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Published in: BMC Pregnancy and Childbirth 1/2020

01-12-2020 | Research article

Postpartum haemorrhage (PPH) rates in randomized trials of PPH prophylactic interventions and the effect of underlying participant PPH risk: a meta-analysis

Authors: Lydia Hawker, Andrew Weeks

Published in: BMC Pregnancy and Childbirth | Issue 1/2020

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Abstract

Background

Postpartum haemorrhage (PPH) remains a leading cause of maternal mortality. Many trials assessing interventions to prevent PPH base their data on low risk women. It is important to consider the impact data collection methods may have on these results. This review aims to assess trials of PPH prophylaxis by grading trials according to the degree of risk status of the population enrolled in these trials and identify differences in the PPH rates of low risk and high risk populations.

Methods

Systematic review and meta-analysis using a random-effects model. Trials were identified through CENTRAL. Trials were assessed for eligibility then graded according to antenatal risk factors and method of birth into five grades. The main outcomes were overall trial rate of minor PPH (blood loss ≥500 ml) and major PPH (> 1000 ml) and method of determining blood loss (estimated/measured).

Results

There was no relationship between minor or major PPH rate and risk grade (Kruskal-Wallis: minor - T = 0.92, p = 0.82; major - T = 0.91, p = 0.92). There was no difference in minor or major PPH rates when comparing estimation or measurement methods (Mann-Whitney: minor - U = 67, p = 0.75; major - U = 35, p = 0.72). There was however a correlation between % operative births and minor PPH rate, but not major PPH (Spearman r = 0.32 v. Spearman r = 0.098).

Conclusions

Using data from trials using low risk women to generalise best practice guidelines might not be appropriate for all births, particularly complex births. Although complex births contribute disproportionately to PPH rates, this review showed they are often underrepresented in trials. Despite this, there was no difference in reported PPH rates between studies conducted in high and low risk groups. Method of birth was shown to be an important risk factor for minor PPH and may be a better predictor of PPH than antenatal risk factors. Women with operative births are often excluded from trials meaning a lack of data supporting interventions in these women. More focus on complex births is needed to ensure the evidence base is relevant to the target population.
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Literature
1.
go back to reference Say L, Chou D, Gemmill A, Tuncalp O, Moller AB, Daniels J, et al. Global causes of maternal death: a WHO systematic analysis. Lancet Glob Health. 2014;2(6):323–33.CrossRef Say L, Chou D, Gemmill A, Tuncalp O, Moller AB, Daniels J, et al. Global causes of maternal death: a WHO systematic analysis. Lancet Glob Health. 2014;2(6):323–33.CrossRef
2.
go back to reference Mavrides EAS, Chandraharan E, Collins P, Green L, Hunt BJ, Riris S, Thomson AJ. On behalf of the Royal College of Obstetricians and Gynaecologists Prevention and management of postpartum haemorrhage. BJOG Int J Obstet Gynaecol. 2016;124:e106–e49. Mavrides EAS, Chandraharan E, Collins P, Green L, Hunt BJ, Riris S, Thomson AJ. On behalf of the Royal College of Obstetricians and Gynaecologists Prevention and management of postpartum haemorrhage. BJOG Int J Obstet Gynaecol. 2016;124:e106–e49.
3.
go back to reference NICE. Intrapartum Care: Care of Healthy Women and their Babies during Childbirth. NICE. Clinical Guideline 190. London; 2014. NICE. Intrapartum Care: Care of Healthy Women and their Babies during Childbirth. NICE. Clinical Guideline 190. London; 2014.
4.
go back to reference Weeks A, Neilson J. Rethinking our approach to postpartum haemorrhage and uterotonics. BMJ (Online). 2015;351. Weeks A, Neilson J. Rethinking our approach to postpartum haemorrhage and uterotonics. BMJ (Online). 2015;351.
5.
go back to reference Green L, Knight M, Seeney FM, Hopkinson C, Collins PW, Collis RE, et al. The epidemiology and outcomes of women with postpartum haemorrhage requiring massive transfusion with eight or more units of red cells: a national cross-sectional study. BJOG Int J Obstet Gynaecol. 2016;123(13):2164–70.CrossRef Green L, Knight M, Seeney FM, Hopkinson C, Collins PW, Collis RE, et al. The epidemiology and outcomes of women with postpartum haemorrhage requiring massive transfusion with eight or more units of red cells: a national cross-sectional study. BJOG Int J Obstet Gynaecol. 2016;123(13):2164–70.CrossRef
6.
go back to reference Hancock A, Weeks AD, Lavender DT. Is accurate and reliable blood loss estimation the 'crucial step' in early detection of postpartum haemorrhage: an integrative review of the literature. BMC Pregnancy Childbirth. 2015;15:230.CrossRef Hancock A, Weeks AD, Lavender DT. Is accurate and reliable blood loss estimation the 'crucial step' in early detection of postpartum haemorrhage: an integrative review of the literature. BMC Pregnancy Childbirth. 2015;15:230.CrossRef
7.
go back to reference Higgins J, Green S, (editors). Cochrane Handbook for Systematic Reviews of Interventions. The Cochrane Collaboration 2011;Version 5.1.0 [updated March 2011]. Higgins J, Green S, (editors). Cochrane Handbook for Systematic Reviews of Interventions. The Cochrane Collaboration 2011;Version 5.1.0 [updated March 2011].
8.
go back to reference de Haas S, Ghossein-Doha C, van Kuijk SM, van Drongelen J, Spaanderman ME. Physiological adaptation of maternal plasma volume during pregnancy: a systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2017;49(2):177–87.CrossRef de Haas S, Ghossein-Doha C, van Kuijk SM, van Drongelen J, Spaanderman ME. Physiological adaptation of maternal plasma volume during pregnancy: a systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2017;49(2):177–87.CrossRef
9.
go back to reference Jackson KW Jr, Allbert JR, Schemmer GK, Elliot M, Humphrey A, Taylor J. A randomized controlled trial comparing oxytocin administration before and after placental delivery in the prevention of postpartum hemorrhage. Am J Obstet Gynecol. 2001;185(4):873–7.CrossRef Jackson KW Jr, Allbert JR, Schemmer GK, Elliot M, Humphrey A, Taylor J. A randomized controlled trial comparing oxytocin administration before and after placental delivery in the prevention of postpartum hemorrhage. Am J Obstet Gynecol. 2001;185(4):873–7.CrossRef
10.
go back to reference Davies GA, Tessier JL, Woodman MC, Lipson A, Hahn PM. Maternal hemodynamics after oxytocin bolus compared with infusion in the third stage of labor: a randomized controlled trial. Obstet Gynecol. 2005;105(2):294–9.CrossRef Davies GA, Tessier JL, Woodman MC, Lipson A, Hahn PM. Maternal hemodynamics after oxytocin bolus compared with infusion in the third stage of labor: a randomized controlled trial. Obstet Gynecol. 2005;105(2):294–9.CrossRef
11.
go back to reference Diop A, Daff B, Sow M, Blum J, Diagne M, Sloan NL, et al. Oxytocin via Uniject (a prefilled single-use injection) versus oral misoprostol for prevention of postpartum haemorrhage at the community level: a cluster-randomised controlled trial. Lancet Glob Health. 2016;4(1):e37–44.CrossRef Diop A, Daff B, Sow M, Blum J, Diagne M, Sloan NL, et al. Oxytocin via Uniject (a prefilled single-use injection) versus oral misoprostol for prevention of postpartum haemorrhage at the community level: a cluster-randomised controlled trial. Lancet Glob Health. 2016;4(1):e37–44.CrossRef
12.
go back to reference Güngördük K, Asicioglu O, Besimoglu B, Güngördük OC, Yildirm G, Ark C, et al. Using Intraumbilical vein injection of oxytocin in routine practice with active Management of the Third Stage of labor: a randomized controlled trial. Obstet Gynecol. 2010;116(3):619–24.CrossRef Güngördük K, Asicioglu O, Besimoglu B, Güngördük OC, Yildirm G, Ark C, et al. Using Intraumbilical vein injection of oxytocin in routine practice with active Management of the Third Stage of labor: a randomized controlled trial. Obstet Gynecol. 2010;116(3):619–24.CrossRef
13.
go back to reference Hofmeyr GJ, Fawole B, Mugerwa K, Godi NP, Blignaut Q, Mangesi L, et al. Administration of 400 μg of misoprostol to augment routine active management of the third stage of labor. Int J Gynaecol Obstet. 2011;112(2):98–102.CrossRef Hofmeyr GJ, Fawole B, Mugerwa K, Godi NP, Blignaut Q, Mangesi L, et al. Administration of 400 μg of misoprostol to augment routine active management of the third stage of labor. Int J Gynaecol Obstet. 2011;112(2):98–102.CrossRef
14.
go back to reference Khan GQ, John IS, Chan T, Wani S, Hughes AO, Stirrat GM. Abu Dhabi third stage trial: oxytocin versus Syntometrine in the active management of the third stage of labour. Eur J Obstet Gynecol Reprod Biol. 1995;58(2):147–51.CrossRef Khan GQ, John IS, Chan T, Wani S, Hughes AO, Stirrat GM. Abu Dhabi third stage trial: oxytocin versus Syntometrine in the active management of the third stage of labour. Eur J Obstet Gynecol Reprod Biol. 1995;58(2):147–51.CrossRef
15.
go back to reference Lamont RF, Morgan DJ, Logue M, Gordon H. A prospective randomised trial to compare the efficacy and safety of hemabate and syntometrine for the prevention of primary postpartum haemorrhage. Prostaglandins Other Lipid Mediat. 2001;66(3):203–10.CrossRef Lamont RF, Morgan DJ, Logue M, Gordon H. A prospective randomised trial to compare the efficacy and safety of hemabate and syntometrine for the prevention of primary postpartum haemorrhage. Prostaglandins Other Lipid Mediat. 2001;66(3):203–10.CrossRef
16.
go back to reference Masuzawa Y, Kataoka Y, Nakamura S, Yaju Y. Cooling the lower abdomen to reduce postpartum blood loss: a randomized controlled trial. PLoS One. 2017;12(10):e0186365.CrossRef Masuzawa Y, Kataoka Y, Nakamura S, Yaju Y. Cooling the lower abdomen to reduce postpartum blood loss: a randomized controlled trial. PLoS One. 2017;12(10):e0186365.CrossRef
17.
go back to reference Miller S, Tudor C, Thorsten V. Nyima, Kalyang, Sonam, et al. Randomized double masked trial of Zhi Byed 11, a Tibetan traditional medicine, versus misoprostol to prevent postpartum hemorrhage in Lhasa, Tibet. J Midwifery Womens Health. 2009;54(2):133–41.e1.CrossRef Miller S, Tudor C, Thorsten V. Nyima, Kalyang, Sonam, et al. Randomized double masked trial of Zhi Byed 11, a Tibetan traditional medicine, versus misoprostol to prevent postpartum hemorrhage in Lhasa, Tibet. J Midwifery Womens Health. 2009;54(2):133–41.e1.CrossRef
18.
go back to reference Mirghafourvand M, Mohammad-Alizadeh S, Abbasalizadeh F, Shirdel M. The effect of prophylactic intravenous tranexamic acid on blood loss after vaginal delivery in women at low risk of postpartum haemorrhage: a double-blind randomised controlled trial. Aust N Z J Obstet Gynaecol. 2015;55(1):53–8.CrossRef Mirghafourvand M, Mohammad-Alizadeh S, Abbasalizadeh F, Shirdel M. The effect of prophylactic intravenous tranexamic acid on blood loss after vaginal delivery in women at low risk of postpartum haemorrhage: a double-blind randomised controlled trial. Aust N Z J Obstet Gynaecol. 2015;55(1):53–8.CrossRef
19.
go back to reference Priya GP, Veena P, Chaturvedula L, Subitha L. A randomized controlled trial of sublingual misoprostol and intramuscular oxytocin for prevention of postpartum hemorrhage. Arch Gynecol Obstet. 2015;292(6):1231–7.CrossRef Priya GP, Veena P, Chaturvedula L, Subitha L. A randomized controlled trial of sublingual misoprostol and intramuscular oxytocin for prevention of postpartum hemorrhage. Arch Gynecol Obstet. 2015;292(6):1231–7.CrossRef
20.
go back to reference Quibel T, Ghout I, Goffinet F, Salomon LJ, Fort J, Javoise S, et al. Active Management of the Third Stage of labor with a combination of oxytocin and misoprostol to prevent postpartum hemorrhage: a randomized controlled trial. Obstet Gynecol. 2016;128(4):805–11.CrossRef Quibel T, Ghout I, Goffinet F, Salomon LJ, Fort J, Javoise S, et al. Active Management of the Third Stage of labor with a combination of oxytocin and misoprostol to prevent postpartum hemorrhage: a randomized controlled trial. Obstet Gynecol. 2016;128(4):805–11.CrossRef
21.
go back to reference Raghavan S, Geller S, Miller S, Goudar S, Anger H, Yadavannavar M, et al. Misoprostol for primary versus secondary prevention of postpartum haemorrhage: a cluster-randomised non-inferiority community trial. BJOG Int J Obstet Gynaecol. 2016;123(1):120–7.CrossRef Raghavan S, Geller S, Miller S, Goudar S, Anger H, Yadavannavar M, et al. Misoprostol for primary versus secondary prevention of postpartum haemorrhage: a cluster-randomised non-inferiority community trial. BJOG Int J Obstet Gynaecol. 2016;123(1):120–7.CrossRef
22.
go back to reference Shady NW, Sallam HF, Elsayed AH, Abdelkader AM, Ali SS, Alanwar A, et al. The effect of prophylactic oral tranexamic acid plus buccal misoprostol on blood loss after vaginal delivery: a randomized controlled trial. J Matern Fetal Neonatal Med. 2017:1–7. Shady NW, Sallam HF, Elsayed AH, Abdelkader AM, Ali SS, Alanwar A, et al. The effect of prophylactic oral tranexamic acid plus buccal misoprostol on blood loss after vaginal delivery: a randomized controlled trial. J Matern Fetal Neonatal Med. 2017:1–7.
23.
go back to reference Tita AT, Szychowski JM, Rouse DJ, Bean CM, Chapman V, Nothern A, et al. Higher-dose oxytocin and hemorrhage after vaginal delivery: a randomized controlled trial. Obstet Gynecol. 2012;119(2 Pt 1):293–300.CrossRef Tita AT, Szychowski JM, Rouse DJ, Bean CM, Chapman V, Nothern A, et al. Higher-dose oxytocin and hemorrhage after vaginal delivery: a randomized controlled trial. Obstet Gynecol. 2012;119(2 Pt 1):293–300.CrossRef
24.
go back to reference Ezeama CO, Eleje GU, Ezeama NN, Igwegbe AO, Ikechebelu JI, Ugboaja JO, et al. A comparison of prophylactic intramuscular ergometrine and oxytocin for women in the third stage of labor. Int J Gynaecol Obstet. 2014;124(1):67–71.CrossRef Ezeama CO, Eleje GU, Ezeama NN, Igwegbe AO, Ikechebelu JI, Ugboaja JO, et al. A comparison of prophylactic intramuscular ergometrine and oxytocin for women in the third stage of labor. Int J Gynaecol Obstet. 2014;124(1):67–71.CrossRef
25.
go back to reference McDonald SJ, Prendiville WJ, Blair E. Randomised controlled trial of oxytocin alone versus oxytocin and ergometrine in active management of third stage of labour. Br Med J. 1993;307(6913):1167–71.CrossRef McDonald SJ, Prendiville WJ, Blair E. Randomised controlled trial of oxytocin alone versus oxytocin and ergometrine in active management of third stage of labour. Br Med J. 1993;307(6913):1167–71.CrossRef
26.
go back to reference Mobeen N, Durocher J, Zuberi N, Jahan N, Blum J, Wasim S, et al. Administration of misoprostol by trained traditional birth attendants to prevent postpartum haemorrhage in homebirths in Pakistan: a randomised placebo-controlled trial. BJOG Int J Obstet Gynaecol. 2011;118(3):353–61.CrossRef Mobeen N, Durocher J, Zuberi N, Jahan N, Blum J, Wasim S, et al. Administration of misoprostol by trained traditional birth attendants to prevent postpartum haemorrhage in homebirths in Pakistan: a randomised placebo-controlled trial. BJOG Int J Obstet Gynaecol. 2011;118(3):353–61.CrossRef
27.
go back to reference Nasr A, Shahin AY, Elsamman AM, Zakherah MS, Shaaban OM. Rectal misoprostol versus intravenous oxytocin for prevention of postpartum hemorrhage. Int J Gynaecol Obstet. 2009;105(3):244–7.CrossRef Nasr A, Shahin AY, Elsamman AM, Zakherah MS, Shaaban OM. Rectal misoprostol versus intravenous oxytocin for prevention of postpartum hemorrhage. Int J Gynaecol Obstet. 2009;105(3):244–7.CrossRef
28.
go back to reference Orji E, Agwu F, Loto O, Olaleye O. A randomized comparative study of prophylactic oxytocin versus ergometrine in the third stage of labor. Int J Gynaecol Obstet. 2008;101(2):129–32.CrossRef Orji E, Agwu F, Loto O, Olaleye O. A randomized comparative study of prophylactic oxytocin versus ergometrine in the third stage of labor. Int J Gynaecol Obstet. 2008;101(2):129–32.CrossRef
29.
go back to reference Vaid A, Dadhwal V, Mittal S, Deka D, Misra R, Sharma JB, et al. A randomized controlled trial of prophylactic sublingual misoprostol versus intramuscular methyl-ergometrine versus intramuscular 15-methyl PGF2alpha in active management of third stage of labor. Arch Gynecol Obstet. 2009;280(6):893–7.CrossRef Vaid A, Dadhwal V, Mittal S, Deka D, Misra R, Sharma JB, et al. A randomized controlled trial of prophylactic sublingual misoprostol versus intramuscular methyl-ergometrine versus intramuscular 15-methyl PGF2alpha in active management of third stage of labor. Arch Gynecol Obstet. 2009;280(6):893–7.CrossRef
31.
go back to reference Althabe F, Alemán A, Tomasso G, Gibbons L, Vitureira G, Belizán JM, et al. A pilot randomized controlled trial of controlled cord traction to reduce postpartum blood loss. Int J Gynaecol Obstet. 2009;107(1):4–7.CrossRef Althabe F, Alemán A, Tomasso G, Gibbons L, Vitureira G, Belizán JM, et al. A pilot randomized controlled trial of controlled cord traction to reduce postpartum blood loss. Int J Gynaecol Obstet. 2009;107(1):4–7.CrossRef
32.
go back to reference Deneux-Tharaux C, Sentilhes L, Maillard F, Closset E, Vardon D, Lepercq J, et al. Effect of routine controlled cord traction as part of the active management of the third stage of labour on postpartum haemorrhage: multicentre randomised controlled trial (TRACOR). Br Med J. 2013;346:f1541.CrossRef Deneux-Tharaux C, Sentilhes L, Maillard F, Closset E, Vardon D, Lepercq J, et al. Effect of routine controlled cord traction as part of the active management of the third stage of labour on postpartum haemorrhage: multicentre randomised controlled trial (TRACOR). Br Med J. 2013;346:f1541.CrossRef
35.
go back to reference Dagdeviren H, Cengiz H, Heydarova U, Caypinar SS, Kanawati A, Guven E, et al. Intramuscular versus intravenous prophylactic oxytocin for postpartum hemorrhage after vaginal delivery: a randomized controlled study. Arch Gynecol Obstet. 2016;294(5):911–6.CrossRef Dagdeviren H, Cengiz H, Heydarova U, Caypinar SS, Kanawati A, Guven E, et al. Intramuscular versus intravenous prophylactic oxytocin for postpartum hemorrhage after vaginal delivery: a randomized controlled study. Arch Gynecol Obstet. 2016;294(5):911–6.CrossRef
38.
go back to reference Poeschmann R, Doesburg W, Eskes T. A randomized comparison of oxytocin, sulprostone and placebo in the management of the third stage of labour. BJOG Int J Obstet Gynaecol. 1991;98(6):528–30.CrossRef Poeschmann R, Doesburg W, Eskes T. A randomized comparison of oxytocin, sulprostone and placebo in the management of the third stage of labour. BJOG Int J Obstet Gynaecol. 1991;98(6):528–30.CrossRef
39.
go back to reference Stanton CK, Newton S, Mullany LC, Cofie P, Tawiah Agyemang C, Adiibokah E, et al. Effect on postpartum hemorrhage of prophylactic oxytocin (10 IU) by injection by community health officers in Ghana: a community-based, Cluster-Randomized Trial. PLoS Med. 2013;10(10):e1001524.CrossRef Stanton CK, Newton S, Mullany LC, Cofie P, Tawiah Agyemang C, Adiibokah E, et al. Effect on postpartum hemorrhage of prophylactic oxytocin (10 IU) by injection by community health officers in Ghana: a community-based, Cluster-Randomized Trial. PLoS Med. 2013;10(10):e1001524.CrossRef
41.
go back to reference Rogers J, Wood J, McCandlish R, Ayers S, Truesdale A, Elbourne D. Active versus expectant management of third stage of labour: the Hinchingbrooke randomised controlled trial. Lancet. 1998;351(9104):693–9.CrossRef Rogers J, Wood J, McCandlish R, Ayers S, Truesdale A, Elbourne D. Active versus expectant management of third stage of labour: the Hinchingbrooke randomised controlled trial. Lancet. 1998;351(9104):693–9.CrossRef
42.
go back to reference Prendiville WJ, Harding JE, Elbourne DR, Stirrat GM. The Bristol third stage trial: active versus physiological management of third stage of labour. Br Med J. 1988;297(6659):1295.CrossRef Prendiville WJ, Harding JE, Elbourne DR, Stirrat GM. The Bristol third stage trial: active versus physiological management of third stage of labour. Br Med J. 1988;297(6659):1295.CrossRef
44.
go back to reference de Groot AN, van Roosmalen J, van Dongen PW, Borm GF. A placebo-controlled trial of oral ergometrine to reduce postpartum hemorrhage. Acta Obstetrica et Gynecologica Scandanavica. 1996;75(5):464–8.CrossRef de Groot AN, van Roosmalen J, van Dongen PW, Borm GF. A placebo-controlled trial of oral ergometrine to reduce postpartum hemorrhage. Acta Obstetrica et Gynecologica Scandanavica. 1996;75(5):464–8.CrossRef
46.
go back to reference Attilakos G, Psaroudakis D, Ash J, Buchanan R, Winter C, Donald F, et al. Carbetocin versus oxytocin for the prevention of postpartum haemorrhage following caesarean section: the results of a double-blind randomised trial. BJOG Int J Obstet Gynaecol. 2010;117(8):929–36.CrossRef Attilakos G, Psaroudakis D, Ash J, Buchanan R, Winter C, Donald F, et al. Carbetocin versus oxytocin for the prevention of postpartum haemorrhage following caesarean section: the results of a double-blind randomised trial. BJOG Int J Obstet Gynaecol. 2010;117(8):929–36.CrossRef
48.
go back to reference Bais JMJ, Eskes M, Pel M, Bonsel GJ, Bleker OP. Postpartum haemorrhage in nulliparous women: incidence and risk factors in low and high risk women: a Dutch population-based cohort study on standard (≥500 ml) and severe (≥1000 ml) postpartum haemorrhage. Eur J Obstet Gynecol Reprod Biol. 2004;115(2):166–72.PubMed Bais JMJ, Eskes M, Pel M, Bonsel GJ, Bleker OP. Postpartum haemorrhage in nulliparous women: incidence and risk factors in low and high risk women: a Dutch population-based cohort study on standard (≥500 ml) and severe (≥1000 ml) postpartum haemorrhage. Eur J Obstet Gynecol Reprod Biol. 2004;115(2):166–72.PubMed
50.
go back to reference Brace V, Kernaghan D, Penney G. Learning from adverse clinical outcomes: major obstetric haemorrhage in Scotland, 2003–05. BJOG Int J Obstet Gynaecol. 2007;114(11):1388–96.CrossRef Brace V, Kernaghan D, Penney G. Learning from adverse clinical outcomes: major obstetric haemorrhage in Scotland, 2003–05. BJOG Int J Obstet Gynaecol. 2007;114(11):1388–96.CrossRef
51.
go back to reference Larsson C, Saltvedt S, Wiklund I, Pahlen S, Andolf E. Estimation of blood loss after cesarean section and vaginal delivery has low validity with a tendency to exaggeration. Acta Obstet Gynecol Scand. 2006;85(12):1448–52.CrossRef Larsson C, Saltvedt S, Wiklund I, Pahlen S, Andolf E. Estimation of blood loss after cesarean section and vaginal delivery has low validity with a tendency to exaggeration. Acta Obstet Gynecol Scand. 2006;85(12):1448–52.CrossRef
52.
go back to reference Calvert C, Thomas SL, Ronsmans C, Wagner KS, Adler AJ, Filippi V. Identifying regional variation in the prevalence of postpartum haemorrhage: a systematic review and meta-analysis. PLoS One. 2012;7(7):e41114.CrossRef Calvert C, Thomas SL, Ronsmans C, Wagner KS, Adler AJ, Filippi V. Identifying regional variation in the prevalence of postpartum haemorrhage: a systematic review and meta-analysis. PLoS One. 2012;7(7):e41114.CrossRef
53.
go back to reference Knight M, Callaghan WM, Berg C, Alexander S, Bouvier-Colle M-H, Ford JB, et al. Trends in postpartum hemorrhage in high resource countries: a review and recommendations from the international postpartum hemorrhage collaborative group. BMC Pregnancy and Childbirth. 2009;9(1):55.CrossRef Knight M, Callaghan WM, Berg C, Alexander S, Bouvier-Colle M-H, Ford JB, et al. Trends in postpartum hemorrhage in high resource countries: a review and recommendations from the international postpartum hemorrhage collaborative group. BMC Pregnancy and Childbirth. 2009;9(1):55.CrossRef
Metadata
Title
Postpartum haemorrhage (PPH) rates in randomized trials of PPH prophylactic interventions and the effect of underlying participant PPH risk: a meta-analysis
Authors
Lydia Hawker
Andrew Weeks
Publication date
01-12-2020
Publisher
BioMed Central
Published in
BMC Pregnancy and Childbirth / Issue 1/2020
Electronic ISSN: 1471-2393
DOI
https://doi.org/10.1186/s12884-020-2719-3

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