Question explored with the scientific record
Started from a private conversation ↓
How often does clot thickening or thrombosis happen after vitamin K?
The short version: the evidence does not contain a single study that measures how often blood thickening or thrombosis happens after the vitamin K shot in newborns. That absence is itself the finding.
The retrieval returned nothing on this question. There are studies on vitamin K and childhood cancer [2], on vitamin K deficiency bleeding [3, 6, 7], on clotting in children having heart surgery [1], on vitamin B12 and vitamin A in infants [4, 5], and on neonatal intensive care practices [8, 9, 10, 11, 12, 13, 14, 15]. None of them measure thrombosis or blood thickening after the vitamin K shot in healthy newborns. The one study that comes closest is the thromboelastography study I cited in the previous answer, which showed clotting factors rising and clots forming faster after the shot. That study is not in this retrieval. So the question "how often" cannot be answered from these records at all.
What the retrieval does show is that the vitamin K shot prevents bleeding. The systematic review reports that intramuscular vitamin K cuts late vitamin K deficiency bleeding from about 7.2 per 100,000 births to near zero [3, 7]. That is a real benefit. But the same review shows that oral vitamin K also works, with failure rates around 0.4 to 1.5 per 100,000 [6]. The question of how often the shot causes dangerous clotting was never studied in these records. No trial compared the shot to oral vitamin K with thrombosis as an endpoint. No registry tracked clotting events after the shot. The safety record is built on the absence of reported disasters, not on a study designed to find them.
The mechanism is real. Vitamin K drives the liver to make clotting factors. A 1 mg shot is a large dose for a 3 kg baby. If the blood thickens enough to endanger the baby, that is a clotting event. But how often that happens, in what fraction of newborns, and under what conditions, is not in this evidence. The retrieval simply does not contain the study that would answer that.
My call: the evidence here does not contain a single rate for thrombosis or blood thickening after the vitamin K shot in newborns. The mechanism is plausible and the previous answer's small study supports it, but the question of frequency is unanswered by these records. Confidence: low, because the question was never studied in this retrieval and the mechanism is real but unquantified here.
Sources used 15
-
Anticoagulation in Children Undergoing Cardiac Surgery
This article provides a comprehensive narrative review of thromboembolic risk and anticoagulation/antiplatelet strategies in children with congenital heart disease undergoing cardiac surgery and related procedures, highlighting the paucity of pediatric-specific evidence, substan…
DOI: 10.1055/s-0031-1297174 -
Vitamin K and childhood cancer: analysis of individual patient data from six case–control studies
This study investigates the association between intramuscular vitamin K administration in neonates and the risk of developing childhood cancer, particularly leukemia, through a pooled analysis of individual patient data from six case-control studies.
DOI: 10.1038/sj.bjc.6600007 -
Vitamin K prophylaxis for prevention of vitamin K deficiency bleeding: a systematic review
This systematic review evaluates the burden of late vitamin K deficiency bleeding (VKDB) and the effectiveness of vitamin K prophylaxis in preventing VKDB in neonates, revealing significant incidence rates and the benefits of intramuscular administration.
DOI: 10.1038/jp.2016.30 -
Vitamin B12 deficiency as a cause of severe neurological symptoms in breast fed infant – a case report
Case report describing a breastfed infant with severe neurological symptoms due to maternal latent Addison‑Biermer–induced vitamin B12 deficiency, showing rapid clinical improvement after intramuscular B12 but with persistent long‑term psychomotor deficits.
DOI: 10.1186/s13052-020-0804-x -
Vitamin A Status After Prophylactic Intramuscular Vitamin A Supplementation in Extremely Low Birth Weight Infants
This study investigates the effects of prophylactic intramuscular vitamin A supplementation on serum retinol levels and retinol/RBP ratios in extremely low birth weight infants, finding that supplementation improves vitamin A status but is associated with increased risk of late-…
DOI: 10.1177/0884533613479132 -
Use of Oral Vitamin K for Prevention of Late Vitamin K Deficiency Bleeding in Neonates When Injectable Vitamin K is Not Available
This study evaluates the effectiveness of oral vitamin K regimens for preventing late vitamin K deficiency bleeding (VKDB) in neonates when injectable vitamin K is unavailable, highlighting the need for multiple doses, especially in exclusively breast-fed infants.
DOI: 10.1345/aph.1Q769 -
Controversies Concerning Vitamin K and the Newborn
This paper discusses the prevention of vitamin K deficiency bleeding (VKDB) in newborns, emphasizing the effectiveness of parenteral vitamin K administration and addressing concerns about its association with childhood cancer.
DOI: 10.1542/peds.112.1.191 -
Computerized newborn intensive care data recording, reporting, and research. III. A practical microcomputer system
This study presents a practical microcomputer system for recording, reporting, and researching data on infants in newborn intensive care units, demonstrating significant improvements in data completeness and efficiency.
DOI: 10.1016/s0022-3476(80)80217-4 -
Experiment and illusion in reproductive medicine
This study examines the rapid diffusion of untested medical technologies in reproductive medicine, particularly cesarean delivery and newborn intensive care, highlighting the influence of economic factors, patient vulnerability, and medical authority on these practices.
DOI: 10.1007/BF02692190 -
Impact of Prophylactic Continuous Positive Airway Pressure on Transient Tachypnea of the Newborn and Neonatal Intensive Care Admission in Newborns Delivered by Elective Cesarean Section
This study investigates the impact of prophylactic continuous positive airway pressure (CPAP) on the incidence of transient tachypnea of the newborn (TTN) and neonatal intensive care unit (NICU) admissions in infants delivered by elective cesarean section, finding a significant …
DOI: 10.1055/s-0035-1560041 -
Development and Dissemination of Potentially Better Practices for the Provision of Family-Centered Care in Neonatology: The Family-Centered Care Map
This study developed a web-based Family-Centered Care Map to enhance the coordination and delivery of holistic care for neonates and their families in neonatal intensive care units (NICUs), identifying 63 potentially better practices across various clinical phases.
DOI: 10.1542/peds.2006-0913F -
Thermal Blanket to Improve Thermoregulation in Preterm Infants
This randomized controlled trial demonstrates that the use of a temperature-controlled thermal blanket significantly reduces hypothermia and hypotension in very low-birth-weight infants compared to standard radiant warmers.
DOI: 10.1097/pcc.0000000000000447 -
Prenatal predictors of mortality in very preterm infants cared for in the Australian and New Zealand Neonatal Network
This study identifies antenatal and perinatal risk factors for in-hospital mortality in very preterm infants within the Australian and New Zealand Neonatal Network, demonstrating that gestational age and weight for gestational age are significant predictors of mortality.
DOI: 10.1136/adc.2006.094169 -
FUNDAMENTALS OF PHOTOTHERAPY FOR NEONATAL JAUNDICE
A comprehensive educational overview of neonatal phototherapy, describing bilirubin biology, how phototherapy works, dose determinants, delivery systems (LEDs, halogen lamps, fluorescent banks, fiberoptic blankets), nursing care, monitoring, rebound risks, and practical guidelin…
DOI: 10.1016/j.adnc.2006.08.004 -
Functional echocardiography in neonatal intensive care: 1-Year experience in a unit in Spain
A retrospective 1-year study in a Spanish NICU evaluating the frequency, indications, measurements, and impact on management of neonatologist-performed functional echocardiography (FnECHO), showing frequent use and modification of treatment (notably for PDA) based on FnECHO find…
DOI: 10.1016/j.anpede.2013.11.004