Is morphine (Morphin) safe for pregnant women with abdominal pain?

From the Guidelines

Morphine is not recommended as a first-line treatment for abdominal pain during pregnancy due to potential risks to both mother and fetus, and safer alternatives like acetaminophen should be considered first. The use of morphine during pregnancy is generally reserved for severe cases under close medical supervision, as it can cross the placenta and affect the developing fetus, potentially causing respiratory depression in the newborn if used near delivery, and regular use may lead to neonatal withdrawal symptoms 1. Non-opioid pain relievers like acetaminophen are usually considered safer during pregnancy. If pain is severe enough to warrant consideration of morphine, this indicates a condition requiring immediate medical evaluation. The underlying cause of abdominal pain during pregnancy should be diagnosed and treated appropriately, as it could indicate serious conditions like appendicitis, placental abruption, or preterm labor. Any pregnant woman experiencing significant abdominal pain should seek immediate medical attention rather than self-medicating.

Some key points to consider when managing pain in pregnant women include:

• Non-opioid pain relievers like acetaminophen and NSAIDs should be used as first-line treatments for pain after a routine vaginal birth or cesarean delivery, unless contraindicated 1.
• A short course of low-dose opioids can be considered for severe pain that is not managed effectively by non-opioid options, but this should be done with caution and under close medical supervision 1.
• Women with opioid use disorder (OUD) should be offered maintenance therapy with methadone or buprenorphine, and their pain management should be tailored to their individual needs 1.
• Neuraxial analgesia during labor and postpartum pain management with a multimodal approach that starts with non-opioid pain relief are also important considerations 1.

Overall, the goal of pain management in pregnant women is to provide effective relief while minimizing risks to both mother and fetus, and this should be done under the guidance of a healthcare provider.

From the FDA Drug Label

Prolonged use of opioid analgesics during pregnancy can cause neonatal opioid withdrawal syndrome [see Warnings and Precautions (5. 4)] . There are no available data with morphine sulfate tablets in pregnant women to inform a drug-associated risk for major birth defects and miscarriage. Published studies with morphine use during pregnancy have not reported a clear association with morphine and major birth defects [see Human Data] In published animal reproduction studies, morphine administered subcutaneously during the early gestational period produced neural tube defects (i.e., exencephaly and cranioschisis) at 5 and 16 times the human daily dose of 60 mg based on body surface area (HDD) in hamsters and mice, respectively, lower fetal body weight and increased incidence of abortion at 0. 4 times the HDD in the rabbit, growth retardation at 6 times the HDD in the rat, and axial skeletal fusion and cryptorchidism at 16 times the HDD in the mouse Administration of morphine sulfate to pregnant rats during organogenesis and through lactation resulted in cyanosis, hypothermia, decreased brain weights, pup mortality, decreased pup body weights, and adverse effects on reproductive tissues at 3 to 4 times the HDD; and long-term neurochemical changes in the brain of offspring which correlate with altered behavioral responses that persist through adulthood at exposures comparable to and less than the HDD [see Animal Data] . Based on animal data, advise pregnant women of the potential risk to a fetus.

Morphine is not recommended for use in pregnant women for abdominal pain, especially during labor, due to the potential risk of neonatal opioid withdrawal syndrome and other adverse effects on the fetus.

• Key risks include:
  • Neonatal opioid withdrawal syndrome
  • Neural tube defects
  • Lower fetal body weight
  • Increased incidence of abortion
  • Growth retardation
  • Axial skeletal fusion and cryptorchidism
• The FDA drug label advises pregnant women of the potential risk to a fetus based on animal data 2, 2, 2. The use of morphine in pregnant women should be carefully considered and alternative treatments should be explored.

From the Research

Morphine Use in Pregnancy for Abdominal Pain

• There is limited research directly addressing the use of morphine for abdominal pain in pregnant women.
• A study on analgesics in pregnancy 3 notes that over 50% of analgesics are in pregnancy category C, and even more are category D specifically in the third trimester, indicating potential risks to the fetus.
• The same study 3 highlights that changes in renal filtration, cardiac output, plasma protein concentration, and plasma volume particularly affect analgesics, and dose adjustments may be necessary to maintain therapeutic concentrations in pregnant women and protect the developing fetus.
• Another study 4 discusses the use of opioids during pregnancy, focusing on the treatment of opioid use disorder, and mentions that methadone and buprenorphine are used during the perinatal period if the benefits outweigh the risks.
• However, there is no direct evidence provided in the studies regarding the safety of morphine for abdominal pain in pregnant women.

Management of Acute Abdomen in Pregnancy

• A study on the management of acute abdomen in pregnancy 5 emphasizes the challenges in diagnosing and treating acute abdominal pain due to anatomical and physiological changes during gestation.
• It highlights the importance of timely diagnosis and management to prevent adverse outcomes for both the mother and fetus but does not specifically address the use of morphine.

Opioid Use for Chronic Abdominal Pain

• Studies on opioid medications for chronic abdominal pain 6, 7 discuss the challenges and limitations of using opioids for chronic pain management, including the risk of misuse and adverse effects.
• These studies do not directly address the use of morphine for abdominal pain in pregnant women but provide insight into the cautious approach needed when considering opioid use for chronic pain.