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11. OTHER SPECIFIC PATIENT GROUPS

11.1 THE PREGNANT PATIENT

11.1.1 Management of acute pain during pregnancy
Pregnant women with pain that is severe enough to warrant drug treatment (self‐
administered or prescribed by attendants) represent a problematic cohort in that drugs given
to them almost always cross the placenta. While most drugs are safe there are particular times
of concern, notably the period of organogenesis (weeks 4 to 10) and just before delivery.
Where possible, non‐pharmacological treatment options should be considered before
analgesic medications are used and ongoing analgesic use requires close liaison between the
obstetrician and the medical practitioner managing the pain.
Drugs used in pregnancy
Drugs that might be prescribed during pregnancy have been categorised according to foetal
risk by the Australian Drug Evaluation Committee (ADEC). The categories used are listed in
Table 11.1 and the classification of some of the drugs that might be used in pain management
is summarised in Table 11.2. A list of these drugs, including regular updates is available from
the Therapeutic Goods Administration (TGA, 1999).
Paracetamol
Paracetamol is regarded as the analgesic of choice during pregnancy (Niederhoff & Zahradnik,
1983), although it has been suggested that prostaglandin actions may have adverse effects in
women at high risk of pre‐eclampsia (Zelop, 2008 Level IV). A large Danish cohort study
suggested an increase risk of preterm birth in mothers with pre‐eclampsia (Rebordosa et al,
2009 Level III‐3) following paracetamol exposure in early pregnancy; no increased prevalence
of congenital anomalies (Rebordosa, Kogevinas, Horvath‐Puho et al, 2008 Level III‐3); but a slight
increase in asthma in infants (Rebordosa, Kogevinas, Sorensen et al, 2008 Level III‐3). A smaller
study reported an increased risk of wheeze in offspring if exposure to paracetamol occurred in
mid to late pregnancy (Persky et al, 2008 Level IV).
Non-selective non-steroidal anti-inflammatory drugs
Non‐selective non‐steroidal anti‐inflammatory drugs (NsNSAIDs) are Category C drugs. Use of
nsNSAIDs during pregnancy was associated with increased risk of miscarriage (Li et al, 2003
Level III‐2; Nielsen et al, 2004 Level III‐2). While relatively safe in early and mid pregnancy, they
can precipitate fetal cardiac and renal complications in late pregnancy, as well as interfere
with fetal brain development and the production of amniotic fluid; they should be CHAPTER 11
nd
discontinued in the 32 gestational week (Ostensen & Skomsvoll, 2004). Fetal exposure to
nsNSAIDs has been associated with persistent pulmonary hypertension in the neonate (Alano
et al, 2001 Level III‐2) and an increased risk of premature closure of the ductus arteriosus (Koren
et al, 2006 Level I).
Opioids
Most opioids are Category C drugs. Much of the information about the effects of opioids on
neonates comes from pregnant patients who abuse opioids or who are on maintenance
programs for drug dependence. Maternal opioid use can have significant developmental
effects in the fetus, although social and environmental factors (eg other drugs, smoking) may
also have an impact (Farid et al, 2008; Winklbaur et al, 2008). Neonatal abstinence syndrome

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