnose a health condition
• Interpret an individual test or scan
• Replace antenatal care
• Recommend a specific medicine or supplement
• Replace personalised advice from a healthcare professional

Contact your doctor, midwife, pharmacist or another qualified healthcare professional for advice about your individual circumstances.

Seek appropriate medical care promptly if you are concerned about your pregnancy or symptoms.