Table of Contents
- Introduction
- Baby Development at 40 Weeks
- Common Pregnancy Symptoms at 40 Weeks
- Preparing for Labor and Delivery
- Overdue Pregnancy: What to Expect
- When to Contact Your Healthcare Provider
- Self-Care Tips for the Final Weeks of Pregnancy
- Conclusion
- References
Introduction
Congratulations on reaching the 40-week milestone in your pregnancy journey! As you approach your due date, you may be experiencing a mix of excitement, anticipation, and perhaps a bit of anxiety. This comprehensive guide will walk you through the final stages of your pregnancy, providing insights into your baby's development, common symptoms, and how to prepare for labor and delivery.
Baby Development at 40 Weeks
Size and Weight
At 40 weeks, your baby is considered full-term and has likely reached their final birth weight and length. The average newborn in the United States weighs between 7 and 8 pounds and measures approximately 20 inches in length 1.
| Percentile | Weight (lbs) | Length (in) |
|---|---|---|
| 10th | 6.2 | 18.9 |
| 50th | 7.5 | 20.2 |
| 90th | 8.8 | 21.4 |
Skin Color
Newborns of all ethnicities are born with reddish-purple skin that gradually changes to a pinkish-red hue within a day or two. This pink tint is attributed to the visibility of red blood vessels through the baby's delicate skin. As your baby's circulation continues to mature, their hands and feet may appear slightly bluish for the first few days. Babies born to darker-skinned parents typically have lighter skin at birth, which gains pigment over time, reaching its permanent color around 6 months of age 2.
Fontanels (Soft Spots)
Unlike an adult's skull, which is a single large bone, a newborn's skull comprises separate bones connected by flexible tissue. These gaps between the bones, known as fontanels or soft spots, allow for the baby's head to mold during the birth process and provide room for the brain to grow during infancy. You will be able to feel these soft spots on the top and back of your newborn's head 3.
Common Pregnancy Symptoms at 40 Weeks
Ripening Cervix
As your body prepares for labor, your healthcare provider may perform a cervical check to assess the "ripeness" of your cervix. They will evaluate the softness, thinning (effacement), and dilation (opening) of the cervix, which can indicate the proximity of labor. However, it is important to note that the condition of the cervix is not a definitive predictor of when labor will begin 4.
Water Breaking (Premature Rupture of Membranes)
Contrary to the dramatic depictions in movies, less than 15% of women experience their water breaking before the onset of other labor symptoms. In most cases, the amniotic sac ruptures once contractions have already begun. If your water does break before labor starts, a condition known as premature rupture of membranes (PROM), labor typically commences within 24 hours. If it doesn't begin naturally, your healthcare provider may recommend inducing labor 5.
Identifying amniotic fluid leakage can be challenging, as it may be mistaken for vaginal discharge or urine. Amniotic fluid is usually clear and has a slightly sweet odor, while urine is typically yellow-hued, and vaginal discharge is often creamy or white. If you suspect that your water has broken, place a pad and wait for 30 minutes. If the pad is wet after this time, it is likely amniotic fluid, and you should contact your healthcare provider 5.
Back Pain
As your baby grows, weighing an average of 7 to 8 pounds at 40 weeks, the added weight of the placenta, amniotic fluid, and enlarged breasts can put significant strain on your back. More than 60% of pregnant women experience back pain during this time 4. Finding relief through swimming, floating, gentle stretching, walking, and prenatal massage can help alleviate discomfort.
Sudden changes in back pain, such as a significant increase in intensity or the onset of pain for the first time, may indicate the beginning of labor. Intense back pain during labor, known as back labor, often occurs when the baby's head presses against the lower back 4.
Contractions: Braxton Hicks vs. Real Labor
Distinguishing between Braxton Hicks contractions and real labor contractions is crucial at this stage. Braxton Hicks contractions are typically painless, do not follow a regular pattern, and can be alleviated by rest and hydration. They are most commonly felt on the front of the belly 4.
Real labor contractions, on the other hand, are painful and occur at regular intervals, becoming more frequent and intense over time. They often start in the back and radiate to the front, persisting even when you change positions or attempt to relax. When you experience regular contractions lasting about a minute each, occurring every four to five minutes for an hour or more, it is usually time to go to the hospital or birthing center, as per your provider's guidance 4.
Insomnia
Insomnia affects approximately two-thirds of women in late pregnancy 4. Coping strategies include establishing a consistent bedtime routine, using multiple pillows to find a comfortable sleep position, resting in a lounge chair, and taking naps during the day when possible.
Pelvic Pain and Pressure
As your baby descends lower into the pelvis in preparation for birth, you may experience increased pelvic pain and pressure, which can manifest as tightness or discomfort in the hips, groin, and pelvic floor. This process, known as "lightening," can cause some women to feel lighter, while others may experience more intense pelvic pain 4.
Resting, applying ice, and finding more comfortable sitting positions may provide relief. If the pain is severe, consult your healthcare provider about additional pain management options. Lightening can also lead to increased waddling and more frequent bathroom visits due to the baby's head engaging in the pelvis. However, it may also allow for easier breathing as the lungs have more room to expand 4.
Preparing for Labor and Delivery
Exercises to Prepare for Labor
While there is no proven way to speed up labor, certain exercises may help your body prepare for the upcoming challenge. Engaging in labor preparation exercises can promote physical and mental well-being during the final weeks of pregnancy 4.
Finalizing Your Baby Names List
If you plan to wait until meeting your baby to make a final decision on their name, ensure that you have a list of preferred options ready. This will allow you to focus on the moment and make a choice that feels right for your family 4.
Learning About Postpartum and Newborn Care
Take the time to educate yourself about what to expect after delivery, including postpartum recovery and newborn care. Familiarize yourself with the hospital or birth center's protocols and review your birth plan to ensure that you are well-prepared for the big day 4.
Relaxation Techniques
In the final weeks of pregnancy, prioritize relaxation and self-care. Engage in activities that bring you joy and help you unwind, such as watching your favorite shows, reading a novel, connecting with friends, sleeping in, or taking naps when possible 4.
Overdue Pregnancy: What to Expect
Factors Contributing to Overdue Pregnancy
While reaching your due date without going into labor can be frustrating, it is a common occurrence, especially for first-time mothers. Several factors can contribute to an overdue pregnancy, including:
- Inaccurate due date calculation based solely on the last menstrual period
- Late ovulation
- Individual variations in pregnancy duration 4
Monitoring Fetal Well-being
If your pregnancy extends beyond your due date, your healthcare provider may recommend additional tests to assess your baby's well-being. These may include:
- Non-stress tests (NST) to monitor fetal heart rate and movement
- Biophysical profile (BPP) to evaluate fetal movement, breathing, muscle tone, and amniotic fluid volume
- Ultrasound to assess fetal growth and placental function 4
Induction of Labor
Some healthcare providers recommend inducing labor once a pregnancy reaches 41 weeks to minimize the risk of complications associated with prolonged gestation. However, the decision to induce labor should be made in consultation with your provider, taking into account your individual circumstances and preferences 4.
When to Contact Your Healthcare Provider
Contact your healthcare provider immediately if you experience any of the following:
- Regular, painful contractions occurring at intervals of 4-5 minutes, lasting about a minute each, for an hour or more
- Suspected amniotic fluid leakage (water breaking)
- Sudden changes in back pain or the onset of severe back pain
- Decreased fetal movement or any concerns about your baby's well-being 4
Self-Care Tips for the Final Weeks of Pregnancy
As you approach your due date, prioritize self-care to promote physical and emotional well-being:
- Engage in relaxation techniques, such as deep breathing, meditation, or prenatal yoga
- Stay hydrated and maintain a balanced, nutritious diet
- Get plenty of rest and sleep when possible
- Seek support from loved ones and communicate your needs and concerns
- Participate in activities that bring you joy and help you manage stress 4
Conclusion
Reaching the 40-week milestone in your pregnancy is a significant achievement, and you should be proud of the incredible journey your body has undergone. As you prepare for labor and delivery, remember to trust your instincts, communicate with your healthcare provider, and surround yourself with a supportive network. While the final weeks of pregnancy can be challenging, they are also a time of great anticipation and excitement as you prepare to welcome your baby into the world.
References
Footnotes
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Hadlock, F. P., Harrist, R. B., & Martinez-Poyer, J. (1991). In utero analysis of fetal growth: A sonographic weight standard. Radiology, 181(1), 129-133. https://doi.org/10.1148/radiology.181.1.1887021 ↩
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American Academy of Pediatrics. (2021). Newborn Skin Color. https://www.healthychildren.org/English/ages-stages/baby/Pages/Newborn-Skin-Color.aspx ↩
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Mayo Clinic. (2022). Fontanels. https://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/expert-answers/fontanels/faq-20058311 ↩
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American College of Obstetricians and Gynecologists. (2024). How Your Fetus Grows During Pregnancy. https://www.acog.org/womens-health/faqs/how-your-fetus-grows-during-pregnancy ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14 ↩15 ↩16 ↩17
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American College of Obstetricians and Gynecologists. (2023). When Pregnancy Goes Past Your Due Date. https://www.acog.org/womens-health/faqs/when-pregnancy-goes-past-your-due-date ↩ ↩2