The First Stage of Pregnancy – What’s Happening in Your Body

When Does Pregnancy Start?

Pregnancy is dated from the first day of your last menstrual period, even though conception typically happens about two weeks later. So when you're “4 weeks pregnant,” the embryo has only been growing for about two weeks.

Early Pregnancy Symptoms

Most people notice they’re pregnant when their period is late, but some symptoms can show up earlier:

• Sore or tender breasts
• Fatigue
• Nausea (commonly called “morning sickness”)
• Mood swings
• Frequent urination
• Mild cramping or a dull ache in your lower abdomen

Keep in mind that everyone is different – some feel symptoms right away, others don’t feel anything at all.

What’s Happening in Your Body?

In the early weeks of pregnancy, your body goes through some major changes:

• A fertilized egg implants in the uterus
• The hormone hCG starts to increase – this is what pregnancy tests measure
• Your body begins forming the placenta
• The uterus starts expanding, although you can’t see it yet

Your immune system also adjusts to avoid rejecting the growing embryo. This can cause tiredness or even mild cold-like symptoms.

What to Keep in Mind Early On

Finding out you’re pregnant often leads to a lot of questions. Here are a few things to keep in mind:

• Schedule your first prenatal visit (typically between weeks 8–12)
• Begin taking folic acid if you haven’t already – it helps reduce the risk of neural tube defects
• Avoid alcohol, smoking, and harmful substances
• Try to eat nutritious meals regularly, even if you’re feeling nauseous
• Rest when you need to – fatigue is your body’s way of adjusting to all the changes

Emotional Changes in Early Pregnancy

It’s common to feel a rollercoaster of emotions. Maybe your pregnancy was planned – or maybe it was unexpected. Either way, it's okay to feel anything from joy to uncertainty. Talk to your partner, a friend, or a healthcare provider if you need support.

When to Contact a Doctor

In most cases, you just need to book a regular appointment with your provider. But if you experience intense pain, bleeding, or fever – reach out to your doctor right away, as these may be signs of something that needs medical attention.