Page 430 Acute Pain Management

(NAS) requiring treatment occurs in over 60% to 90% of infants exposed to opioids in utero
(Farid et al, 2008) and there is no clear relationship between maternal dose and the likelihood
or duration of NAS (Bakstad et al, 2009 Level III‐2). Outcomes tend to be better in mothers on
maintenance therapy rather than heroin (Farid et al, 2008 Level IV), and although initial studies
suggested an advantage of buprenorphine over methadone (Farid et al, 2008 Level IV), a recent
trial (Bakstad et al, 2009 Level III‐2) and a meta‐analysis (Minozzi et al, 2008 Level I) reported no
difference in maternal or neonatal outcome with methadone, buprenorphine or oral
morphine. A small study suggested that neonatal outcome was better in mothers receiving
opioids for chronic pain rather than addiction, although differences in dose and other
environmental factors may contribute (Sharpe & Kuschel, 2004 Level III‐2). Overall, the short‐
term use of opioids to treat pain in pregnancy appears safe (Wunsch et al, 2003), but minimising
use of opioid therapy for chronic pain during pregnancy has been recommended (Chou et al,
2009).
Musculoskeletal pain syndromes
Low back pain and/or pelvic girdle pain are common during pregnancy (Gutke et al, 2008; Borg‐
Stein & Dugan, 2007) and although low back pain may persist, pelvic girdle pain tends to resolve
following delivery (Elden et al, 2008; Vleeming et al, 2008). Epidural techniques in labour did not
increase the risk of long‐term backache (RR 1.0; 95%CI 0.89 to 1.12) (Anim‐Somuah et al, 2005
Level I), headache or migraine (Orlikowski et al, 2006 Level II).

Pregnancy‐specific back support garments reduced movement pain and analgesic use (Kalus et
al, 2008 Level III‐2) but strengthening exercises reduced back pain (Pennick & Young, 2007 Level I),
and exercise rather than a pelvic belt was recommended for pelvic girdle pain during
pregnancy (Vleeming et al, 2008 Level I). Weak evidence for improvements with acupuncture
(Pennick & Young, 2007 Level I; Ee et al, 2008 Level I; Vleeming et al, 2008 Level I) and chiropractic
care (Stuber & Smith, 2008 Level I) has been found in systematic reviews, but studies included
were of low quality. Oral magnesium therapy did not reduce the frequency or severity of
painful leg cramps during pregnancy (Nygaard et al, 2008 Level II).
Meralgia paresthetica
This variable condition comprising some or all of the sensations of pain, tingling and numbness
in the lateral thigh affects pregnant women in particular, with an increased odds ratio of 12 in
comparison with a non‐pregnant population (van Slobbe et al, 2004 Level III‐2). Multiple
therapies have been reported, but have not been fully evaluated or compared, including ice
packs, local infiltration with steroid and local anaesthetic, topical lignocaine or capsaicin,
CHAPTER 11 [TCAs], antiepileptics) and surgical intervention (Van Diver & Camann, 1995 Level IV; Harney &
transcutaneous electrical nerve stimulation (TENS), drug therapy (eg tricyclic antidepressants
Patijn, 2007 Level IV). Other compressive neuropathies, such as carpal tunnel syndrome and
Bell's palsy also occur more commonly during pregnancy (Sax & Rosenbaum, 2006 Level IV).
Symphysial diastasis
This occasionally disabling disorder (sometimes called osteitis pubis) involving separation of
the symphysis pubis during pregnancy or immediately after delivery, has a quoted incidence of
1:600 (Taylor & Sonson, 1986 Level IV) and can produce persistent pain, but there are limited
data to inform management (Aslan & Fynes, 2007).

382 Acute Pain Management: Scientific Evidence