Management of Primigravida at 20 Weeks with History of PPROM at 34 Weeks
Start 17-alpha-hydroxyprogesterone caproate (17P) 250 mg intramuscularly weekly immediately and continue until 36 weeks of gestation, as this is the evidence-based standard of care for women with prior spontaneous preterm birth, including PPROM. 1, 2
Primary Intervention: Progesterone Therapy
17P 250 mg IM weekly is the first-line therapy for women with a history of spontaneous preterm birth (including PPROM), starting at 16-20 weeks and continuing until 36 weeks of gestation or delivery 1, 2, 3
This patient should have already started therapy, but since she is at 20 weeks, initiate immediately 2, 3
17P has demonstrated consistent efficacy in reducing delivery at <37, <35, and <32 weeks of gestation in women with prior spontaneous preterm birth 2, 4
Important caveat: While 17P reduces recurrent preterm birth overall, there is insufficient evidence that it specifically prevents PPROM as a complication 1, 2
Cervical Length Surveillance Strategy
Perform serial transvaginal cervical length assessments every 2-4 weeks from 16-24 weeks of gestation 2
This is not "weekly ultrasound" as suggested in option B, but rather targeted cervical length monitoring 2
If cervical length shortens to ≤25 mm before 24 weeks despite 17P therapy, offer cervical cerclage 1, 2
Approximately 69% of women with prior spontaneous preterm birth maintain cervical length >25 mm, so universal cerclage is not indicated 1
Why Vaginal Progesterone Is NOT Appropriate
Vaginal progesterone should not be considered a substitute for 17P in patients with prior spontaneous preterm birth 1
Multiple high-quality RCTs (including the OPPTIMUM study with 903 women with prior spontaneous preterm birth) showed no significant differences in preterm birth rates at <34 weeks between vaginal progesterone and placebo (15.9% vs 18.8%) 1
Vaginal progesterone is reserved for women with sonographically short cervix (≤20-25 mm) who do NOT have a history of prior spontaneous preterm birth 1
Risk Stratification for This Patient
The risk of recurrent preterm birth after PPROM at 34 weeks is substantial, though lower than previable PPROM 1, 2
Nearly 50% of subsequent pregnancies after previable/periviable PPROM result in recurrent preterm birth 1, 5
The most important predictor of recurrence is having another previous preterm birth beyond the PPROM pregnancy itself 2, 5
What NOT to Do
Do not prescribe vaginal progesterone as primary prevention in this patient with prior spontaneous preterm birth, as it lacks proven efficacy for this indication 2, 5
Do not recommend bed rest or activity restriction, as these have no proven benefit and may cause harm through deconditioning and thromboembolic risk 2, 5
Do not place prophylactic cerclage at this time with normal cervical length—cerclage is only indicated if cervical shortening develops to ≤25 mm 1, 2
Do not perform weekly ultrasounds as suggested in option B; the appropriate interval is every 2-4 weeks for cervical length assessment 2
Monitoring for Complications
Monitor for contraindications to 17P including thromboembolic disorders, uncontrolled hypertension, and liver disease 3
Watch for common adverse reactions including injection site pain (34.8%), injection site swelling (17.1%), and urticaria (12.3%) 3
Monitor glucose tolerance in prediabetic or diabetic women, as progestins may decrease glucose tolerance 3
Clinical Implementation Summary
The correct answer is A (progesterone from week 16), though the patient is already at 20 weeks, so initiate immediately. Option B (weekly ultrasound) is incorrect—the appropriate surveillance is cervical length assessment every 2-4 weeks, not weekly ultrasounds. 1, 2