• LMWH should not be given for 4 hours after use of spinal anaesthesia or after the epidural catheter has been removed
• and the catheter should not be removed within 12 hours of the most recent injection.

The Green Top Guidleine 37 a  ( VTE Prevention in Pregnancy and Puerperium) has very useful charts for VTE risk assessment-  these can be downloaded HERE

Regional techniques should be avoided if possible until at least 12 hours after the previous prophylactic dose of LMWH.

Women receiving antenatal LMWH having an elective caesarean section should receive a thromboprophylactic dose of LMWH on the day prior to delivery and, on the day of delivery, any morning dose should be omitted and the operation performed that morning.

Bonus info- There is at least one more condition in which the delivery should be delayed for some time after appearance of the condition- Chickenpox ! In varicella rash- planned delivery should normally be avoided for at least 7 days after the onset of the maternal rash to allow for the passive transfer of antibodies from mother to child.

• Warfarin use in pregnancy is restricted to the few situations where heparin is considered unsuitable,e.g. some women with mechanical heart valves.
• Women with previous VTE associated with antithrombin deficiency (who will often be on long-term
  oral anticoagulation) should be offered thromboprophylaxis with higher dose LMWH (either 50%,
  75% or full treatment dose)
• Danaparoid is a heparinoid that is mostly used in patients intolerant of heparin, either because of HIT or a skin allergy to heparins

With Remifentanyl PCA- Respiratory depression is reported in up to 32% of patients and
oxygen saturations below 90% are seen in about 5%.

Some suggested contraindications of Remifentanyl PCA include- morbid obesity, clinical features of a chest infection and primigravida women who are at risk of prolonged labour.

Risk of anal sphincter injury in women undergoing VBAC is 5%.

Birthweight is the strongest predictor of anal sphincter injury in women undergoing VBAC.