Abnormal labor and its managment, 2020

simple appreach to abnormal labor,
made by a 6th year medical student at NNU

1. Abnormal Labor and its Management 6 th year, Gynecology and Obstetrics R otation 2020, Dialla Sandouka

2. Abnormal Labor and its Management Definitions Stages and Phases of Normal Labor. Causes of Abnormal Labor. Types of Abnormal Labor. Diagnosis and Management of Abnormal Labor. Occiput posterior position . cephalopelvic disproportion.

3. Normal labor refers to the presence of regular uterine contractions that cause progressive dilation and effacement of the cervix and fetal descent. Abnormal labor, dystocia, and failure to progress : Terms used to describe a difficult labor pattern that deviates from that observed in the majority of women who have spontaneous vaginal deliveries. This problem is the most common indication for primary cesarean birth, accounting for three times more cesarean deliveries than malpresentation or fetal heart rate abnormalities.

4. First stage : Latent phase Active phase Acceleration Phase Maximum slope Deceleration phase Time from the onset of labor until complete cervical dilatation. Second stage : Time from complete cervical dilatation to expulsion of the fetus. Third stage : Time from expulsion of the fetus to expulsion of the placenta.

5. CLASSIFICATION – Of Labor Abnormalities: Protraction disorders : refer to slower-than-normal labor progress. Arrest disorders : refer to complete cessation of progress . Protraction and arrest disorders may occur in the first, second and third stage of labor.

6. ETIOLOGY OF PROTRACTION AND ARREST DISORDERS Abnormal labor can be the result of one or more abnormalities: The cervix. The uterus. The maternal pelvis. The Fetus i.e ., 3P’s , (power , passenger, or pelvis).

7. RISK FACTORS OF ABNORMAL LABOR Older maternal age pregnancy complications non-reassuring fetal heart rate epidural anesthesia macrosomia pelvic contraction occiput posterior position nulliparity short stature (less than 150cm) high station at full dilation chorioaminionitis postterm pregnancy

8. NORMAL UTERINE ACTIVITY Quantitatives Assessment: Palpation . External tocodynamometry . Internal uterine pressure catheters. 95 % of women in labor will have 3-5 contractions per 10 minutes . Quantifying assessment: The Montevideo units (i.e., the peak strength of contractions in mmHg measured by an internal monitor multiplied by their frequency per 10 minutes) 90 % of women in spontaneous active labor achieved contractile activity of > 200 Montevideo units (in 40 % reaches 300 units ). Uterine contractions are considered adequate if the have: A frequency of 1-3 every 2-3 minutes, duration of 45-60 seconds and an intensity of 50 mmHg or more.

9. THE FIRST STAGE OF LABOR latent phase : begins as short, mild, irregular uterine contractions that soften, efface, and begin to dilate the cervix (< 1 cm/h). Active phase : starts at 3 to 5 cm ( almost 4) dilation cervical dilation accelerate to at least 1 to 2 cm/ h (various depending on parity ) per hour and the fetus descends into the birth canal ends when the cervix is fully dilated. The total duration of labor also varies between nulliparous and multiparous. One report of 25,000 women at term revealed the average duration of active labor ( onset defined as 3 cm dilation) in nulliparous and parous women was 6.4 and 4.6 hours, respectively.

10. PROLONGED LATENT PHASE begins as short, mild, irregular uterine contractions that soften, efface, and begin to dilate the cervix. The average duration of latent phase in nulliparous and multiparous women is 6.4 and 4.8 hours. An abnormally long latent phase is defined as 20 hours for the nulliparous and 14 hours for the multiparous woman in the face of regular uterine contractions and cervical dilation of <6 cm . Occurs in 4-6% of delivires . Prolonged latent phase is responsible for 30 % abnormalities in nulliparous and over 50 % of abnormalities in multiparous women.

11. PROLONGED LATENT PHASE Latent-phase abnormalities are most commonly caused by: reckless use of anesthesia. Abnormal uterine contraction, which can be either hypotonic (inadequate frequency, duration, or intensity) or hypertonic (high intensity but inadequate duration or frequency). It is the most common cause of protraction or arrest disorders in the first stage of labor . It occurs in 3 to 8 percent of parturients and can be quantified as uterine contraction pressures less than 200 Montevideo units. Management involves: Therapeutic rest with narcotics or sedation. Oxytocin administration. Aminotomy . Cesarean delivery is never appropriate management for prolonged latent phase.

12. ARRESTED ACTIVE PHASE An arrested active phase is defined as: No cervical dilation change despite 4 hours of adequate uterine activity or 6 or more hours of oxytocin with inadequate uterine activity in a woman with a dilation of 6 or more cm with ruptured membranes. It is commonly caused by either abnormalities of: The passenger (excessive fetal size or abnormal orientation in the uterus). The pelvis (bony pelvis size). Powers (dysfunctional or inadequate uterine contractions). Management includes: The assessment of the uterine contraction quality, if they’re hypertonic give morphine sedation and if they’re hypotonic IV oxytocin are administered. If contractions are adequate proceed to cesarean section.

13. THE SECOND STAGE OF LABOR The median duration varies in nulliparous and multiparous women is 50 and 20 minutes, respectively. The upper limit of duration associated with a normal perinatal outcome had been defined as two hours ( but was subsequently lengthened up to 2, 3hours for multiparous and nulliparous without epidural respectively). Other factors may affect its duration: Epidural analgesia, duration of the first stage, parity, maternal size, birth weight, and station at complete dilation. The normal duration of 2nd stage of labor should be based upon parity and presence of regional anesthesia, with no intervention as long as the fetal heart rate pattern is normal and some degree of progress is observed.

14. PROLONGED SECOND STAGE A prolonged second stage is defined as: In nulliparous women, No progress in either descent or rotation of the fetus after 3 or more hours without epidural anesthesia and 4 or more hours with epidural anesthesia after complete dilation. In multiparous women, No progress in either descent or rotation of the fetus after 2 or more hours without epidural anesthesia and 3 or more hours with epidural anesthesia after complete dilation . Risk factors include: nulliparity, diabetes, macrosomia, epidural anesthesia, oxytocin usage, and chorioamnionitis . The management involves: Assessment of uterine contractions and managed as mentioned before. Assessment of maternal pushing efforts which can be enhanced through coaching. If both are adequate, fetal head engagement should be assessed. If its engaged, consider a trial of either obstetric forceps or a vacuum delivery. If the fetal head isn't engaged proceed to emergency cesarean section.

15. THE THIRD STAGE OF LABOR the duration of this stage is usually between 5 and 10 minutes but may be up to 30 minutes in all women.

16. PROLONGED THIRD STAGE A prolonged third stage is defined as: Failure to deliver the placenta within 30 minutes. It is caused by either: Inadequate uterine contractions Abnormal placental implantation ( e.g , placenta accrete, placenta increta, and placenta percreta ), which we think of if the first cause is ruled out after IV oxytocin stimulation of the myometrium contractions. Management: It may require manual placental removal or rarely even hysterectomy.

17. Occiput posterior position Dystocia due to malposition : 5 % of cephalic presenting fetuses experience malposition with persistent occiput posterior (OP) position or transverse arrest . It increases the risk of: Longer second stage . higher incidence of operative delivery. larger episiotomies. more severe perineal lacerations. Management of OP: Operative Delivery From OP Position, Manual Or Instrumental Rotation To Occiput Anterior and Cesarean Delivery . A small increase in second stage length in the presence of a reassuring fetal heart rate, favorable clinical assessment of fetal relative to maternal size, and progress in the second stage does not mandate rotation or operative delivery.

18. cephalopelvic disproportion Dystocia due to cephalopelvic disproportion (Relative or Absolute) : This diagnosis is currently based upon slow or arrested labor during the active phase . Absolute : true disparity between fetal and maternal pelvic dimensions. Relative : due to fetal malposition (e.g., extended or asynclitic fetal head) or malpresentation ( mentum posterior, brow ). Management : If it is severe and diagnosed early, a planned C-section is indicated. In other cases,  CPD  may be treated with a symphysiotomy (the surgical division of pubic cartilage) or an emergency C-section after a trial of labor.