Prolonged or complicated labour in the predelivery stage
- Age, genetics, and lifestyle are not significant factors
The first stage of labour begins with the onset of regular, strong contractions of the uterus and ends when the cervix is fully dilated. In this period, the cervix widens until it is 10 cm (4 in) in diameter to allow the fetus to pass into the vagina. The average length of the first stage of labour is 6–12 hours, but it can take much longer in a first pregnancy. Labour is delayed when the first stage is prolonged and the cervix is not dilating normally. A prolonged labour occurs in about 3 in 10 first births and about 1 in 8 subsequent births.
When it has been recognized that the first stage of labour is not progressing, the problem can usually be treated successfully with modern techniques and monitoring. The mother may become exhausted during a long first stage of labour and this can cause problems during delivery. Left untreated, a delay in the first stage may threaten the life of the mother and/or the fetus.
What are the causes?
A delay in the first stage of labour may be due to uterine contractions that are too weak to fully dilate the cervix. In first pregnancies, weak uterine contractions are especially common, and the cervix often takes longer to dilate than normal. Drugs given to relieve pain in labour, such as epidural anaesthesia (see Epidural anaesthesia in labour), may also weaken contractions.
Sometimes, the cervix fails to dilate because it is scarred from surgery. In some labours, the fetus is in an unusual position and cannot put enough pressure on the cervix to assist dilation (see Abnormal presentation).
What can I do?
If your labour is taking an abnormally long time, try to keep changing position and walking around because gentle movement encourages the uterus to contract more effectively, and gravity increases the pressure from the fetus on the cervix. If you cannot get out of bed, try to sit upright. A prolonged labour can be exhausting and may cause dehydration. It is therefore important that you keep your fluid intake up.
What might the doctor do?
At regular intervals during your labour, a midwife will measure your blood pressure and check whether your cervix is dilating. Your contractions and the heart rate of the fetus will be monitored continually (see Fetal monitoring). If the fetal heart rate is abnormal, a blood sample may be taken from the fetus’s scalp to check for signs of distress. An intravenous drip may be used to maintain your fluid levels. If your uterine contractions cannot dilate the cervix effectively, your doctor may be able to speed up labour by using a number of different methods (see Induction of labour). If labour is still delayed, you may need to have a caesarean section.
What is the prognosis?
With careful monitoring and management, a delayed first stage of labour is unlikely to cause problems.
The chance of having a delayed first stage of labour in future pregnancies depends on the cause. Weak or ineffective uterine contractions are less likely to occur in subsequent pregnancies, and dilation of the cervix is usually quicker. However, if the cervix has been scarred by surgery or damaged by a difficult delivery, a caesarean section may be necessary in future births.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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