Medications and Pregnancy

NSAIDs

  • Generally avoided in pregnancy unless really necessary
  • They are particularly avoided in the third trimester, as they can cause premature closure of the ductus arteriosus in the fetus
  • They can also delay labour

Beta-blockers

  • Labetalol is the most frequently used beta-blocker in pregnancy, and is first-line for high blood pressure caused by pre-eclampsia
  • Beta-blockers can cause:
    • Fetal growth restriction
    • Hypoglycaemia in the neonate
    • Bradycardia in the neonate

ACEi and ARBs

ACE inhibitors and ARBs, when used in pregnancy, can cause:
  • Oligohydramnios (reduced amniotic fluid)
  • Miscarriage or fetal death
  • Hypocalvaria (incomplete formation of the skull bones)
  • Renal failure in the neonate
  • Hypotension in the neonate

Opiates

  • The use of opiates during pregnancy can cause withdrawal symptoms in the neonate after birth → neonatal abstinence syndrome
  • NAS presents between 3 – 72 hours after birth with irritability, tachypnoea (fast breathing), high temperatures and poor feeding

Warfarin

  • Crosses the placenta and is considered teratogenic
  • Can cause:
    • Fetal loss
    • Congenital malformations, particularly craniofacial problems
    • Bleeding during pregnancy, postpartum haemorrhage, fetal haemorrhage and intracranial bleeding

Sodium valproate

  • The use of sodium valproate in pregnancy causes neural tube defects and developmental delay

Lithium

  • Lithium is avoided in pregnant women or those planning pregnancy unless other options (i.e. antipsychotics) have failed
  • It is particularly avoided in the first trimester, as this is linked with congenital cardiac abnormalities, particularly Ebstein’s anomaly
  • When lithium is used, levels need to be monitored closely (NICE says every four weeks, then weekly from 36 weeks)
  • Lithium also enters breast milk and is toxic to the infant, so should be avoided in breastfeeding

SSRIs

  • SSRIs can cross the placenta
  • The risks feed to be balanced against the benefits of treatment as the risks associated with untreated depression can be very significant
  • Women need to be aware of the potential risks of SSRIs in pregnancy:
    • First-trimester use has a link with congenital heart defects
    • First-trimester use of paroxetine has a stronger link with congenital malformations
    • Third-trimester use has a link with persistent pulmonary hypertension in the neonate
    • Neonates can experience withdrawal symptoms, usually only mild and not requiring medical management

Isotretinoin (roaccutane)

  • Highly teratogenic, causing miscarriage and congenital defects