Heparin Following a prophylactic dose of unfractionated heparin (UFH) subcutaneously (maximum 10,000 IU/d), advice varies from no delay to a delay MLN0128 concentration of 4 h [433] and [443]; 4 h is consistent with the known non-pregnancy

UFH pharmacokinetics despite an earlier peak effect in pregnancy [444]. While generally unnecessary, aPTT can be checked prior to neuraxial analgesia/anaesthesia [433] and [445]. With therapeutic subcutaneous UFH, an aPTT ⩾4 h after the last dose should be confirmed to be normal prior to initiating neuraxial analgesia/anaesthesia or removing a neuraxial catheter. When to initiate prophylactic or therapeutic UFH after neuraxial block is at least one hour following either block placement or catheter removal [433], [443] and [446]. Women on LMWH are ineligible for neuraxial anaesthesia until at least 10–12 h (prophylactic dose) or 24 h (therapeutic dose) after their last dose, based on non-pregnancy reports of neuraxial haematomas [443]. Some anaesthesiologists prefer

to wait 24 h after any dose. Therefore, switching from prophylactic LMWH to UFH is common in late pregnancy [447]. If there were blood in the needle or epidural catheter when siting a neuraxial block, initiating LMWH should be delayed for 24 h [443], during which period early mobilization and non-pharmacological methods can be used in women at higher thromboembolic risk. Indwelling neuraxial catheters can be maintained with prophylactic doses of UFH (⩽10,000 IU/day) and single-daily prophylactic LMWH, without Quizartinib cell line use of other haemostasis-altering agents. Aspirin and heparin 1. Pre-conceptual counselling for women with pre-existing hypertension is recommended (III-C; Very low/Weak). The major issues to address are the teratogenicity of antihypertensives, continuing antihypertensives

during pregnancy, and continuing pre-pregnancy cardiovascular risk reduction therapy (e.g., aspirin, statins). Pre-conceptual counselling is ideal, but as 50% of pregnancies are unplanned, inadvertent antihypertensive exposures will occur. Contraception efficacy and the potential for teratogenicity must be considered when prescribing antihypertensives to reproductive age women, all of whom should take ⩾0.4 mg/day of folate prior to pregnancy. Terminal deoxynucleotidyl transferase As BP usually falls in pregnancy (nadir ≈20 weeks), before rising towards pre-pregnancy levels by term, women with pre-existing hypertension may not need to continue antihypertensives from early pregnancy. Antihypertensive discontinuation does not alter preeclampsia risk [448] (see Antihypertensive therapy.) Any potential teratogenicity must be assessed relative to the baseline risk of major malformations: 1–5% of pregnancies. Most antihypertensives have not been found to be teratogenic, but the quality of the information is only fair for most. The 2010 UK NICE guidelines describe thiazides as teratogenic (unsupported statement).