13 Weeks Pregnant: Baby Development, Symptoms and Tips
Short Answer: At 13 week pregnancy, your baby is about 7 cm long, roughly the size of a peach or a lemon, and weighs around 23 to 25 grams. The organs are formed and working, the fingerprints have developed, and the baby can kick, stretch and suck a thumb. For many people this week marks the start of the second trimester. Nausea and tiredness often ease, energy returns and the miscarriage risk is much lower. You may start to show. The nuchal translucency scan must be done by 13 weeks and 6 days, so book it now if you have not already. Keep taking folic acid, eat well, stay active and call a doctor for heavy bleeding, severe pain or vomiting you cannot control.
Pregnancy weeks are counted from the first day of your last period, not from conception. Thirteen weeks pregnant means about eleven weeks since conception. You are at the end of the third month with about 27 weeks to go. Some guides place the start of the second trimester at week 13 and others at week 14, so both labels are correct. For the week before, read our guide to 12 weeks pregnant, for the next, 14 weeks pregnant, and to follow the whole journey see our pregnancy guidelines week by week.
Week 13 at a glance
| Detail | At 13 weeks |
|---|---|
| Trimester | End of first, or start of second |
| Months | About 3 |
| Baby’s length | About 7 cm (2.8 inches) |
| Baby’s weight | About 23 to 25 grams |
| Heart rate | About 150 to 160 beats per minute |
| Weeks to go | About 27 |
| Size comparison | A peach or a lemon |
Your baby at 13 weeks
Growth. Your baby has more than doubled in length since week 9, and the body is now catching up with the head. The head is still about a third of the body length. Growth over the next weeks is mostly weight and length.
Face. The face looks more distinct. The eyes have moved toward the front of the head, and the ears are close to their final position. The eyelids stay closed. The nose, lips and cheeks are more defined, and tooth buds are forming in the gums.
Hands and feet. Fingers and toes are separate, and tiny nails are growing. The fingerprint pattern has formed. Your baby can open and close the fists, curl the toes and put a hand to the mouth.
Movement. Your baby kicks, stretches, turns and may hiccup. The muscles and nerves are linking up, and reflexes are starting. You will not feel these movements yet. Most people notice the first flutters between 16 and 22 weeks, and later in a first pregnancy. An ultrasound can show the movement clearly.
Organs. The intestines have moved back into the belly, the kidneys make urine, the liver makes bile and the pancreas is producing insulin. The bone marrow is making blood cells. The vocal cords are formed. The bones are hardening from cartilage, and the skull is still soft.
Sex. The genitals are developing. Some scans can hint at the sex at 13 weeks, but a guess this early is often wrong. The routine anomaly scan at 18 to 22 weeks is when most parents find out.
Placenta. The placenta now produces the hormones that sustain the pregnancy and feeds your baby. That is why symptoms such as nausea often fade at this point. The amniotic fluid is increasing, and your baby swallows and breathes it in, which helps the lungs develop.
Your body at 13 weeks
Womb. Your womb is about the size of a grapefruit or a small melon, and it is rising out of the pelvis. Many people see a firmer, rounder lower belly. Some start to show a bump now, especially in a second or later pregnancy. Others show later, and both are normal.
Hormones. hCG has fallen from its peak. Estrogen and progesterone stay high. Many people notice that nausea, extreme tiredness and breast pain ease around now, though they last longer for some.
Energy and appetite. Energy often returns. You may feel hungry after weeks of nausea. Your calorie needs rise slightly in the second trimester, but you still do not need to eat for two.
Blood and circulation. Your blood volume keeps rising. You may feel dizzy when you stand up quickly, notice veins on your breasts and legs or get nosebleeds and a stuffy nose.
Skin and hair. Hormones can cause a glow, acne, dry skin or darker patches on the face, called melasma. A dark line may appear down the belly in the coming weeks. Hair often looks thicker.
Libido. Many people notice that their sex drive returns or rises as nausea fades.
Mood. Mood swings often settle as hormone levels stabilise. Worry about scan results and about changes to come is normal.
Common symptoms and what helps
| Symptom | Why it happens | What helps |
|---|---|---|
| Lingering nausea | Falling but still high hormone levels | Small meals every 2 to 3 hours, dry biscuits before getting up, ginger tea, cold sips of water |
| Tiredness | Progesterone, extra blood volume | Early bedtime, a short afternoon rest |
| Round ligament pain, a sharp pull in the lower belly or groin | Ligaments stretch as the womb grows | Move slowly, change position, rest, warm bath |
| Bloating and gas | Slower digestion | Smaller meals, avoid fizzy drinks, short walks |
| Constipation | Slow gut, iron tablets | Fibre, water, daily movement |
| Heartburn | Relaxed valve at the top of the stomach | Smaller meals, avoid spicy and oily food, stay upright after eating |
| Frequent urination | Womb still presses on the bladder | Drink water by day, less before bed |
| Headaches | Hormones, tiredness, dehydration | Rest, fluids, ask your doctor before taking medicine |
| Dizziness | Blood pressure changes, low blood sugar | Eat regularly, stand up slowly |
| Stuffy nose, nosebleeds | More blood flow to the nose lining | Saline spray, a humidifier |
| Bleeding gums | More blood flow to the gums | Soft brush, gentle flossing, dental check |
| Increased vaginal discharge | Hormones | Cotton underwear, no douching |
| Leg cramps | Circulation and mineral changes | Gentle stretching, drink water, ask your doctor about calcium |
Do not start vitamin B6, anti-nausea medicine or herbal remedies without your doctor’s advice.
When to call a doctor
| Usually normal | Call a doctor soon |
|---|---|
| Mild period-like cramps | Severe or constant abdominal pain |
| Short sharp pulls in the lower belly | Bleeding that soaks a pad in an hour, or with clots |
| Light spotting that stops | Cannot keep water down for 24 hours, dark urine or fast weight loss |
| Tiredness, mood swings | Fainting, severe dizziness or shoulder-tip pain |
| Milky white discharge | Fever, burning urination, foul or itchy discharge |
| Occasional headache | Severe headache with blurred vision or swelling |
| Breast tenderness | Passing tissue or fluid |
Report any bleeding to your doctor, even if it is light. Severe, constant vomiting can be hyperemesis gravidarum, which is treatable. If you feel sad, anxious or hopeless for more than two weeks, tell your doctor. If you ever have thoughts of harming yourself, seek help right away.
Tests and scans this week
This is the last week for first-trimester screening. The nuchal translucency scan and combined screening must be done by 13 weeks and 6 days. Which tests you can choose depends on where you live and what your doctor offers.
| Test | When | What it does |
|---|---|---|
| Nuchal translucency scan | 11 to 13 weeks and 6 days | Measures fluid at the back of the baby’s neck |
| Combined screening blood test | 11 to 13 weeks and 6 days | Checks pregnancy hormones, used with the scan |
| NIPT (blood test) | From 10 weeks | Screens for Down syndrome and some other conditions |
| CVS (chorionic villus sampling) | 10 to 13 weeks | Diagnostic test offered when risk is high |
| Amniocentesis | From 15 to 16 weeks | Diagnostic test, if screening shows a higher chance |
| Anomaly scan | 18 to 22 weeks | Checks organs, growth and often the sex |
| Glucose test | 24 to 28 weeks | Screens for gestational diabetes |
The nuchal translucency scan. A sonographer measures your baby’s length and a small fold of fluid at the back of the neck. With your age and blood test results, this gives an estimate of the chance of conditions such as Down syndrome, Edwards syndrome and Patau syndrome. The scan also confirms your due date, counts the number of babies and checks the heartbeat. If you have missed this window, ask your doctor about NIPT or other options.
What the results mean. A screening result is a chance, not a diagnosis. A low chance is reassuring but not a guarantee. A higher chance means you can talk to your doctor about CVS or amniocentesis, which give a firm answer. Most people with a higher chance result still have a healthy baby.
Other checks. Ask about your hemoglobin, blood group and Rh factor, blood sugar, blood pressure and urine. If your blood group is Rh negative, ask about anti-D injections, usually given around 28 weeks. Ask about thalassemia screening, which is common in South Asia. Ask your doctor about the tetanus-diphtheria vaccine during pregnancy and the right time to get it.
Nutrition and weight gain
Eat more of:
- Protein: eggs, well-cooked fish, chicken, lentils (dal), beans and milk
- Iron-rich foods: leafy greens (shak), lean meat and lentils, with lemon or guava for vitamin C
- Fruit and vegetables: a variety of colours every day
- Whole grains and fibre: brown rice, whole wheat roti and oats
- Calcium: milk, yogurt and small fish eaten with the bones
- Water: about 8 to 10 glasses across the day
Take as advised: folic acid, usually 400 micrograms a day, and the iron, calcium and vitamin D your doctor prescribes. Do not add extra supplements on your own.
Limit: caffeine to about 200 mg a day, which is one or two cups of tea or a single small coffee, and sugary and fried snacks.
Avoid:
- Alcohol and all tobacco, including second-hand smoke and products like zarda and jorda
- Raw or undercooked meat, fish and eggs
- Unpasteurized milk and cheese
- Unwashed fruit and vegetables
- Large predatory fish that can be high in mercury, such as shark and swordfish
- High-dose vitamin A supplements, and large amounts of liver
- Herbal tonics and remedies your doctor has not approved
Weight gain. Your doctor will track your weight at each visit. Total gain over the whole pregnancy depends on your weight before pregnancy. These are general guides, and Asian-specific BMI ranges may apply, so ask your doctor.
| Weight before pregnancy | Recommended total gain |
|---|---|
| Underweight | 12.5 to 18 kg |
| Normal weight | 11.5 to 16 kg |
| Overweight | 7 to 11.5 kg |
| Obese | 5 to 9 kg |
Most people gain only 0.5 to 2 kg in the first trimester. In the second trimester, a person of normal weight usually gains about 0.4 to 0.5 kg a week. Your calorie needs rise by about 300 calories a day. A banana, a glass of milk and a handful of nuts is about that much.
Everyday tips for week 13
Rest. Go to bed early and nap when you can. Start sleeping on your side, with a pillow between your knees. This position is recommended later in pregnancy, and the habit is easier to build early.
Move. A daily walk helps digestion, sleep and mood. Swimming, prenatal yoga and pelvic floor exercises are fine for most people. Avoid contact sports, heavy lifting and anything with a risk of falls. Stop and call your doctor if you have pain, bleeding or dizziness.
Medicines. Do not take any medicine, including painkillers and herbal products, without asking a doctor or pharmacist. Do not stop prescribed medicine on your own.
Heat. Avoid saunas, steam rooms and very hot baths.
Dental care. Hormones can make gums bleed. Brush gently, floss and have a dental check. Dental treatment is safe in pregnancy, and the second trimester is the best time for it.
Clothes. Switch to loose, comfortable clothes, a supportive bra and flat, comfortable shoes. You may need larger sizes soon.
Skin. Use sunscreen and a hat to limit dark patches on the face.
Travel. The second trimester is often the most comfortable time to travel. Check with your doctor before long trips and carry your prenatal records.
Sex. It is safe for most healthy pregnancies unless your doctor advises otherwise. Many people find their desire returns now.
Partners. Come to appointments if you can, help with chores and ask how she feels, then listen.
Work, maternity leave and sharing the news
Many people feel better in the second trimester and can work more comfortably. Tell your doctor about night shifts, chemicals, heavy lifting or long standing. Under Bangladesh’s labour law, working mothers in the private sector are entitled to 16 weeks of paid maternity leave, eight weeks before and eight weeks after the birth. Government employees receive six months. Check your own contract, because policies differ, and plan when to tell your employer.
Many people wait until after the first-trimester scan to share the news, because the chance of miscarriage falls. This week is a common time to tell family and friends, but it is your choice. You do not owe anyone an explanation if you prefer to wait.
What comes next
At 14 weeks, you are firmly in the second trimester. Many people have more energy, a visible bump and less nausea. Around weeks 16 to 22 you may feel the first flutters of movement. The anomaly scan is at 18 to 22 weeks, and the gestational diabetes test usually comes at 24 to 28 weeks. Prenatal visits are usually every four weeks at this stage. Keep your appointments, because blood pressure, weight, urine and hemoglobin checks catch problems early.
Checklist for this week
- Book or confirm your nuchal translucency scan before 13 weeks and 6 days
- Ask about NIPT, CVS and the costs
- Take folic acid and any prescribed supplements
- Ask about thalassemia screening, Rh factor and the tetanus-diphtheria vaccine
- Keep a list of your medicines and share it with your doctor
- Stock simple snacks, and aim for balanced meals now that appetite is returning
- Cut caffeine, alcohol and tobacco
- Save your doctor’s number and the nearest hospital’s emergency number
- Check your work and maternity leave plans
- Book a dental check
- Tell one trusted person how you are feeling
FAQ
How big is the baby at 13 weeks?
About 7 cm long and 23 to 25 grams, roughly the size of a peach or a lemon. Sizes vary a little between babies.
Is 13 weeks the second trimester?
Some sources say the second trimester starts at week 13, and others at week 14. Both are used, so your doctor may call it either.
Is the risk of miscarriage lower at 13 weeks?
Yes. The risk falls sharply after the first trimester, especially once a heartbeat has been seen. Call your doctor for any bleeding or severe pain.
Should I have a bump at 13 weeks?
Not necessarily. Many people do not show until week 14 or later, and some show a small bump now. Both are normal.
When does morning sickness stop?
It often eases between weeks 12 and 14, but it lasts longer for some. Tell your doctor if it is severe.
What is round ligament pain?
A short, sharp pain in the lower belly or groin, caused by the ligaments that support the womb stretching. It is usually harmless and eases with rest. Call your doctor if it is severe or comes with bleeding or fever.
Can I find out the baby’s sex at 13 weeks?
Not reliably. The anomaly scan at 18 to 22 weeks is when most parents find out.
Can I feel the baby move at 13 weeks?
No. Your baby moves, but you will not feel it until around 16 to 22 weeks.
Is it safe to exercise at 13 weeks?
Yes for most healthy pregnancies. Walking, swimming, gentle yoga and pelvic floor exercises are good. Avoid contact sports and heavy lifting.
Note: This article gives general information and does not replace advice from your doctor or midwife. Every pregnancy is different. Call your doctor or go to a hospital if you have bleeding, severe pain, fainting or any symptom that worries you.
