Table 2

Characteristics and pregnancy outcomes of individuals treated with progesterone or placebo for abortion reversal in the four studies included in this review

CaseGA (days or weeks)Treatment initiation timeRegimenOutcomes (pregnancy outcome, complications or side effects)
Delgado & Davenport28 (2012)
18 weeks30–40 hours200 mg in oil, IM, daily x 2 days; then two doses every other day x 2; then twice weekly until 9 weeks 5 days; then restarted at 11 weeks 2 days, twice weekly; then decreased to 100 mg twice weekly until 29 weeks 5 daysViable infant at 37 weeks
211 weeks72 hours200 mg in oil, IM; continued for 2 weeks (unknown frequency); then PO micronised progesterone for 5 months (unknown frequency and dosage)Viable infant
37 weeks36–48 hours200 mg in oil, IM; then two more times the first week, then weekly for 5–6 weeks, then 200 mg in oil twice weekly for 2 weeks, then micronised progesterone orally for 5 monthsViable infant at 39 weeks
47 weeks 4 days46 hours200 mg in oil, IM, twice weekly for 19 weeksViable infant at 40 weeks
5UnknownUnknown200 mg in oil, route and frequency unknownAbortion soon after injection
67 weeks7 hours200 mg PV; followed by IM 200 mg after 11 hours; then 2 days laterAbortion complete 3 days after mifepristone
7Lost to follow-up; no information available
Garratt & Turner30 (2107)
N43 days28 hoursVaginal progesterone: 400 mg twice daily for 3 days, then 400 mg nightly for 6 days, then 200 mg nightly for 6 days; routine antenatal care after 2 weeks of progesteroneViable pregnancy at 8 weeks 4 days on ultrasound at 2 weeks; viable infant at 39 weeks
T61 days3.5 hoursSame as aboveLTFU at 2-week follow-up ultrasound; reported delivery of live infant “7 months later, likely at term”
O7.5 weeks31 hoursOne dose of vaginal progesterone 400 mg; discontinued as experienced heavy vaginal bleeding soon after treatment initiationHeavy vaginal bleeding soon after starting progesterone; follow-up US at 1 week showed empty uterus, completed abortion
Delgado et al 29
N/A754 treated
5 weeks: 19
6 weeks: 113
7 weeks: 102
8 weeks: 88
9 weeks: 30
Unknown: 138
Variable (72 hours or less)High-dose oral progesterone: 31
IM progesterone: 125
Oral, all groups: 119*
Vaginal caps: 156
Vaginal suppository: 34
Unknown: 82
Outcomes available for 547:
Births: 257
LTFU before 20 weeks: 112
LTFU after 20 weeks: 4
Excluded because chose to complete abortion: 57
Excluded because wrong time interval: 38
Ongoing pregnancies by progesterone regimen:
High-dose oral: 21/31 (68%)
IM progesterone all groups: 80/125 (64%)
Oral, all groups: 64/119 (54%)
Vaginal caps: 61/156 (39%)
Vaginal suppository: 11/34 (32%)
Ongoing pregnancies by gestational age:
5 weeks: 19/76 (25%)
6 weeks: 61/113 (46%)
7 weeks: 50/102 (49%)
8 weeks: 54/88 (61%)
9 weeks: 23/30 (77%)
Birth defects: 6 (2 absent digits; 1 choroid plexus cyst, 1 cystic kidney, 1 failed hearing test, 1 heart murmur)
Creinin et al 31 (2020)
153 days24 hoursMifepristone 200 mg, followed by oral progesterone 400 mg 24 hours later - twice daily for 3 days, then once daily until planned surgical abortion 14–16 days after enrollmentContinuing GCA at 17 days
250 days24 hoursSame as aboveContinuing GCA at 16 days
549 days24 hoursSame as aboveContinuing GCA at 16 days
856 days24 hoursSame as aboveExpelled pregnancy, haemorrhage not requiring transfusion or uterine aspiration at day 3
947 days24 hoursSame as aboveNausea, vomiting, dehydration; requested aspiration at day 3
1248 days24 hoursSame as aboveContinuing GCA at 15 days
350 days24 hoursPlaceboContinuing GCA at 16 days
448 days24 hoursPlaceboNo GCA at 4 days
661 days24 hoursPlaceboContinuing GCA at 16 days
748 days24 hoursPlaceboD&C requested (bleeding, anxiety) at day 4
1060 days24 hoursPlaceboExpelled pregnancy, incomplete, emergent D&C at day 5
1160 days24 hoursPlaceboExpelled pregnancy, incomplete, emergent D&C, transfusion at day 6
  • *Unclear if this group includes the individuals treated with high-dose oral progesterone.

  • D&C, dilation and curettage; GA, gestational age; GCA, gestational cardiac activity; IM, intramuscular; LTFU, lost to follow-up; N/A, not available; PO, per os; PV, per vagina; US, ultrasound.