A treatment strategy with nifedipine versus labetalol for women with pregnancy hypertension: study protocol for a randomised controlled trial (Giant PANDA) by Ashworth, D, Battersby, C, Bick, D, Green, M, Hardy, P, Leighton, L, Magee, LA, Maher, A, McManus, RJ, Moakes, C, Morris, RK, Nelson-Piercy, C, Sparkes, J, Rivero-Arias, O, Webb, A, Wilson, H, Myers, J, Chappell, LC