36 O B .GYN. NEWS • January 1, 2007 M ASTER C LASS Induction of Labor he timing of parturi- nancies that require induction because of medical com- of labor induction, the timing of labor induction, and the tion remains a conun- plications in the mother. advisability of the various conditions under which in- Tdrum in obstetric Increasingly, however, patients are apt to have labor in- duction can and does occur. medicine in that the majority duced for their own convenience, for personal reasons, This month’s guest professor is Dr. William F. Rayburn, of pregnancies will go to for the convenience of the physician, and sometimes for professor and chairman of the department of ob.gyn. at term and enter labor sponta- all of these reasons. the University of New Mexico, Albuquerque. Dr. Ray- neously, whereas another This increasingly utilized social option ushers in a burn is a maternal and fetal medicine specialist with a na- portion will go post term and whole new perspective on the issue of induction, and the tional reputation in this area. E. ALBERT REECE, often require induction, and question is raised about whether or not the elective in- M.D., PH.D., M.B.A. still others will enter labor duction of labor brings with it added risk and more com- DR. REECE, who specializes in maternal-fetal medicine, is prematurely. plications. Vice President for Medical Affairs, University of Maryland, The concept of labor induction, therefore, has become It is for this reason that we decided to develop a Mas- and the John Z. and Akiko K. Bowers Distinguished very important in obstetric management, especially in ad- ter Class feature on this topic. It gives us the important Professor and Dean, School of Medicine. He is the medical dressing pregnancies that either go post term or preg- opportunity to examine and consider the pros and cons editor of this column. Elective, Marginal Inductions on the Rise he goal of to both the patient’s desire and the physi- further fetal growth should reduce the risks Appreciating the Risks Tan induc- cian’s convenience; to the acceptance of of shoulder dystocia and perhaps of ce- Studies have shown that induced labor is tion of labor is added risks of cesarean delivery; and to in- sarean delivery. However, there is no evi- associated with an increase in epidurals, to achieve a creases in marginal or elective inductions dence-based justification for labor induction with the greatest risk of uterine rupture in vaginal deliv- for term pregnancies, especially those past in these patients. Studies have shown, in patients with a scarred uterus, with per- ery by stimu- 40 weeks. Inductions in which the reason fact, that the procedure approximately dou- haps an increase in instrumental vaginal lating uterine is not evidence based now account for at bles the cesarean delivery risk, does not re- deliveries, and with an increase in cesare- contractions least half of all term inductions, or up to duce neonatal morbidity, and does not ap- an deliveries, particularly among nulli- WILLIAM F. before the 10% of all deliveries. The increase in med- pear to reduce the risk of shoulder dystocia. paras undergoing an induction with an un- RAYBURN, M.D. spontaneous ically indicated in- favorable cervix. onset of labor. ductions was slow- Investigators of a large study published Generally, labor induction has merit as a er than the overall Induction Rate Continues to Climb in 2005 found a 1.5-fold greater risk of di- therapeutic option when the benefits of increase, suggesting 25% agnosing a nonreassuring fetal heart rate expeditious delivery outweigh the risks of that inductions for pattern, a twofold increase in the need for continuing the pregnancy. We must also, marginal or elective 20% epidural anesthesia, and a 1.5-fold in- however, weigh the benefits of induction reasons have risen creased risk of having a cesarean delivery against the potential maternal or fetal more rapidly. 15% among women who had elective induc- risks associated with the procedure. Also contributing tions of labor compared with women who The American College of Obstetricians to the rising rate in had spontaneous labor. 10% EWS and Gynecologists (ACOG) has described inductions is our in- N The risks of oxytocin use are principal- examples of commonly accepted indica- creasing success ly dose related. Excess or undesired uter- tions, contraindications, and clinical con- with cervical ripen- 5% EDICAL ine hyperstimulation and subsequent fetal ditions requiring special attention for an ing and the fact M heart rate decelerations (“hyperstimula- induction of labor. (See box p. 37.) We that, in the current 0 LOBAL tion syndrome”) are the most common must remember that indications for labor era of ultrasound 1989 1991 1993 1995 1997 1999 2001 2003 G side effects. In addition, hyperstimulation induction are often not absolute and need availability and a Source: Dr. Rayburn is associated with a greater risk of abrup- LSEVIER to take maternal and fetal conditions, ges- more accurate dat- E tio placentae or uterine rupture. There tational age, and cervical status into ac- ing of gestational does not appear to be a significant increase count. Many contraindications are the age, we have had to worry less about There is also no published evidence to in adverse fetal outcomes from uterine same as those for either spontaneous labor iatrogenic prematurity. support the induction of labor for preterm tachysystole. or vaginal delivery; several obstetric con- When considering labor induction, we mild preeclampsia, prior shoulder dystocia, Uterine hyperstimulation is an adverse ditions are not contraindications, but do can view “elective” and “marginal” indi- and prior cephalopelvic disproportion. effect that is also dose-dependent for necessitate special attention. cations as being very similar, or we can dif- ACOG weighed into the issue by ap- prostaglandins (misoprostol, dinopros- In 1988, the National Center for Health ferentiate the two, with “elective” mean- proving “logistic reasons” for labor in- tone) used as cervical-ripening agents. The Statistics began requiring hospitals to in- ing there is no plausible medical or duction, such as a risk of rapid labor, a pa- potential risks associated with amniotomy dicate on birth certificates whether labor obstetric reason for the induction, and tient’s unacceptable distance from the include prolapse of the umbilical cord, was induced or not. This requirement has “marginal” referring to cases in which ob- hospital, and psychosocial indications. This chorioamnionitis, significant umbilical provided us with remarkable insight into stetricians face or suspect problems but has left ob.gyns. with a substantial amount cord compression, and rupture of vasa labor induction rates—insight that should have no data to suggest that the benefits of latitude. For instance, one could argue previa. With close monitoring and proper cause us to pause, to reflect on available of labor induction outweigh the risks. I be- that “psychosocial” reasons could include precaution, these hazards are fortunately data and our own practices, and to de- lieve it is valuable to consider the terms alleviating the concerns of a mother who uncommon. mand that the issue receive more wide- separately as we attempt to understand previously had a stillborn infant, or allevi- Even if no additional risks are found spread attention. the changes in induction rates. ating the anxiety of a woman whose with elective and marginal indications, it Over a 10-year period beginning in Marginal indications include gestational spouse is scheduled for deployment to is important to consider issues related to 1989, the rate of labor induction doubled hypertension; unexplained and mild fetal- Iraq before the delivery date. personnel and cost. In addition to in- from about 9% to almost 19% of live growth restriction; idiopathic decreased In analyzing the increased rate of labor creasing the primary cesarean rate—and births. (See chart.) The trend steadily con- amniotic fluid (which does not pose sub- inductions, we can simply and easily make even a small additional risk of cesarean de- tinued into the new millennium, to the stantial danger unless it is accompanied by our own justifications for elective and livery for nulliparous women who have point where, in 2003, nearly 23% of all a recognized complication, such as hyper- marginal inductions—we are making our their labor induced translates into a sig- births involved induction of labor. Clear- tension or a small-for-gestational-age baby); patients happy, for one thing—and put on nificantly larger number of cesarean de- ly, labor induction is one of the most and a pregnancy beyond 40 weeks. Prospec- the back burner the lack of evidence fa- liveries nationally—labor that is induced common procedures in obstetrics. tive studies to recommend induction for voring non–medically indicated induction. requires more one-on-one care and thus these and other marginal indications are No matter how appealing our justifica- more nurses or nursing time. Examining the Increase limited in size or design, or are nonexistent. tions might be, however, we cannot ignore It also independently leads to signifi- The reasons for this significant increase There is some rationale behind induction the paucity of published data on benefits, cantly longer time in labor and delivery, as over just 15 years relate to the availability for suspected fetal macrosomia in nondia- nor can we ignore the data that do exist on well as a prolonged maternal length of of FDA-approved cervical ripening agents; betic pregnancies. Theoretically, eliminating the risks of labor induction. Continued on following page January 1, 2007 • www.obgynnews.com 37 Continued from previous page assess the effectiveness of therapies for la- this point in time the only known condi- ripening; formally evaluate physician and bor induction—are more likely to use the tions are a favorable cervix and a patient patient satisfaction with induction; and de- hospital stay.