Induction (birth)
Encyclopedia
Labor induction is a method of artificially or prematurely stimulating childbirth
in a woman.
If an induction causes complications during labor, a Caesarean section
is almost always conducted. An induction is most likely to result in successful vaginal delivery when a woman is close to or in the early stages of labor. Signs of impending labor may include softening of the cervix, dilation and increasing frequency or intensity of contractions. The Bishop score
may be used to assess the advisability of induction, and is based on such factors.
Inducing labor before 39 weeks increases the risk of complications and premature death, from factors including under-developed lungs, infection due to under-developed immune system, problems feeding due to under-developed brain, and jaundice
from under-developed liver. Some hospitals in the United States noticed a significant increase in neonatal intensive care unit
patients when women schedule deliveries for convenience, and are taking steps to reduce induction for non-medical reasons.
The odds of having a vaginal delivery after labor induction are assessed by a "Bishop Score". A Bishop Score is done to assess the progression of the cervix prior to an induction. In order to do this, the cervix must be checked to see how much it has effaced, thinned out, and how far open it is. The score goes by a points system depending on five factors. Each factor is scored on a scale between 0-3, any score that adds up to be less than 5 holds a higher risk of delivering by cesarean section.
s and other pain-relieving pharmaceuticals. These interventions have been said to lead to an increased likelihood of caesarean section
delivery for the baby. However, studies into this matter show differing results. One study indicated that while overall cesarean section rates from 1990-1997 remained at or below 20%, elective induction was associated with a doubling of the rate of caesarean section . Two more recent studies have shown that induction may increase the risk of caesarean section if performed before the 40th week of gestation, but it has no effect or actually lowers the risk if performed after the 40th week. Research published in the Journal of Perinatal and Neonatal Nursing showed that elective induction in women who were not post-term increased a woman's chance of a C-section by two to three times..
With early induction comes the increased risk of a caesarian section. A benefit to vaginal births are that the pressure of the birth canal helps squeeze out fluid from the babies lungs, which helps prevent transient tachypnea
.
Childbirth
Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...
in a woman.
Indications
Common suggested reasons for induction include:- Postterm pregnancy, i.e. if the pregnancy has gone past the 42 week mark.
- Intrauterine fetal growth retardation (IUGR).
- There are health risks to the woman in continuing the pregnancy (e.g. she has pre-eclampsiaPre-eclampsiaPre-eclampsia or preeclampsia is a medical condition in which hypertension arises in pregnancy in association with significant amounts of protein in the urine....
). - Premature rupture of the membranes (PROM); this is when the membranes have ruptured, but labor does not start within a specific amount of time.
- Premature termination of the pregnancy (abortion).
- Scheduling concerns.
- Fetal death in utero.
- Twin pregnancy continuing beyond 38 weeks.
Methods of induction
Methods of inducing labor include medication and processes.If an induction causes complications during labor, a Caesarean section
Caesarean section
A Caesarean section, is a surgical procedure in which one or more incisions are made through a mother's abdomen and uterus to deliver one or more babies, or, rarely, to remove a dead fetus...
is almost always conducted. An induction is most likely to result in successful vaginal delivery when a woman is close to or in the early stages of labor. Signs of impending labor may include softening of the cervix, dilation and increasing frequency or intensity of contractions. The Bishop score
Bishop score
Bishop score, also Bishop's score, is a pre-labour scoring system to assist in predicting whether induction of labour will be required. It has also been used to assess the odds of spontaneous preterm delivery.-Components:...
may be used to assess the advisability of induction, and is based on such factors.
Medication
- IntravaginalIntravaginal administrationIntravaginal administration is a route of administration where the substance is applicated inside the vagina. Pharmacologically, it has the potential advantage to result in effects primarily in the vagina or nearby structures with limited systemic adverse effects compared to other routes of...
, endocervical or extra-amniotic administrationExtra-amniotic administrationExtra-amniotic administration is a route of administration to the space between the fetal membranes and endometrium inside the uterus of a pregnant woman.It can be used to administer drugs affecting uterus motility, such as oxytocin and prostaglandins, e.g...
of prostaglandinProstaglandinA prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring....
, such as dinoprostoneDinoprostoneThe naturally occurring prostaglandin E2 is known in medicine as dinoprostone. It has important effects in labour and also stimulates osteoblasts to release factors that stimulate bone resorption by osteoclasts...
or misoprostolMisoprostolMisoprostol is a drug that is used for the prevention of non steroidal anti inflammatory drug induced gastric ulcers, for early abortion, to treat missed miscarriage, and to induce labor. The latter use is controversial in the United States. Misoprostol was invented and marketed by G.D...
. In the few controlled trials that have been done, extra-amniotic administration appears to be more efficient than intravaginal or endocervical administration of prostaglandins in labor induction, with no differential effects on other outcome measures. - Intravenous administration of synthetic oxytocinOxytocinOxytocin is a mammalian hormone that acts primarily as a neuromodulator in the brain.Oxytocin is best known for its roles in sexual reproduction, in particular during and after childbirth...
preparations, such as Pitocin. - Natural InductionNatural InductionInduction is a method of artificially or prematurely stimulating labour in a pregnant woman. There are several artificial methods of stimulating labour but these may increase the propensity of having a caesarian section-Methods:...
- Many midwives or other holistic providers practice "natural" induction, which may include use of herbs, castor oil or other medically unconventional agents to stimulate or advance a stalled labor. - Use of mifepristoneMifepristoneMifepristone is a synthetic steroid compound used as a pharmaceutical. It is a progesterone receptor antagonist used as an abortifacient in the first months of pregnancy, and in smaller doses as an emergency contraceptive. During early trials, it was known as RU-38486 or simply RU-486, its...
has been described. - RelaxinRelaxinRelaxin is a protein hormone first described in 1926 by Frederick Hisaw.The relaxin-like peptide family belongs in the insulin superfamily and consists of 7 peptides of high structural but low sequence similarity; relaxin-1 , 2 and 3 , and the insulin-like peptides, INSL3, INSL4, INSL5 and INSL6...
has been investigated, but is not currently commonly used.
Processes
- "Membrane sweep", also known as membrane stripping, or "stretch and sweep" in Australia and the UK - during an internal examination, the midwife moves her finger around the cervix to stimulate and/or separate the membranes around the baby from the cervix. This causes a release of prostaglandins which can help to kick-start labor.
- Artificial rupture of the membranes (AROM or ARM) ("breaking the waters")
When to induce
Until recently, the most common practice has been to induce labor by the end of the 42nd week of gestation. This practice is still very common. In the UK, a dating scan is usually conducted around the 12th week of pregnancy to determine the estimated due date. Research suggests that scans done after this date can cause the estimated due date to become less accurate, with the longer time that passes. In the cases of late dating scans, the estimated due date is less accurate which could therefore provoke a woman to be induced unnecessarily. While recent studies have shown a very slightly increased risk of infant mortality for births in 41st and particularly 42nd week of gestation, as well as a slightly higher risk of injury to the mother and child. The recommended date for induction of labor has therefore been moved to the end of the 41st week of gestation in many countries including Sweden and Canada.Inducing labor before 39 weeks increases the risk of complications and premature death, from factors including under-developed lungs, infection due to under-developed immune system, problems feeding due to under-developed brain, and jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
from under-developed liver. Some hospitals in the United States noticed a significant increase in neonatal intensive care unit
Neonatal intensive care unit
A Neonatal Intensive Care Unit —also called a Special Care Nursery, newborn intensive care unit, intensive care nursery , and special care baby unit —is an intensive care unit specializing in the care of ill or premature newborn infants.The problem of premature and congenitally ill infants is not a...
patients when women schedule deliveries for convenience, and are taking steps to reduce induction for non-medical reasons.
The odds of having a vaginal delivery after labor induction are assessed by a "Bishop Score". A Bishop Score is done to assess the progression of the cervix prior to an induction. In order to do this, the cervix must be checked to see how much it has effaced, thinned out, and how far open it is. The score goes by a points system depending on five factors. Each factor is scored on a scale between 0-3, any score that adds up to be less than 5 holds a higher risk of delivering by cesarean section.
Criticisms of induction
Induced labor tends to be more intense and painful for the woman. This can lead to the increased use of analgesicAnalgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
s and other pain-relieving pharmaceuticals. These interventions have been said to lead to an increased likelihood of caesarean section
Caesarean section
A Caesarean section, is a surgical procedure in which one or more incisions are made through a mother's abdomen and uterus to deliver one or more babies, or, rarely, to remove a dead fetus...
delivery for the baby. However, studies into this matter show differing results. One study indicated that while overall cesarean section rates from 1990-1997 remained at or below 20%, elective induction was associated with a doubling of the rate of caesarean section . Two more recent studies have shown that induction may increase the risk of caesarean section if performed before the 40th week of gestation, but it has no effect or actually lowers the risk if performed after the 40th week. Research published in the Journal of Perinatal and Neonatal Nursing showed that elective induction in women who were not post-term increased a woman's chance of a C-section by two to three times..
With early induction comes the increased risk of a caesarian section. A benefit to vaginal births are that the pressure of the birth canal helps squeeze out fluid from the babies lungs, which helps prevent transient tachypnea
Transient tachypnea of the newborn
Transient tachypnea of the newborn is a respiratory problem that can be seen in the newborn shortly after delivery. Amongst causes of respiratory distress in term neonates, it is the commonest . It consists of a period of rapid breathing...
.
External links
- Family.doctor.org
- Harman & Kim. "Current Trends in Cervical Ripening and Labor Induction" American Family Physician 1999; 60:477-84.
- Inducing Labor - WebMD.com
- Induction of labour. Clinical guideline, UK National Institute for Health and Clinical Excellence, June 2001.
- Josie L. Tenore: Methods for cervical ripening and induction of labor. American Family Physician, 15 May 2003.
- "Catecholamines - blood ." National Library of Medicine . N.p., n.d. Web. 28 Mar. 2011.