Pain Management in the pregnant patient is unique as every therapeutic intervention effects two patients at the same time. The goal of avoiding side effects, especially for the developing fetus, makes the goal of satisfactory pain control more complex to achieve.
However, trauma during pregnancy, the need for non-elective surgery, or preexisting chronic pain conditions routinely result in the need to manage pain in pregnant patients.
Furthermore, the physiological changes seen in pregnancy can per se cause pain that in most cases disappears post partum. Increased weight and the hormonal changes associated with pregnancy can put considerable stress on the musculoskeletal system resulting in
- Low Back Pain (impacts approximately half of pregnancies)
- Pelvic Girdle Pain
- Abdominal and Chest Wall Pain
- Hip Pain
- Arthritis
- Acetaminophen is considered the drug of choice for mild pain during pregnancy.
- NSAIDS can be used during the first and second trimester, but there are differences between agents in terms of risk category. Ibuprofen, diclofenac, ketorolac and celecoxib can be considered safer options in cases NSAIDS are indicated.
- In general, short-term, episodic use of opioids appears to be safe in pregnancy. Morphine, fentanyl, or hydromorphone appear to be the opioids of choice for pain management during pregnancy.
- Regional anesthesia techniques (peripheral nerve blocks and infusions, epidural anesthesia) are considered safe and preferable approaches to pain management in pregnant patients.
The fetus is at greatest risk of teratogenic malformations in the first trimester, but second- or third-trimester medication exposure that does not result in anatomic anomalies may still cause functional and behavioral anomalies as detailed below.
Maternal NSAID usage during the third trimester of pregnancy is contraindicated as it is associated with neonatal pulmonary hypertension secondary to the premature closure of the ductus arteriosus.
IV Ketamine is contraindicated in the treatment of acute pain during pregnancy, despite its occasional use in anesthesia for labor and delivery. (Shwenk, 2018)
IV lidocaine is in general considered safe, but there is limited data available on the safety of continuous lidocaine infusions in pregnant patients, as pregnancy was an exclusion criterium in most clinical studies.
Gabapentin also has been associated with more severe neonatal withdrawal when used chronically in conjunction with opioids.
Schwenk ES, Viscusi ER, Buvanendran A, Hurley RW, Wasan AD, Narouze S, Bhatia A, Davis FN, Hooten WM, Cohen SP. Consensus Guidelines on the Use of Intravenous Ketamine Infusions for Acute Pain Management From the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists. Reg Anesth Pain Med. 2018 Jul;43(5):456-466.
Macfarlane AJR, Gitman M, Bornstein KJ, El-Boghdadly K, Weinberg G. Updates in our understanding of local anaesthetic systemic toxicity: a narrative review. Anaesthesia. 2021 Jan;76 Suppl 1:27-39.