A pregnancy guide for moms in Thailand: trimester by trimester, what's normal and what to tell your doctor fast

From the day you see two lines, your head fills up with questions. Is this normal? Do I need to see a doctor about that? Can I eat this? The older relatives say one thing, your friends say another, and the internet makes it worse, until some nights you’re lying awake going round in circles at 2 a.m.

So we wanted this page to be a “map” of the whole 9 months. We go trimester by trimester: what usually comes up when, which symptoms are normal and which ones you should tell your doctor about fast. If you want to go deeper on anything, just click through. Save this page and come back to it whenever you start to feel unsettled.

How the 1st, 2nd and 3rd trimesters are counted, and why it matters

Quick Answer: Roughly, the first trimester runs to about 13 weeks, the second from about 14 to 27 weeks, and the third from 28 weeks until birth. It’s worth knowing because a lot of advice changes with how far along you are.

Gestational age is counted from the first day of your last period, not the day of conception, and your doctor will fine-tune it with an early ultrasound. Simply put: go by the number your doctor writes in your antenatal record book.

Trimester	Approximate gestational age	Main focus of this stage
First	Start to about 13 weeks	Starting antenatal care early, morning sickness, spotting
Second	About 14 to 27 weeks	Ultrasound, first movements, vaccines, food and eating
Third	28 weeks until birth	Sleep position, baby’s movements, pre-eclampsia, getting ready for birth

Different sources may draw the lines a week or two apart. Don’t overthink this part.

First trimester: what’s normal, what to tell your doctor fast

Quick Answer: Tiring easily, nausea, sore breasts and peeing a lot are normal. But heavy bleeding, severe or one-sided abdominal pain, and vomiting so much you can’t keep water down all mean going to hospital quickly.

First thing to do: start antenatal care

The Royal Thai College of Obstetricians and Gynaecologists and the WHO recommend your first antenatal visit in the first trimester, by 12 weeks at the latest. This is to work out your gestational age accurately, run blood tests to screen for conditions such as thalassemia, syphilis, hepatitis B and HIV, and start supplements like folic acid, iron and iodine as your doctor prescribes.

As for the old belief that you should “wait three months before going,” we’d really love to see that one change. When you tell the relatives is up to you, but don’t wait to see a doctor.

Read more: First antenatal visit: how many weeks, what to bring, and questions to write down for your doctor

Morning sickness

Nausea and vomiting are something most moms go through in the first trimester, and it usually eases at around 16 to 20 weeks. Ordinary morning sickness doesn’t add risk to the baby. But if you can’t keep water or food down for 24 hours, you’re passing little urine and it’s dark, or you feel faint, it may be severe morning sickness that needs IV fluids and medicine.

Read more: Morning sickness so bad you throw up water: is that still normal?

Spotting

Light bleeding in early pregnancy is common, and many women go on to have a normal pregnancy. What you need to look at alongside it is how much blood there is, whether there’s pain with it, and whether your doctor has confirmed the pregnancy is in the uterus. Call the hospital every time you bleed.

Read more: Light bleeding in early pregnancy: look at these 3 things together

Eating, drinking and medicines in the first trimester

This is when baby is forming their organs, so there are especially lots of questions about what you can and can’t have. The short rule: eat food that’s cooked through, don’t buy medicines or herbal remedies on your own, and always ask a doctor or pharmacist first.

• Foods to avoid in pregnancy
• How much coffee can you drink a day when pregnant?
• Can you take paracetamol when pregnant?

Second trimester: the stage many people say is the most comfortable

Quick Answer: Morning sickness usually eases, your energy comes back, and you start to feel baby move at around 16 to 24 weeks. But keep going to your appointments, because many conditions start without symptoms.

What often comes up

• Less morning sickness, and food tastes good again (if you suddenly crave som tam, the spicy papaya salad, read Can you eat som tam when pregnant? first)
• Your bump starts to show, and your usual pants won’t button up
• Backache and a dragging ache at the sides of your belly from the growing uterus
• Baby starts to move. In a first pregnancy you may feel it after 20 weeks, and in later pregnancies usually earlier. At first it feels like a fish nibbling or little bubbles popping

Checks you’ll often have this trimester

The WHO recommends at least one ultrasound before 24 weeks to confirm gestational age, check for abnormalities in the baby, and see whether it’s twins. Your doctor may also book Down syndrome screening, gestational diabetes testing for those at risk, and talk to you about the vaccines recommended during pregnancy.

Read more: Which vaccines should you get when pregnant, and when?

Tell your doctor fast in the second trimester if…

• You have vaginal bleeding
• You have regular, rhythmic abdominal pain, or clear fluid leaking from the vagina, before your due date
• You get a severe headache, blurred vision, or sudden swelling of the face, hands or feet (from 20 weeks, think pre-eclampsia)
• You have a high fever, or burning or difficulty when you pee
• You’ve been feeling baby move regularly, but the movements have slowed down

Third trimester: counting down to birth

Quick Answer: After 28 weeks, start going to sleep on your side, get to know baby’s movement pattern by heart, know the signs of pre-eclampsia, and have your hospital bag ready.

Sleep position

After 28 weeks of pregnancy, it’s recommended that you start going to sleep on your side, left or right are both fine, both at night and for daytime naps. If you wake up on your back, don’t panic. Just roll back over and go back to sleep.

Read more: Do pregnant women have to sleep only on their left side?

Baby’s movements

The NHS advises moms to get to know their own baby’s normal movement pattern, and if you feel baby is moving less than usual, call the hospital right away, even in the middle of the night, don’t wait until tomorrow. You also shouldn’t use a home fetal heart monitor instead of going in to be checked.

Many hospitals in Thailand teach you how to count baby’s kicks and include a chart in your antenatal record book. Just follow what your own hospital recommends.

Read more: How to count baby’s kicks, and how few counts as “less”?

Pre-eclampsia

Pre-eclampsia usually happens from 20 weeks onward. The first signs are high blood pressure and protein in the urine, which moms usually can’t feel themselves, but which are picked up at antenatal checkups. Symptoms that mean going to hospital fast:

• A severe headache that ordinary painkillers don’t fix
• Blurred vision, or seeing flashing lights
• Pain just below the ribs
• Swelling of the face, hands or feet that comes on quickly

Read more: Pre-eclampsia warning signs you shouldn’t wait for your appointment over

Unusual itching

An itchy belly from stretching skin is normal. But if you have intense itching on the palms of your hands and soles of your feet, especially at night, tell your doctor quickly.

Read more: Itchy palms and soles in pregnancy: why doctors want to hear about it fast

False labor or real labor

Toward the end, many women get their belly tightening on and off, irregularly. Most of the time that’s false labor. Real labor gets more frequent, stronger and more clearly rhythmic as it goes on.

Read more: False labor vs real labor: how to tell, and when to go to hospital

Getting ready for the birth

Start packing your hospital bag at around 32 to 36 weeks. Call the hospital first to ask what they already provide, so you don’t haul along things twice. And have the car seat installed before the day you bring baby home.

Read more: Hospital bag: the complete checklist

How many antenatal visits, and which benefits can you use?

Quick Answer: The WHO recommends at least 8, and the NHSO (สปสช.) says Thai citizens under every health coverage scheme are entitled to 8 quality antenatal visits matched to gestational age.

The WHO schedule is a first visit within 12 weeks, then at around 20, 26, 30, 34, 36, 38 and 40 weeks. Many hospitals in Thailand book appointments along these lines or more often, and the Royal Thai College of Obstetricians and Gynaecologists guideline lets doctors adjust the frequency to each woman’s risk.

On benefits, news from the NHSO (August 2026) says antenatal care covers blood tests, ultrasound, Down syndrome screening, vaccines and supplements such as iron, folic acid and iodine. Check participating service units in the Pao Tang app (เป๋าตัง) or on the 1330 hotline. The details change from time to time, so check every time before you go.

Advice from the elders: what to trust and what to ask your doctor about

Quick Answer: A lot of it comes from a good place and has some truth to it, but some of it has no evidence behind it or can cause needless worry. For medicines, herbal remedies and unusual symptoms, go by your doctor’s advice.

What you often hear	The short truth
“Wait three months before starting antenatal care”	Go as soon as you know you’re pregnant, by 12 weeks at the latest
“Sickness this bad means it’s definitely a girl”	You can’t tell the sex from morning sickness
“Bleeding means you’ve miscarried”	Not always. Many women go on with the pregnancy, but a doctor needs to check
“You must sleep on your left side only”	After 28 weeks, left or right are both fine
“Drink coconut water and baby will have beautiful skin”	No evidence it changes baby’s skin. Fine to drink in moderation like any other drink
“Herbal tonics and boiled herbal brews (ยาต้ม, ยาหม้อ) strengthen the pregnancy”	Some herbs aren’t safe in pregnancy. Always ask a doctor or pharmacist first

The elders really do mean well. When you talk with them, try the line “this is what my antenatal doctor recommends.” Most of the time it makes the conversation much easier.

Go to hospital straight away if… (any trimester)

Quick Answer: For the symptoms below, don’t wait for your appointment. Go to the emergency room or the labor ward, or call 1669 (Thailand’s emergency medical number) if it’s serious.

• Heavy vaginal bleeding, or bleeding with severe abdominal pain, shoulder pain or feeling faint
• Vomiting so much you can’t keep water down for 24 hours, passing little urine that’s dark
• A severe headache, blurred vision, pain below the ribs, sudden swelling of the face, hands or feet
• Baby moving less than usual (after you’ve been feeling regular movements)
• Clear fluid leaking from the vagina, or regular contractions before 37 weeks
• A high fever with chills
• Intense itching on the palms and soles (call the same day)

Ask for the labor ward or antenatal clinic phone number on day one. Save it in both mom’s and dad’s phones, so on the day you actually need it you’re not sitting there searching for it.

Mom’s mind needs care too

Quick Answer: Worry, mood swings and crying easily are things many moms go through. But if the sadness or worry keeps going until you can’t eat or sleep, tell your doctor or nurse at your antenatal visit.

Reading a lot can help, but sometimes the more you read the more you worry. Try sticking to trustworthy sources, write your questions down for your doctor, and let the medical team carry some of the load. You don’t have to know everything on your own.

If you’re thinking about work or income during pregnancy and after the birth, have a look at Starting a business while raising kids for some ideas.

Every trimester brings its own worries, but you’re not on this journey alone. Read one thing at a time, ask your doctor one question at a time, and we hope you sleep a little more easily tonight.