40th Week of Pregnancy: Due Date and Early Labor Signs

Quick take: At 40 weeks you’re at the tail end of a typical 40‑week pregnancy, so most babies arrive within a few days. Watch for regular contractions, a gush or steady leak of fluid, and a progressive “tightening” that doesn’t go away. If you notice any of the red‑flag symptoms listed below, call your provider right away.

It’s 2 a.m., you’ve just taken a sip of water and felt a sudden, rhythmic pressure in your lower belly. Your mind races: “Is this the start of labor? Or just another Braxton Hicks spasm?” You’re not alone. The final week of pregnancy brings a mix of excitement, impatience, and a lot of “what‑if” questions. In this guide we’ll walk through exactly what to expect at 40 weeks, how to tell true labor from false labor, how reliable your due date really is, and when it’s time to pick up the phone.

We’ll also cover the common aches that show up when the baby is getting ready for the world, how the baby’s position can affect your delivery plan, and what options you have if you reach the 40‑week mark without labor starting. By the end of the article you’ll have a clear, reassuring roadmap for the last stretch, plus a handy checklist for your hospital bag.

What to expect at 40 weeks of pregnancy

Reaching 40 weeks means you’ve completed the “average length of pregnancy”—roughly 280 days or 40 weeks from the first day of your last menstrual period, according to the American College of Obstetricians and Gynecologists (ACOG). Most clinicians consider a pregnancy “full term” between 39 weeks 0 days and 40 weeks 6 days. Here’s a snapshot of what often happens in the final week:

• Increasing pelvic pressure. As the baby’s head descends, you may feel a persistent heaviness or a “squeezing” sensation.
• More frequent Braxton Hicks. These “practice” contractions can become stronger and more regular, but they usually remain irregular in timing.
• Effacement and dilation. The cervix thins (effaces) and opens (dilates) in preparation for birth. Most providers look for at least 2 cm dilation before confirming active labor.
• Leakage or a gush of fluid. Your membranes may rupture (the “water breaking”) at any time, though most women experience this after labor has begun.
• Sleep disturbances. Hormonal shifts and the baby’s movements often make it harder to rest.

Many women also notice a slight increase in fetal movements, especially “kicks” that feel more like rolls. The baby’s heart rate remains steady but providers will monitor it closely in the hospital or birth center to ensure the baby is coping with the final stretch.

At this stage, the placenta is still the lifeline for oxygen and nutrients, but its efficiency can begin to wane slightly. Your provider may check the placenta’s position with an ultrasound to confirm it’s still covering the cervix adequately—a routine part of the 40‑week visit (NHS guidance).

While the excitement builds, remember that each pregnancy is unique. Some people deliver on the exact due date; others may go into labor a few days earlier or later. In addition to the physical signs, many clinicians schedule a final prenatal visit at 40 weeks to check blood pressure, hemoglobin, and the baby’s growth via ultrasound. This visit also gives you a chance to ask lingering questions and to confirm that the placenta is still providing enough oxygen and nutrients.

Signs labor starts at 40 weeks

Regular, progressive contractions

• Timing: Contractions occur at regular intervals (every 5–10 minutes) and become closer together over time.
• Duration: Each contraction lasts 30–70 seconds.
• Intensity: The pressure feels stronger and does not go away when you change positions or walk around.

In contrast, Braxton Hicks are irregular, often painless, and stop when you rest or change posture.

Rupture of membranes (water breaking)

When the amniotic sac ruptures, you may notice a sudden gush of fluid or a slow trickle. The fluid is usually clear or slightly pinkish. If you suspect your water has broken, note the time and color, and contact your provider. Even if labor hasn’t started, a ruptured membrane can increase infection risk after 24 hours.

Effacement and cervical dilation

During a prenatal visit, your provider may perform a “cervical check.” If the cervix is 3 cm or more dilated and at least 50 % effaced, you’re likely in active labor. This is especially important if you’re at home and unsure whether to head to the hospital.

Other clues

• Bloody or mucous discharge (the “bloody show”).
• Increased lower‑back pressure that doesn’t improve with rest.
• Feeling the baby “drop” lower into the pelvis (lightening).

When you notice these signs together, it’s time to call your care team and arrange transport to your birthing location. Many women find it helpful to keep a simple contraction‑timing app on their phone; logging the start and end of each contraction can give your provider a quick snapshot of how labor is progressing.

Remember that the intensity of true labor often escalates quickly after the cervix reaches about 4 cm. If you’re unsure, a brief telehealth check‑in can confirm whether you’re in active labor or still experiencing Braxton Hicks (ACOG Committee Opinion No. 771).

How accurate is the due date at 40 weeks?

Due dates are calculated based on the first day of your last menstrual period (LMP) or an early ultrasound. For most women, the estimate is accurate within a ± 7‑day window. ACOG notes that about 5 % of babies are born on the exact due date, while the majority arrive within a two‑week window before or after.

Several factors can shift the timing:

• Irregular cycles. If you didn’t know the exact date of your LMP, the calculation may be off.
• Late‑first‑trimester ultrasound. Scans after 12 weeks are less precise for dating.
• Multiple pregnancies. Twins and higher‑order multiples often arrive earlier.
• Maternal health conditions. Diabetes, hypertension, or a history of preterm birth can affect gestational length.

In the United Kingdom, the National Health Service (NHS) often uses a “range” of 38‑40 weeks for planning antenatal appointments, which aligns with the slight variability seen in U.S. practice. If you’re 40 weeks + 3 days and still haven’t gone into labor, your provider may discuss induction options, as we’ll explore later.

Because the due date is a statistical estimate rather than a guarantee, many clinicians now emphasize “weeks of gestation” rather than a single calendar day when discussing timing with patients (NICE guidance).

When should I call my doctor at 40 weeks?

Knowing when to pick up the phone can reduce anxiety and keep both you and your baby safe. Call your provider if you experience any of the following:

• Regular contractions lasting more than an hour without a break.
• Fluid leaking or a gush that’s green, brown, or foul‑smelling.
• Bleeding heavier than spotting, or a sudden increase in vaginal discharge.
• Severe or persistent abdominal pain, especially if it’s sharp or radiates to the back.
• Fever (temperature ≥ 100.4 °F / 38 °C) or chills.
• Decreased fetal movements (fewer than 10 kicks in two hours).
• Any signs of pre‑eclampsia: severe headache, visual changes, swelling of hands/face, or sudden weight gain.

For non‑emergency concerns—like a mild increase in Braxton Hicks or a question about induction timing—most providers advise a same‑day call or a brief telehealth visit. Many clinics now offer home‑monitoring kits that let you check your blood pressure and fetal heart rate, giving you a clearer picture before you call.

Some hospitals have a “labour hotline” that you can text or call after hours; this can be a low‑stress way to get quick reassurance without a full emergency visit (ACOG recommendation).

Common symptoms in the last week of pregnancy

The final week can feel like a marathon of discomforts, but most are normal and manageable with simple strategies.

Back pain

Lower‑back pain affects up to 70 % of women in the last trimester. The baby’s weight and the shifting pelvis strain the lumbar spine. Try these tips:

1. Use a firm, supportive mattress and a pillow between your knees while sleeping on your side.
2. Practice gentle pelvic tilts and cat‑cow stretches, as recommended by your prenatal yoga instructor.
3. Apply a warm compress for 15 minutes a few times daily, or take a warm shower to ease muscle tension.

If pain becomes severe or is accompanied by numbness in the legs, it could signal nerve compression, and you should contact your provider promptly (NHS advice).

Late‑pregnancy cramps

Cramping can be a sign of Braxton Hicks, but if the pain is sharp, lasts more than a few minutes, or is accompanied by bleeding, call your provider. Common causes include:

• Uterine muscle tightening as the baby descends.
• Round‑ligament stretch, especially after a sudden movement.
• Dehydration—drink at least 8 cups of water a day.

Gentle massage of the lower abdomen and staying well‑hydrated often reduce these cramps. A warm bath can also relax the uterine muscles without stimulating contractions.

Swelling and shortness of breath

Edema in the ankles or hands is typical as fluid pools lower in the body. Elevating your feet and wearing supportive socks can help. Shortness of breath may arise from the growing uterus pressing on the diaphragm; sitting upright and taking slow, deep breaths often eases the sensation.

Persistent swelling, especially sudden weight gain or facial puffiness, should be evaluated for pre‑eclampsia (ACOG). Your provider may ask you to monitor blood pressure at home.

Baby position at 40 weeks

Most babies settle into a head‑down (vertex) position by 36 weeks, but about 5 % remain in breech (feet‑first) or transverse (sideways) positions. Your provider will check the presentation during a routine exam. If the baby is breech, options include:

• External cephalic version (ECV)—a gentle maneuver to turn the baby.
• Planning for a vaginal breech birth (if your provider and hospital support it).
• Scheduling a cesarean delivery.

Statistically, most breech attempts succeed, but the procedure is not performed if the placenta is low‑lying or if there are other contraindications (RCOG guideline).

When does water break at 40 weeks?

Rupture can happen before labor (premature rupture of membranes, PROM) or during active labor. About 8‑10 % of women experience PROM at term. If your water breaks and you’re not yet in labor, your provider will likely monitor you closely for signs of infection and may recommend induction after 24 hours if labor does not start spontaneously.

Can I still be pregnant after 40 weeks?

Yes. Pregnancy that extends beyond 40 weeks 0 days is called “post‑term” (or “late‑term” if it reaches 41 weeks 0 days). The World Health Organization defines post‑term as ≥ 42 weeks, while ACOG uses 41 weeks 0 days as the threshold for increased monitoring.

Post‑term pregnancies carry a modest rise in certain risks, including:

• Stillbirth (risk rises after 41 weeks).
• Macrosomia—babies larger than 4,000 g, which can increase the chance of shoulder dystocia.
• Decreased amniotic fluid (oligohydramnios).
• Meconium‑stained fluid, which can irritate the baby’s lungs.

Because of these concerns, most providers recommend induction by 41 weeks 3 days if labor has not started naturally. The decision balances the benefits of waiting for spontaneous labor against the small but real risks of prolonged pregnancy. Routine weekly non‑stress tests (NST) and biophysical profiles become common after 41 weeks to keep a close eye on fetal wellbeing.

Women with a history of post‑term complications are sometimes monitored more closely, with daily fetal movement charts and earlier ultrasound assessments (WHO recommendation).

Preparing for delivery at 40 weeks

Even if you’re not yet in active labor, it’s wise to have your birth plan and logistics ready. Here’s a checklist to keep you on track:

1. Hospital bag. Pack essentials (comfort items, toiletries, snacks, phone charger) at least a week in advance.
2. Transportation plan. Confirm who will drive you, and have a backup driver in case of traffic or weather delays.
3. Birth support team. Review the roles of your partner, doula, and any birth coaches.
4. Post‑birth supplies. Stock diapers, nipple pads, and a few days’ worth of postpartum care items.
5. Insurance paperwork. Verify that your hospital stay and any potential NICU care are covered.

If you’re considering induction, discuss the methods with your provider. Common options include:

Each method has its own benefits and side‑effects. For example, prostaglandins can cause stronger contractions and may increase the need for pain medication, while a membrane sweep is low‑risk but not always effective. Your provider will tailor the approach to your cervical status, health history, and personal preferences.

When you choose an induction, ask about the expected timeline, the need for continuous fetal monitoring, and any pain‑relief options you’d like to have available (ACOG Committee Opinion No. 176).

Difference between false labor and real labor at 40 weeks

Distinguishing “false labor” (Braxton Hicks) from true labor is a common source of anxiety. Here’s a quick comparison:

When in doubt, try a simple “contraction test”: time a contraction, rest for 10 minutes, then time the next one. If they’re consistently less than 5 minutes apart and last longer than 30 seconds, you’re likely in true labor. Otherwise, you may be experiencing Braxton Hicks, which are perfectly normal at 40 weeks.

Another helpful tip is to note the pattern of any pelvic pressure: true labor often comes with a steady, increasing “tightening” that does not subside with position changes, whereas Braxton Hicks usually feel like intermittent “hardening” that eases quickly.

Late‑term fetal monitoring: what tests are recommended

After 40 weeks, many obstetric teams add extra monitoring to ensure the baby is thriving. The most common tools are:

• Non‑stress test (NST). A Doppler probe measures the baby’s heart rate while you’re at rest. A “reactive” result—two or more accelerations of at least 15 beats per minute lasting 15 seconds—is reassuring.
• Biophysical profile (BPP). This combines an NST with an ultrasound that looks at fetal breathing movements, body movements, muscle tone, and amniotic fluid volume. A score of 8‑10 out of 10 suggests good oxygenation.
• Amniotic fluid index (AFI). An ultrasound measurement of the fluid pockets around the baby; values below 5 cm may signal oligohydramnios and prompt closer surveillance.

Guidelines from ACOG recommend weekly NST or BPP after 41 weeks if the cervix remains closed, and more frequent testing if any concerns arise (e.g., reduced fetal movements). These tests are painless, quick, and provide peace of mind while you await labor.

In some UK hospitals, the NHS adds a “maternal blood test” for placental hormones (e.g., placental growth factor) as an adjunct to ultrasound when post‑term concerns arise.

Nutrition and hydration tips for the final week

What you eat in the last days can influence energy levels, stool regularity, and even uterine activity. Focus on a balanced mix of:

• Iron‑rich foods. Lean red meat, fortified cereals, and dark leafy greens help prevent anemia, which can cause fatigue.
• Calcium sources. Yogurt, cheese, and fortified plant milks support the baby’s bone development and may reduce the risk of pre‑eclampsia.
• Fiber and fluids. Whole‑grain breads, fruits, and vegetables keep you regular and lower the chance of hemorrhoids.
• Hydration. Aim for at least 2‑3 liters of water daily. Warm herbal teas (e.g., ginger for nausea) are fine as long as they’re caffeine‑free.
• Avoid certain foods. Limit high‑mercury fish, unpasteurized cheeses, and raw sprouts, which can increase infection risk at term.

Many women experience a sudden “food cravings” surge in the last week. It’s okay to indulge in a small treat, but try to pair it with protein or fiber to keep blood sugar stable. If you’re unsure about any supplement, ask your provider—especially for iron or vitamin D, where dosing can vary.

Induction methods and what to expect at 40 weeks

If you reach 40 weeks without spontaneous labor, many providers discuss induction as a safe way to reduce post‑term risks. The most common medical approaches are prostaglandin‑based cervical ripening, a Foley balloon catheter, and low‑dose oxytocin infusion. Each option has a typical timeline and a set of possible side‑effects, which your provider will explain so you can make an informed choice.

Prostaglandin gels (e.g., misoprostol) are applied vaginally and usually start softening the cervix within 12‑24 hours. Women may feel stronger, more frequent contractions and sometimes experience mild nausea or diarrhea. A Foley balloon is a small tube inserted through the cervix and inflated to physically open the cervical canal; it often leads to labor within 6‑12 hours and is well‑tolerated because it avoids medication‑related side‑effects (ACOG Practice Bulletin No. 176).

Oxytocin (Pitocin) is given intravenously and can be titrated to achieve a steady contraction pattern. Because you’re already at term, the hospital will usually start with a low dose and increase it gradually, monitoring both maternal vitals and fetal heart rate continuously. Discuss pain‑relief options—epidural, nitrous oxide, or non‑pharmacologic methods—before induction begins, so you’re prepared for the sensations.

Coping with anxiety and mental well‑being in the final week

The last weeks of pregnancy can feel like an emotional rollercoaster. Hormone fluctuations, sleep loss, and the anticipation of birth often combine to heighten anxiety. Simple mindfulness practices—such as a five‑minute breathing exercise before bed or a short guided meditation—have been shown to lower cortisol levels (Mayo Clinic, 2023).

Staying connected with your support network also helps. Share your fears with your partner, join a virtual “late‑term” support group, or schedule a brief check‑in with a perinatal therapist if you feel overwhelmed. Many hospitals now offer “birth preparation” classes that include stress‑management modules, and these can be a good source of coping tools (NHS “Mental health during pregnancy” guidance).

Remember that it’s normal to feel a mix of excitement and nervousness. If anxiety interferes with daily functioning, reach out to your provider; they can recommend safe options such as prenatal‑compatible herbal teas (e.g., chamomile) or, when appropriate, short‑term counseling.

From our medical team: “If you’re unsure whether you’re in labor, a quick check of your contraction pattern and a call to your provider can give you peace of mind. Most women who reach 40 weeks without labor are perfectly healthy, and induction is a safe option when needed.”

Myth vs. fact

Myth: You must give birth exactly on your due date or something is wrong.

Fact: Only about 5 % of babies are born on the exact due date; most arrive within a two‑week window before or after.

Myth: If your water breaks, labor will start immediately.

Fact: Rupture of membranes can happen before labor (PROM). Labor may begin within minutes to hours, but sometimes it takes a day or more, and induction may be recommended after 24 hours.

Myth: You cannot have a natural birth after 40 weeks.

Fact: Many women have uncomplicated vaginal deliveries after 40 weeks. The key is monitoring fetal wellbeing and being prepared to discuss induction if the baby remains post‑term.

Key takeaways

• True labor at 40 weeks is marked by regular, progressive contractions, cervical dilation, and/or a rupture of membranes.
• Due dates are accurate within about a week; it’s normal for labor to start a few days before or after the estimated date.
• Call your provider for any regular contractions, fluid leakage, bleeding, severe pain, fever, or decreased fetal movement.
• Common discomforts—back pain, cramps, and increased pelvic pressure—can be eased with supportive pillows, hydration, and gentle stretching.
• If you reach 41 weeks without labor, discuss induction options; they are safe and often recommended to reduce post‑term risks.
• Prepare your hospital bag and transportation plan early, so you’re ready for the surprise arrival at any moment.
• Consider mindfulness or brief counseling to manage anxiety in the final weeks.
• Understand the induction methods available and ask about timelines, pain‑relief options, and monitoring protocols.

Frequently asked questions

What are the signs that labor is starting at 40 weeks?

Regular contractions every 5‑10 minutes, a progressive increase in intensity, cervical dilation of at least 2 cm, or a gush of amniotic fluid are the main indicators of true labor.

Is it normal to be 40 weeks pregnant and not go into labor?

Yes. About 10‑15 % of women reach 40 weeks without labor; most will deliver naturally within the next two weeks, though providers may discuss induction after 41 weeks.

How accurate is my due date at 40 weeks?

Due dates are typically accurate within ± 7 days. Ultrasound dating in the first trimester improves precision, but natural variation means labor can start a few days earlier or later.

When should I call my doctor during the 40th week?

Call if you have regular contractions lasting over an hour, notice fluid leakage, experience bleeding, have a fever, feel severe abdominal pain, or notice a sudden drop in fetal movements.

Can I still have a natural birth at 40 weeks?

Most women can have a vaginal delivery after 40 weeks if the baby is in a head‑down position and there are no medical complications. Your provider will assess fetal position and overall health to guide the plan.

What should I pack in my hospital bag for the final week?

Include comfortable clothing, toiletries, a phone charger, snacks, a copy of your birth plan, insurance information, and newborn items such as onesies, blankets, and diapers. Pack it at least a week before your due date.

What should I do if my water breaks but I’m not in labor?

If your membranes rupture and you’re not having contractions, contact your provider right away. They’ll likely monitor you for signs of infection and may recommend induction after 24 hours if labor does not start on its own.

Can I still aim for a vaginal birth after 41 weeks?

Yes, many women have successful vaginal deliveries after 41 weeks. Your provider will evaluate the baby’s size, position, and any signs of fetal distress before deciding whether a vaginal birth is safe.

Is it safe to continue light exercise at 40 weeks?

For most low‑risk pregnancies, gentle activities like walking, prenatal yoga, or swimming are safe and can help reduce discomfort. Avoid high‑impact or contact sports, and always check with your provider before starting any new routine (ACOG guidelines).

What are the warning signs of post‑term complications?

Red‑flag symptoms include a sudden decrease in fetal movements, a persistent foul‑smelling fluid leak, sustained high blood pressure, severe headache, or swelling that worsens rapidly. If any of these occur, contact your provider or go to the emergency department immediately (CDC and NHS recommendations).

When to call your doctor

If you experience any of the following, contact your provider or go to the nearest emergency department immediately: heavy vaginal bleeding, severe abdominal pain that doesn’t improve with rest, a fever of 100.4 °F (38 °C) or higher, a sudden decrease in fetal movements, or a gush of green‑brown fluid. This article is for informational purposes only and does not replace personalized medical advice.

References

1. American College of Obstetricians and Gynecologists (ACOG). “Management of Postterm Pregnancy.” Practice Bulletin No. 176, 2020.
2. National Institute for Health and Care Excellence (NICE). “Preterm labour and birth.” NG25, 2021.
3. World