[SẢN] W4.3 - Newborn Care - Umbilical cord clamping ACOG 2012.pdf

8/9/2019 [SẢN] W4.3 - Newborn Care - Umbilical cord clamping ACOG 2012.pdf http://bsquochoai.ga

1/5

Before the mid 1950s, the term “early clamping” was

defined as umbilical cord clamping within 1 minute ofbirth, and “late clamping,” as umbilical cord clampingmore than 5 minutes after birth. In a series of studies ofblood volume changes after birth carried out by investi-gators in Sweden, the United States, and Canada, it wasreported that in healthy term infants, more than 90% ofblood volume was achieved within the first few breathsthe infant took after birth (1). Because of these findingsand the lack of specific recommendations regarding theoptimal timing, the interval between birth and umbili-cal cord clamping began to be shortened. In most cases,umbilical cord clamping is performed within 15–20 sec-onds after birth, with the infant maintained at or below

the level of the placenta. Although many randomizedcontrolled trials of term and preterm infants have evaluat-ed the benefits of immediate umbilical cord clamping ver-sus delayed umbilical cord clamping (generally defined asumbilical cord clamping performed 30–60 seconds afterbirth) (2–26), the ideal timing for umbilical cord clamp-ing has yet to be established and continues to be a subjectof controversy and debate (21, 27–29).

Concerns exist regarding universally adopting delayedumbilical cord clamping. Delay in umbilical cord clamp-ing may jeopardize timely resuscitation efforts, if needed,

especially in preterm infants. However, because the pla-

centa continues to perform gas exchange after delivery,sick and preterm infants are likely to benefit most fromadditional blood volume derived from a delay in umbili-cal cord clamping. Another concern has been raised thatdelay in umbilical cord clamping increases the potentialfor excessive placental transfusion, which can lead toneonatal polycythemia, especially in the presence of riskfactors for fetal polycythemia, such as maternal diabetes,severe intrauterine growth restriction, and high altitude.Additionally, delayed umbilical cord clamping (with theinfant placed at or below the level of the placenta) may betechnically difficult in some circumstances. Another issueis that delayed umbilical cord clamping might interfere

with attempts to collect cord blood for banking. However,the routine practice of umbilical cord clamping shouldnot be altered for the collection of umbilical cord bloodfor banking (30).

Neonatal Outcomes

Physiologic studies in term infants have shown that atransfer from the placenta of approximately 80 mL ofblood occurs by 1 minute after birth, reaching approxi-mately 100 mL at 3 minutes after birth (16, 31, 32). Thisadditional blood can supply extra iron, amounting to

Timing of Umbilical Cord Clamping After Birth

ABSTRACT: The optimal timing for clamping the umbilical cord after birth has been a subject of controversy

and debate. Although many randomized controlled trials in term and preterm infants have evaluated the benefits

of delayed umbilical cord clamping versus immediate umbilical cord clamping, the ideal timing for cord clamping

has yet to be established. Several systematic reviews have suggested that clamping the umbilical cord in all birthsshould be delayed for at least 30–60 seconds, with the infant maintained at or below the level of the placenta

because of the associated neonatal benefits, including increased blood volume, reduced need for blood transfu-

sion, decreased incidence of intracranial hemorrhage in preterm infants, and lower frequency of iron deficiency

anemia in term infants. Evidence exists to support delayed umbilical cord clamping in preterm infants, when

feasible. The single most important clinical benefit for preterm infants is the possibility for a nearly 50% reduction

in intraventricular hemorrhage. However, currently, evidence is insufficient to confirm or refute the potential for

benefits from delayed umbilical cord clamping in term infants, especially in settings with rich resources.

COMMITTEE OPINION

The American College ofObstetricians and GynecologistsWOMEN’S HEALTH CARE PHYSICIANS

Committee on Obstetric PracticeThis Committee Opinion was developed by the Committee on Obstetric Practice with the assistance of the American

Academy of Pediatrics. The American Academy of Pediatrics endorses this document. This information should not

be construed as dictating an exclusive course of treatment or procedure to be followed.

Number 543 • December 2012


2/5

2 Committee Opinion No. 543

40–50 mg/kg of body weight. This extra iron, combinedwith body iron (approximately 75 mg/kg of body weight)present at birth in a full-term newborn, may help preventiron deficiency during the first year of life (33).

Several systematic reviews have suggested thatclamping the umbilical cord in all births should bedelayed for at least 30–60 seconds, with the infant main-

tained at or below the level of the placenta because of theassociated neonatal benefits (1, 21, 29, 33–35), includ-ing increased blood volume (2, 3, 13, 31, 36–40), reducedneed for blood transfusion (17, 22, 41), decreased inci-dence of intracranial hemorrhage in preterm infants (10,18, 29), and decreased frequency of iron deficiency anemiain term infants (7–9, 13, 24–26, 35–37, 40, 42).

In addition, a longer duration of placental transfu-sion after birth may be beneficial because this blood isenriched with immunoglobulins and stem cells, whichprovide the potential for improved organ repair andrebuilding after injury from disorders caused by pretermbirth (39, 43). Although the magnitude of the benefits

from enhanced placental stem cell transfusion has notbeen well studied, the other neonatal benefits have ledinvestigators to consider revising umbilical cord clamp-ing practice guidelines (4, 28, 40, 44–48).

Maternal Outcomes

The effect of delayed umbilical cord clamping on mater-nal outcomes has not been adequately studied. Somestudies have shown no increase in the incidence of post-partum hemorrhage from delayed umbilical cord clamp-ing. However, this remains a theoretic concern becauseblood flow through the spiral arteries and veins in a termuterus is approximately 600 mL/min. Concerns regard-ing maternal risks become particularly relevant in specialcircumstances in which the benefits of delayed umbilicalcord clamping need to be balanced with the timely resus-citation of the woman (eg, in cases of hemorrhage fromplacenta previa or placental abruption after delivery of apreterm infant).

Clinical Trials in Term Infants

A 2008 Cochrane review assessed the effect of umbili-cal cord clamping in term infants on maternal and fetaloutcomes in 11 clinical trials that involved 2,989 womenand their infants (42). Reviewers found no significant dif-

ferences in postpartum hemorrhage between the womenwhose infants underwent early umbilical cord clamping(within 1 minute after birth) and late umbilical cordclamping group (at least 1 minute after birth or after ces-sation of cord pulsation) in any of the five trials (2,236women) that measured this outcome (relative risk [RR]for postpartum hemorrhage of 500 mL or more, 1.22;95% confidence interval [CI], 0.96–1.55). The review-ers found that late umbilical cord clamping had positiveand negative effects on neonatal outcomes. In five tri-als, which involved a total of 1,762 infants, a significantincrease was noted in the need for phototherapy for jaun-

dice after birth among infants in the late umbilical cordclamping group (RR, 1.69; 95% CI, 1.08–2.63). How-ever, infants who underwent late umbilical cord clamp-ing had significantly higher levels of hemoglobin (Hb)compared with infants in the early umbilical cord clamp-ing group (weighted mean difference, 2.17 g/dL; 95% CI,0.28–4.06). Infant ferritin levels remained higher in

infants in the late umbilical cord clamping group com-pared with those in the early umbilical cord clampinggroup until 6 months (weighted mean difference, 11.8micrograms per liter; 95% CI, 4.07–19.53).

Clinical Trials in Preterm Infants

In a systematic review of 10 trials of early umbilical cordclamping versus delayed umbilical cord clamping in 454preterm infants (at less than 37 weeks of gestation), nostatistically significant differences were found betweenthe groups for cord blood pH (mean difference, 0.01;95% CI, –0.03–0.05), Apgar scores (RR for 5-minuteApgar score of less than 8, 1.17; 95% CI, 0.62–2.2), and

body temperature at admission (mean difference, 0.14 °C;95% CI, –0.31–0.03) (2, 29). Benefits of delayed umbili-cal cord clamping included a reduced need for bloodtransfusions for low blood pressure (RR, 0.39; 95% CI,0.18 to 0.85) and anemia (RR, 0.49; 95% CI, 0.31–0.81).No significant differences were noted for infant deaths(RR, 0.71; 95% CI, 0.3–1.69), but a significant reductionin the incidence of intraventricular hemorrhage withdelayed umbilical cord clamping was reported by 7 of the10 published studies (RR, 0.53; 95% CI, 0.35–0.79).

Another systematic review on this topic analyzed theresults from 15 eligible studies (738 premature infants)(21). Infants were born between 24 weeks of gestationand 36 weeks of gestation. The maximum delay in umbil-ical cord clamping was 180 seconds. Delaying umbilicalcord clamping was associated with fewer infants whorequired transfusion for anemia (seven trials, 392 infants;RR, 0.61; 95% CI, 0.46–0.81) and for low blood pressure(four trials with estimable data for 90 infants; RR, 0.52;95% CI, 0.28–0.94); and less intraventricular hemorrhage(ultrasound diagnosis all grades) (10 trials, 539 infants;RR; 0.59; 95% CI, 0.41–0.85) compared with immedi-ate umbilical cord clamping. For other outcomes (infantdeath, severe [grade 3–4] intraventricular hemorrhage, andperiventricular leukomalacia), no clear differences were

identified between groups; however, many trials wereaffected by incomplete reporting and wide confidenceintervals. Outcome after discharge from the hospital wasreported for one small study, and no significant differ-ences were reported between the groups in mean BayleyII scores at age 7 months (corrected for gestation at birthand involved 58 children) (21).

Umbilical Cord Milking

One clinical trial and a secondary analysis from the sametrial have compared “milking” of a 20-cm segment of theumbilical cord versus immediate umbilical cord clamp-


3/5

Committee Opinion No. 543 3

the benefits of delayed umbilical cord clamping versusimmediate umbilical cord clamping, the ideal timing forumbilical cord clamping has yet to be established. Furtherstudies also are needed to evaluate the optimal timing ofumbilical cord clamping, the management of the thirdstage of labor in relation to umbilical cord clamping,and the timing of umbilical cord clamping in relation

to the initiation of voluntary or assisted ventilation inthe neonate. The ideal time for clamping the umbilicalcord after cesarean delivery versus vaginal birth is anespecially important area for future research. Prematureinfants, who may benefit most from delayed umbilicalcord clamping, are more likely to be delivered by cesareandelivery because their mothers may have other medicaland obstetric complications.

Large clinical trials are needed to investigate the effectof delayed umbilical cord clamping on infants deliveredat less than 28 weeks of gestation. Further investigationis required to evaluate management of umbilical cordclamping in women with high-risk pregnancies whoseinfants are prone to develop polycythemia. The risks ofumbilical cord milking remain unknown, and morestudies are needed to compare milking of the umbilicalcord with delayed umbilical cord clamping. The valueof enhanced stem cell and plasma transfusion associatedwith delayed cord clamping with respect to immediateand long-term immunity, host defense, and repair isanother important area for future research.

References

1. Philip AG, Saigal S. When should we clamp the umbilicalcord? Neoreviews 2004;5:e142–54.^

2. Aladangady N, McHugh S, Aitchison TC, Wardrop CA,Holland BM. Infants’ blood volume in a controlled trial ofplacental transfusion at preterm delivery. Pediatrics 2006;117:93–8. [PubMed] [Full Text]^

3. Baenziger O, Stolkin F, Keel M, von Siebenthal K, FauchereJC, Das Kundu S, et al. The influence of the timing of cordclamping on postnatal cerebral oxygenation in pretermneonates: a randomized, controlled trial. Pediatrics 2007;119:455–9. [PubMed] [Full Text] ^

4. Bell EF. When to transfuse preterm babies. Arch Dis ChildFetal Neonatal Ed 2008;93:F469–73. [PubMed] [Full Text] ^

5. Ceriani Cernadas JM, Carroli G, Pellegrini L, Otano L,Ferreira M, Ricci C, et al. The effect of timing of cordclamping on neonatal venous hematocrit values and clinicaloutcome at term: a randomized, controlled trial. Pediatrics2006;117:e779–86. [PubMed] [Full Text] ^

6. Chaparro CM, Fornes R, Neufeld LM, Tena Alavez G,Eguia-Liz Cedillo R, Dewey KG. Early umbilical cord clamp-ing contributes to elevated blood lead levels among infantswith higher lead exposure. J Pediatr 2007;151:506–12.[PubMed]^

7. Chaparro CM, Neufeld LM, Tena Alavez G, Eguia-LizCedillo R, Dewey KG. Effect of timing of umbilical cord

ing in preterm singleton infants born between 24 weeksof gestation and 28 weeks of gestation (49, 50). Significantfindings in the clinical study included higher initial Hbconcentration, higher mean systemic blood pressure,reduced need for blood transfusion, and higher urineoutput during the first 72 hours in the group that under-went umbilical cord milking compared with the group

that underwent immediate umbilical cord clamping.The group that underwent umbilical cord milking alsorequired a shorter duration of supplemental oxygen andmechanical ventilation. A 2011 randomized controlledtrial of 58 preterm neonates (born at 24–32 6/7 weeks ofgestation) randomized to receive either repeated milkingof the umbilical cord (4 times) or delayed umbilical cordclamping of 30 seconds found that the two strategies hadsimilar effects on Hb levels after birth (51). More studiesare needed to evaluate the potential benefits and risks ofumbilical cord milking, and at this time there is insuf-ficient evidence to support umbilical cord milking inpreterm infants.

Conclusion

Currently, insufficient evidence exists to support or torefute the benefits from delayed umbilical cord clamp-ing for term infants that are born in settings with richresources. Although a delay in umbilical cord clampingfor up to 60 seconds may increase total body iron storesand blood volume, which may be particularly beneficialin populations in which iron deficiency is prevalent,these potential benefits must be weighed against theincreased risk for neonatal phototherapy. In addition,no difference is apparent between infants who undergoearly umbilical cord clamping versus those who undergodelayed umbilical cord clamping with respect to imme-diate birth outcomes, such as Apgar scores, umbilicalcord pH, or respiratory distress caused by polycythemia(51). Although maternal outcomes have not been rigor-ously studied, the incidence of postpartum hemorrhageis reported to be similar between immediate umbilicalcord clamping groups and late umbilical cord clampinggroups.

However, evidence supports delayed umbilical cordclamping in preterm infants. As with term infants, delay-ing umbilical cord clamping to 30–60 seconds after birthwith the infant at a level below the placenta is associated

with neonatal benefits, including improved transitionalcirculation, better establishment of red blood cell volume,and decreased need for blood transfusion. The singlemost important clinical benefit for preterm infants is thepossibility for a nearly 50% reduction in intraventricularhemorrhage. It is important to note that the timing ofumbilical cord clamping should not be altered for the pur-pose of collecting umbilical cord blood for banking (30).

Future Research

Although many randomized controlled trials thatinvolved term infants and preterm infants have evaluated

http://www.ncbi.nlm.nih.gov/pubmed/16396865http://pediatrics.aappublications.org/content/117/1/93.longhttp://www.ncbi.nlm.nih.gov/pubmed/17332197http://pediatrics.aappublications.org/content/119/3/455.longhttp://www.ncbi.nlm.nih.gov/pubmed/18653585http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664522/http://www.ncbi.nlm.nih.gov/pubmed/16567393http://pediatrics.aappublications.org/content/117/4/e779.longhttp://www.ncbi.nlm.nih.gov/pubmed/17961694http://www.ncbi.nlm.nih.gov/pubmed/17961694http://pediatrics.aappublications.org/content/117/4/e779.longhttp://www.ncbi.nlm.nih.gov/pubmed/16567393http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664522/http://www.ncbi.nlm.nih.gov/pubmed/18653585http://pediatrics.aappublications.org/content/119/3/455.longhttp://www.ncbi.nlm.nih.gov/pubmed/17332197http://pediatrics.aappublications.org/content/117/1/93.longhttp://www.ncbi.nlm.nih.gov/pubmed/16396865


4/5

4 Committee Opinion No. 543

22. Rabe H, Wacker A, Hulskamp G, Hornig-Franz I, Schulze-Everding A, Harms E, et al. A randomised controlled trialof delayed cord clamping in very low birth weight preterminfants. Eur J Pediatr 2000;159:775–7. [PubMed]^

23. Ultee CA, van der Deure J, Swart J, Lasham C, van Baar AL.Delayed cord clamping in preterm infants delivered at 3436 weeks’ gestation: a randomised controlled trial. Arch DisChild Fetal Neonatal Ed 2008;93:F20–3. [PubMed]^

24. van Rheenen P, Brabin BJ. Late umbilical cord-clampingas an intervention for reducing iron deficiency anaemiain term infants in developing and industrialised countries:a systematic review. Ann Trop Paediatr 2004;24:3–16.[PubMed] ^

25. van Rheenen P, de Moor L, Eschbach S, de Grooth H,Brabin B. Delayed cord clamping and haemoglobin levelsin infancy: a randomised controlled trial in term babies.Trop Med Int Health 2007;12:603–16. [PubMed] [Full Text] ^

26. van Rheenen PF, Gruschke S, Brabin BJ. Delayed umbilicalcord clamping for reducing anaemia in low birthweight

infants: implications for developing countries. Ann TropPaediatr 2006;26:157– 67. [PubMed] ^

27. Mercer JS, Skovgaard RL. Neonatal transitional physiology:a new paradigm. J Perinat Neonatal Nurs 2002;15:56–75.[PubMed] ^

28. Oh W. Timing of umbilical cord clamping at birth in full-term infants. JAMA 2007;297:1257–8. [PubMed] [Full Text] ^

29. Rabe H, Reynolds G, Diaz-Rossello J. A systematic reviewand meta-analysis of a brief delay in clamping the umbili-cal cord of preterm infants. Neonatology 2008;93:138–44.[PubMed] ^

30. Umbilical cord blood banking. ACOG Committee Opin-ion No. 399. American College of Obstetricians andGynecologists. Obstet Gynecol 2008;111:475–7. [PubMed] [Obstetrics & Gynecology ] ^

31. Linderkamp O, Nelle M, Kraus M, Zilow EP. The effect ofearly and late cord-clamping on blood viscosity and otherhemorheological parameters in full-term neonates. ActaPaediatr 1992;81:745–50. [PubMed] ^

32. Yao AC, Lind J. Effect of early and late cord clampingon the systolic time intervals of the newborn infant. ActaPaediatr Scand 1977;66:489–93. [PubMed] ^

33. Pisacane A. Neonatal prevention of iron deficiency. BMJ1996;312:136–7. [PubMed] [Full Text] ^

34. Eichenbaum-Pikser G, Zasloff JS. Delayed clamping of theumbilical cord: a review with implications for practice.J Midwifery Womens Health 2009;54:321–6. [PubMed] [Full Text] ^

35. Hutton EK, Hassan ES. Late vs early clamping of theumbilical cord in full-term neonates: systematic review andmeta-analysis of controlled trials. JAMA 2007;297:1241–52.[PubMed] [Full Text]^

36. Emhamed MO, van Rheenen P, Brabin BJ. The early effectsof delayed cord clamping in term infants born to Libyanmothers. Trop Doct 2004;34:218–22. [PubMed] ^

clamping on iron status in Mexican infants: a randomisedcontrolled trial. Lancet 2006;367:1997–2004. [PubMed] [Full Text] ^

8. Geethanath RM, Ramji S, Thirupuram S, Rao YN. Effect oftiming of cord clamping on the iron status of infants at 3months. Indian Pediatr 1997;34:103–6. [PubMed] ^

9. Grajeda R, Perez-Escamilla R, Dewey KG. Delayed clamp-

ing of the umbilical cord improves hematologic status ofGuatemalan infants at 2 mo of age. Am J Clin Nutr 1997;65:425–31. [PubMed] [Full Text] ^

10. Hofmeyr GJ, Bolton KD, Bowen DC, Govan JJ. Peri-ventricular/intraventricular haemorrhage and umbilicalcord clamping. Findings and hypothesis. S Afr Med J 1988;73:104–6. [PubMed] ^

11. Hofmeyr GJ, Gobetz L, Bex PJ, Van der Griendt M,Nikodem C, Skapinker R, et al. Periventricular/intraven-tricular hemorrhage following early and delayed umbilicalcord clamping. A randomized controlled trial. Online JCurr Clin Trials 1993;Doc No 110. [PubMed] ^

12. Ibrahim HM, Krouskop RW, Lewis DF, Dhanireddy R.

Placental transfusion: umbilical cord clamping and preterminfants. J Perinatol 2000;20:351–4. [PubMed] ^

13. Jahazi A, Kordi M, Mirbehbahani NB, Mazloom SR. Theeffect of early and late umbilical cord clamping on neonatalhematocrit. J Perinatol 2008;28:523–5. [PubMed] ^

14. Jaleel R, Deeba F, Khan A. Timing of umbilical cord clamp-ing and neonatal haematological status. J Pak Med Assoc2009;59:468–70. [PubMed]^

15. Kugelman A, Borenstein-Levin L, Riskin A, Chistyakov I,Ohel G, Gonen R, et al. Immediate versus delayed umbilicalcord clamping in premature neonates born


5/5

Committee Opinion No. 543 5

46. Philip AG. Delayed cord clamping in preterm infants.Pediatrics 2006;117:1434–5. [PubMed] [Full Text] ^

47. Rabe H, Alvarez JR, Lawn C, Seddon P, Amess PN. A man-agement guideline to reduce the frequency of blood trans-fusion in very-low-birth-weight infants. Am J Perinatol2009;26:179–83. [PubMed] [Full Text]^

48. Weeks A. Umbilical cord clamping after birth. BMJ 2007;

335:312–3. [PubMed] [Full Text] ^

49. Hosono S, Mugishima H, Fujita H, Hosono A, Minato M,Okada T, et al. Umbilical cord milking reduces the needfor red cell transfusions and improves neonatal adaptationin infants born at less than 29 weeks’ gestation: a ran-domised controlled trial. Arch Dis Child Fetal Neonatal Ed2008;93:F14–9. [PubMed]^

50. Hosono S, Mugishima H, Fujita H, Hosono A, Okada T,Takahashi S, et al. Blood pressure and urine output duringthe first 120 h of life in infants born at less than 29 weeks’gestation related to umbilical cord milking. Arch Dis ChildFetal Neonatal Ed 2009;94:F328–31. [PubMed] ^

51. Rabe H, Jewison A, Alvarez RF, Crook D, Stilton D, Bradley R,

et al. Milking compared with delayed cord clamping toincrease placental transfusion in preterm neonates: a ran-domized controlled trial. Brighton Perinatal Study Group.Obstet Gynecol 2011;117:205–11. [PubMed] [Obstetrics & Gynecology ]^

37. Gupta R, Ramji S. Effect of delayed cord clamping on ironstores in infants born to anemic mothers: a randomizedcontrolled trial. Indian Pediatr 2002;39:130–5. [PubMed] ^

38. Kinmond S, Aitchison TC, Holland BM, Jones JG, TurnerTL, Wardrop CA. Umbilical cord clamping and pre-term infants: a randomised trial. BMJ 1993;306:172–5.[PubMed] [Full Text] ^

39. Levy T, Blickstein I. Timing of cord clamping revisited. JPerinat Med 2006;34:293–7. [PubMed] ^

40. van Rheenen PF, Brabin BJ. A practical approach to tim-ing cord clamping in resource poor settings. BMJ 2006;333:954–8. [PubMed] [Full Text] ^

41. Strauss RG, Mock DM, Johnson K, Mock NI, CressG, Knosp L, et al. Circulating RBC volume, measuredwith biotinylated RBCs, is superior to the Hct to docu-ment the hematologic effects of delayed versus immediateumbilical cord clamping in preterm neonates. Transfusion2003;43:1168–72. [PubMed] ^

42. McDonald SJ, Middleton P. Effect of timing of umbilical

cord clamping of term infants on maternal and neonataloutcomes. Cochrane Database of Systematic Reviews 2008,Issue 2. Art. No.: CD004074. DOI: 10.1002/14651858.CD004074.pub2. [PubMed] [Full Text] ^

43. Sanberg PR, Park DH, Borlongan CV. Stem cell transplantsat childbirth. Stem Cell Rev 2010;6:27–30. [PubMed] ^

44. Coggins M, Mercer J. Delayed cord clamping: advan-tages for infants. Nurs Womens Health 2009;13:132–9.[PubMed] ^

45. Hutchon DJ. Delayed cord clamping may also be beneficialin rich settings. BMJ 2006;333:1073. [PubMed] [Full Text] ^

Copyright December 2012 by the American College of Obstetriciansand Gynecologists, 409 12th Street, SW, PO Box 96920, Washington,DC 20090-6920. All rights reserved.

ISSN 1074-861X

Timing of umbilical cord clamping after birth. Committee OpinionNo. 543. American College of Obstetricians and Gynecologists. ObstetGynecol 2012;120:1522–6.
http://www.ncbi.nlm.nih.gov/pubmed/16585344http://pediatrics.aappublications.org/content/117/4/1434.longhttp://www.ncbi.nlm.nih.gov/pubmed/19085812https://www.thieme-connect.com/ejournals/html/10.1055/s-0028-1103024http://www.ncbi.nlm.nih.gov/pubmed/17703005http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1949472/http://www.ncbi.nlm.nih.gov/pubmed/17234653http://www.ncbi.nlm.nih.gov/pubmed/19221402http://www.ncbi.nlm.nih.gov/pubmed/21252731http://journals.lww.com/greenjournal/Fulltext/2011/02000/Milking_Compared_With_Delayed_Cord_Clamping_to.2.aspxhttp://journals.lww.com/greenjournal/Fulltext/2011/02000/Milking_Compared_With_Delayed_Cord_Clamping_to.2.aspxhttp://journals.lww.com/greenjournal/Fulltext/2011/02000/Milking_Compared_With_Delayed_Cord_Clamping_to.2.aspxhttp://journals.lww.com/greenjournal/Fulltext/2011/02000/Milking_Compared_With_Delayed_Cord_Clamping_to.2.aspxhttp://www.ncbi.nlm.nih.gov/pubmed/11867842http://www.ncbi.nlm.nih.gov/pubmed/8443480http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1676623/pdf/bmj00003-0022.pdfhttp://www.ncbi.nlm.nih.gov/pubmed/16856818http://www.ncbi.nlm.nih.gov/pubmed/17082547http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633763/http://www.ncbi.nlm.nih.gov/pubmed/12869126http://www.ncbi.nlm.nih.gov/pubmed/18425897http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004074.pub2/fullhttp://www.ncbi.nlm.nih.gov/pubmed/20020331http://www.ncbi.nlm.nih.gov/pubmed/19368679http://www.ncbi.nlm.nih.gov/pubmed/17110735http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1647371/http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1647371/http://www.ncbi.nlm.nih.gov/pubmed/17110735http://www.ncbi.nlm.nih.gov/pubmed/19368679http://www.ncbi.nlm.nih.gov/pubmed/20020331http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004074.pub2/fullhttp://www.ncbi.nlm.nih.gov/pubmed/18425897http://www.ncbi.nlm.nih.gov/pubmed/12869126http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1633763/http://www.ncbi.nlm.nih.gov/pubmed/17082547http://www.ncbi.nlm.nih.gov/pubmed/16856818http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1676623/pdf/bmj00003-0022.pdfhttp://www.ncbi.nlm.nih.gov/pubmed/8443480http://www.ncbi.nlm.nih.gov/pubmed/11867842http://journals.lww.com/greenjournal/Fulltext/2011/02000/Milking_Compared_With_Delayed_Cord_Clamping_to.2.aspxhttp://journals.lww.com/greenjournal/Fulltext/2011/02000/Milking_Compared_With_Delayed_Cord_Clamping_to.2.aspxhttp://www.ncbi.nlm.nih.gov/pubmed/21252731http://www.ncbi.nlm.nih.gov/pubmed/19221402http://www.ncbi.nlm.nih.gov/pubmed/17234653http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1949472/http://www.ncbi.nlm.nih.gov/pubmed/17703005https://www.thieme-connect.com/ejournals/html/10.1055/s-0028-1103024http://www.ncbi.nlm.nih.gov/pubmed/19085812http://pediatrics.aappublications.org/content/117/4/1434.longhttp://www.ncbi.nlm.nih.gov/pubmed/16585344

Documents

[SẢN] W4.3 - Newborn Care - Umbilical cord clamping ACOG 2012.pdf