Physiological Changes before Labor Starts
What starts labor? The actual mechanism is still being researched, but there seems to be shifts in blood factors and immune proteins. We do know there is a series of changes in the gestational parent and baby that begins two to three weeks before the onset of progressive contractions. Even if you birth an early term baby, say 38 gestational weeks, those chemical changes can be detected two to three weeks prior to that birth date. Some changes are detailed below.
Changes in your baby include:
Fine tuning of the sympathetic and parasympathetic nervous systems takes place. The adrenal glands increase cortisol production that initiate changes to prepare for labor and life on the outside of the womb. Norepinephrine and epinephrine receptors in the heart and lungs develop, which in turn help your little one adapt and prepare for the normal stress of labor.
The lungs increase surfactant production. This allows your baby to take their first breaths.
The thyroid gland matures, which not only helps clear fluid from lungs but plays an important role in temperature regulation post birth.
The gut and metabolisms alter so your baby can utilize their stored brown fat in the initial days after birth.
Significant brain development occurs to further support the brain in releasing regulatory hormones.
Changes in your body:
In addition to cortisol, your baby’s adrenal gland releases another hormone called dehydroepiandrosterone (DHEA). This is sent to the placenta and the placenta converts it to estrogen. The estrogen then enters the adult circulation.
The increasing level of circulating estrogen structurally changes the uterus, creating receptors for oxytocin. Recall, oxytocin is the hormone that drives patterned, progressive contractions of labor. Estrogen helps develop oxytocin receptors in the uterus, brain, and mammary glands.
Prostaglandins act on these receptors so they become very sensitive to oxytocin.
During pregnancy, progesterone remains high to sustain the pregnancy and blocks the uterus’s ability to contract. As estrogen and cortisol rises and increases, the contraction blocking action of progesterone is deactivated.
Prostaglandin production from the amniotic membrane/sac increases and acts on the cervix to increase elastin and water and decrease firm collagen fibers. This is why you may experience more watery discharge (not leaking amniotic fluid) in your last weeks of your pregnancy.
So, how can you support all these hormones and pathways to do their thing?
Promote Hormones to Flow
Unwind If you’ve taken our Childbirth Class you’ve probably heard me tell the story about the impala being stalked by the lion. If the antelope is in labor, it needs energy to flee to safety, rather than continue to labor. So, the birth hormones will decrease temporarily. Once that impala reaches a place of safety, the labor hormones surge once again for the birth process to take place. In humans, the hormone oxytocin drives contractions during labor. And oxytocin responds to stress. When stress goes up, oxytocin goes down.
Your body is more likely to go into labor when you feel safe and confident and have time to unwind. This can help support the hormone shifts necessary in late pregnancy and the hormones necessary for labor and birth. When you feel supported, loved, and at ease, oxytocin flows freely. If you feel stressed, the hormone adrenaline increases and your bodies decrease the release of oxytocin.
Rest and Relax. Structure your life in late pregnancy to take a breather each day. And I know, this can be hard when watching and waiting for labor to begin! Can you work from home rather than going into the office each day? Are you able to take a longer lunch to allow for a bit of feet-up rest time? Are there projects at home that can be put on hold?
Perhaps develop a daily/bedtime routine to create space for calm and peace. Share a positive affirmation about your day with your baby. Perhaps create a reassuring phrase such as,
“All is well. All will be well. Everyone will play their part in this process. I look forward to meeting you!”
Try a visit to a prenatal massage therapist or acupuncturist [password: DCBDresources] as a way to balance your body and release tension.
Oxytocin is often referred to as the “hormone of love”, as it is released from the brain’s pituitary gland during sexual arousal. If you are up to it/in the mood, stimulating nipples and an erogenous zone may cause oxytocin to flow and may trigger those warm up uterine contractions. If your body is ready for labor (oxytocin receptors active in your uterus which happens in late pregnancy), then contractions may occur. If receptors are not present, the methods below will not have the desired contraction-inducing effect, nor will it do any harm.
Orgasm: Enjoy some self-pleasure and/or sex. If semen is available, it contains prostaglandins that help soften the cervix, which is an important initial phase of labor.
Nipple Stimulation: If you are after 38 weeks you can try nipple stimulation. Generally, stimulate by hand one breast/nipple at a time for no more than 10-15 minutes on each side. Alternate sides every 10-15 minutes and do not exceed one hour of stimulation. If you start feeling cramping/consistent contractions, stop stimulation, hydrate, and see if the contractions continue into early labor.
Evidence on acupuncture and acupressure (massage) along with nipple stimulation can be found here.
Promote Optimal Fetal Positioning
You can help your baby get into an optimal position for birth by doing some daily movement. Ensure you balance rest with movement! Some ideas for movement include:
Daily walking
Soften the pelvic floor with the side-lying release position
If you have a yoga/birth ball on hand, try some of these movements on the ball to help your baby move into the inlet of your pelvis (gendered video).
Join our Mindful Movement Sessions on Tuesday evenings at 6:30pm (Zoom Meeting ID: 938 952 7571 Passcode: DCBDroom) or checkout the Mindful Movement Playlist on your own time
Consuming Things to Kickstart Labor?
If you are with midwifery care, you have likely received suggestions from them ranging from eating dates, to red raspberry leaf tea, to evening primrose.
It is important to chat with your provider about various methods and decide what, when, how to use these different approaches. There is not research on every method one hears about (pineapple, spicy foods…) . Among the scientific studies that do exist, many do not include persons with ‘higher-risk’ or with pregnancy complications.
Evidence Based Birth has a Natural Labor Induction Series which we draw upon heavily for our research summary on these topics.
Eat some dates, starting at or before 36 gestational weeks, as long as you don’t have any blood sugar level concerns. (Decent level of research and results on this method).
If you are at or beyond your due date, talk to your provider about castor oil. Additional listening/reading on dates and castor oil can be found here.
Evening Primrose Oil (EPO). There are more promising results from vaginal EPO than from oral consumption, but “differing opinions in the research about whether EPO should be used clinically for cervical ripening” (Evidence Based Birth).
While many people talk about red raspberry leaf tea for uterine health, currently there is no conclusive evidence to support its use as a natural labor stimulation method. So, we await future funding and research!
Your Provider May Offer to Sweep Your Membranes
Sweeping membranes (irritating the space between the amniotic sac and the cervix) can be a low risk way to encourage labor. Your cervix will need to be at least a fingertip open for this to be an option. The exam lasts a few minutes. Some people feel the exam is a bit uncomfortable while others describe it as painful. After the sweep you can expect cramping and light spotting. The sweep may start labor; but, the most common side effect is moderate to heavy cramping with some spotting/discharge without the onset of either labor or progressing contractions. That said, some feel it is worth trying in an effort to avoid a medical induction and/or help soften the cervix in preparation for an induction.
~ Rena, Birth and Education Expert*
*If you are approaching your due date and looking for ways to stimulate labor, please consult your provider and reach out to your birth doula team for encouragement and support. birth@dcbirthdoulas.com
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