Monday, August 31, 2009

The Evidence Says: Inductions

Induction of labor has become a highly controversial topic for the last…51 years.

Most obstetrical and nursing books will site the following as potential clinical indications for induction:

  • abruptio placenta (placenta prematurely detaches from the uterus),

  • premature rupture of membranes,

  • severe preeclampsia,

  • pregnancy-induced hypertension (PIH),

  • intrauterine growth retardation (IUGR)-fetus not growing or thriving, oligohydramnios or polyhydramnios--too little or too much amniotic fluid

  • fetal anomalies requiring intervention, fetal demise,

  • maternal diabetes or heart disease,

  • postterm pregnancy

The American College of Obstetricians & Gynecologists released Practice Bulletin No. 107 in August: Induction of Labor. In this practice bulletin, it also states that labor may be “induced for logistic reasons, for example, risk of rapid labor, distance from hospital, or psychosocial indications.In such circumstances, at least one of the gestational age criteria in the box should be met or fetal lung maturity should be established. A mature fetal lung test result before 39 weeks of gestation, in the absence of appropriate clinical circumstances, is not an indication for delivery.”

In such circumstances, at least one gestational age criteria in the box should be met…should…not must….should.

Lacking is the definition of logistical or psychosocial indications for induction. Scheduling seems to be a very common reason for induction. Perhaps the baby is due on or near another relative's birthday and the parents want this baby to have his "own" birthday. Maybe the parents want to schedule the birthday to coincide with the arrival of out-of-town relatives or guests. Perhaps the woman has to return to work after six weeks of leave and she wants as much time off with the baby as possible. Or, the woman is just "tired of being pregnant" and wants to get to get on with the labor. On the other side of the coin is the caregiver. It is much nicer for the caregiver to know when their patient will be in the hospital so as to minimize conflicts with their other patients or in their personal life. In fact, the caregiver can even choose the hour of induction to coincide with his/her schedule and sleep. Also, the caregiver can plan vacation time around the scheduled delivery dates. Clearly not all caregivers would choose to encourage a woman to get induced based on his/her schedule, however this is certainly not unrealistic.

In the March 2009 issue of Evidence Report/Technology Assessment (Maternal and neonatal outcomes of elective induction of labor by Caughey et al), the conclusion was drawn that the evidence regarding elective induction of labor prior to 41 weeks of gestation is insufficient to draw any conclusion. Further, in the Annuls of Internal Medicine August 2009 (Systemic review: elective induction of labor versus expectant management of pregnancy), RCTs suggest that elective induction of labor at 41 weeks of gestation and beyond is associated with a decreased risk for cesarean delivery and meconium-stained amniotic fluid. Again, 41 weeks and not 39 weeks.

A woman's body goes through a series of preparatory steps prior to beginning labor. As the diagram below indicates, both the fetus and the mother seem to work together in determining when labor will begin. In order for an induction to be successful, oxytocin receptors must be in abundance on the uterus for the oxytocin to bind and produce contractions. That may explain why a woman who is brought into the hospital for induction, may not respond to the Pitocin given to her. Unless her uterus is ready to accept the Pitocin (oxytocin), the induction may not work.

There is a scoring system physicians should use which identifies those women who most likely will respond to an induction. This is known as the Bishop Score (refer to the chart on our website). Women who score relatively high (8-9) will have a greater chance of the induction taking. For a woman with a cervix that is not dilated, effaced, softened, or anterior will likely have a long, difficult labor, often ending in a cesarean delivery. Unfortunately, many doctors are ignoring this assessment and going ahead with an induction which may not be medically necessary.

Methods of induction include cervical ripening agents, stripping of membranes (similar to loosening the edible portion of an orange from the peel to stimulate production of prostaglandin hormones) , artificial rupture of membranes, nipple stimulation , laminaria tents (a mechanical opening of the cervix with seaweed) , Foley catheter (a mechanical forcing of the cervix with a catheter used typically for draining the urine from the bladder), Pitocin (a synthetic derivative of the naturally occurring hormone oxytocin but lacking several important properties), and Cytotec (also known as misoprostol – a medication not FDA approved for use during pregnancy or labor, and has been termed an abortifacient.

The introduction of the practice bulletin states “the purpose of this document is to review current methods for cervical ripening and induction of labor and to summarize the effectiveness of these approaches based on appropriately conducted outcomes-based research.” Unfortunately, over 50% (50 out of 90) references given at the end of the Practice Bulletin are over 10 years old. The cry still goes out for best practice guides, and evidence-based practice. Perhaps the definition of “best practice” and “evidence-based practice” should also include words such as “current”.

Regretfully, no where in the practice bulletin or nearly any research observed for this blog is any consideration given to the mother (her emotional state, physical state, pain levels, etc) or the newborn beyond the word “outcome”.

Absent are concerns for the newborn’s ability to bond, breastfeed or withstand the mechanical management of labor.

For inductions and maternity care, we have witnessed a gigantic step backwards.

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