Obstetric Pain Management: Causes and Treatment Options

Types of Pain and Their Origins

Pain is classified as either nociceptive or neuropathic (ICEA, 2014). Nociceptive pain develops from tissue, muscle, or bone. It presents as dull, aching, burning, stretching, or throbbing and travels through myelinated nerve fibers. Neuropathic pain, by contrast, originates in the nerves when damage has been inflicted on them (ICEA, 2014). It may become chronic and manifest as numbness, tingling, or burning. Over-stimulation of nerve fibers can damage them, effectively burning them out (ICEA, 2014).

Labor and birth pains are primarily physical in nature (ICEA, 2014), but they may also be mental or psychological—expressed as fear, anxiety, and panic. These arise from the complex linkage among the endocrine, nervous, and reproductive systems, and may be compounded by a lack of preparation for the event. Furthermore, pain can be experienced in cultural, spiritual, developmental, or environmental dimensions. All these possible sources must be examined carefully when planning a pain management program (ICEA, 2014).

The sensation of pain originates in the brain—specifically in the cortex, the neurotransmitters, and the hormones involved in the pain mechanism (ICEA, 2014). These structures all contribute to the perception and memory of pain. Brain regions within the amygdala, hippocampus, and limbic system also contribute to the development of anxiety, fear, and panic. Psychological reactions develop from the fear of the unknown, especially when accompanied by a sensation of pain. These reactions intensify when a woman reaches the threshold of pain without any pain relief measure being introduced.

Stages of Labor and Associated Pain

The three stages of the birth process are antepartum (before birth), intrapartum (during delivery), and postpartum (following childbirth) (ICEA, 2014).

Antepartum

Antepartum pain is classified as visceral or somatic (ICEA, 2014). Visceral pain emanates from the internal organs located in the abdominal and pelvic cavities and is referred through nerve pathways. This occurs during the first stage of labor, when sporadic uterine contractions begin and gradually become regular, more frequent, more intense, and longer in duration. The uterine muscles alternately expand and relax. The cervix opens, and small blood vessels at the walls of the vagina and cervix rupture. This inflammatory response creates significant pain but is considered normal. Somatic pain is a sharp sensation arising from connective tissue, muscle, bone, and skin. It occurs during the second stage of labor, when the ligaments stretch and the cartilage and bones relax. The pain sensation travels through the pudendal and perineal nerve pathways of the lower sacral region (ICEA, 2014).

Intrapartum

Sources of intrapartum pain may be emotional, functional, or physiological (Limaz, 2010). Emotional sources often stem from a lack of knowledge, experience, or preparation for the event. Functional sources include the stretching of the uterus, contractions, fetal descent, maternal sleep position, and certain birth procedures. Physiological causes include the incorrect positioning of the baby and other conditions co-occurring with childbirth (Limaz, 2010).

Postpartum

Afterpains, or cramping, are commonly experienced following delivery. They are most intense on the second and third days, particularly when breastfeeding or taking prescribed medication for contraction pain (NWH, 2014). This problem is most common after the birth of a second or third child. Uterine contractions may also cause pain until the uterus returns to its normal pre-pregnancy size. Additional pain may result from a laceration or tear, or from an episiotomy—a surgical incision made in the vaginal opening to facilitate delivery. The tissues surrounding the vagina may swell because of a deep tear, but this is normal and will eventually resolve. Hemorrhoids may also develop and cause pain and pressure around the rectum. They typically emerge during late pregnancy or labor and may be worsened by constipation after childbirth, causing swelling, itching, or bleeding (NWH, 2014).

Pharmacological Pain Management

Benefits

Scientific investigations have shown that epidural analgesia in childbirth provides effective pain relief when administered early in labor, without adverse consequence (Landau, 2009). These studies also demonstrated that large doses of diluted local anesthesia combined with opioids may prove more effective than epidural analgesia alone (Landau, 2009).

Risks

Analgesia may also be used in the late stages of labor as a pudendal block to relieve pain in the vaginal and perineal areas (Schrock, 2012). Because it is administered close to the time of delivery, systemic absorption is minimal. However, large doses may be required to achieve the desired effect, and risks such as local anesthetic toxicity, hematoma, and abscess formation may occur (Schrock, 2012).

Non-Pharmacological Pain Management

Water Immersion

Benefits: When performed during the first stage of labor, water immersion substantially reduces pain perception and thereby reduces the need for analgesia.

Risks: A 2004 study found that this approach decreased the speed of delivery and slowed overall labor progress (Schrock, 2012).

Water immersion is also commonly used during the second stage of labor (Schibed, 2009). Both its benefits and risks warrant further review and research. Currently, however, the method shows potential benefits for laboring women. The general concept is that water birth aligns with the requirements of natural birth: the mother achieves a sense of privacy and bodily autonomy, moves with complete freedom, and is unfettered by technology and the anxiety it can produce (Schibed, 2009).

Mindfulness Meditation

Benefits: Mindfulness meditation is a method of reframing pain as something controllable and of reducing stress and anxiety (Hughes, 2009). It employs cognitive therapy to manage these experiences and to reduce the recurrence of depression. At the same time, it allows the mother greater attentiveness toward her newborn (Hughes, 2009).

Risks: Nine recent studies on psychosocial approaches to childbirth pain showed that these methods reduce depression, but only in the short term (Dennis and Hodnet, 2007, as cited in Hughes, 2009). Moreover, these approaches do not appear to produce measurable beneficial effects on the mother–child relationship or on the child's development (Hughes, 2009).