What do systematic reviews say?

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

Any antihypertensive drug vs no antihypertensive drugs/placebo

The review found no eligible studies for this question.

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found
• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Any antihypertensive drug vs no antihypertensive drugs/placebo

It is very uncertain whether any antihypertensive drug changes severe pre‐eclampsia compared with no antihypertensive drugs/placebo (very low certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.56 [0.15, 2.02]
  3 studies · 416 participants
  Very low

Any antihypertensive drug vs no antihypertensive drugs/placebo

It is very uncertain whether any antihypertensive drug changes eclampsia compared with no antihypertensive drugs/placebo (very low certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.52 [0.13, 2.06]
  7 studies · 713 participants
  Very low

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in changed/stopped drugs due to maternal side‐effects compared with no antihypertensive drugs/placebo (low certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 1.93 [0.92, 4.06]
  16 studies · 1503 participants
  Low

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in elective delivery (induction of labour + elective caesarean section) compared with no antihypertensive drugs/placebo (moderate certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.93 [0.84, 1.04]
  4 studies · 710 participants
  Moderate

Any antihypertensive drug vs no antihypertensive drugs/placebo

The review found no eligible studies for this question.

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found
• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in admission to neonatal or intensive care nursery compared with no antihypertensive drugs/placebo (low certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 1.01 [0.83, 1.22]
  10 studies · 1570 participants
  Low

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug probably leads to lower severe hypertension compared with no antihypertensive drugs/placebo (moderate certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.49 [0.4, 0.6]
  20 studies · 2558 participants
  Moderate

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in proteinuria/pre‐eclampsia compared with no antihypertensive drugs/placebo (low certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.92 [0.75, 1.14]
  23 studies · 2851 participants
  Low

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in total reported fetal or neonatal deaths (including miscarriage) compared with no antihypertensive drugs/placebo (moderate certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.72 [0.5, 1.04]
  29 studies · 3365 participants
  Moderate

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in small‐for‐gestational age compared with no antihypertensive drugs/placebo (moderate certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.96 [0.78, 1.18]
  21 studies · 2686 participants
  Moderate

Any antihypertensive drug vs no antihypertensive drugs/placebo

Any antihypertensive drug showed no clear difference in preterm birth (< 37 weeks) compared with no antihypertensive drugs/placebo (moderate certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.96 [0.83, 1.12]
  15 studies · 2141 participants
  Moderate

Any antihypertensive drug vs no antihypertensive drugs/placebo

It is very uncertain whether any antihypertensive drug changes maternal death compared with no antihypertensive drugs/placebo (very low certainty).

• Antihypertensive drug therapy for mild to moderate hypertension during pregnancy 2018 · Cochrane Headline outcomes only
  RR 1.11 [0.18, 7.02]
  5 studies · 525 participants
  Very low

Progesterone vs placebo or no treatment

Progesterone probably leads to lower miscarriage compared with placebo or no treatment (moderate certainty).

• Progestogen for treating threatened miscarriage 2018 · Cochrane Headline outcomes only
  RR 0.64 [0.47, 0.87]
  7 studies · 696 participants
  Moderate

Progesterone vs placebo or no treatment

Progesterone showed no clear difference in preterm birth compared with placebo or no treatment (low certainty).

• Progestogen for treating threatened miscarriage 2018 · Cochrane Headline outcomes only
  RR 0.86 [0.52, 1.44]
  5 studies · 588 participants
  Low

Progesterone vs placebo or no treatment

It is very uncertain whether progesterone changes congential abnormalities compared with placebo or no treatment (very low certainty).

• Progestogen for treating threatened miscarriage 2018 · Cochrane Headline outcomes only
  RR 0.7 [0.1, 4.82]
  2 studies · 337 participants
  Very low