The Evidence For and Against Birth Induction

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The Evidence For and Against Birth Induction
When is the fetus better off outside the mother's uterus, and if so, how should that be brought about?

Abstract: Smith (2003) found unexplained stillbirth occurs once in 2000 births (0.5/1000) after 34 weeks among low risk second pregnancies, following a first vaginal birth in the absence of induction for postdates.  If induction for postdates could prevent stillbirth by expediting the deliver, one would expect to save 0.5/1000.   Four systematic reviews performing meta-analysis of the data regarding the effect of induction for postdates draw three different conclusions.  Cochrane (2012) concludes that inducing at 41 weeks can prevent 1 stillbirth/perinatal death for every 410 inductions or 2.5/1000 perinatal deaths, a number exceeding the rate of unexplained stillbirth at term without induction. Hussain (2011) looking at inductions after 41 weeks concludes that performing  inductions at 41 weeks does not prevent stillbirth but does prevent 1 perinatal death in the first week of life for every 650 inductions (1.5/1000) performed. None of the studies look at mortality after 7 days. Therefore it is not known whether those 'saved' babies die after the one week mark.  Wennerholm (2009) and Sanchez-Ramos (2003) look at the same data for inductions after 41 weeks and found no evidence supporting induction for postdates, stating, that induction for postdates is not supportable from a scientific point of view.   There is limited and inconsistent data suggesting that induction might improve outcomes in the cases of: Postdates, Oligohydramnios, Suspected worsening of fetal anomaly at 34-39 weeks, Fetal Demise, Multiple gestation with fetal death, Poorly controlled diabetes, Hypertension at 38-39 weeks, Maternal Chronic Pulmonary disease, Maternal Chronic Renal disease, Intrahepatic cholestasis of pregnancy, Mild (after 37 weeks) or Severe (after 34 weeks) preeclampsia,  Isoimmunization, and Premature rupture of membranes-  after 34 week. There is a complete lack of research evidence suggesting that induction improves outcomes in the case of: History of unexplained stillbirth after 39 weeks, logistical such as distance from hospital or risk of precipitous labor, Antiphospholipid antibody, severe growth restriction or chorioamnionitis. Consistent reliable evidence is lacking for all justifications for induction.

When asked, 50% of pregnant women said they would like to deliver early. (Chauhan and Ananth 2012)  Asking pregnant women such questions derives from our current mental hygiene that presumes that people ought to be rich, insured against damage and anything unexpected should be eliminated. More and more women with normal pregnancies, who would have approached a mother, aunt, or pastor in former days, now confront doctors with anxiety about "when and how will I deliver?"  These women are not in need of an obstetrician. Their pregnancies are disease-free.  They need reassurance and changing their attitude towards labor and the meaning of the pain of the contractions.   

Whether she is aware of it or not, the woman decides when, where and how to give birth.  Our bodies are under our control whether we have accessed the keys to that control or not.  Extreme control has been demonstrated by highly trained martial arts experts who can prevent themselves from ovulating. Mothers at term have put themselves into labor by simply walking up a steep hill for an hour to start contractions.   A woman who is ready to give birth sometimes swallows a glass of castor oil and the contractions start one minute later, before an actual physical effect of the castor oil has taken place.

On the other hand, a woman who is driven to finish her PhD thesis or attend their daughter's wedding will not go into labor until they finish their task.   A mother who is deathly afraid to give birth, will not go into labor until the fear subsides.  This is true for all mammals.  Perhaps this explains why many women wake up in the middle of the night with contractions.   The fear has to subside when she is deeply sleeping and the body is able to start labor.   Often the body has been signaling the woman that it is ready to give birth for weeks.  Eventually the scared woman may get tired out by those contractions, and decide it will be easier to give birth than suffer the ineffective contractions she is having. Or she may fall into a deep sleep and wake up in effective labor.  One cannot put off labor forever.

How long can a woman put off going into labor?  No one knows the answer to this question because no one has ever studied it.  The average pregnancy is 284 days long or 40.6 weeks or 40 +4 days long.   By convention, we define it as 40 weeks, which defines the average pregnancy as 4 days less than it is.   Convention mistakenly defines all women as being due to deliver 4 days before they actually are due to deliver. Therefore the most common reason for going past one's date is because the date given was 4 days early to begin with.   First births are on average a week later than all other births. Fear is likely involved in that delay.  What is badly needed is reassurance and eliminating fear of childbirth, to enable women to go into labor naturally.

25% of US births are artificially induced. (22% in 2006 and  23% in 2008).  Induction means that the pregnant mother is considered a mortal danger to the fetus and if it stays in, it will die.  Under what conditions is the mother's body a danger to her fetus?

'There is no good or consistent scientific evidence supporting any indication for induction.' (Chauhan and Ananth 2012).  Chauhan states: "Induction is contraindicated for some of these complications (for examples: previa, suspected accreta, or prior classical cesarean).   When comparing the list of indications by  ACOG, SOGC (Canada), RCOG (UK), the only indications for induction that  all 3 agree on are  fetal death, logistical reasons of "distance from hospital," and premature rupture of membranes.  RCOG clearly specifies that suspected macrosomia is not a reason for induction; however, ACOG and SOGC do not comment on it. Considering that close to half of the inductions in the USA were because the "baby is too big," this is an important omission. (Chauhan and Ananth 2012)

Four systematic reviews combining the results of more or less the same 17 studies disagree on what the studies show. Not a single study was high quality concerning validity and precision. Only three trials were of fair quality. The other 14 studies were poor quality, despite a randomized design.  The only thing for sure is that perinatal death is a rare event. A total of 9 or 10 perinatal deaths, excluding nonviable babies, occurred among 3,600 births that were randomized to the expectant management.  All those births might have been induced, since many of the women randomized to expectant management were induced and many of the women randomized to induction group did not undergo induction.  The studies are from around the world, including countries which might not be generalizable to western medicine.   

Of the nine perinatal deaths, six are from 6 small studies - one each in Turkey, Thailand, Tunisia, UK, Austria, and Norway. The stillbirth in the UK was an uncontrolled gestational diabetic.  Perhaps they all were gestational diabetics and/or heavy smokers and the other studies neglected to note it. Perhaps they were all induced, but randomized to the expectant management. Based on this data, millions of women in the US have had inductions for postdates.   A similarly carried out systematic review of inductions from 41 weeks by Wennerholm (2009) found induction did not save fetuses from stillbirth or dying in the first week.   

A third review of inductions from 41 weeks on found that induction can decrease stillbirth by about 0.5/1000 by decreasing macrosomic births. (Hussain 2011)  From this it can be said that the concept that induction can prevent stillbirth or perinatal death is a theory, thus far lacking evidence to support it.  The theory is built upon the premise that the mother can be toxic to her fetus.  The theory never blames the fetus.  The theory does not include the possibility or theory that perhaps certain babies die no matter what care is given, sometimes in the first week and sometimes after 2 weeks in which case induction only prolongs their death. Because theory only blames the mother, none of the studies looking neonatal mortality of the newborns in the first 28 days or 6 months after induction.  

Like any mammal, when the fetus is ready and the mother feels safe - she goes into labor. Now that I have 30 years of experience, I am more confident and that is transmitted to my women.  I reassure them, I come whenever they call and when they stop worrying about it, they simply go into labor.

Where women are confident and supported, they go into labor at the right time.  With the exception of malnutrition such as diabetics and toxemia, there is only a need for induction where women are not reassured.   Where women have access to midwives they trust, partners who are supportive, there is no need for induction.

  • No matter what method of induction is used, a woman will only deliver when she is allows it to happen, unless the baby is cut out of her. 
  • Even in the presence of 25% rates of induction at term, term fetuses continue to die in utero at the rate of about 1 in 2000 full term births.
  • An unknown percent of the babies, delivered by cesarean die a few weeks after birth instead of in utero.  If stillbirth can be prevented by induction, which has never been shown with certainty, lowering the stillbirth or perinatal mortality rates might merely delay the tragedy by several weeks or months.  Therefore the elimination of death in the first week after birth may not indicate an actual lowering of death.  There is an absence of high quality research showing better outcomes from induction, and no research on long term follow up.
  • Medical attention improves outcomes.   It can diagnose and treat diabetics, high blood pressure and Rh isoimmunization, and give women confidence so she can let go and go into labor.

When we are talking about ways to induce labor, we are talking about ways to consciously or unconsciously release the mother's desire to go into labor.

Castor oil: Can cause diarrhea. The further along the pregnancy, the better it works. Does castor oil work because the woman lets go after drinking it?  In addition to causing diarrhea, it may involve a placebo affect since it can work without ever causing diarrhea.  

Can castor oil put women into such strong tetanic contractions (hyperstimulation) that the fetus dies? This is unknown.  Based on anecdotes of that happening, I think a woman should not take castor oil alone, but rather with a birth attendant there to reassure her and relax her.  But isn't that always the case?

Walking uphill: Walking up and down hill often causes contractions.  Walking up a steep hill for 2 to 4 hours at term puts postterm women into labor.  Perhaps this is psychological.  But walking up 8 flights of stairs does not have the same effect.   Stairs are good to get the fetal head settled into the pelvis.

Nipple massage: sometimes releases oxytocin, which can bring on contractions.  Some women prefer using a breast pump.  The half life of oxytocin in the body is 2 minutes.   Therefore, when this works to bring on a contraction, she might have to continue doing it until delivery.  Among 719 women, who used nipple stimulation, they were more likely to be in labor after 72 hours than the controls. The study group had a reduction in postpartum hemorrhage rates and no instances of uterine hyper-stimulation.  (Kavanagh 2005)

Stripping:  Stripping means massaging the cervix and putting a finger inside the cervix between the cervix and the amniotic sac.   It has not been shown to work in randomized studies.  A Cochrane review (Boulvain et al 2005) of 22 studies with women randomized to stripping or no stripping (N=2797) in uncomplicated term deliveries demonstrated no significant differences in fetal outcomes. The groups showed similar rates of maternal infection and fever, neonatal infection, and Apgar scores <7 at 5 minutes. Two perinatal deaths were reported in each group.  Uncontrolled, non randomized experiments suggest stripping might reduce induction rates by 41% at 41(+0) weeks and by 72% at 42(+0) weeks, without increasing maternal or neonatal infection or cesarean section rates. (Vayssière etal. 2013)  Perhaps stripping works where the woman is given confidence to let herself go into labor.

Unprotected intercourse: Unprotected intercourse works for some women. (Caughey etal 2008)  These same women have to avoid unprotected intercourse sperm emissions until full term, because it can put them into premature labor.

Amniotomy: A recent review found that one cord prolapse occurs for about every 300 vertex, singleton full term low risk births in which the sac is ruptured artificially.  (Cohain 2013) The rate at which amniotomy increases the occurrence of early onset GBS disease of the newborn has never been researched, even though ruptured membranes is a known risk factor for Early Onset GBS. (Crago et al 2012)

Evening Primrose Oil (EPO):  Evening primrose seed oil contains about 10% gamma linolenic acid (GLA), a fatty acid also found in meat, oats, barley, and spirulina. GLA is a precursor for various prostaglandins which are known to both cause and suppress inflammation. Evening primrose oil is generally well tolerated, with reported minor adverse effects, including gastrointestinal upset, headaches, reduction in hemoglobin, hematuria, and fatigue.  In the only controlled study, the group that swallowed 500 mg of evening primrose oil twice a day from 37-38 weeks and once a day from 38 weeks on,  had labors on average 3 hours longer, and 2 days later than matched controls who did not take evening primrose oil. Taking evening primrose oil was associated with not only longer labor but also an increased incidence of premature rupture of membranes, arrest of descent, Pitocin administration, and vacuum extraction (Dove & Johnson 1999).           

The effects of EPO supplementation during pregnancy and lactation remain largely unknown. Extensive but transient petechiae and ecchymoses have been reported in a newborn infant whose mother took 1000 mg daily during the week before giving birth. Additional concerns have been raised about adverse effects of EPO supplementation on conditions including platelet aggregation, cholesterol, and blood pressure, although there is insufficient evidence to assess these concerns. (Bayles & Usatine 2009)

Other herbal remedies frequently recommended by midwives to induce labor include raspberry leaf, blue cohosh, and black cohosh have not been studied systematically.

Foley Catheter and Laminaria sticks:  Laminaria tents are sticks of kelp that expand when wet.  They work the same way as Foley Catheters to mechanically expand the cervix if they don't fall out.  There is good science showing that placement of an intracervical Foley catheter is a relatively safer means of inducing labor, in comparison to protaglandins or oxytocin, causing less uterine hyperstimulation than prostaglandins or oxytocin and resulting in similar cesarean section rates. However they appear to involve and increased risk of infection when compared to prostaglandins. This technique requires more robust evaluation before entering general practice. (Vayssière et al 2013, Jozwiak et al 2012) 


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