The due date refers to the estimated date of delivery for a pregnant woman. There are several calculation methods:
1. Based on the first day of the last menstrual period: Add 9 months and 1 week (280 days) to the first day of your last period. Example: If your last period started on January 1st, add 9 months to October 1st, then add 1 week (7 days) to arrive at October 8th.October 8th is your estimated due date. This method has up to 90% accuracy; the more precise the LMP date, the higher the prediction accuracy.
2. Calculation based on basal body temperature (BBT) chart: Identify the last day of the low-temperature phase on your BBT chart as your ovulation date. Count forward 264–268 days, or add 38 weeks.
This method has lower accuracy than the LMP method, typically around 80%, and is more suitable for mothers who cannot recall their exact LMP date.
3. Calculation based on first fetal movement: For primiparas, count 20 weeks from the date of first fetal movement.
This method has lower accuracy than the LMP or BBT methods, typically around 70%, and is suitable for mothers who cannot recall their LMP date or first fetal movement date.Accuracy is lower than the LMP method, reaching about 80%. This is more suitable for expectant mothers who cannot recall their last menstrual period. 3. Calculation based on first fetal movement: For primiparas, add 20 weeks to the date of first fetal movement; for multiparas, add 22 weeks. This method has lower accuracy, only about 58%, because some pregnant women experience very noticeable fetal movements while others do not, and it can be difficult to determine if it is the first pregnancy.
4. Estimation based on ultrasound measurements: During an ultrasound, the doctor measures the biparietal diameter (BPD), crown-rump length (CRL), and femur length (FL) to estimate fetal age and calculate the due date. This method achieves up to 98% accuracy and is currently the most precise medical approach for determining the due date.
Reminder for expectant mothers: The due date is not an exact delivery date. Only a portion of mothers give birth on their due date, while the rest deliver within two weeks before or after.
Understanding the Three Major Signs of Labor
As a foundation for labor preparation, expectant mothers must accurately calculate and remember their due date. However, the due date is only an approximate time for the baby's arrival, and the actual onset of labor can occur 1-2 weeks earlier or later.Therefore, as you approach your due date, pay close attention to various signs of labor. For example:
About two weeks before labor begins, you may feel relief in your upper abdomen, easier breathing, and reduced discomfort from stomach pressure. Your appetite may also increase slightly. This is due to the uterine fundus beginning to descend.
Subsequently, the fetal part that will emerge first during delivery descends to the pelvic inlet. This causes symptoms like a heavy feeling in the lower abdomen, bladder pressure, backaches, leg pain, difficulty walking, and frequent urination.
Additionally, some expectant mothers may feel irritable on the day of labor, experience loss of appetite or intense hunger, or have an intuitive sense that meeting their baby is imminent.
However, the most reliable signs of impending labor are the following three major indicators, which should guide your decision to go to the hospital. It's crucial to understand them.
1. Bloody Show
Timing: 24–48 hours before delivery.
Explanation: As the baby's head descends into the pelvis, the lower uterine segment and cervix begin to dilate. This causes separation between the amniotic sac and uterine wall, rupturing capillaries and leading to bleeding. This blood mixes with cervical mucus, forming a bloody mucous discharge.
Characteristics: A thick, sticky discharge of brownish, pink, or red mucus—commonly called "bloody show"—appears in the vagina. This is one of the reliable signs of impending labor. Bleeding volume is typically less than a normal menstrual period. If heavier, consider possible complications like placenta previa or placental abruption.
What expectant mothers should do: After spotting, labor may still be one to two days or longer away. If regular uterine contractions haven't started, avoid rushing to the hospital. Observe at home, refrain from excessive exertion, avoid strenuous exercise, and maintain perineal hygiene. If bright red bleeding exceeds normal menstrual flow or is accompanied by abdominal pain, seek immediate medical attention.
2. Labor Contractions
Timing: Intermittent abdominal pain occurring 12–14 hours before delivery, often beginning between 10 PM and 6 AM, is the strongest indicator of impending labor.
Mystery of Contractions: Contractions primarily result from powerful uterine contractions causing temporary oxygen deprivation, which triggers the release of pain-inducing factors. Additionally, fetal pressure on the birth canal and nerves contributes to discomfort. These rhythmic, forceful uterine contractions gradually push the fetus toward the cervical opening, causing cervical dilation and expulsion of the baby. Thus, regular uterine contractions signal the onset of labor.
Characteristics of Labor Pain: Labor pain sensations vary among individuals and can be categorized as whole-body pain, stretching pain, or pressure pain. The pain may be felt in the lower back, abdomen, and buttocks; some expectant mothers experience pain throughout their entire body, even in their heels. Initially, it may feel like a dull backache or a stabbing pain radiating down the thigh. Later, contractions may occur in the abdomen, causing abdominal pain and a sensation of the belly hardening.Over time, contractions become regular and increasingly frequent—occurring every 3 to 4 minutes and lasting 30 to 60 seconds each. They do not lessen with massage, walking, lying down, or medication. Concurrently, the cervix thins and dilates effectively.
What to do: During early contractions, rest at home. If your water hasn't broken, take a warm bath to relax or have a light snack. When contractions become very strong—occurring about every 5 minutes, intense enough to cause abdominal distension or lower back pain, and lasting 30 seconds or longer—prepare for admission regardless of whether you've spotted or your water has broken.
3. Water Breaking
Timing: Occurs several hours before or near the onset of labor.
The Mechanism: A fluid-filled sac surrounding the fetus, medically termed the amniotic sac, may rupture when uterine contractions intensify and intrauterine pressure rises. This causes the cool, pale yellow amniotic fluid to leak out, commonly known as water breaking.
Characteristics of Rupture: Fluid may gush out of the vagina in a jet-like stream, feeling like urine to the mother. Alternatively, it may trickle out slowly or even drop by drop, as the baby's head has descended into the pelvis, obstructing the flow of fluid.
What to do: After your water breaks, labor usually begins soon. Whether you have contractions or not, have someone take you to the hospital immediately. Lie flat—do not stand or sit up—to prevent the umbilical cord from prolapse, which can cause serious complications. Use a sterile perineal pad to prevent infection.
Questions About Labor
1. What are false contractions? How do they differ from true contractions?
Answer: Within one month of the due date, hormonal changes increase uterine muscle excitability, causing expectant mothers to feel intermittent tightening and hardening of the abdomen—the onset of contractions.However, these contractions are irregular, with varying intervals ranging from as short as ten minutes to as long as two hours. They often occur at night and subside by morning. They can be relieved by massage, walking, or rest and do not cause cervical dilation. These are known as false labor or false contractions, and there is no need to rush to the hospital. While false contractions do not dilate the cervix, they can soften it, preparing it for dilation.
True contractions develop from false contractions, characterized by regularity and increasing frequency. They do not lessen with massage, movement, bed rest, or medication. Most importantly, the cervix thins and dilates effectively. For example, contractions may start every 10 minutes, lasting 10–30 seconds each, then progress to every 3–4 minutes, lasting 30–60 seconds each.
Of course, the most qualified person to distinguish between them is an obstetrician, who can most accurately determine the type of contractions by observing the thickness and dilation of the cervix.
2. After entering the due date, is it necessary to wear sanitary pads frequently due to concerns about water breaking?
Answer: It is not necessary. Frequent use of sanitary pads may increase the risk of infection.If your water has already broken, use sanitary pads, but ensure they are clean and hygienic to prevent bacterial invasion and intrauterine infection.
3. Can I still move around before labor?
Answer: Not only can you, but doctors also encourage appropriate activity—provided there are no pregnancy-related, medical, or obstetric complications, and the fetus shows no abnormalities. Increased movement aids uterine contractions and fetal head descent, helping shorten labor.
4. Can I drink water during contractions?
Answer: Yes. The reason is that contractions often cause increased sweating and faster breathing, leading to dry mouth and throat. There's no need to endure this discomfort—you can sip water while waiting for the moment of delivery.
5. What if I suddenly need to use the restroom during contractions?
Answer: Seeking restroom permission during contractions requires medical approval, as the urge to deliver closely mimics the urge to defecate. Cases where women independently used the restroom, leading to full cervical dilation and spontaneous delivery, are not uncommon. If examination reveals your cervix is fully dilated, restroom use is prohibited.
6. Can I apply light makeup before going to the hospital to cover up my pale complexion?
Answer: No. Childbirth is a major event that is both physically demanding and involves bleeding. Makeup masks your natural complexion, hindering the doctor's assessment of your condition. Therefore, you should arrive at the hospital without makeup to await delivery.