Protracted Labor - Causes, Diagnosis, and Treatment

Introduction

Labor is the body's natural childbirth process. A first birth typically lasts 12 to 24 hours. After that, it is typically shorter. Labor is characterized by a series of continuous, progressive uterine contractions that help the cervix open (dilate) and thin (efface), allowing the fetus to move through the birth canal. Labor usually begins two weeks before or after the expected delivery date. Labor is a three-stage process. The first stage commences with the onset of labor and ends with full cervical dilation and effacement. The second stage starts with complete cervical dilation and ends with the fetus's delivery. The third stage begins after the fetus is delivered and ends with the delivery of the placenta.

What Are the Stages of Labor?

Every labor is unique. Labor is typically divided into three stages:

1. The First Stage

• The first stage of labor is known as the latent phase, during which contractions become more frequent (usually 5 to 20 minutes apart) and stronger. However, the discomfort is minor. The cervix dilates (opens three to four centimeters) and effaces (thins out). Some women may not realize they are in labor if the contractions are mild and irregular.

• Latent phase of labor is usually the most prolonged and least intense. During this stage, the expectant mother is usually admitted to the hospital. Pelvic exams are performed to determine cervix dilation.

• The dilation of the cervix from four to seven centimeters indicates the second phase of the first stage (active phase). Contractions lengthen, become more severe, and become more frequent (typically three to four minutes apart).

• The third and final phase is known as transition. The cervix dilates from eight to ten centimeters during the transition. Contractions are typically very strong and last 60 to 90 seconds every few minutes. During this stage, most women feel the urge to push. The active and transition phases are usually shorter than the latent phase.

2. The Second Stage

• The second stage begins when the cervix is fully opened and ends with the baby's delivery. The second stage is commonly known as the "pushing" stage. The woman becomes actively involved in the second stage by pushing the fetus through the birth canal to the outside world. "Crowning" occurs when the baby's head is visible through the vaginal opening. For a woman's first pregnancy, the second stage is shorter than the first and can last anywhere from 30 minutes to two hours.

3. The Third Stage

• After the baby is born, the new mother enters the third and final stage of labor: placenta delivery (the organ that nourishes the fetus inside the uterus). This stage usually lasts only a few minutes and involves the placenta exiting the uterus and passing through the vagina.

What Is Protracted Labor?

Prolonged labor is characterized by abnormally slow cervical dilation or fetal descent during active labor. Prolonged active phase dilation should be considered a significant risk factor for later labor dysfunction. In the mothers-to-be, the risk of subsequent dilation or descent arrest, prolonged deceleration phase, and prolonged descent may be increased from 2.5-fold to 8-fold. Later problems should be expected as a clinical rule of thumb when active labor begins more slowly than usual. Prolonged active phase dilation should be diagnosed in nulliparas when the dilation rate is less than 1 cm/h (centimeter per hour). The lower limit of normal for the multipara is 1.5 cm/h.

What Causes Protracted Labor?

Prolonged active phase dilation is a common labor dysfunctional pattern. Many prolonged active phase dilation cases may have previously been labeled as primary uterine inertia or hypertonic uterine inertia, implying uterine dysfunction. However, the actual cause of protraction is still unclear.

• Protracted labor can be caused by fetopelvic disproportion (the fetus is not able to fit through the maternal pelvis), which can occur when the maternal pelvis is abnormally small, the fetus is abnormally large, or the fetus is abnormally positioned (fetal dystocia).

• Another factor contributing to protracted labor is uterine contractions that are either too weak or infrequent (hypotonic uterine dysfunction) or, on rare occasions, too intense or close together (hypertonic uterine dysfunction).

• There may also be an iatrogenic part to this labor abnormality, as the supine position may decrease uterine contractility, resulting in slowed cervical dilation.

• Furthermore, while active labor is generally resistant to analgesia, narcotics may be associated with precipitating slow dilation in the active phase in some cases.

• Early epidural anesthesia is also associated with an increased risk for this labor abnormality.

How Is Protracted Labor Diagnosed?

The diagnosis of protracted labor is frequently clinical. Identifying the cause is important because it determines treatment. Fetal and pelvic dimensions and fetal position can sometimes be used to determine whether the cause is fetopelvic disproportion. Fetal weight greater than 5000 g (greater than 4500 g in diabetic women) indicates fetopelvic disproportion.

Uterine dysfunction is diagnosed by palpating the uterus or using an intrauterine pressure catheter to assess the strength and frequency of contractions. The response to treatment is frequently used to make a diagnosis.

How Is Protracted Labor Treated?

A reasonable approach to protracted labor includes early detection of abnormal labor progress during the active phase, fetal monitoring, lateral positioning, and careful oxytocin use. Given the possibility of a link between mild disproportion and malposition, this can be difficult for both the patient and the physician. Avoiding unnecessary sedation and anesthesia is a conservative approach.

• If the first or second stage of labor takes too long and the fetal weight is over 5000 g (or 4500 g in diabetic women), labor can be accelerated with oxytocin, which is used to treat hypotonic dysfunction. Labor can resume if normal progress is restored. If not, fetopelvic disproportion or intractable hypotonic dysfunction may be present, necessitating a cesarean delivery.

• Hypertonic uterine dysfunction can be difficult to treat; however, repositioning, discontinuation of oxytocin if it is being used, short-acting tocolytics (Terbutaline 0.25 mg IV once), and analgesics may be useful.

What Are the Risks Associated With Protracted Labor?

If the labor lasts longer than expected and medical care is not provided promptly or appropriately, the following issues may arise:

• Lack of Oxygen - Depriving a fetus's brain of oxygen can result in long-term disabilities such as speech and mobility problems, learning difficulties, autism, epilepsy, and cerebral palsy.

• Fetal Distress - As the signs of fetal distress can be difficult to detect, the healthcare providers must properly monitor the mother and the fetus for abnormal signs. Reduced fetal movement is something that mothers can notice. Sometimes this happens while the fetus is sleeping, and other times when the fetus' oxygen levels drop to dangerous levels. If it goes undetected or is not treated promptly, the long-term effects could result in hypoxic-ischemic encephalopathy, a type of permanent brain damage.

• Abnormal heart rhythm in the baby.

• Abnormal substances in the amniotic fluid.

Conclusion

Labor is the body's natural childbirth process and every labor is unique. Labor is typically divided into three stages. Protracted labor refers to an abnormally prolonged active phase of labor or a delayed fetal descent. Attending all prenatal visits during pregnancy is essential, along with following the doctor's advice and instructions regarding pregnancy and delivery.