What is difference between normal and abnormal labor? Is it different from Dystocia?
@judhajit To define abnormal labor, a definition of normal labor must be understood and accepted. Normal labor is defined as uterine contractions that result in progressive dilation and effacement of the cervix. By following thousands of labors resulting in uncomplicated vaginal deliveries, time limits and progress milestones have been identified that define normal labor. Failure to meet these milestones defines abnormal labor, which suggests an increased risk of an unfavorable outcome. Thus, abnormal labor alerts the obstetrician to consider alternative methods for a successful delivery that minimize risks to both the mother and the infant.
Dystocia of labor is defined as difficult labor or abnormally slow progress of labor. Other terms that are often used interchangeably with dystocia are dysfunctional labor, failure to progress (lack of progressive cervical dilatation or lack of descent), and cephalopelvic disproportion (CPD).
Friedman's original research in 1955 defined the following three stages of labor:
The first stage starts with uterine contractions leading to complete cervical dilation and is divided into latent and active phases. In the latent phase, irregular uterine contractions occur with slow and gradual cervical effacement and dilation. The active phase is demonstrated by an increased rate of cervical dilation and fetal descent. The active phase usually starts at 3-4 cm cervical dilation and is subdivided into the acceleration, maximum slope, and deceleration phases.
The second stage of labor is defined as complete dilation of the cervix to the delivery of the infant.
The third stage of labor involves delivery of the placenta.
Abnormal labor constitutes any findings that fall outside the accepted normal labor curve. However, the authors hesitate to apply the diagnosis of abnormal labor during the latent phase because it is easy to confuse prodromal contractions for latent labor. In addition, the original labor curve, as defined by Friedman, may not be completely applicable today.