Month 3: End of First Trimester
Weeks 9–13 of Pregnancy
Month 3 brings the 12-week scan and the end of the first trimester.
Congratulations on reaching the final month of your first trimester. This is an exciting milestone as the risk of miscarriage significantly decreases after week 12. Many couples choose to share their pregnancy news after the 12-week scan. Your baby is now officially a fetus and looks remarkably human.
What is happening this month
Month 3 marks the completion of your baby's basic physical structure. All organs, muscles, limbs, and bones are in place, and now they will continue to grow and mature. This month typically brings the much-anticipated 12-week scan, where you will see your baby moving and may even catch them sucking their thumb.
Week-by-week development
Your baby is now a fetus. All essential organs are formed. Tiny muscles allow movement, though you cannot feel it yet.
Vital organs begin to function. The brain is developing rapidly, with 250,000 neurons created every minute.
Your baby can open and close their fists. Hair follicles and nail beds are forming. They are becoming very active.
Reflexes kick in. Your baby can suck, swallow, and even hiccup. The 12-week scan shows incredible detail.
Your baby's vocal cords develop. Fingerprints form on tiny fingertips. The intestines move into their proper position.
Your baby's development
By the end of month 3, your baby has grown to about the size of a lime (5–6cm) and weighs approximately 14–18 grams. The developments this month are truly remarkable:
- Face looks unmistakably human with eyes moving closer together
- Fingers and toes are fully separated with tiny nails beginning to grow
- External genitals are developing, though it is still too early to determine sex
- Vocal cords are forming
- Kidneys start producing urine
- Bone marrow begins making white blood cells
- The pancreas starts producing insulin
- Intestines, which were partially in the umbilical cord, move into the abdomen
Size comparison
Your baby is about the size of a lime
5–6 cm (2–2.5 inches)Changes in your body
As you near the end of the first trimester, many women experience a welcome shift in symptoms. While everyone's experience is unique, common changes during month 3 include:
Easing Nausea
Morning sickness often begins to subside for many women
Energy Return
The extreme fatigue starts lifting as you approach the second trimester
Visible Changes
Clothes may feel tighter as your uterus grows above the pelvic bone
Skin Changes
The pregnancy glow may appear, though some women experience acne
Gum Sensitivity
Hormones can make your gums more sensitive and prone to bleeding
Heartburn
Digestive changes may cause heartburn or indigestion
Important care tips
12-week dating scan
This dating scan checks your baby's development, confirms your due date, and screens for chromosomal abnormalities such as Down's syndrome. You will receive photos and may be offered additional screening tests including the combined test. It is an emotional moment seeing your baby move for the first time.
Sharing the news
Many couples feel comfortable announcing their pregnancy after the 12-week scan. Consider how and when you want to share your news with family, friends, and your employer. Remember you have employment rights during pregnancy in the UK, and should inform your employer by week 25 at the latest.
Free NHS dental care
Schedule a dental check-up if you have not already. Pregnancy hormones can affect your oral health. Dental care is free on the NHS during pregnancy and for one year after birth with your MatB1 certificate, issued by your midwife, GP or obstetrician. Maintain good oral hygiene to prevent pregnancy gingivitis.
Maternity clothes
You may need to start thinking about maternity clothes. Your regular clothes might feel uncomfortable around the waist. Consider investing in a few basic pieces that can grow with you. Stretchy waistbands and flowing tops are your friends.
When to contact your midwife, maternity unit or call 999
If you experience any of the following, contact your midwife or go directly to your nearest maternity assessment unit. In an emergency, call 999.
- Heavy vaginal bleeding or passing clots
- Severe abdominal pain or persistent cramping
- Sudden loss of pregnancy symptoms
- Severe headaches or vision changes
- Persistent vomiting preventing fluid intake
- Signs of urinary tract infection (burning, frequency, fever)
Looking ahead
As you complete your first trimester, you are entering what many women call the golden period of pregnancy. The second trimester often brings renewed energy, a visible baby bump, and the amazing experience of feeling your baby's first movements around 16–20 weeks. You have navigated the most critical developmental period. Well done! Your next routine antenatal appointment will typically be around 16 weeks. Take time to celebrate this milestone and look forward to the exciting months ahead.
Frequently asked questions
In month 3, your baby becomes a fetus and all major organs are formed. You will have your 12-week scan, morning sickness often begins to ease, and the risk of miscarriage significantly decreases after week 12.
The 12-week dating scan checks your baby's development, confirms your due date, and screens for chromosomal abnormalities. You will see your baby moving and will receive photos. It is often when couples feel comfortable sharing their pregnancy news.
Morning sickness often begins to ease during month 3 as you approach the second trimester. Many women experience significant improvement after week 12, though every pregnancy is different.
At 12 weeks, your baby is about the size of a lime, measuring 5–6cm (2–2.5 inches) and weighing approximately 14–18 grams. All major organs are formed and beginning to function.
Many couples choose to announce their pregnancy after the 12-week scan because the risk of miscarriage significantly decreases after this point. However, the timing of your announcement is entirely personal.
Normal symptoms include easing nausea, returning energy, clothes feeling tighter, skin changes, gum sensitivity, and possible heartburn. Many women start to feel more like themselves again as they enter the second trimester.
You may start needing maternity clothes around month 3 as your uterus grows above the pelvic bone. Look for stretchy waistbands and flowing tops for comfort as your body changes.
The 12-week scan includes screening for chromosomal abnormalities such as Down's syndrome. Additional tests like the combined test or chorionic villus sampling (CVS) may be offered based on your individual circumstances.
