What do systematic reviews say?

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… 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

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

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 · 1481 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 live birth per woman compared with gonadotropins (with GnRH agonist or midcycle antagonist) (low certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  RR 1.16 [0.49, 2.79]
  2 studies · 357 participants
  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 clinical pregnancy rate per woman compared with gonadotropins (with GnRH agonist or midcycle antagonist) (low certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  RR 0.85 [0.64, 1.12]
  8 studies · 1462 participants
  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… may leads to higher cancellation rate per woman compared with gonadotropins (with GnRH agonist or midcycle antagonist) (low certainty).

• Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian… 2017 · Cochrane Headline outcomes only
  RR 1.46 [1.18, 1.81]
  10 studies · 1601 participants
  Low