What do systematic reviews say?

Routine/revealed vs selective/concealed ultrasound

Routine/revealed probably leads to lower detection of multiple pregnancy by 24 to 26 weeks' gestation (number… compared with selective/concealed ultrasound (moderate certainty).

• Ultrasound for fetal assessment in early pregnancy 2015 · Cochrane Headline outcomes only
  RR 0.07 [0.03, 0.17]
  7 studies · 295 participants
  Moderate

Intramuscular (IM) progesterone vs no treatment or placebo

Intramuscular (IM) progesterone showed no clear difference in perinatal death compared with no treatment or placebo (low certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 1.45 [0.6, 3.51]
  6 studies · 3089 participants
  Low

Vaginal progesterone vs no treatment or placebo

Vaginal progesterone showed no clear difference in infant birthweight less than 2500 g compared with no treatment or placebo (moderate certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.95 [0.84, 1.07]
  3 studies · 2640 participants
  Moderate

Vaginal progesterone vs no treatment or placebo

Vaginal progesterone showed no clear difference in preterm birth less than 37 weeks compared with no treatment or placebo (moderate certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.97 [0.89, 1.06]
  6 studies · 1597 participants
  Moderate

Vaginal progesterone vs no treatment or placebo

Vaginal progesterone showed no clear difference in preterm birth less than 28 weeks compared with no treatment or placebo (low certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 1.53 [0.79, 2.97]
  3 studies · 1345 participants
  Low

Intramuscular (IM) progesterone vs no treatment or placebo

Intramuscular (IM) progesterone may leads to higher preterm birth less than 34 weeks compared with no treatment or placebo (low certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 1.54 [1.06, 2.26]
  2 studies · 399 participants
  Low

Intramuscular (IM) progesterone vs no treatment or placebo

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Intramuscular (IM) progesterone vs no treatment or placebo

Intramuscular (IM) progesterone showed no clear difference in infant birthweight less than 2500 g compared with no treatment or placebo (moderate certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.99 [0.9, 1.08]
  5 studies · 4071 participants
  Moderate

Intramuscular (IM) progesterone vs no treatment or placebo

Intramuscular (IM) progesterone showed no clear difference in preterm birth less than 28 weeks compared with no treatment or placebo (moderate certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 1.08 [0.75, 1.55]
  5 studies · 1920 participants
  Moderate

Intramuscular (IM) progesterone vs no treatment or placebo

Intramuscular (IM) progesterone showed no clear difference in preterm birth less than 37 weeks compared with no treatment or placebo (high certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 1.05 [0.98, 1.13]
  5 studies · 2010 participants
  High

Vaginal progesterone vs no treatment or placebo

Vaginal progesterone showed no clear difference in perinatal death compared with no treatment or placebo (low certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 1.23 [0.74, 2.06]
  3 studies · 2287 participants
  Low

Vaginal progesterone vs no treatment or placebo

Vaginal progesterone showed no clear difference in preterm birth less than 34 weeks compared with no treatment or placebo (low certainty).

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.9 [0.66, 1.23]
  5 studies · 1503 participants
  Low

Vaginal progesterone vs no treatment or placebo

• Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy 2019 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Intervention not reported

The intervention showed no clear difference in very preterm birth (less than 34 weeks) ‐ assuming complete… (low certainty).

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  RR 1.02 [0.66, 1.58]
  5 studies · 495 participants
  Low

Intervention not reported

The intervention showed no clear difference in prelabour preterm rupture of the membrane (low certainty).

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  RR 1.51 [0.69, 3.3]
  1 study · 141 participants
  Low

Intervention not reported

The intervention showed no clear difference in small‐for‐gestational age ‐ assuming independence between twins (low certainty).

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  RR 0.93 [0.69, 1.26]
  1 study · 282 participants
  Low

Intervention not reported

The review found no eligible studies for this question.

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Intervention not reported

The intervention showed no clear difference in perinatal mortality ‐ assuming independence between twins/triplets (low certainty).

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  RR 0.65 [0.35, 1.21]
  5 studies · 1016 participants
  Low

Intervention not reported

The intervention showed no clear difference in low birthweight (less than 2500 g) ‐ assuming independence between… (low certainty).

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  RR 0.95 [0.75, 1.21]
  3 studies · 502 participants
  Low

Intervention not reported

The intervention showed no clear difference in prelabour preterm rupture of the membrane (low certainty).

• Bed rest with and without hospitalisation in multiple pregnancy for improving perinatal outcomes 2017 · Cochrane Headline outcomes only
  RR 1.3 [0.71, 2.38]
  3 studies · 276 participants
  Low