Blocking Mifepristone Action With Progesterone

Medical abortion commonly refers to early pregnancy termination (usually before 10 weeks'
gestation) performed without primary surgical intervention and resulting from the use of
abortion-inducing medications. The use of medications to cause abortion has been around for
almost 70 years but the modern era of medical abortion treatment evolved with the development
of mifepristone, a progesterone-receptor blocker with an affinity for the receptor greater
than progesterone itself.

Medical abortion with mifepristone and misoprostol is highly effective; however, the risk of
continuing pregnancy is still present, especially as gestation advances. While most women opt
for further treatment in these scenarios, such as surgical aspiration, there are some who
decide to continue the pregnancy. Thus, even following treatment, some women do change their
mind.

No well-done study has evaluated whether such treatment works. Poorly controlled case series
are not evidence and systematic reviews of continuing pregnancy rates after
mifepristone/prostaglandin analogue treatment failure do not reflect real life outcomes. This
study is also a first step to understanding if large studies evaluating mifepristone
antagonization with high-dose progesterone are indicated and if placebo-controlled randomized
trials can be successfully completed when evaluating this question.

Inclusion Criteria:

1. Pregnant females 18 years and older at enrollment.

2. Seeking surgical abortion at 44-63 days' gestation on Study day 1.

3. Have received counseling and signed informed consent per UCD standard procedures for
surgical abortion.

4. Presence of embryonic gestational cardiac activity on transvaginal ultrasonography.

5. English-speaking

6. Willing to sign informed consent and follow study protocol.

7. Willing to experience potential expulsion of the pregnancy with mifepristone
treatment.

Exclusion Criteria:

1. Medical contraindications to medical abortion.

1. Poorly controlled hypertension (systolic BP >160 or diastolic BP >95)

2. Significant anemia - known recent hemoglobin <9.5 gm/dL

3. Clinically significant cardiovascular disease (angina, valvular disease,
arrhythmia, or congestive heart failure)

4. Breastfeeding

5. Coagulopathy or therapeutic coagulation

6. Ultrasound evidence of molar or ectopic pregnancy

7. Chronic systemic corticosteroid use

8. Adrenal disease

9. Sickle cell anemia with frequent/recent crises

10. Glaucoma

2. IUD in place during conception, even if removed.

3. Peanut allergy.

4. Known intolerance of mifepristone or progesterone.

5. Any other condition, that in the opinion of the clinician, would contraindicate
mifepristone, progesterone or medical abortion.