Favorable Efficacy (RCT)

Vitamin K prophylaxis for newborns

Vitamin K at birth (intramuscular preferred) vs. No prophylaxis, placebo, or oral regimen · for Vitamin K deficiency bleeding (VKDB) · real-time analysis of 5 studies · updated 2026-05-29

Vitamin K at birth markedly reduces vitamin K deficiency bleeding. Two 1960s randomized trials show large reductions in early clinical bleeding, and surveillance data show that intramuscular prophylaxis nearly eliminates the severe late form, which oral regimens and no prophylaxis do not.

Efficacy (RCT): Efficacy evidence on clinical outcomes. Effects are risk ratios with number-needed-to-treat where a baseline risk is available. Glossary →

Interpretation & tips

Late VKDB has never been tested in an RCT, so those estimates are observational. The large NNT reflects how rare the outcome is, not a weak treatment. Where a study shows a reported risk ratio instead of a 2×2 table, the original per-arm counts are not published.

82% lower risk of early clinical bleeding
Pooled RR 0.18 (95% CI 0.10–0.34) across 2 studies, 3,808 patients (random-effects, I² 0%).
0.18
Pooled RR
0.10–0.34
95% CI
2
Studies
3,808
Patients
16
NNT

Forest plot—Early clinical bleeding

Sutherland 1967 0.19 [0.08–0.46] Vietti 1960 0.18 [0.08–0.42] Pooled (RE) 0.18 [0.10–0.34] 0.1 0.25 0.5 1 2 4 ← favors treatment favors control →

Study results—Early clinical bleeding

Study Design Dose / regimen Treatment Control RR [95% CI] Improvement NNT Weight
Sutherland 1967 note RCT Vitamin K vs placebo at birth 0.19 [0.08–0.46] 81% 74 47%
Vietti 1960 note RCT Vitamin K1 IM at birth 0.18 [0.08–0.42] 82% 9 53%

RR < 1 favors treatment for outcomes where lower is better. Rows in gray have a confidence interval crossing 1 (individually inconclusive). “~” marks effects reported as OR/HR and treated as RR-approximations. “excl” = excluded from pooling (e.g. reviews).

Notes & interpretation

  • Sutherland 1967—Moderate-to-severe bleeding. Per-arm counts not available; entered as the reported RR. Control risk set to reproduce the published NNT ≈ 74. Any-bleeding RR was 0.73 (0.56-0.96). Source: Sankar 2016 (PMC4862383).
  • Vietti 1960—Per-arm counts not available in accessible sources; entered as the reported RR. Control risk set to reproduce the published NNT ≈ 9. Source: Sankar 2016 (PMC4862383).

Background

VKDB (hemorrhagic disease of the newborn) is bleeding from the low vitamin K stores of newborns: early (≤24 h), classic (days 1–7), and late (weeks 2–12, often intracranial). A single dose at birth—intramuscular preferred—is standard prophylaxis. Clinical VKDB is rare, so most quantitative evidence is observational rather than randomized.

Topic methodology & caveats

Early-bleeding figures come from the only two RCTs (Vietti, Sutherland), entered as reported risk ratios because per-arm counts are unpublished; control risks reproduce the published NNTs. Late-VKDB figures are observational (Sankar 2016), expressed as IM vs oral. Status set to favorable given consistent evidence and universal guidelines.

Studies