What do systematic reviews say?

Metformin vs placebo co‐treatment

Metformin showed no clear difference in multiple pregnancy rate (per woman) compared with placebo co‐treatment (low certainty).

• Metformin during ovulation induction with gonadotrophins followed by timed intercourse or intrauterine insemination… 2017 · Cochrane Headline outcomes only
  OR 0.55 [0.15, 1.95]
  4 studies · 232 participants
  Low

Long‐term GnRH agonist therapy vs no additional therapy

It is very uncertain whether long‐term GnRH agonist therapy changes multiple pregnancy rate compared with no additional therapy (very low certainty).

• Long‐term GnRH agonist therapy before in vitro fertilisation (IVF) for improving fertility outcomes in women with… 2019 · Cochrane Headline outcomes only
  Peto OR 0.14 [0.04, 0.56]
  2 studies · 208 participants
  Very low

Natural cycle vs programmed cycle

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Transdermal oestrogens vs oral oestrogens

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Starting administration of the progestogen earlier vs starting administration of the progestogen later

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 282 participants
  Very low

GnRH agonists vs control

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

GnRH agonists vs placebo

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Stimulated cycle vs programmed

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

GnRH agonists vs GnRH antagonists

GnRH agonists showed no clear difference in multiple pregnancy rate compared with gnRH antagonists (low certainty).

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  OR 0.69 [0.45, 1.07]
  1 study · 473 participants
  Low

Aspirin vs control

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Steroids vs control

The review found no eligible studies for this question.

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found