Written by : Dr.M.D.Mazumdar, MD
Labor is said to be prolonged when the combined duration of both the first stage and second stages of labor is more than 18 hours. It is more common in a first pregnancy and in women over the age of 35 years.
Causes of Prolonged Labor
MalpresentationsThe normal position of the fetus is longitudinal with the fetal spine parallel to the mother's spine. The fetus lies in a completely flexed position with the chin touching the chest and the arms and legs flexed in front. The fetus normally faces the mother's back for a smooth delivery.
Any change in this position can cause prolongation in the duration in labor. A breech presentation in which the fetus is in the buttocks down position, a face presentation in which the fetus faces the mother's abdomen, or a deflexed position of the head in which the neck of the fetus is less flexed or even straight or extended can all cause prolonged labor.
Cephalopelvic Disproportion (CPD)
CPD is said to occur when the diameter of the presenting part of the fetal head is larger then the size of the maternal pelvic passage or birth canal. In most pregnant women in labor, ligaments and joints tend to become more flexible, enabling them to relax more at the time of labor.
The baby's skull bones are also capable of overlapping each other normally to some extent, decreasing the size of the head ('moulding'). So, it is difficult to estimate by physical examination alone if CPD is actually present.
Problems with Uterine ContractionThe uterine muscles may fail to contract properly when it is grossly distended as in cases of twin pregnancy and hydramnios (excess liquor amnii). Presence of tumours like fibroids in the uterine musculature can also affect uterine contraction.
Use of Sedatives and AnesthesiaExcessive use of painkillers or anesthesia can cause inefficient uterine action. They can also decrease the pain of normal labour and prevent voluntary effort by the mother to deliver the baby during the second stage of labor.
Cervical Dystocia or StenosisThe term cervical dystocia is used when the cervix fails to dilate properly and remains at the same position for more than 2 hours after the latent phase of labor. The cervix may fail to dilate when it is fibrosed due to previous operations like cone biopsy or due to the presence of tumors like cervical polyps and fibroids.
Signs and Symptoms of Prolonged Labour
- Labor extends for more than 18 hours.
- Patient looks exhausted and distressed. Dehydration may be present. Mouth may be dry due to prolonged mouth breathing.
- Pain may be more at the back and sides of the body, radiating to the thighs rather than from the uterus in the abdomen. This is due to excessive and prolonged pressure over the muscles and ligaments of the back.
- Labor pains may initially be severe, frequent and prolonged but later decrease and become very mild as the muscles become fatigued.
- Pulse rate is often high due to dehydration, exhaustion and stress.
- The large intestines are dilated and can be palpated along both sides of the uterus as large, thick structures filled with air. They give off the hollow sound of drums on tapping.
- The uterus is tender on palpation and does not relax fully between contractions.
- Ketosis may develop due to prolonged starvation.
- Fetal distress may develop.
- Membranes may or may not rupture early. In early rupture, there is a risk of infection of the uterine contents if proper antibiotics are not prescribed.
Risks of Prolonged Labour
- Fetal Distress due to decreased oxygen reaching the fetus.
- Intracranial hemorrhage or bleeding inside the fetal head.
- Increased chances of operative delivery like Cesarian sections.
- Longterm risks of the baby developing cerebral palsy.
- Intrauterine infections
- Trauma and injuries in the maternal birth passage like vulvar hematoma, perineal tears, cervical tears and vaginal wall tears.
- Postpartum hemorrhage.
- Postpartum infection.
There are two main methods of monitoring the baby:
- Intermittent Auscultation - By this method, the heart beat of the fetus is checked by either a stethoscope or a handheld doppler monitor. The heartbeats are counted and manually recorded at least every two hours.
- Continuous Electronic Fetal Monitoring (EFM) - Two sensors are placed on the abdomen - one measuring the uterine contractions and the other measuring the baby's heartbeats. Comparison of the graphs produced by these sensors can help identify fetal distress. A fetal scalp electrode (FSE) may also be placed on the fetal scalp for a more accurate reading of the fetal heartbeat.
Management / Treatment of Prolonged Labour
With the discovery of various drugs capable of accelerating labour, prolonged labour is a rarity nowadays.
- After 3cms of dilation (that is, after the latent phase), the cervix should dilate at the rate of 1cm per hour. If there is lack of dilation for a reasonable period of time, then an oxytocin drip is started.
Drugs like epidosin causes softening of tissues in the cervix. If the cervix fails to dilate in spite of adequate uterine contraction, epidosin or buscopan can be safely given to cause softening of the cervix.
- Intensive clinical monitoring should be done, recording the pulse, BP, fetal heart sound (FHS) every hour and dilation of the cervix at intervals of two hours. FHS should be checked even more frequently if necessary.
- If, in spite of the above procedures, labour fails to get accelerated or if foetal distress develops, Cesarian Section should be done.
- Sheehan's Syndrome.
- Female Anatomy - the vulva, the clitoris etc.
- Diet in Pregnancy .
- Vulvar Hematoma.