40 Weeks Pregnant: What to Expect at Full Term

How Big Is My Baby at 40 Weeks?

At 40 weeks pregnant, your baby weighs approximately 3.5 kilograms (7.7 pounds) and measures about 51 centimeters (20 inches) from crown to heel. However, healthy babies can vary significantly in size, ranging from 2.5 to 4.5 kilograms at full term. The placenta weighs around 500 grams and continues to provide nutrients until birth.

Your baby has been growing steadily throughout pregnancy, and by week 40, they have reached their full birth size. While averages provide useful benchmarks, it is important to understand that every baby develops at their own pace. Factors such as genetics, maternal nutrition, and overall health influence your baby's final birth weight and length.

The variation in baby size at full term is significant and completely normal. First-time mothers often have slightly smaller babies compared to subsequent pregnancies. Male babies tend to be marginally larger than female babies on average. Your healthcare provider has been monitoring your baby's growth throughout pregnancy through fundal height measurements and ultrasound examinations to ensure healthy development.

At this stage, the placenta remains a vital organ, weighing approximately half a kilogram. Despite being 40 weeks into pregnancy, the placenta continues to function efficiently, transferring oxygen, nutrients, and antibodies to your baby while removing waste products. This remarkable organ will continue supporting your baby until the moment of delivery, after which it is no longer needed and is delivered as the afterbirth.

Fetal Development at 40 Weeks

Your baby is now fully developed and ready for birth. All major organ systems have matured, including the lungs, which are the last organs to fully develop. The lungs are now producing adequate surfactant, a substance that helps the air sacs remain open after birth, enabling your baby to breathe independently.

The brain continues to develop rapidly, and this development will continue throughout infancy and early childhood. Your baby's skull bones remain soft and unfused, connected by flexible sutures and fontanelles (soft spots). This flexibility is essential as it allows the skull to mold and compress slightly during passage through the birth canal, protecting the brain while facilitating delivery.

Fat stores accumulated during the third trimester now account for approximately 15% of your baby's body weight. This fat is crucial for temperature regulation after birth, as newborns cannot shiver to generate heat like adults can. The layer of vernix caseosa (the waxy protective coating) may have mostly dissolved, though some babies are born with remnants still visible on their skin.

What Your Baby Can Do

Your 40-week baby is remarkably capable and ready for the outside world. They can see and focus on objects about 20-30 centimeters away - the perfect distance to see your face during breastfeeding. Their hearing is fully developed, and they recognize familiar voices, particularly yours and your partner's, having heard them throughout pregnancy.

Your baby has developed reflexes essential for survival, including the rooting reflex (turning toward touch on the cheek), sucking reflex, and grasp reflex. These primitive reflexes help with feeding immediately after birth. Your baby can also swallow, breathe (practicing with amniotic fluid), and has a regular sleep-wake cycle, though it may not align with yours.

What Are the Signs That Labor Is Starting?

Signs that labor may be starting include regular contractions that increase in intensity and frequency, your water breaking (rupture of membranes), loss of the mucus plug (bloody show), persistent lower back pain, increased pelvic pressure, and sometimes diarrhea. True labor contractions typically last 30-60 seconds and come at regular intervals that gradually get closer together.

As you reach your due date, you may experience various signs indicating that your body is preparing for labor. Understanding the difference between preparatory signs and actual labor helps you know when to contact your healthcare provider and when to head to your birth location. Every woman's experience is different, and some may experience multiple signs while others have very few warning signals before labor begins.

In the days or weeks before labor, you may notice your baby "dropping" or engaging lower into your pelvis. This process, called lightening, can make breathing easier as pressure on your diaphragm decreases, but it often increases pressure on your bladder, leading to more frequent urination. Some women experience this weeks before labor, while others don't notice it until labor begins.

Braxton Hicks contractions, also known as practice contractions, may become more frequent and noticeable as you approach your due date. Unlike true labor contractions, Braxton Hicks are irregular, do not increase in intensity over time, and typically stop when you change position or activity. They help prepare your uterus for labor but do not cause cervical dilation.

True Labor Contractions

True labor contractions have distinct characteristics that differentiate them from Braxton Hicks. They occur at regular intervals and become progressively closer together over time. Initially, contractions may be 15-20 minutes apart, gradually shortening to 5 minutes apart or less. Each contraction typically lasts between 30 and 60 seconds, eventually lengthening to 60-90 seconds as labor progresses.

The intensity of true labor contractions increases steadily over time. Unlike practice contractions that remain relatively mild, labor contractions become stronger and more intense. Many women describe them as a tightening or cramping sensation that starts in the lower back and radiates around to the front of the abdomen. Walking or changing position does not stop true labor contractions - they persist regardless of what you do.

A helpful method for timing contractions is the 5-1-1 rule: consider going to your birth location when contractions are 5 minutes apart, lasting 1 minute each, for at least 1 hour. However, every situation is different, and your healthcare provider may give you specific guidance based on your individual circumstances, especially if you have had a previous rapid labor or live far from your hospital.

Water Breaking

The rupture of membranes, commonly called water breaking, occurs when the amniotic sac surrounding your baby tears, releasing amniotic fluid. This can happen as a sudden gush of fluid or a slow, steady trickle that you might initially mistake for urine. Amniotic fluid is typically clear and odorless, though it may have a slightly sweet smell.

Only about 10-15% of women experience their water breaking before labor contractions begin. For most women, the membranes rupture during active labor or are artificially ruptured by their healthcare provider to help progress labor. If your water breaks before contractions start, labor usually begins within 24 hours.

It is important to note the time your water breaks, the color and odor of the fluid, and approximately how much fluid there was. Contact your healthcare provider immediately when your water breaks. If the fluid is green, brown, or has a foul smell, this could indicate meconium (baby's first stool) in the amniotic fluid or infection, both of which require prompt medical attention.

Loss of Mucus Plug and Bloody Show

Throughout pregnancy, a thick plug of mucus seals your cervix, protecting your baby from infection. As your cervix begins to soften, thin (efface), and open (dilate) in preparation for labor, this mucus plug may be released. It can come out all at once as a gelatinous blob or gradually over several days.

The mucus plug may be clear, slightly pink, or blood-tinged - this blood-tinged discharge is often called "bloody show." The presence of small amounts of blood is normal and results from tiny blood vessels in the cervix breaking as it dilates. Losing your mucus plug can occur hours, days, or even weeks before labor begins, so it is not a reliable indicator that labor is imminent.

What Happens If I Go Past My Due Date?

Going past your due date is common and usually not a cause for concern. A normal pregnancy can last from 37 to 42 weeks. Only about 5% of babies arrive on their exact due date, and approximately 80% are born within two weeks of the estimated date. Your healthcare provider will typically offer increased monitoring after 40 weeks and discuss induction options if pregnancy extends beyond 41-42 weeks.

It is completely normal for pregnancy to extend beyond the estimated due date. The due date calculation is based on a 40-week pregnancy from the first day of your last menstrual period, but this assumes a 28-day cycle with ovulation occurring on day 14. Since many women have irregular cycles or may not ovulate exactly on day 14, the actual conception date - and therefore the true due date - can vary.

Medical definitions distinguish between late-term pregnancy (41 weeks 0 days through 41 weeks 6 days) and post-term pregnancy (42 weeks 0 days and beyond). While most pregnancies that extend past 40 weeks result in healthy outcomes, post-term pregnancy does carry slightly increased risks, which is why healthcare providers typically recommend induction by 42 weeks if labor has not begun spontaneously.

The risks associated with post-term pregnancy include decreased amniotic fluid (oligohydramnios), placental insufficiency (the placenta becoming less effective at delivering nutrients), macrosomia (a larger baby that may complicate delivery), and meconium aspiration (the baby passing stool before birth and potentially inhaling it). While these risks are relatively small, they increase as pregnancy extends further past 42 weeks.

Monitoring After Your Due Date

If you pass your due date, your healthcare provider will likely recommend increased monitoring to ensure your baby remains healthy. This typically includes more frequent prenatal visits, often twice weekly, to check on both you and your baby's wellbeing.

Non-stress tests (NST) are commonly performed after 40 weeks. During this test, monitors track your baby's heart rate in response to their movements. A healthy baby's heart rate increases when they move, indicating they are receiving adequate oxygen. The test is painless and typically takes 20-30 minutes.

Amniotic fluid levels may also be checked via ultrasound. Adequate amniotic fluid is important for protecting your baby and supporting healthy development. If fluid levels become too low, your provider may recommend induction to prevent complications.

Labor Induction

If pregnancy extends to 41-42 weeks or if monitoring reveals concerns about your baby's wellbeing, your healthcare provider may recommend labor induction. Induction involves using medical interventions to start labor artificially. Several methods can be used, depending on your cervical readiness and individual circumstances.

Cervical ripening agents, such as prostaglandin medications, help soften and thin the cervix in preparation for labor. Mechanical methods, like a Foley balloon catheter, can also help dilate the cervix. Once the cervix is favorable, oxytocin (Pitocin) may be administered intravenously to stimulate contractions.

The decision to induce labor is made collaboratively between you and your healthcare provider, weighing the risks of continuing pregnancy against the risks of induction. Research shows that elective induction at 39-40 weeks in low-risk pregnancies does not increase cesarean delivery rates and may actually reduce them slightly in some populations.

Can I Naturally Induce Labor at 40 Weeks?

There is no scientifically proven method to naturally induce labor at home. Popular suggestions like walking, climbing stairs, having sex, eating spicy food, or stimulating nipples have not been shown in research to reliably start labor. Your body and baby will typically begin the labor process when they are ready, driven by complex hormonal signals between mother and baby.

As you approach and pass your due date, you may hear numerous suggestions for naturally inducing labor. It is important to understand that while many of these methods have been passed down through generations and are widely believed to work, scientific research has not found reliable evidence that any of them consistently trigger labor.

The initiation of labor is a complex process involving hormonal signals from both you and your baby. When your baby's lungs are mature, they release surfactant and other substances that trigger a cascade of hormonal changes, ultimately leading to the onset of labor. This intricate biological process cannot be easily overridden by external interventions.

Understanding why labor starts naturally helps explain why home remedies are generally ineffective. The process involves the maturation of your baby's hypothalamic-pituitary-adrenal axis, changes in progesterone and estrogen levels, increased prostaglandin production, and the release of oxytocin. These interconnected processes work together to prepare your body for labor and cannot be replicated by eating certain foods or engaging in specific activities.

Common Myths About Natural Induction

Walking and exercise: While staying active is healthy during pregnancy, walking or climbing stairs does not cause labor to start. The theory is that gravity and movement help the baby move lower into the pelvis and put pressure on the cervix, but there is no evidence that this triggers labor in a body not yet ready to deliver.

Sexual intercourse: The idea behind this suggestion is that semen contains prostaglandins (which can soften the cervix) and that orgasm causes uterine contractions. While these facts are true, the prostaglandin concentration in semen is much lower than what is used medically for cervical ripening, and the contractions from orgasm are not labor contractions. Studies have not shown that sex induces labor.

Spicy food: The theory suggests that spicy food stimulates the gut, which could stimulate the nearby uterus. There is no scientific support for this claim. What spicy food is more likely to give you is heartburn and digestive discomfort.

Nipple stimulation: This method has slightly more theoretical basis, as nipple stimulation does release oxytocin, the hormone that causes contractions. However, the results of studies are mixed, and the amount and duration of stimulation required could cause excessively strong contractions or uterine hyperstimulation, making this approach potentially risky without medical supervision.

Castor oil: Castor oil is a strong laxative that causes intestinal cramping, which some believe stimulates the uterus. While some studies show a possible weak association with labor onset, castor oil frequently causes unpleasant side effects including nausea, vomiting, diarrhea, and dehydration. Medical organizations generally advise against its use.

How Should I Prepare for Labor at 40 Weeks?

Preparation for labor at 40 weeks includes having your hospital bag packed, knowing the route to your birth location, having contact numbers readily available, ensuring your car seat is installed, and getting plenty of rest. Focus on eating regular, nutritious meals to maintain energy and review your birth preferences with your support person.

At 40 weeks, you have likely already completed most of your preparations for your baby's arrival. However, this is a good time to review your preparations and ensure everything is in place for when labor begins. Being well-prepared can help reduce anxiety and allow you to focus on the birthing process when the time comes.

The final weeks of pregnancy are an excellent time to rest as much as possible. Your body is working hard to support your full-term baby, and you will need energy reserves for labor and delivery. While it may be difficult to sleep comfortably at this stage, try to rest when you can, using pillows to support your body in comfortable positions.

Continue eating regular, nutritious meals even if you experience reduced appetite due to your baby taking up stomach space. Small, frequent meals may be more comfortable than large ones. Stay well-hydrated by drinking plenty of water. Good nutrition supports your energy levels and helps prepare your body for the physical demands of labor.

Hospital Bag Essentials

Your hospital bag should be packed and ready by 40 weeks. Essential items for you include comfortable clothes for labor and postpartum, toiletries, phone charger, identification and insurance cards, and your birth plan if you have one. Many hospitals provide basics like soap and towels, but you may prefer your own products.

For your baby, pack a few newborn-sized outfits (including something for the trip home), diapers, and a blanket. You will also need a properly installed infant car seat - hospitals typically will not discharge you without one. Remember that newborns need layers to maintain body temperature, so have a hat and appropriate clothing for the weather.

Consider packing items for your support person as well, such as snacks, a change of clothes, and entertainment for what can sometimes be a lengthy process. Having these items prepared reduces stress and allows everyone to focus on the birth.

Know Your Birth Location

Ensure you know the route to your hospital or birth center and have a backup route in case of traffic or road closures. Know where to park and which entrance to use, especially if arriving outside regular hours. Many hospitals have different entrances for labor and delivery than for general admissions.

Have your healthcare provider's contact number easily accessible, as well as the hospital's labor and delivery direct line. Know the criteria for when you should call or come in - this is typically when contractions follow the 5-1-1 pattern, when your water breaks, or if you have concerns about reduced fetal movement or other symptoms.

How Can I Take Care of Myself While Waiting?

Self-care at 40 weeks involves resting when possible, eating nutritious meals regularly, staying gently active with walks or prenatal exercises, managing discomfort with warm baths or massage, staying connected with your support system, and practicing relaxation techniques. Monitor your baby's movements daily and contact your healthcare provider with any concerns.

The waiting period at 40 weeks can feel challenging both physically and emotionally. Your body is working hard, you may be uncomfortable, and the anticipation of labor can create anxiety. Focusing on self-care during this time supports your wellbeing and helps you approach labor with strength and calm.

Physical comfort measures become increasingly important at this stage. Warm baths can help relieve muscle tension and promote relaxation - just ensure the water is not too hot (below 38C/100F). Gentle stretching, prenatal yoga, or swimming can help manage discomfort and maintain mobility. Massage, particularly of the lower back and feet, can provide relief and relaxation.

Sleep may be challenging due to your size, frequent urination, and general discomfort. Try sleeping on your left side with a pillow between your knees and another supporting your belly. Some women find sleeping partially propped up helps with breathing and heartburn. Nap during the day if nighttime sleep is disrupted.

Emotional Wellbeing

It is completely normal to experience a range of emotions at 40 weeks - excitement, anxiety, impatience, and even frustration. Acknowledging these feelings without judgment is an important aspect of emotional self-care. Talk to your partner, friends, or family about how you are feeling.

Mindfulness and relaxation techniques can help manage anxiety about labor and birth. Deep breathing exercises, progressive muscle relaxation, or guided meditation can promote calm. Many women find that practicing these techniques before labor helps them use them effectively during the birthing process.

Avoid constantly watching for signs of labor, as this can increase anxiety and make the wait feel longer. Instead, try to stay engaged with normal activities and enjoy this final time before your baby arrives. Spend quality time with your partner, watch movies, read books, or engage in hobbies you enjoy.

Monitoring Your Baby

Continuing to monitor your baby's movements is important at 40 weeks. You should feel regular movement throughout the day. While movement patterns may change slightly as your baby has less room, you should still notice movement at least 10 times within a 2-hour period during your baby's active time.

If you notice decreased fetal movement - significantly fewer movements than normal for your baby - contact your healthcare provider immediately. Do not wait to see if movement improves on its own. While reduced movement often has a benign explanation, it can sometimes indicate that the baby is in distress and needs evaluation.

When Should I Go to the Hospital?

Go to the hospital when your contractions follow the 5-1-1 pattern (5 minutes apart, lasting 1 minute, for 1 hour), when your water breaks, if you have heavy bleeding, severe pain, or if you notice reduced fetal movement. First-time mothers typically have longer labors, so there is usually time to travel safely once labor begins.

Knowing when to go to your birth location is one of the most common concerns for expectant parents, especially first-time mothers. Going too early may result in being sent home, while waiting too long could mean an uncomfortable car ride during advanced labor. Understanding the signs and guidelines helps you make the best decision for your situation.

The 5-1-1 rule is a helpful guideline for most full-term pregnancies: go to the hospital when contractions are 5 minutes apart, lasting 1 minute each, for at least 1 hour. However, if you have had a previous rapid labor, live far from your hospital, or have other risk factors, your healthcare provider may give you different guidance.

Time your contractions from the start of one contraction to the start of the next to determine how far apart they are. Also note how long each contraction lasts. True labor contractions typically become longer, stronger, and closer together over time. If you are unsure whether you are in labor, call your healthcare provider for guidance.

Situations Requiring Immediate Care

Certain situations require immediate medical attention, regardless of whether you think you are in labor. Go to the hospital immediately if your water breaks, especially if the fluid is green, brown, or has a foul odor. While clear amniotic fluid is normal, discolored or smelly fluid may indicate meconium or infection.

Heavy vaginal bleeding (soaking through a pad in an hour) requires immediate evaluation. While some blood-tinged mucus is normal during labor, heavy bleeding could indicate a problem with the placenta and needs urgent attention.

Reduced fetal movement is always a reason to seek evaluation. If you notice significantly fewer movements than normal, or if you cannot get your baby to move after trying (drinking cold water, eating, lying on your side), contact your healthcare provider or go to the hospital for monitoring.

Other reasons to seek immediate care include severe or persistent headache with visual changes (possible preeclampsia), severe abdominal pain that does not subside between contractions, fever or signs of infection, or any time you feel that something is wrong. Trust your instincts - it is always better to be evaluated and reassured than to delay care when there is a genuine problem.

Preparing for Breastfeeding After Birth

Your breasts have been preparing for breastfeeding throughout pregnancy. After birth, skin-to-skin contact helps initiate breastfeeding. Colostrum, the first milk, is rich in antibodies and perfect for your newborn's tiny stomach. Most babies feed frequently in the first days - 8 to 12 times per 24 hours is normal.

As you await labor, you may be thinking about feeding your baby after birth. Whether you plan to breastfeed, formula feed, or use a combination approach, understanding what to expect can help you feel more prepared. Breastfeeding is recommended by major health organizations as the optimal nutrition for infants, but the most important thing is that your baby is fed and you are supported.

Your body has been preparing for breastfeeding throughout pregnancy. The hormonal changes that support pregnancy also stimulate breast development for lactation. Some women notice their breasts produce small amounts of colostrum (the first milk) during the third trimester. This thick, yellowish fluid is perfectly designed for newborns, packed with antibodies, proteins, and other protective factors.

After birth, skin-to-skin contact with your baby helps initiate breastfeeding and supports bonding. Most hospitals practice immediate skin-to-skin after vaginal delivery, placing your naked baby on your bare chest. Babies have instinctive reflexes that help them find the breast and latch within the first hour after birth when given this opportunity.

What to Expect in the First Days

Newborns have tiny stomachs - about the size of a marble on day one, growing to the size of a ping-pong ball by day ten. This means they need to feed frequently but take small amounts at each feeding. It is normal for newborns to feed 8 to 12 times per 24 hours, and some may cluster feed (feeding very frequently for periods of time).

Your milk typically "comes in" (transitions from colostrum to mature milk in larger volumes) between days two and five after birth. Signs include breast fullness, heavier feeling breasts, and possibly some leaking. Until your milk comes in, the small amounts of colostrum you produce are exactly what your baby needs.

Breastfeeding is a learned skill for both you and your baby. While it is natural, it is not always easy at first. Seek help early if you are experiencing difficulties such as pain, concerns about milk supply, or challenges with latching. Most hospitals have lactation consultants available, and community resources exist for ongoing support.

Preparing to Care for Your Newborn

Newborns require frequent feeding, diaper changes, sleep, and lots of gentle care. They are sensitive to temperature extremes, loud noises, and need protection from infections. Skin-to-skin contact, responding to cries, and establishing routines help your baby feel secure. Bonding develops over time through everyday caregiving activities.

While waiting for labor, you may be thinking about caring for your newborn in the days and weeks after birth. Understanding what to expect can help you feel more confident as you transition into parenthood. Newborn care involves meeting your baby's basic needs while providing the emotional security that forms the foundation for healthy development.

Newborns sleep a lot - typically 16 to 17 hours per day - but not in long stretches. Their stomachs are small and need frequent filling, so they wake every 2 to 3 hours to feed, around the clock. While this sleep fragmentation is exhausting for parents, it is normal and temporary. Most babies begin sleeping longer stretches by 3 to 4 months of age.

Temperature regulation is challenging for newborns. They cannot shiver to generate heat like adults and have a large surface area relative to their body mass. Keep your baby comfortably dressed, typically in one more layer than you are wearing. A good rule is to dress your baby in what you are wearing plus one light layer. Check your baby's temperature by feeling their back or tummy rather than their hands or feet, which are often cooler.

Protecting Your Newborn

Newborns have immature immune systems and are vulnerable to infections. While you do not need to keep your baby in a sterile bubble, some precautions are sensible. Everyone who holds your baby should wash their hands first. Avoid contact with people who are sick, and limit visitors in the first weeks while your baby's immune system is developing.

Keep your baby away from cigarette smoke, which increases the risk of sudden infant death syndrome (SIDS), respiratory infections, and other health problems. If anyone in your household smokes, they should do so outside and change their outer clothing before holding the baby.

Always place your baby on their back to sleep, on a firm, flat surface without soft bedding, pillows, or toys. This "back to sleep" position significantly reduces the risk of SIDS. Your baby may sleep in your room (but not in your bed) for the first 6 to 12 months for convenience and safety.

The Importance of Bonding

Bonding with your newborn is a process that develops over time through everyday caregiving activities. Responding to your baby's cries, feeding them, changing diapers, and providing comfort all build the attachment relationship that is fundamental to your child's emotional and social development.

Some parents feel an immediate, intense connection with their newborn, while for others, bonding develops more gradually. Both experiences are normal. The exhaustion, hormonal changes, and adjustment to parenthood can affect how quickly you feel bonded. What matters is that you are responding to your baby's needs and spending time together.

Skin-to-skin contact promotes bonding and has numerous benefits for both you and your baby, including stabilizing baby's heart rate and temperature, promoting breastfeeding, and reducing crying. Both mothers and partners can practice skin-to-skin, and it can continue to benefit your baby beyond the newborn period.