A Week-by-Week Pregnancy Calendar

It all starts when you notice a light pink line on that pee-stick. And suddenly, your entire world changes. The next few months? They feel like you’ve stepped onto an extraordinary rollercoaster. One that takes you on a journey filled with new surprises, emotions, and changes with every turn. And every passing week makes you wonder what’s next.

In this blog, we’ll take you through the guide map of this rollercoaster journey, aka, a week-by-week pregnancy calendar. The calendar will help you understand what’s happening inside you each week. And what those little milestones truly mean.

Ready to begin? Dive in!

Exploring Pregnancy Trimester Wise

Pregnancy has been divided into 40 weeks or nine months with three trimesters. The weeks 1-12 comprise the first trimester, weeks 13-26 the second trimester and weeks 37-40 the third or last trimester.¹

Let’s read about them in more detail.

1) First Trimester (Weeks 1–12)

The first trimester covers the earliest and most critical period of your baby’s development.²

• During the first two weeks, your body prepares for ovulation and then fertilisation. 
• By week 3, fertilisation occurs and the tiny embryo (which later forms the fetus) begins to form. 
• Around week 5–6, the neural tube (which becomes the brain and spinal cord) develops, and the baby’s heart starts beating. 
• Major organs such as the lungs, heart, and ears also start forming by week 8.

For an expectant mom, this phase may bring along nausea, fatigue, breast tenderness, and a lot of hormonal changes.

Routine checkups become essential, and so does taking prenatal supplements like folic acid. It helps support early fetal development and prevent birth defects such as neural tube defects.

2) Second Trimester (Weeks 13–26)

By the second trimester, the risk of miscarriage significantly goes down. This is also the time by which many women start feeling better physically.²

• The fetus starts to move at around week 16–20, and you may feel these movements as gentle flutters. 
• Facial features, fingerprints, and nails also form gradually. 
• Their organs continue to mature, and by week 24, the fetus can hear and respond to sound. 
• Around the midpoint of the second trimester, an ultrasound scan is usually done to assess your baby’s growth and check for any structural abnormalities.

For the mother, this trimester brings noticeable weight gain, and her belly bump starts becoming noticeable. And it’s also common to experience back pain or mild swelling in the legs due to increased blood volume and pressure around this time.

3) Third Trimester (Weeks 27–40)

In the final trimester, the fetus grows rapidly and prepares for birth.³

• Fat accumulates under their skin, and the lungs continue to mature until around week 36. 
• Your baby’s bones harden, though the skull remains soft so that it can easily pass through the vaginal canal during delivery. 
• By weeks 37–40, most babies position themselves head-down in the uterus.

For the mother, common symptoms include shortness of breath, frequent urination, and difficulty sleeping due to the growing uterus. Regular prenatal checks are more important than ever now as they help her & her doctor keep track of blood pressure, fetal position and signs of labour.

Understanding Due Dates

Your ideal estimated due date (EDD) is 40 weeks from the first day of the last menstrual period. However, like its name, this date is just an estimate. In fact, only about 5% of babies are born on their exact due date. Most of them arrive between 37 and 42 weeks, which is considered full term. ⁵

That said, doctors may adjust your due date as you proceed with the pregnancy based on early ultrasound measurements, especially if your cycles are irregular. 

Tracking your trimesters and due date is essential. It helps ensure timely checkups, vaccinations, and prompt preparation for delivery.

Getting Started

To dive deeper into your week-by-week pregnancy journey, simply click on the pregnancy week you’re interested in.