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Third Trimester

39 Weeks Pregnant

Your baby is the size of a Mini watermelon 🍉

🍉
Ashok Kumar Poudel
Written by
Ashok Kumar Poudel
Health & Wellness Writer
Dr. Bina Basnet
Medically reviewed by
MBBS, MD — Gynecologist & Obstetrician
Last reviewed:
Feb 2026
📏
Size
Mini watermelon
📐
Length
50.7 cm
⚖️
Weight
3.3 kg
🗓️
Trimester
Third
⏱️
Week
39 of 40

🌱 Baby Development at Week 39

FULL TERM (optimal). Studies show 39 weeks is the safest time for birth. All systems go! Baby has a firm grip. Skull is malleable for birth. Vernix caseosa will lubricate baby during delivery. Immune system primed and ready.

OPTIMAL BIRTH WEEK 🌟All systems readyCervix dilating

🤱 Common Symptoms

Cervix dilating and effacing
Contractions may begin
Mucus plug passage
Loose stools (natural labor prep)
Strong nesting urge

🥗 Nutrition Tips

  • Light easily digestible labor food
  • Coconut water for electrolytes
  • Avoid large meals

🏃‍♀️ Exercise Tips

  • Walking to encourage labor
  • Nipple stimulation (with provider advice) to increase oxytocin
  • Rest and stay calm

🏥 Medical Tests & Appointments

Weekly appointmentsDiscuss induction if no labor begins soon

🔬 Hormone Changes

Progesterone sharply declines. Oxytocin, prostaglandins, and estrogen surge triggering labor. CRH from fetal lungs signals readiness.

📖 Week 39 Pregnancy — In-Depth Guide

At 39 weeks, you’ve probably reached the height of anxiety waiting for your baby.

Given that you are getting mentally prepared for your baby, you are most likely feeling uncomfortable and impatient and may be a little freaked out about your delivery especially if you’re going to be a first time mom.

Your baby is fully developed when you’re 39 weeks pregnant, and is similar in size to a winter melon Even though he/she is fully developed, they will continue to plump up until they enter the real world.

🩺39th Week Pregnancy Symptoms

You’ve been experiencing in the last few weeks of your pregnancy. Without further ado, here are the common symptoms you may experience in week 39.

Pressure in the pelvic area

pelvic area pressure during pregnancy

This is mainly caused by the fact that your baby is now moved a further down in your body to get ready for the right position of birth.

Braxton Hicks contractions

Braxton Hicks contractions during pregnancy

You may regularly feel cramping or tightening of your uterus, which can be easily confused for labor pains. But these pains are temporary and you generally get some relief by switching positions.

Lightning crotch

Lightning crotch

Given your baby has moved down so low, he or she is bound to hit some sensitive nerves resulting in lightning type sensations in your pelvis.

Urge to nest

Some moms clam that when their between 37 – 39 weeks pregnant, they feel the strong urge to do stuff such as clean out closets and mop floors.

Body show/mucus plug

This is when your body releases mucus like thick discharge that can sometimes have a tinge of blood in it. This is generally a good sign that you’ll go into labor soon, so pay attention to it.

🤰Inside your Belly in Week 39

At 39 weeks, you should be looking out for the early signs of labor. It is important if you haven’t already, to educate yourself on what they are.

But in most cases they are extremely strong that they can’t be ignored.Call your doctor immediately if you experience any of these signs:

Regular contractions

It may be a good idea to start timing your contractions if you find your belly tightening and constantly for some time. The time this phase lasts varies across women hence it is important to keep your OB in the loop.

Water breaking

You may not always have a huge gush of water, but a small trickle could also mean your water is broken. If the discharge is thin and watery rather than what it was in the previous weeks of pregnancy, it is sign that you’ll go into labor very soon.

Inducing Labor when you’re 39 Weeks Pregnant

At this stage, you may be wondering how to induce labor so here’s a quick primer: But before we get to them, note that taking herbal remedies or guzzling down castor oil isn’t considered safe,

Acupuncture to induce pregnancy labor

Even though this is not a proven way to induce pregnancy, many going-to-be moms claim it works hence worth the mention. What is ancient practice is proven to do is regulate blood flow resulting in regulated blood flow that stimulates your cervix to dilate.

Walking

Short and long walks are a great and medically proven way to help induce labor owing to the fact that the pressure triggers the dilating process of the cervix.

There may be times where your OB may recommend a medical induction for one or more reasons.

Including pregnancy complications such as gestational diabetes, preeclampsia, heart condition, uterus infection or placenta problems.

📷39th Week Pregnant Ultrasound - What to Expect ?

At 39 weeks pregnant, your doctor might conduct a biophysical profile, which is a combination of an ultrasound and non-stress test to assess your baby’s wellbeing.

This test is especially done if you’re pregnant with twins, and if all good, your OB may recommend an early delivery.

ultrasound week 39

👶Your Baby's Development in Week 39

When you’re 39 weeks pregnant, your little munchkin weighs roughly 7.25 lbs and measures 19.96 inches.

Your baby’s position in most cases is their head facing down, and if so is ready to set foot in the real world.

However, some babies prefer the heads up position medically termed as breech, which does pose some health risks and usually requires a C-Section.

Pregnancy Week 39 Checklist

Finalize baby names if you haven’t done so already
Educate yourself on the delivery process
Make a baby diary
📅 Track Your Pregnancy:Due Date CalculatorSymptoms by WeekTrimester Guide← Week 38Week 40

Frequently Asked Questions

Common questions answered by our medical team

At 39 weeks, your baby is approximately the size of a Mini watermelon (🍉). FULL TERM (optimal). Studies show 39 weeks is the safest time for birth. All systems go! Baby has a firm grip. Skull is malleable for birth. Vernix caseosa will lubricate baby during delivery. Immune system primed and ready.

← Week 38Calculate Your Due DateWeek 40

🔗 Related Third Trimester Resources

Second Trimester
Weeks 14–27 guide
Trimesters Explained
Guide to all three trimesters
Symptoms Week by Week
What to expect each week
How Many Weeks Pregnant Am I?
Calculate your pregnancy weeks

All Pregnancy Weeks

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