Pregnancy Week 39
Pregnancy Week 39
What to expect on pregnancy week 39
Pregnancy Week 39 marks the beginning of the full-term period. The fetal chest continues getting larger, body fat continues accumulating and the brain, lungs and nervous system continue important final prenatal maturation while labor may begin at any time.
Pregnancy Week 39 Overview
Pregnancy Week 39 is an important milestone because the pregnancy has entered the medically defined full-term period.
The fetus looks increasingly like a newborn, but development has not stopped. The chest continues becoming larger, additional fat forms throughout the body and the brain, lungs and nervous system continue preparing for life outside the uterus.
Pregnancy Week 39 Is Full Term
According to ACOG and the Society for Maternal-Fetal Medicine, full term begins at 39 weeks 0 days.
| Pregnancy Stage | Gestational Age |
|---|---|
| Early Term | 37 weeks 0 days through 38 weeks 6 days |
| Full Term | 39 weeks 0 days through 40 weeks 6 days |
| Late Term | 41 weeks 0 days through 41 weeks 6 days |
| Postterm | 42 weeks 0 days and later |
How Big Is the Fetus at Pregnancy Week 39?
The NHS describes a Week 39 fetus as approximately 50.7 centimeters from head to heel.
The NHS compares this with the approximate size of a small watermelon.
Fetal size varies naturally, especially during the final weeks of pregnancy.
There is therefore no single Week 39 length or weight that every healthy fetus must match.
More Body Fat Forms at Pregnancy Week 39
Mayo Clinic specifically identifies continued body-fat accumulation as a Week 39 developmental change.
Fat is added across the fetal body and helps produce the smoother, fuller appearance associated with late pregnancy.
These fat stores also play an important role after birth by helping the newborn maintain body temperature.
Additional subcutaneous fat creates increasingly rounded fetal proportions.
Fat beneath the skin supports the smooth late-pregnancy appearance.
Fat stores help the newborn maintain body temperature after birth.
Fetal growth and body composition continue changing as birth approaches.
The Fetal Chest Continues Getting Larger
Mayo Clinic identifies enlargement of the fetal chest as another specific Pregnancy Week 39 development.
The chest contains the lungs and other structures that have undergone major development throughout pregnancy.
The larger chest is part of the fetus's overall growth and changing body proportions.
This does not mean respiratory development has completely stopped.
Brain Development Continues at Week 39
The fetal brain remains in an important stage of maturation at Week 39.
ACOG includes the brain and nervous system among the systems still finishing development during Weeks 37 through 40.
The nervous system supports increasingly sophisticated coordination of fetal movement, swallowing, sensory responses and other functions.
Neurological development continues after birth as well.
Lung Development at Pregnancy Week 39
The lungs are highly developed by Pregnancy Week 39.
However, ACOG still includes the lungs among the systems completing important maturation during Weeks 37 through 40.
Inside the uterus, oxygen continues reaching the fetus through the placenta.
Air breathing begins only after birth.
Vernix at Pregnancy Week 39
A white, creamy or waxy coating called vernix caseosa may still cover parts of the fetal skin.
The NHS explains that vernix helps protect fetal skin during pregnancy.
The amount present at birth varies.
Some newborns have noticeable vernix while others have relatively little.
Its presence or absence should not be used as a home method of judging gestational age or fetal health.
Baby Position at Pregnancy Week 39
Most fetuses are in a head-down position by Week 39.
The head may sit low within the pelvis as the body prepares for labor.
This can increase pressure in the lower abdomen, pelvis and bladder.
Some people notice their bump appearing lower.
However, engagement does not predict the exact day labor will begin.
Fetal Movement at Pregnancy Week 39
Movement remains important throughout Pregnancy Week 39.
There is less room for dramatic flips, so the type of movement may feel different from earlier pregnancy.
You may notice rolls, stretches, pushes, wiggles and strong localized pressure.
The fetus should continue moving in its usual pattern.
Maternal Changes During Pregnancy Week 39
Late-pregnancy discomfort can be especially noticeable as the fetus occupies substantial space and may sit lower in the pelvis.
The NHS notes that vaginal discharge may increase.
Back pain and pressure at the bottom of the abdomen can also become more noticeable as the fetal head moves lower.
Some people experience bursts of energy or a strong desire to prepare the home, often referred to as nesting.
Vaginal Discharge at Pregnancy Week 39
Increased vaginal discharge can occur as the estimated delivery date approaches.
The NHS describes normal late-pregnancy discharge as usually thin, white and without a strong unpleasant smell.
Mucus from the cervix may also become noticeable as cervical changes occur.
What Is a “Show” at Pregnancy Week 39?
The cervix is sealed by thick mucus during pregnancy.
As the cervix begins changing in preparation for labor, some or all of this mucus may be released.
The NHS calls this a “show” and notes that the mucus may appear yellow or slightly bloody.
A show can occur before labor, but it does not tell you exactly when labor will start.
Possible Signs of Labor at Pregnancy Week 39
Labor can begin at any point during Week 39.
ACOG describes several changes that may occur as labor approaches.
True labor contractions tend to develop a pattern and become closer together.
Amniotic fluid can appear as a gush or a persistent trickle.
Clear, pink, yellow or slightly blood-streaked mucus may appear.
The fetal head may settle lower into the pelvis before labor.
Braxton Hicks vs True Labor Contractions
Braxton Hicks contractions can remain common at Week 39.
They are usually irregular and may not steadily become stronger or closer together.
ACOG notes that true labor contractions generally occur at regular intervals and become closer together with time.
They also tend to become stronger as labor progresses.
What If Your Waters Break at Week 39?
Rupture of membranes occurs when the amniotic sac breaks.
This can produce a noticeable gush of fluid or a slower persistent trickle.
It can sometimes be difficult to distinguish amniotic fluid from urine or normal vaginal discharge.
The timing of labor and any need for induction after membrane rupture depends on individual circumstances and clinical assessment.
Nesting at Pregnancy Week 39
The NHS notes that some people experience sudden bursts of energy and a strong desire to clean, organize or prepare for the baby's arrival.
This is commonly called the nesting instinct.
Not everyone experiences nesting.
It also does not reliably predict that labor will begin within a specific number of hours or days.
Possible Pregnancy Week 39 Symptoms
Practice contractions may occur frequently as birth approaches.
A lower fetal position and late-pregnancy posture can contribute to back discomfort.
A low fetal head can increase pressure around the pelvis and bladder.
Vaginal discharge and cervical mucus changes may become more noticeable.
Physical discomfort and anticipation of labor can interfere with sleep.
Indigestion or reflux can continue during the final weeks.
Calf and foot cramps can continue, particularly at night.
Mild swelling can occur, while sudden or severe swelling needs assessment.
Symptoms That Need Prompt Medical Attention
Being full term does not mean that pregnancy warning signs can be ignored.
Contact your maternity or healthcare team promptly for concerning symptoms.
A significant change in the baby's usual activity pattern needs assessment.
Heavy bleeding is different from a small blood-streaked mucus show.
A severe headache that does not improve can be a warning symptom.
Blurred vision, flashing lights or seeing spots needs attention.
Persistent pain under the ribs or in the upper abdomen can be concerning.
Sudden or extreme swelling of the face or hands deserves prompt assessment.
Preeclampsia Awareness at Pregnancy Week 39
Preeclampsia can develop during pregnancy and can also occur after birth.
ACOG emphasizes continued blood-pressure monitoring during prenatal care because hypertension may sometimes occur without obvious symptoms.
Cervical Changes Before Labor
As labor approaches, the cervix generally begins becoming softer, thinner and more open.
These changes are commonly described as cervical ripening, effacement and dilation.
The amount of cervical change does not always predict exactly when labor will begin.
Some people can have early cervical changes for days before active labor.
Can Labor Be Induced at Pregnancy Week 39?
Yes, labor induction can be performed at Week 39 when appropriate.
ACOG states that an elective 39-week induction may be discussed when certain conditions are met.
Examples include:
ACOG specifically discusses this option for some people having their first full-term pregnancy.
The elective 39-week approach discussed by ACOG applies to a singleton pregnancy.
The pregnant person and fetus should be healthy for elective induction to be considered in this context.
The benefits, disadvantages and personal preferences should be discussed with the healthcare professional.
When Earlier or Medically Indicated Delivery May Be Recommended
The timing of delivery can change when there are maternal or fetal health concerns.
ACOG lists conditions such as hypertension, preeclampsia, problems with fetal growth or rupture of membranes among situations in which delivery timing may need individualized planning.
The risks of continuing pregnancy are weighed against the risks and benefits of delivery.
A recommendation for induction should therefore be based on the specific pregnancy rather than a generic week-by-week rule.
Membrane Sweep Around Pregnancy Week 39
In some maternity systems, a membrane sweep may be discussed or offered from around Week 39.
A membrane sweep is performed during a vaginal examination by a trained healthcare professional.
The purpose is to stimulate local hormonal activity that may help labor begin naturally.
Whether and when it is offered depends on your healthcare system, pregnancy history, cervical findings and personal preferences.
Prenatal Care Around Pregnancy Week 39
There is not one universal Week 39 appointment schedule.
Visit timing depends on your healthcare system, whether this is your first pregnancy and whether additional monitoring is needed.
Late-pregnancy care can include:
Blood-pressure monitoring remains important until delivery.
The healthcare professional may assess whether the fetus is head down.
Any change in the baby's usual activity should be discussed promptly.
You can review when to call and what to do when labor begins.
Planned Birth at Pregnancy Week 39
When a planned cesarean birth is needed and there is no medical reason to deliver earlier, many maternity systems schedule the procedure at or after 39 weeks.
The exact timing depends on the reason for cesarean birth, pregnancy history, maternal health and fetal wellbeing.
Some medical circumstances require birth before Week 39.
Your own delivery date should therefore be determined by your healthcare team.
Healthy Choices During Pregnancy Week 39
Continue Eating Regularly
Choose balanced meals and nutrient-rich foods suited to your individual needs and appetite.
Stay Hydrated
Drink fluids regularly according to your activity, climate and medical circumstances.
Keep Moving When Comfortable
Gentle pregnancy-appropriate activity may support mobility and wellbeing if your healthcare professional has not advised restriction.
Prioritize Rest
Labor can begin unpredictably, so balance practical preparation with adequate sleep and rest.
Keep Important Information Ready
Have your maternity contact details and relevant pregnancy records easy to access.
Follow Your Medication Plan
Do not stop prescribed medicines or change supplements without speaking with the healthcare professional responsible for your care.
Pregnancy Week 39 and Your Estimated Due Date
Pregnancy is conventionally dated from the first day of the last menstrual period.
Our Pregnancy Due Date Calculator can help estimate an expected delivery date using relevant pregnancy dating information.
At Pregnancy Week 39, approximately one week remains until a 40-week estimated due date.
That does not mean labor will necessarily begin exactly one week later.
ACOG notes that only about 1 in 20 pregnant people give birth on their exact estimated due date.
The due date is therefore an estimate used for pregnancy dating and clinical planning rather than a guaranteed birth date.
Pregnancy Week 39 Development Timeline
ACOG defines Week 39 as the beginning of the full-term period.
Mayo Clinic identifies enlargement of the fetal chest at Week 39.
Additional fat supports a fuller body and temperature regulation after birth.
Neurological maturation remains active before and after birth.
Rolls, stretches, pushes and other usual movements should continue.
Regular contractions, a show or waters breaking can occur at any time.
What Happens After Pregnancy Week 39?
Pregnancy Week 40 includes the conventional estimated due date.
Mayo Clinic gives an approximate Week 40 crown-to-rump length of 36 centimeters and average weight of about 3,400 grams or 7½ pounds.
Healthy babies can be considerably smaller or larger than these averages.
Reaching the estimated due date without labor starting is not by itself unusual.
Fetal movement should continue in the baby's usual pattern while pregnancy continues.
Pregnancy Tools You May Find Useful
Estimate an expected delivery date using relevant pregnancy dating information.
Estimate the current gestational week using appropriate pregnancy dating information.
Estimate a possible conception date or range while recognizing natural biological variation.
See approximately how much estimated time remains until the due date.
When Professional Healthcare Guidance Is Important
Pregnancy week-by-week information provides general education and cannot determine whether an individual pregnancy or fetus is developing normally.
Contact your maternity team if you think labor is beginning, your waters may have broken or you are unsure whether contractions are true labor.
Seek prompt professional assessment for heavy vaginal bleeding, severe or constant abdominal pain, fever, fainting, significantly reduced fetal movement or other concerning symptoms.
Persistent severe headache, vision changes, sudden face or hand swelling, significant upper abdominal pain, chest pain, severe breathing difficulty or significant one-sided leg swelling also requires professional assessment.
Pregnancy Week 39 FAQs
What happens during Pregnancy Week 39?
During Pregnancy Week 39, the pregnancy is full term, the fetal chest continues getting larger, additional body fat forms throughout the body and the brain, lungs and nervous system continue final prenatal maturation.
How big is the fetus at 39 weeks?
The NHS describes the fetus as around 50.7 centimeters from head to heel at Pregnancy Week 39, approximately the size of a small watermelon, although individual fetal size varies.
Is Pregnancy Week 39 full term?
Yes. ACOG defines full term as 39 weeks 0 days through 40 weeks 6 days, so Pregnancy Week 39 marks the beginning of the full-term period.
Does fetal movement decrease at Pregnancy Week 39?
No. Movement may feel different because space is limited, but your baby's usual movement pattern should continue. Reduced movement, no movement or a significant change in the usual pattern needs prompt professional assessment.
What are common signs of labor at Week 39?
Possible signs of labor include contractions that become regular and stronger, lightening, loss of the mucus plug or bloody show, and rupture of membranes.
What is a bloody show at Pregnancy Week 39?
A bloody show is mucus that may look pink, yellow or slightly blood-streaked as the cervix changes before labor. Heavy vaginal bleeding is different and requires urgent medical assessment.
What should I do if my water breaks at Week 39?
If you think your water has broken, contact your maternity or obstetric healthcare team and follow their instructions, even if regular contractions have not started.
Can labor be induced at Pregnancy Week 39?
Yes. ACOG states that elective induction may be discussed at 39 weeks in certain healthy pregnancies, including some first full-term pregnancies with one fetus, but the decision should be individualized with a healthcare professional.
Is vernix still present at Pregnancy Week 39?
Yes. Vernix can still coat some of the fetal skin at Pregnancy Week 39, although the amount varies and some babies have more vernix than others when they are born.
What happens during Pregnancy Week 40?
Pregnancy Week 40 includes the estimated due date for a conventionally dated pregnancy. Fetal movement should continue, and the fetus may weigh around 3,400 grams on average, although healthy babies vary widely in size.
Medical References and Further Reading
This Pregnancy Week 39 guide uses established medical and public-health guidance for general educational information.
Next: Pregnancy Week 40
Pregnancy Week 40 includes the estimated due date. The fetus remains full term, movement should continue in the usual pattern and labor may begin before or after the estimated due date.
Comments
Post a Comment