Ask the PharmD: How to Manage Pain Meds During Pregnancy?

Chronic pain conditions, including migraine and fibromyalgia are common among women of childbearing age.¹ Patients being managed for chronic pain who become pregnant can present a challenge for providers, as specific clinical guidance does not exist. This population is therefore at risk for suboptimal pain management.²

Analgesic Use during Pregnancy: Safety Concerns to Mother and Fetus

Exposure to opioid analgesics during pregnancy has been associated with both maternal and fetal risks.^3,4 An association is suspected between maternal opioid use before pregnancy and during the first trimester and an increased risk for birth defects, including spina bifida and hypoplastic left heart syndrome.³

A case-controlled study found increased incidence of conoventricular septal defects (OR, 2.7; 95% CI 1.1 to 6.3), atrioventricular septal defects (OR, 2.0; 95% CI 1.2 to 3.6), hypoplastic left heart syndrome (OR, 2.4; 95% CI 1.4 to 4.1), spina bifida (OR, 2.0; 95% CI 1.3 to 3.2), and gastroschisis (OR, 1.8; 95% CI 1.1 to 2.9) in infants whose mothers were exposed to opioids before pregnancy or during the first trimester.³ Along with fetal risk, continuous maternal use of analgesics, especially opioids, may increase the risk of pre-eclampsia and preterm birth.⁵

The exact consequence of opioid use during pregnancy is unclear, but there is a known potential of neonatal abstinence syndrome (NAS, dependence) in the first few days of infant life.^6-8 The occurrence of NAS has been linked to daily maternal opioid use by descriptive evidence.⁹ Thereare also reports of worsened pregnancy outcomes in mothers that went through withdrawal during pregnancy, as withdrawal (both acute and severe) has been associated with spontaneous abortion and premature labor.^9,10 Women who are provided opioids should be counseled about the risk of CNS depression for both the mother and infant.¹¹ For women using potentially teratogenic medications, a daily prenatal vitamin (specifically with folic acid supplementation if the patient is taking an antiepileptic) can be helpful.¹²

Understanding pharmacokinetics throughout pregnancy can aid prescribers in choosing therapy for their patients. The placenta is a lipid membrane; both highly lipophilic molecules and small molecules (molecular weight < 500) can readily cross this membrane. Maternal GFR increases by approximately 50% as early as 14 weeks of pregnancy, which can cause an increased elimination of renally-excreted molecules.¹³

Approximately one-half of the pregnancies in the United States are unplanned, so prescribers should ask patients about current or future plans of pregnancy. (Image: iStock)

Patient Counseling and Treatment Plans

Approximately one-half of the pregnancies in the United States are unplanned, so providers should ask patients about current or future plans of pregnancy.¹² This will allow the patient and provider to communicate on if, and how, therapy will change if the patient does become pregnant.

Enhanced assessments in pregnant patients should be utilized to determine the patient’s risk for opioid use disorder and/or dependence. Significant opioid use risk factors include single marital status, tobacco use, various mental health diagnoses, and substance use disorder. Targeted interventions can reduce unnecessary opioid prescribing and use, especially during pregnancy.¹

It is imperative to develop a pain protocol with each patient and to provide education on both the risks and benefits of using analgesics during pregnancy. Alternative treatments should be offered when necessary (see details on alternatives below).¹⁴

During Pregnancy

Given the high potential for adverse effects with analgesic use during pregnancy, an almost exclusive recommendation is to implement non-pharmacological pain management strategies.² However, not all patients will have access to non-pharmacological options. In general, any drug therapy during pregnancy should focus on minimal fetal exposure using the lowest-effective pharmacological dose and shortest duration possible.¹²

If NSAIDs – OTC or prescribed – are used during pregnancy, limit use to the first two trimesters, as increased risk for adverse effects is seen with near-term administration.¹⁵ Acetaminophen is considered to be generally safe throughout pregnancy. Many OTC pain relievers contain acetaminophen, so it is important to counsel patients on the maximum daily recommended amount of 4000 mg daily.¹⁶

For migraine, sumatriptan is the preferred therapy during pregnancy, as this is the most widely studied agent.^10,17

If possible, opioid use should be avoided during pregnancy. As noted, continuous opioid use could increase the risk of pre-eclampsia or other complications.¹⁵ If a patient is on opioid therapy and becomes pregnant, therapy should be slowly tapered and discontinued to prevent opioid-related complications.If this is not possible, the lowest effective dose should be maintained after reviewing risks and benefits of opioid use with the patient.^2,9

According to the HHS, the opioid tapering schedule (for the general population) will look different depending on the patient’s opioid tolerance. For example, if the patient has been taking opioids for a few months, a 10% dose reduction per week would be a reasonable taper schedule. On the other hand, if the patient had been taking opioids for years, a 10% decrease per month may be more reasonable.¹⁸ Patients should receive appropriate psychosocial support, as the taper process can become difficult.¹⁹ Exercise caution when tapering opioids during pregnancy, as withdrawal can cause spontaneous abortion or premature labor.⁹ Neonates exposed to opioids during pregnancy should be monitored by a pediatric provider to assess for NAS using the Finnegan Scoring Tool.¹⁰

Table I outlines additional pregnancy-specific considerations with various analgesics.

During Labor

A multi-medication treatment plan including NSAIDs and acetaminophen is typically needed to provide adequate relief of intrapartum and postpartum pain.¹⁰ The goal of using a multi-medication algorithm is to use analgesics with different modes of action, as pain is multifactorial.¹¹ Often, patients with chronic pain conditions experience heightened anxiety and fear prior to labor and can benefit from reassurance and discussions of their pain management plans.¹²

Postpartum

When it comes to breastfeeding, paracetamol, ibuprofen, and naproxen have a low amount of transfer into breastmilk and are generally considered safe.²⁹ Codeine and hydrocodone are not preferred agents for breastfeeding mothers, as there have been reports of unexplained apnea, bradycardia, cyanosis, and sedation in nursing infants whose mothers were taking codeine, and both codeine and hydrocodone are associated with an increased risk of fetal sedation.^30,31 If a breastfeeding mother is taking sumatriptan, infant exposure can be significantly reduced by discarding all breastmilk until 8 hours after taking the dose of sumatriptan.²⁹ There is some data that suggests that tramadol has low transfer into breastmilk, but should not be used as first-line. Morphine experiences high first-pass metabolism and also has low transfer into milk, so it is usually considered safe.²⁹

Following delivery, benefits have been seen when using scheduled ibuprofen and acetaminophen.¹² Some patients will require opioids following delivery. When an opioid is needed in a lactating woman, hydromorphone is preferred.^30,31 Gabapentin is not routinely recommended for postpartum analgesia, but may be considered as a part of a multi-medication regimen in patients with chronic pain or pain not relieved by the standard analgesia protocols.¹¹ During the acute postpartum period, a plan should be formulated to transition the patient back to their prior pain management plan.¹²

Alternatives to Analgesics

Non-pharmacological interventions for chronic pain during pregnancy may include acupuncture (from an experienced therapist), physical therapy, chiropractic care, behavioral approaches, transcutaneous electrical nerve stimulation (TENS) units, and exercise. Acupuncture, however, should be avoided during the 1^st trimester, used cautiously in other trimesters, and avoided altogether in high-risk pregnancies.⁽¹⁵⁾

A study has shown that for low back pain (LBP) during pregnancy, TENS units reduced LBP more effectively than exercise alone or acetaminophen.³²More data is needed on the safety and efficacy of TENS units before making a universal recommendation.¹⁵

Caution should be used when considering chiropractic care for chronic pain, as abdominal pressure (1^st trimester) and lying on the back (3^rd trimester) should be avoided.¹⁵

Physical exercise is a widely-recommended pain management strategy.^1,15,15,32 Studies have produced promising data on water aerobics for pain management, but hot tubs should be avoided during pregnancy.¹⁵ If pain is not relieved by activity modifications and proper education, physical therapy may be beneficial.¹⁵

More on opioid use disorder in pregnant patients.

More on the ACR's reproductive health guidelines.

Practical Takeaways

Treating chronic pain during pregnancy raises unique challenges. Treatment regimens should be patient-specific and outline risks and reasons for choosing certain therapies. Opioid use should be avoided as much as possible during pregnancy.

Patients should be educated on the risks and benefits associated with analgesic use leading up to, during, and after pregnancy. These individuals’ pain management plans should be both realistic and goal-specific, ideally utilizing the lowest-effective dose of medication to avoid unnecessary fetal exposure.