A 30-year-old gravida 3 with two previous first-trimester miscarriages presents at 7 weeks with vaginal spotting. Ultrasound shows an intrauterine gestational sac with fetal cardiac activity. Which intervention has been shown to improve the chance of a live birth in this situation?
- A Low-dose aspirin 75 mg daily alone
- B Strict bed rest until 14 weeks
- C Vaginal micronized progesterone 400 mg twice daily ✓
- D Intramuscular hydroxyprogesterone caproate weekly
Explanation
The PRISM randomised trial demonstrated that vaginal micronized progesterone 400 mg twice daily given in early pregnancy increases live births specifically among women with early pregnancy bleeding who have had one or more previous miscarriages. This matches the vignette exactly. Bed rest has never been shown to prevent miscarriage. Low-dose aspirin benefits antiphospholipid syndrome, not unexplained threatened miscarriage. Intramuscular hydroxyprogesterone caproate is used for preventing recurrent spontaneous preterm birth in the second trimester, not for first-trimester loss, so it does not apply here.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.