What medication can be taken to prevent miscarriage?

Medications to Prevent Miscarriage

For women with recurrent pregnancy loss and antiphospholipid antibody syndrome, low-dose aspirin combined with heparin therapy is recommended. For women with previous miscarriage and early pregnancy bleeding, vaginal micronized progesterone is beneficial. For most other women without specific risk factors, no medication is recommended to prevent miscarriage.

Antiphospholipid Antibody Syndrome (APLA)

• Women with recurrent early pregnancy loss (three or more miscarriages before 10 weeks) should be screened for antiphospholipid antibodies 1
• For women who meet both laboratory criteria for APLA syndrome and clinical criteria based on three or more pregnancy losses, the recommended treatment is prophylactic or intermediate-dose unfractionated heparin or prophylactic low-molecular-weight heparin (LMWH) combined with low-dose aspirin (75-100 mg/day) 1
• This combination therapy has been shown to significantly reduce miscarriage risk in women with APLA syndrome 1

Progesterone Therapy

• Vaginal micronized progesterone (400mg twice daily) is beneficial for women with previous miscarriage(s) who present with bleeding in early pregnancy 2, 3
• The benefit increases with the number of previous miscarriages:
  • For women with one or more previous miscarriages and current pregnancy bleeding: live birth rate increased by 5% (75% vs 70%) 2
  • For women with three or more previous miscarriages and current pregnancy bleeding: live birth rate increased by 15% (72% vs 57%) 2
• Treatment should be started at diagnosis of bleeding and continued until 12 weeks of pregnancy, as there is no evidence of additional benefit beyond this point 4
• There is no evidence supporting progesterone use for women without a history of miscarriage 3

Thrombophilia and Anticoagulation

• For women with inherited thrombophilia and a history of pregnancy complications, antithrombotic prophylaxis is not recommended 1
• For women with two or more miscarriages but without APLA or thrombophilia, antithrombotic prophylaxis is not recommended 1
• LMWH is the preferred anticoagulant for prevention and treatment of VTE during pregnancy when indicated for other reasons 1

Folic Acid and Other Supplements

• Daily folic acid supplementation (at least 400 mcg) is recommended for all women attempting pregnancy, starting at least 3 months before conception to reduce neural tube defects 1
• Women taking sulfasalazine should receive concomitant folic acid supplementation due to the drug's inhibition of folate absorption 1

Medications to Avoid During Pregnancy

• Isotretinoins must be avoided due to high risk of miscarriage and birth defects 1
• Methotrexate, cyclophosphamide, and mycophenolate are teratogenic and should be discontinued before pregnancy (methotrexate: 1-3 months; mycophenolate: 1.5 months; cyclophosphamide: 3 months) 1
• NSAIDs should be used cautiously and discontinued after 28 weeks of gestation due to risks of oligohydramnios and premature closure of the ductus arteriosus 1

Special Populations

Women with History of Preterm Birth

• For women with prior spontaneous preterm birth, 17-alpha-hydroxyprogesterone caproate (17P) 250 mg IM weekly from 16-20 weeks until 36 weeks is recommended to prevent recurrent preterm birth 1
• This treatment is not indicated for prevention of miscarriage but rather for prevention of preterm birth 1

Women with Multiple Gestations

• Progesterone therapy is not effective in preventing miscarriage or preterm birth in women with multiple gestations 1

Common Pitfalls and Caveats

• Avoid unnecessary medication use in women without specific risk factors for miscarriage 1
• Do not use antithrombotic therapy for women with unexplained recurrent miscarriage without APLA syndrome 1
• The duration of progesterone therapy should not extend beyond 12 weeks of pregnancy without clear indication, as placental progesterone production is established by this time 4
• Routine progesterone supplementation is not recommended for all pregnant women or those with threatened miscarriage who have no history of previous miscarriage 3, 5