D0L:10.1111/1471-0528.17515RCOG GREEN-TOP GUIDELINESRecurrent MiscarriageGreen-top Guideline No.17Lesley Regan Rajendra Rai Sotirios Saravelos Tin-Chiu Li on behalf of the RoyalCollege of Obstetricians and GynaecologistsCorrespondenceRoyal College of Obstetricians andKey recommendationsGynaecologists,10-18 Union Street,LondonIn this guideline,recurrent miscarriage has been defined as three or more firstSE1 1SZ,UK.Email:clinicale ffectiveness@rcog.org uktrimester miscarriages.However,clinicians are encouraged to use their clinicalThis is the fourth edition of this guideline,discretion to recommend extensive evaluation after two first trimester miscar-which was published in 1998 and 2003 underriages,if there is a suspicion that the miscarriages are of pathological and not ofthetitle The Invest igation and Treatment ofsporadic nature.Couples with Recurrent Miscar ringe.The thirdedition was published in 2011 under the titleWomen with recurrent miscarriage should be offered testing for acquiredThe Investigation and Treatment of Couplesthrombophilia,particularly for lupus anticoagulant and anticardiolipin anti-with Recurrent First-trimester and Second-bodies,prior to pregnancy.[Grade C]trimester Miscarriage.Women with second trimester miscarriage may be offered testing for Factor VLeiden,prothrombin gene mutation and protein S deficiency,ideally within aresearch context.[Grade C]Inherited thrombophilias have a weak association with recurrent miscarriage.Routine testing for protein C,antithrombin deficiency and methylenetetrahy-drofolate reductase mutation is not recommended.[Grade C]Cytogenetic analysis should be offered on pregnancy tissue of the third andsubsequent miscarriage(s)and in any second trimester miscarriage.[Grade D]Parental peripheral blood karyotyping should be offered for couples in whomtesting of pregnancy tissue reports an unbalanced structural chromosomal ab-normality [Grade D]or there is unsuccessful or no pregnancy tissue availablefor testing.[GPP]Women with recurrent miscarriage should beoffered assessment for congenitaluterine anomalies,ideally with 3D ultrasound.[Grade B]Women with recurrent miscarriage should be offered thyroid function testsand assessment for thyroid peroxidase (TPO)antibodies.[Grade C]Women with recurrent miscarriage should not be routinely offered immuno-logical screening(such as HLA,cytokine and naturalkiller cell tests),infectionscreening or sperm DNA testing outside a research context.[Grade C]Women with recurrent miscarriage should be advised to maintain a BMI be-tween 19 and 25kg/m2,smoking cessation,limit alcohol consumption andlimit caffeine to less than 200mg/day.[Grade D]For women diagnosed with antiphospholipid syndrome,aspirin and heparinshould be offered from a positive test until at least 34 weeks of gestation,fol-lowing discussion of potential benefits versus risks.[Grade B]Aspirin and/orheparin should not be given to women with unexplained recurrent miscarriage[Grade B]2023 Royal College of Ob
