6 Weeks Pregnant- What to Expect? | Baby’s First Milestones

At 6 weeks pregnant, your baby is sweet pea-sized, their heart starts beating, and morning sickness often begins—time for your first prenatal visit.

The size of a sweet pea doesn’t sound dramatic. But at 6 weeks pregnant, that tiny measurement marks a stage where a lot is happening—and where a lot of questions begin. You may have just missed your period, or you’ve known for a week or two, and the reality is setting in with new physical changes.

At 6 weeks, your baby’s heart starts beating. Morning sickness often starts, and fatigue may hit harder than expected. It’s also the right time to schedule your first prenatal visit. Here’s what you can expect during these early days of pregnancy, along with guidance on when symptoms are normal and when to call your doctor.

Baby Development at 6 Weeks

Your embryo is about the size of a sweet pea—roughly 1/8 to 1/4 of an inch long. That’s tiny, but it’s doubling in size at this stage. The heart begins to beat, and the neural tube, which will become the brain and spinal cord, is closing.

The baby’s head, jaw, cheeks, and chin are starting to take shape. Small buds that will grow into arms and legs are forming. The digestive and respiratory systems are also beginning to develop. Your baby’s face is slowly becoming more defined, though still microscopic.

All of this growth happens rapidly during week 6. Many women don’t realize how much is going on behind the scenes. Your body is working hard to support this early development.

Why the Symptoms Hit So Hard

By week 6, changing hormone levels—especially hCG and progesterone—can affect nearly every system. That’s why symptoms that felt subtle earlier may suddenly feel more noticeable. It’s not in your head; it’s biology.

• Morning sickness: About 90% of people experience nausea, which often starts by week 6, peaks around week 10, and improves by week 14. It can include vomiting or just feeling queasy.
• Metallic taste and smell sensitivity: You might notice a metallic taste in your mouth or find that certain smells—even ones you used to enjoy—trigger nausea.
• Fatigue and bloating: Your body is working overtime to support the growing embryo. Fatigue can feel like a heavy fog, and bloating is common as digestion slows.
• Mood swings and breast tenderness: Hormonal shifts can cause emotions to feel more intense. Breasts may feel swollen, heavy, or tender to the touch.
• Frequent urination: Your kidneys are processing more fluid, and the growing uterus adds pressure to your bladder. You may find yourself running to the bathroom more often.

Symptoms vary widely from person to person. Some women have few symptoms; others feel them intensely. Both can be normal. The key is knowing which symptoms are expected and which deserve a call to your doctor.

What to Do: Schedule Your First Prenatal Appointment

The NHS recommends making your first antenatal appointment when you’re about 6 to 8 weeks pregnant. That timing lets your doctor or midwife confirm the pregnancy, estimate your due date, and discuss early prenatal care. If you haven’t scheduled yet, aim to call soon.

At this appointment, you’ll likely review your health history, get bloodwork, and talk about lifestyle adjustments. Your doctor can also address any early symptoms and give you a sense of what’s coming in the weeks ahead. The baby size at 6 weeks page from the NHS provides a helpful overview of what’s developing.

A table of common symptoms and when to call can help you feel more prepared.

This table covers the most common experiences. Your own symptoms may differ. Always trust your gut—if something feels off, call your provider.

Five Signs That Warrant a Call to Your Doctor

While many symptoms are normal, some warrant a conversation with your healthcare provider. The CDC and other experts highlight these warning signs.

1. Vaginal bleeding or spotting that becomes heavy, or any bleeding that worries you. Light spotting can be normal, but heavier bleeding needs evaluation.
2. Severe abdominal or pelvic pain that doesn’t go away. Cramping is common, but persistent sharp pain is not.
3. Fever, dizziness, or lightheadedness. These can signal infection or low blood pressure. A temperature over 100.4°F (38°C) is a good reason to call.
4. Painful or burning urination, or blood in the urine. These are signs of a possible urinary tract infection, which should be treated promptly during pregnancy.
5. Sudden swelling in your hands, face, or eyes, or rapid weight gain. These can be early signs of preeclampsia, which needs attention.

If you experience any of these, call your doctor, midwife, or nurse advice line without delay. Don’t worry about being overly cautious—your provider wants to hear from you.

How Your Baby Is Growing This Week

Beyond the sweet pea size, your baby’s body is busy forming essential structures. The head, jaw, cheeks, and chin are beginning to take shape. According to baby head and limbs forming resources, small buds for arms and legs are visible. The neural tube, which becomes the brain and spinal cord, closes during this week, and the tiny heart is now beating.

The digestive and respiratory systems are also developing. It’s remarkable how much is happening inside an embryo that’s still smaller than a pea. This rapid growth is why getting enough nutrients—especially folic acid—matters so much early in pregnancy.

These milestones are part of why the first trimester is so crucial for development. Your body is building an entire tiny human from scratch.

The Bottom Line

Week 6 of pregnancy brings rapid development for your baby and noticeable symptoms for you. Morning sickness, fatigue, and breast tenderness are common. Scheduling your first prenatal visit around this time sets the stage for healthy monitoring. Pay attention to warning signs, but try not to worry about minor fluctuations.

If you have heavy bleeding, severe pain, or a fever, reach out to your obstetrician or midwife right away. They can evaluate your specific situation and provide personalized guidance for the weeks ahead.