Mamas on Bedrest: Preterm Labor-> Full Term Delivery-The Bedrest Paradox

February 13th, 2013

Babies are cheeky little creatures. One minute, they are all gunho to get out, the next minute, it’s as if they want to stay inside forever! And why wouldn’t they? They live inside a warm, comfortable environment, get lots of good food, are rocked to and fro with the movements of their mamas, are soothed by mama’s heartbeat and generally are in the one of the most secure places they’ll ever be in their entire lives.  This month as many mamas from our Facebook Community prepare to birth their babies, I am struck by how many of them have gone really pretty far into their pregnancies, several are at term, when yet just a few months ago they were gripped with fear as they fought to keep their babies inside. What changed?

The entire process of labor and delivery is orchestrated by an interaction between the mama’s brain, the baby brain and the placenta. When baby is preparing to “exit” its brain begins sending out neurochemicals so that mama’s body begins preparing not only to deliver the baby, but also to receive her baby with love and adoration. This is primarily carried out by increased levels of oxytocin put out by the fetal brain as well as the placenta in an effort to prepare the uterus for contractions and expulsion of the fetus. Mama’s brain also begins secreting increasing amounts of opioids, corticotropin releasing hormone (CRH) and catecholamines which aid in pain management and management of inflammation during labor and delivery. Mama’s brain also begins releasing prolactin as it prepares mama’s body for lactation.

All of these systems work in concert to bring baby into this world safely. Unfortunately, sometimes “the signals get crossed” and neurochemicals begin releasing and sending signals for labor and delivery when it isn’t time. This is an overly simplified explanation of preterm labor, which is in reality a fairly complex neurochemical process.

At this time, most clinicians and researchers aren’t entirely sure why some women experience preterm labor. To date most people agree that when a mama is stressed, her body will produce and secrete increased levels of adrenal hormones, the flight or fight hormones, and these catecholamines do play a role in labor and delivery. But they are not fully responsible for preterm labor. In many women, elevated levels of Corticotropin Releasing Hormone (CRH),  a hormone secreted by the hypothalamic pituitary axis in the brain is and elevated. Since CRH also secreted by the placenta (at term, levels rise in preparation for labor and delivery) its clear that the signal to secrete CRH has malfunctioned in mother, placenta or both in the case of preterm labor. Oxytocin levels are also elevated in preterm labor, further signaling an abnormal activation of this hormone that acts to relax maternal muscles and soft tissue for delivery, to increase uterine contractility and to enhance mama/baby bonding.  Several other hormones and neurochemicals are activated (?inappropriately/prematurely) and add to the cascade that becomes preterm labor.

So what, if anything, does bed rest do to halt the production and release of these hormones and neurochemicals? To date, the research is not able to attribute any efficacy to bedrest for the slowing of this cascade and the halting of preterm labor. But perhaps if we look at the stress reaction, we may be able to gleen a bit of insight into how bed rest may help prevent preterm laobr. Keep in mind, this is all theory, supposition. Physicians and researchers still have not been able to produce concrete evidence  that bed rest prevents preterm labor.

As previously stated, the catecholamines responsible for the flight or fight response, are increased during stress. They are also increased in women experiencing preterm labor. But what isn’t clear is if the hormones are increased as a result of preterm labor or if mother’s stress increased their secretion and caused preterm labor. What we do know is that if mama’s stress is reduced, these hormones decrease.  The stress reaction also causes the release of cytokines which help soften the cervix and “ripen” it in preparation for delivery. In addition to being a stress response, cytokines also are an indication of inflammation. Again, if mama’s stress levels are reduced, cytokine secretion decreases.

So while there is no evidence that bed rest actually “halts” preterm labor, if a mama has been under stress placing her in a state of relaxation (bed rest) may in fact help her preterm labor. Interestingly, many mamas say that being on bed rest is more stressful than not because they worry about what might happen and feel powerless, as if they are not doing enough. So is bed rest helping?

The only thing that I can say is that if the number of healthy babies being born to our mamas in our Facebook Community is any indication, then bed rest has some benefit. Of late we are having a run of healthy term or nearly term (36 weeks or so) deliveries. The next task is to look at the medical interventions as well as the role support, actual and virtual, is having on mamas and their babies. For now we don’t know the actual benefit of bed rest, but we will continue to support Mamas on Bedrest in every way we can to do our part to help mamas deliver healthy term babies.

References

Felice Petragliam, MD, Alberto Imperatore, MD  and John R. G. Challis “Neuroendocrine Mechanisms in Pregnancy and Parturition” Endocrine Reviews December 1, 2010 vol. 31 no. 6 783-816

Roger Smith, M.B., B.S., Ph.D. “Parturition” New England Journal of Medicine  2007; 356:271-283 January 18, 2007 DOI: 10.1056/NEJMra061360

Hormones In Labour & Birth – How Your Body Helps You by Dr. Sarah J. Buckley. 

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