What do systematic reviews say?

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

Clomiphene citrate or letrozole with or without gonadotropins (with… may leads to lower ovarian hyperstimulation syndrome per woman compared with gonadotropins (with GnRH agonists or midcycle antagonist) (low certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  Peto OR 0.21 [0.11, 0.41]
  5 studies · 1067 participants
  Low

Combined oral contraceptive pill vs no pretreatment

Combined oral contraceptive pill probably leads to lower live birth or ongoing pregnancy (COCP + Ant vs Ant) compared with no pretreatment (moderate certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.74 [0.58, 0.95]
  6 studies · 1335 participants
  Moderate
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.89 [0.64, 1.25]
  4 studies · 724 participants
  Moderate

Combined oral contraceptive pill vs no pretreatment

Combined oral contraceptive pill showed no clear difference in pregnancy loss (COCP + Ant vs Ant) compared with no pretreatment (moderate certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 1.36 [0.82, 2.26]
  5 studies · 868 participants
  Moderate
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.4 [0.22, 0.72]
  5 studies · 780 participants
  Moderate

Combined oral contraceptive pill vs no pretreatment

Combined oral contraceptive pill showed no clear difference in multiple pregnancy rate (COCP + Ant vs Ant) compared with no pretreatment (low certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 2.21 [0.53, 9.26]
  2 studies · 125 participants
  Low
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 1.36 [0.85, 2.19]
  4 studies · 546 participants
  Moderate

Combined oral contraceptive pill vs no pretreatment

Combined oral contraceptive pill showed no clear difference in OHSS rate (COCP + Ant vs Ant) compared with no pretreatment (low certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.98 [0.28, 3.4]
  2 studies · 642 participants
  Low
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.63 [0.2, 1.96]
  2 studies · 290 participants
  Low

Summary of findings table ‐ Progestogens vs placebo or no pretreatment

Progestogen showed no clear difference in live birth or ongoing pregnancy (Prog + Ant vs Ant) compared with placebo or no pretreatment (low certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.67 [0.18, 2.54]
  1 study · 47 participants
  Low
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 1.35 [0.69, 2.65]
  2 studies · 222 participants
  Low

Summary of findings table ‐ Progestogens vs placebo or no pretreatment

Progestogen showed no clear difference in pregnancy loss (Prog + Ag vs Ag) compared with placebo or no pretreatment (low certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 2.26 [0.67, 7.55]
  2 studies · 222 participants
  Low
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.36 [0.06, 2.09]
  1 study · 47 participants
  Low

Summary of findings table ‐ Progestogens vs placebo or no pretreatment

The review found no eligible studies for this question.

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 1.05 [0.06, 17.76]
  1 study · 47 participants
  Low

Summary of findings table ‐ Progestogens vs placebo or no pretreatment

The review found no eligible studies for this question.

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Oestrogen vs no pretreatment

Oestrogen showed no clear difference in live birth or ongoing pregnancy (Oestr + Ant vs Ant) compared with no pretreatment (moderate certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.79 [0.53, 1.17]
  2 studies · 502 participants
  Moderate
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.88 [0.51, 1.5]
  2 studies · 242 participants
  Very low

Oestrogen vs no pretreatment

It is very uncertain whether oestrogen changes pregnancy loss (Oestr + Ant vs Ant) compared with no pretreatment (very low certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 0.16 [0.02, 1.47]
  1 study · 49 participants
  Very low
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 1.59 [0.62, 4.06]
  1 study · 220 participants
  Very low

Oestrogen vs no pretreatment

The review found no eligible studies for this question.

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found
• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 2.24 [0.09, 53.59]
  1 study · 22 participants
  Very low

Oestrogen vs no pretreatment

The review found no eligible studies for this question.

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Oestrogen vs no pretreatment

It is very uncertain whether oestrogen changes OHSS rate (Oestr + Ant vs Ag) compared with no pretreatment (very low certainty).

• Oral contraceptive pill, progestogen or oestrogen pretreatment for ovarian stimulation protocols for women undergoing… 2017 · Cochrane Headline outcomes only
  OR 1.54 [0.25, 9.42]
  1 study · 220 participants
  Very low

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

Clomiphene citrate or letrozole with or without gonadotropins (with… showed no clear difference in live birth per woman compared with gonadotropins (with GnRH agonists or midcycle antagonist) (low certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  RR 0.92 [0.66, 1.27]
  4 studies · 493 participants
  Low

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  3 studies · 136 participants
  Moderate

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  8 studies · 1203 participants
  Moderate

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

Clomiphene citrate or letrozole with or without gonadotropins (with… showed no clear difference in clinical pregnancy rate per woman compared with gonadotropins (with GnRH agonists or midcycle antagonist) (moderate certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  RR 1 [0.86, 1.16]
  12 studies · 1998 participants
  Moderate

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

Clomiphene citrate or letrozole with or without gonadotropins (with… may leads to higher cancellation rate per woman compared with gonadotropins (with GnRH agonists or midcycle antagonist) (low certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  RR 1.87 [1.43, 2.45]
  9 studies · 1784 participants
  Low

Clomiphene citrate or letrozole with or without gonadotropins (with or without midcycle antagonist) vs gonadotropins (with GnRH agonists or midcycle antagonist)

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  no estimate extracted
  6 studies · 1098 participants
  Moderate