Labor induction is pretty much something that none of my doula clients ever wants or even really expects. Care might be going great, everyone's healthy and happy, and then at 38/39 weeks the OB or midwife starts to talk about scheduling a chemical induction. This is especially frustrating when someone has expressed a commitment to a natural birthing process, and felt supported in those intentions by their provider.
The American College of Obstetrics and Gynecology (ACOG) defines “term” as 40 weeks, with late term at 41 weeks and postterm beginning at 42 weeks. Most women begin labor spontaneously by the 42-week mark (75% by 41 weeks and 2 days). In 2013, ACOG recommended that no induction should be scheduled prior to 39 weeks unless medically indicated (due to complications this can present for the baby, because of really important things like lung maturation), and no induction should be scheduled prior to 41 weeks unless the cervix is favorable, meaning basically that it's soft and stretchy.
Yet, induction remains a routine practice, with over a fifth of births induced in 2013 (having doubled in the previous decade). According to the Listening to Mothers survey—in which half of mothers reported their labors induced either medically (41%) or by the mother herself (22%)—the primary medical concern behind induction of labor was that the mother was “overdue” (25%). Another reason given for induction is a suspected big baby, an indication that is itself rather suspect (see the excellent work on this from Evidence Based Birth).
Since 1812, the length of pregnancy has been calculated using Naegele’s rule, which assumes that pregnancy lasts 40 weeks (280 days) from the first day of the last menstrual cycle. But research within the past few decades has questioned its standard interpretation, and challenges the use of Naegele’s rule to define term; in a 2001 study Smith found the average duration to be 283 days, which rises to 287.2 weeks for the average first time mother.
Common sense dictates that there is no single universal length of complete gestation. Rather, one should anticipate a normal range during which a healthy pregnant person will spontaneously begin labor.
Nonetheless, in that bell curve of normalcy, early term and postterm pregnancies are associated with higher risk. How great a risk is rarely explained, at least in relative terms. And one of the problems as I see it is that the risk is going to be different for healthy mothers versus mothers with other risk factors, like diabetes for example.
One of the arguments my clients sometimes hear is that the complications of a "postdates" pregnancy are due to the “aging placenta,” which is conventionally understood to malfunction as women reach the end of gestation. Yet recent research has questioned this idea, calling it “an uncritical acceptance of the overly facile concept.” Rather, there are various factors that may cause postdatism, and which amplify the risks of postdatism.
Mothers at risk of postdatism include those with a higher BMI, greater weight gain in pregnancy, a first pregnancy, a baby that measures small by 10-24 weeks (identified by ultrasound), relatively longer luteal phase (post-ovulation until the first day of your period), older maternal age, stress in late pregnancy (33-36 weeks), and close female relatives with longer pregnancies. However, each of these must be understood in terms of the parent's overall context, because we don't come out of a box all the same. However, the most common reason for a postdates pregnancy is inaccurate dating.
There are some important reasons to induce a labor, for example, when someone is developing preeclampsia. Routine induction for postdates in an otherwise healthy and normal pregnancy is performed on the assumption that risks associated with continued gestation are greater than risk associated with induction procedures. And because induction is associated with higher rates of cesarean section, forceps and vacuum delivery, and higher use of pain medications (as well as risks associated with inaccurate dating and an induction of labor for a baby who might not be completely physically ready to be born), we have to take into account the risks associated with each of those interventions when making a choice about how to proceed.
So, what to do?
The Conversations with Your OB/Midwife
- Make it clear to your doctor or midwife that it's important to you to avoid induction until it is either medically indicated or you reach postterm. They can't make you do anything you don't want to do or feel is important for you to do. Make it clear that you've reviewed the relative risk to your baby, and considering your excellent health during this pregnancy and your baby's healthy state, that you feel confident in waiting. It's useful to remember the ACOG definition of term and postterm. Postterm doesn't begin until 42 weeks. So, you're not postterm until 42 weeks. And so, without medical indication, why induce before 42 weeks?
- Second, discuss your "Bishop's Score," which is the "favorability" of your cervix to respond positively to induction. The higher the score, the more likely you'll go into labor. A low score is associated with less likelihood to start labor, and a greater likelihood of cesarean. Here's an unofficial Bishop's Score calculator, but it gives you a sense of what to discuss with your doctor. The ACOG recommends that for elective inductions, the Bishop's Score be at least an 8 out of 10. So if that's true for an elective induction, then it should also be true for a non-elective induction, no? So if your score is less than 8, then why not wait a little while longer?
- Make it clear that you're willing to do kick-counts, non-stress test (NST) and a biophysical profile (BPP) if needed to delay induction. A BPP measures four different markers of fetal well being, for a total score of 8. This is considered reliable for three days, after which you can have another BPP and keep on gestating. When combined with a NST, it's reliable for up to five days.
- Request a membrane sweep instead of a medical induction - "sweeping the membranes" refers to sweeping a finger between the interior of the cervix and the amniotic sac. Breaking that seal (but not the sac) releases prostaglandins.
- And if you want to go for it, you can say that you're willing to sign something saying that you're going "against medical advice" if necessary.
- In the US typically practitioners do not break the amniotic sac. If this is suggested to you I strongly recommend against it; research has not shown it to work well and it just increases the risk of infection and also puts you on a clock, and if you don't go into labor within a certain period other interventions will be used, increasing the risk of cesarean.
- Keep it positive, say that you understand what they're saying and that you're taking it into consideration, but that you feel confident in your decision.
What You Can do to Get Labor Going
Unless your body is ready, basically we can't force it to have a baby. However, what we hope for in using tricks to self-induce is that you're close enough to the borderline to just nudge your body into labor. To get things going yourself:
- Acupuncture. No joke, acupuncture. It's amazing.
- Acupressure point stimulation.
- Nipple stimulation, ideally with a breast pump (or get your toddler to nurse!). When you feel that crampy menstrual feeling, pump for 10-15 minutes at a time and then take a break.
- Chiropractic care (sometimes it's helpful to get the baby into an optimal position to get the right kind of pressure against your cervix).
- Homeopathic caulophyllum 30C 3x daily for two days, then again three days later if needed, or alternating doses of caulophyllym 30C and cimicifuga 30C for two days.
- Sex (and orgasms), because semen has helpful prostaglandins that can ripen the cervix, and it's more fun than castor oil.
- Castor oil.
There may come a point when you're just done and nothing seems to be working. It's up to you, and there's no one saying that you need to wait it out until you've been pregnant for a whole year (j/k). All of this is to say that you can use this information as you wish, do your research, and make your own choices.
 Jukic et al. “Length of human pregnancy and contributors to its natural variation,” Human Reproduction (2013), Vol. 28, No. 10, pp. 2848-2855.
 Baskett, Thomas F. and Nagele, Fritz. “Naegele’s rule: a reappraisal,” BJOG (2000). Vol, 107, No. 11 pp. 1433-1435; Boone, Cosette, “Establishing Estimated Date of Birth (EDB),” ACNM Clinical Bulletin, December 2000, accessed December 20, 2015; Smith, Gordon, “Use of time to event analysis to estimate the normal duration of human pregnancy,” Human Reproduction (2001), Vol. 16, No. 7 pp. 1497-1500.
 Halloran, et al. “Effect of Maternal Weight on Postterm Delivery,” J Perinatol (2012), Vol. 32, No. 2, pp. 85-90; Jucik et al, “Length of human pregnancy and contributors to its natural variation,” Hum Reprod (2013), Vol. 28, No. 10, pp. 2848-2855; Oberg et al. “Maternal and Fetal Genetic Contributions to Postterm Birth: Familial Clustering in a Population-Based Sample of 475,429 Swedish Births,” Am. J. Epidemiol (2013), Vol. 177, No. 6, pp. 531-537; Olesen et al. “Perinatal and maternal complications related to postterm delivery: a national register-based study, 1978-1993,” Am J Obstet Gynecol (2003), Vol. 189, No. 1, pp. 222-227; Margerison-Zilko et al. “Post-term birth as a response to environmental stress,” Evol Med Public Health (2015), no. 1, pp. 13-20; Johnsen et al. “Fetal size in the second trimester is associated with the duration of pregnancy, small fetuses have longer pregnancies,” BMC Pregnancy Childbirth (2008), Vol. 8, No. 25.
 Bennett KA, Crane JM, O'shea P, et al. First trimester ultrasound screening is effective in reducing postterm labor induction rates: a randomized controlled trial. Am J Obstet Gynecol. 2004 Apr. 190(4):1077-81.