The literature on recurrence rates suggests that 3-23% of patients with HELLP syndrome in one pregnancy may have it in another, and up to 40% approximately may have preeclampsia in one of its myriad forms. Because of the expense to test for all of the known thrombophilias, not all patients are thoroughly tested for these in all venues. Thus there is not, to my knowledge, a large corpus of patients who have had HELLP syndrome and were thoroughly tested for thrombophilias and then followed up for subsequent pregnancy outcome. We are probably several years away from having the precision you desire for accurate individual patient prediction and prognosis. Thus I usually use ranges in individual patient consultations because these are population statistics, while appreciating the multitude of unknowns and the knowledge that our testing techniques for thrombophilias are incomplete, imperfect and they represent only a portion of the possible risk factors for recurrent disease.