Should all pregnant women receive progesterone prophylactically before emergency orthopedic surgery to prevent miscarriage?

Progesterone Should NOT Be Started Routinely Before Emergency Orthopedic Surgery for Miscarriage Prevention

No, pregnant patients should not routinely receive progesterone prophylactically before emergency orthopedic surgery to prevent miscarriage. There is no evidence that progesterone prevents miscarriage in the general pregnant population undergoing surgery, and current guidelines restrict progesterone use to specific high-risk obstetric indications that are unrelated to surgical stress.

Why Progesterone Is Not Indicated in This Context

Progesterone Has No Proven Benefit for Surgical Stress or General Miscarriage Prevention

• Progesterone is not effective as a tocolytic agent and should not be used for preventing intra-operative or post-operative preterm contractions. 1

• For singleton pregnancies without specific risk factors (no prior preterm birth and normal cervical length), progesterone has no proven benefit and should not be used. 1

• The most recent Cochrane systematic review (2025) analyzing 1276 participants found that progesterone supplementation probably results in little to no difference in miscarriage rates for women with recurrent miscarriage of unclear etiology (RR 0.91,95% CI 0.76 to 1.07), and probably little to no difference in live birth rates (RR 1.04,95% CI 0.96 to 1.12). 2

Evidence-Based Indications Are Narrow and Specific

Progesterone therapy in pregnancy is only supported for two specific scenarios, neither of which involves surgical prophylaxis:

1. Prior Spontaneous Preterm Birth (Not First-Trimester Miscarriage)

• 17-alpha-hydroxyprogesterone caproate (17P) 250 mg intramuscularly weekly from 16-20 weeks until 36 weeks is recommended only for women with a singleton pregnancy and documented history of prior spontaneous preterm birth between 20-36 weeks. 3, 1

• This indication addresses preterm birth prevention in the second and third trimesters, not first-trimester miscarriage prevention. 3

2. Short Cervical Length ≤20 mm (Detected Around Mid-Pregnancy)

• Vaginal progesterone (90 mg gel or 200 mg suppository daily) is recommended only for women without prior spontaneous preterm birth but with cervical length ≤20 mm detected around 24 weeks, continuing until 36 weeks. 1, 4

• This is a mid-pregnancy intervention for preterm birth prevention, not relevant to emergency surgery scenarios. 1, 4

Management of Patients Already on Progesterone

Continue Established Therapy Through Surgery

If a pregnant patient is already receiving progesterone for one of the evidence-based indications above:

• Maintain scheduled 17P injections without regard to the timing of non-obstetric surgery; the injection schedule can be kept unchanged peri-operatively. 1

• Continue vaginal progesterone in women whose cervical length is ≤20 mm; treatment can proceed through the peri-operative period. 1

• Intramuscular and vaginal progesterone formulations are not affected by altered oral drug absorption that may occur after certain surgeries. 1

Special Consideration: Threatened Miscarriage with Bleeding

The only scenario where progesterone might be considered in early pregnancy involves women with both a history of prior miscarriage and current vaginal bleeding:

• For women with a history of one or more prior miscarriages who present with bleeding in early pregnancy, vaginal micronized progesterone 400 mg twice daily may provide benefit, with a 5% absolute increase in live birth rate (75% vs 70%, RR 1.09,95% CI 1.03-1.15). 5

• This benefit increases to a 15% absolute difference for women with three or more prior miscarriages and current bleeding (72% vs 57%, RR 1.28,95% CI 1.08-1.51). 5

• However, this indication requires active bleeding and documented prior miscarriage history—not simply the stress of upcoming surgery. 5

Common Pitfalls to Avoid

• Do not extrapolate preterm birth prevention data to first-trimester miscarriage prevention—these are distinct pathophysiologic processes with different evidence bases. 2

• Do not use progesterone as prophylaxis for surgical stress—there is no mechanism or evidence supporting this practice. 1

• Do not confuse threatened miscarriage (vaginal bleeding) with prophylaxis before elective surgery—the former has limited evidence in specific populations, while the latter has none. 5

• Recognize that progesterone supplementation for unexplained recurrent miscarriage shows no clear benefit even in that high-risk population, making routine use in lower-risk surgical patients unjustified. 2