Vitamin B12 supplementation during pregnancy for maternal and child health outcomes.

Finkelstein JL ，Fothergill A ，Venkatramanan S ，Layden AJ ，Williams JL ，Crider KS ，Qi YP ... -  《Cochrane Database of Systematic Reviews》

Treatment for women with postpartum iron deficiency anaemia.

Postpartum iron deficiency anaemia is caused by antenatal iron deficiency or excessive blood loss at delivery and might affect up to 50% of labouring women in low- and middle-income countries. Effective and safe treatment during early motherhood is important for maternal well-being and newborn care. Treatment options include oral iron supplementation, intravenous iron, erythropoietin, and red blood cell transfusion. To assess the benefits and harms of the available treatment modalities for women with postpartum iron deficiency anaemia. These include intravenous iron, oral iron supplementation, red blood cell transfusion, and erythropoietin. A Cochrane Information Specialist searched for all published, unpublished, and ongoing trials, without language or publication status restrictions. We searched databases including CENTRAL, MEDLINE, Embase, CINAHL, LILACS, WHO ICTRP, and ClinicalTrials.gov, together with reference checking, citation searching, and contact with study authors to identify eligible studies. We applied date limits to retrieve new records since the last search on 9 April 2015 until 11 April 2024. We included published, unpublished, and ongoing randomised controlled trials (RCTs) that compared treatments for postpartum iron deficiency anaemia with placebo, no treatment, or alternative treatments. Cluster-randomised trials were eligible for inclusion. We included RCTs regardless of blinding. Participants were women with postpartum haemoglobin ≤ 12 g/dL, treated within six weeks after childbirth. We excluded non-randomised, quasi-randomised, and cross-over trials. The critical outcomes of this review were maternal mortality and fatigue. The important outcomes included persistent anaemia symptoms, persistent postpartum anaemia, psychological well-being, infections, compliance with treatment, breastfeeding, length of hospital stay, serious adverse events, anaphylaxis or evidence of hypersensitivity, flushing/Fishbane reaction, injection discomfort/reaction, constipation, gastrointestinal pain, number of red blood cell transfusions, and haemoglobin levels. We assessed risk of bias in the included studies using the Cochrane RoB 1 tool. Two review authors independently performed study screening, risk of bias assessment, and data extraction. We contacted trial authors for supplementary data when necessary. We screened all trials for trustworthiness and scientific integrity using the Cochrane Trustworthiness Screening Tool. We conducted meta-analyses using a fixed-effect model whenever feasible to synthesise outcomes. In cases where data were not suitable for meta-analysis, we provided a narrative summary of important findings. We evaluated the overall certainty of the evidence using GRADE. We included 33 RCTs with a total of 4558 postpartum women. Most trials were at high risk of bias for several risk of bias domains. Most of the evidence was of low or very low certainty. Imprecision due to few events and risk of bias due to lack of blinding were the most important factors. Intravenous iron versus oral iron supplementation The evidence is very uncertain about the effect of intravenous iron on mortality (risk ratio (RR) 2.95, 95% confidence interval (CI) 0.12 to 71.96; P = 0.51; I² = not applicable; 3 RCTs; 1 event; 572 women; very low-certainty evidence). One woman died of cardiomyopathy, and another developed arrhythmia, both in the groups treated with intravenous iron. Intravenous iron probably results in a slight reduction in fatigue within 8 to 28 days (standardised mean difference -0.25, 95% CI -0.42 to -0.07; P = 0.006; I² = 47%; 2 RCTs; 515 women; moderate-certainty evidence). Breastfeeding was not reported. Oral iron probably increases the risk of constipation compared to intravenous iron (RR 0.12, 95% CI 0.06 to 0.21; P < 0.001; I² = 0%; 10 RCTs; 1798 women; moderate-certainty evidence). The evidence is very uncertain about the effect of intravenous iron on anaphylaxis or hypersensitivity (RR 2.77, 95% CI 0.31 to 24.86; P = 0.36; I² = 0%; 12 RCTs; 2195 women; very low-certainty evidence). Three women treated with intravenous iron experienced anaphylaxis or hypersensitivity. The trials that reported on haemoglobin at 8 to 28 days were too heterogeneous to pool. However, 5 of 6 RCTs favoured intravenous iron, with mean changes in haemoglobin ranging from 0.73 to 2.10 g/dL (low-certainty evidence). Red blood cell transfusion versus intravenous iron No women died in the only trial that reported on mortality (1 RCT; 7 women; very low-certainty evidence). The evidence is very uncertain about the effect of red blood cell transfusion on fatigue at 8 to 28 days (mean difference (MD) 1.20, 95% CI -2.41 to 4.81; P = 0.51; I² = not applicable; 1 RCT; 13 women; very low-certainty evidence) and breastfeeding more than six weeks postpartum (RR 0.43, 95% CI 0.12 to 1.57; P = 0.20; I² = not applicable; 1 RCT; 13 women; very low-certainty evidence). Constipation and anaphylaxis were not reported. Red blood cell transfusion may result in little to no difference in haemoglobin within 8 to 28 days (MD -1.00, 95% CI -2.02 to 0.02; P = 0.05; I² = not applicable; 1 RCT; 12 women; low-certainty evidence). Intravenous iron and oral iron supplementation versus oral iron supplementation Mortality and breastfeeding were not reported. One trial reported a greater improvement in fatigue in the intravenous and oral iron group, but the effect size could not be calculated (1 RCT; 128 women; very low-certainty evidence). Intravenous iron and oral iron may result in a reduction in constipation compared to oral iron alone (RR 0.21, 95% CI 0.07 to 0.69; P = 0.01; I² = not applicable; 1 RCT; 128 women; low-certainty evidence). There were no anaphylaxis or hypersensitivity events in the trials (2 RCTs; 168 women; very low-certainty evidence). Intravenous iron and oral iron may result in little to no difference in haemoglobin (g/dL) at 8 to 28 days (MD 0.00, 95% CI -0.48 to 0.48; P = 1.00; I² = not applicable; 1 RCT; 60 women; low-certainty evidence). Red blood cell transfusion versus no transfusion Mortality, fatigue at day 8 to 28, constipation, anaphylaxis, and haemoglobin were not reported. Red blood cell transfusion may result in little to no difference in breastfeeding more than six weeks postpartum (RR 0.91, 95% CI 0.78 to 1.07; P = 0.24; I² = not applicable; 1 RCT; 297 women; low-certainty evidence). Oral iron supplementation versus placebo or no treatment Mortality, fatigue, breastfeeding, constipation, anaphylaxis, and haemoglobin were not reported. Two trials reported on gastrointestinal symptoms, but did not report results by study arm. Intravenous iron probably reduces fatigue slightly in the early postpartum weeks (8 to 28 days) compared to oral iron tablets, but probably results in little to no difference after four weeks. It is very uncertain if intravenous iron has an effect on mortality and anaphylaxis/hypersensitivity. Breastfeeding was not reported. Intravenous iron may increase haemoglobin slightly more than iron tablets, but the data were too heterogeneous to pool. However, changes in haemoglobin levels are a surrogate outcome, and treatment decisions should preferentially be based on patient-relevant outcomes. Iron tablets probably result in a large increase in constipation compared to intravenous iron. The effect of red blood cell transfusion compared to intravenous iron on mortality, fatigue, and breastfeeding is very uncertain. No studies reported on constipation or anaphylaxis/hypersensitivity. Red blood cell transfusion may result in little to no difference in haemoglobin at 8 to 28 days. The effect of intravenous iron and oral iron supplementation on mortality, fatigue, breastfeeding, and anaphylaxis/hypersensitivity is very uncertain or unreported. Intravenous iron and oral iron may result in a reduction in constipation compared to oral iron alone, and in little to no difference in haemoglobin. The effect of red blood cell transfusion compared to non-transfusion on mortality, fatigue, constipation, anaphylaxis/hypersensitivity, and haemoglobin is unreported. Red blood cell transfusion may result in little to no difference in breastfeeding. The effect of oral iron supplementation on mortality, fatigue, breastfeeding, constipation, anaphylaxis/hypersensitivity, and haemoglobin is unreported. This Cochrane review had no dedicated funding. Protocol and previous versions are available: Protocol (2013) [DOI: 10.1002/14651858.CD010861] Original review (2004) [DOI: 10.1002/14651858.CD004222.pub2] Review update (2015) [DOI: 10.1002/14651858.CD010861.pub2].

Jensen MCH ，Holm C ，Jørgensen KJ ，Schroll JB ... -  《Cochrane Database of Systematic Reviews》

Vitamin D supplementation for women during pregnancy.

Vitamin D supplementation during pregnancy may help improve maternal and neonatal health outcomes (such as fewer preterm birth and low birthweight babies) and reduce the risk of adverse pregnancy outcomes (such as severe postpartum haemorrhage). To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve certain maternal and neonatal outcomes. We searched the Cochrane Pregnancy and Childbirth Trials Register (which includes results of comprehensive searches of CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, and relevant conference proceedings) (3 December 2022). We also searched the reference lists of retrieved studies. Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention. Two review authors independently i) assessed the eligibility of studies against the inclusion criteria, ii) assessed trustworthiness based on pre-defined criteria of scientific integrity, iii) extracted data from included studies, and iv) assessed the risk of bias of the included studies. We assessed the certainty of the evidence using the GRADE approach. The previous version of this review included 30 studies; in this update, we have removed 20 of these studies to 'awaiting classification' following assessments of trustworthiness, one study has been excluded, and one new study included. This current review has a total of 10 included studies, 117 excluded studies, 34 studies in awaiting assessment, and seven ongoing studies. We used the GRADE approach to assess the certainty of the evidence. This removal of the studies resulted in evidence that was downgraded to low-certainty or very low-certainty due to study design limitations, inconsistency between studies, and imprecision. Supplementation with vitamin D compared to no intervention or a placebo A total of eight studies involving 2313 pregnant women were included in this comparison. We assessed four studies as having a low risk of bias for most domains and four studies as having high risk or unclear risk of bias for most domains. The evidence is very uncertain about the effect of supplementation with vitamin D during pregnancy compared to placebo or no intervention on pre-eclampsia (risk ratio (RR) 0.53, 95% confidence interval (CI) 0.21 to 1.33; 1 study, 165 women), gestational diabetes (RR 0.53, 95% CI 0.03 to 8.28; 1 study, 165 women), preterm birth (< 37 weeks) (RR 0.76, 95% CI 0.25 to 2.33; 3 studies, 1368 women), nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 study, 135 women), or hypercalcaemia (1 study; no cases reported). Supplementation with vitamin D during pregnancy may reduce the risk of severe postpartum haemorrhage; however, only one study reported this outcome (RR 0.68, 95% CI 0.51 to 0.91; 1 study, 1134 women; low-certainty evidence) and may reduce the risk of low birthweight; however, the upper CI suggests that an increase in risk cannot be ruled out (RR 0.69, 95% CI 0.44 to 1.08; 3 studies, 371 infants; low-certainty evidence). Supplementation with vitamin D + calcium compared to no intervention or a placebo One study involving 84 pregnant women was included in this comparison. Overall, this study was at moderate to high risk of bias. Pre-eclampsia, gestational diabetes, and maternal adverse events were not reported. The evidence is very uncertain about the effect of supplementation with vitamin D and calcium on preterm birth (RR not estimable; very low-certainty evidence) or for low birthweight (RR 1.45, 95% CI 0.14 to 14.94; very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D) One study involving 1298 pregnant women was included in this comparison. We assessed this study as having a low risk of bias in all domains. Pre-eclampsia was not reported. The evidence is very uncertain about the effect of supplementation with vitamin D, calcium, and other vitamins and minerals during pregnancy compared to no vitamin D on gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73; very low-certainty evidence), maternal adverse events (hypercalcaemia no events and hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; very low-certainty evidence), preterm birth (RR 1.04, 95% CI 0.68 to 1.59; low-certainty evidence), or low birthweight (RR 1.12, 95% CI 0.82 to 1.51; low-certainty evidence). This updated review using the trustworthy assessment tool removed 21 studies from the previous update and added one new study for a total of 10 included studies. In this setting, supplementation with vitamin D alone compared to no intervention or a placebo resulted in very uncertain evidence on pre-eclampsia, gestational diabetes, preterm birth, or nephritic syndrome. It may reduce the risk of severe postpartum haemorrhage; however, only one study reported this outcome. It may also reduce the risk of low birthweight; however, the upper CI suggests that an increase in risk cannot be ruled out. Supplementation with vitamin D and calcium versus placebo or no intervention resulted in very uncertain evidence on preterm birth and low birthweight. Pre-eclampsia, gestational diabetes, and maternal adverse events were not reported in the only study included in this comparison. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D) resulted in very uncertain evidence on gestational diabetes and maternal adverse events (hypercalciuria) and uncertain evidence on preterm birth and low birthweight. Pre-eclampsia was not reported in the only study included in this comparison. All findings warrant further research. Additional rigorous, high-quality, and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Palacios C ，Kostiuk LL ，Cuthbert A ，Weeks J ... -  《Cochrane Database of Systematic Reviews》

Daily oral iron supplementation during pregnancy.

Iron and folic acid supplementation have been recommended in pregnancy for anaemia prevention, and may improve other maternal, pregnancy, and infant outcomes. To examine the effects of daily oral iron supplementation during pregnancy, either alone or in combination with folic acid or with other vitamins and minerals, as an intervention in antenatal care. We searched the Cochrane Pregnancy and Childbirth Trials Registry on 18 January 2024 (including CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, WHO's International Clinical Trials Registry Platform, conference proceedings), and searched reference lists of retrieved studies. Randomised or quasi-randomised trials that evaluated the effects of oral supplementation with daily iron, iron + folic acid, or iron + other vitamins and minerals during pregnancy were included. Review authors independently assessed trial eligibility, ascertained trustworthiness based on pre-defined criteria, assessed risk of bias, extracted data, and conducted checks for accuracy. We used the GRADE approach to assess the certainty of the evidence for primary outcomes. We anticipated high heterogeneity amongst trials; we pooled trial results using a random-effects model (average treatment effect). We included 57 trials involving 48,971 women. A total of 40 trials compared the effects of daily oral supplements with iron to placebo or no iron; eight trials evaluated the effects of iron + folic acid compared to placebo or no iron + folic acid. Iron supplementation compared to placebo or no iron Maternal outcomes: Iron supplementation during pregnancy may reduce maternal anaemia (4.0% versus 7.4%; risk ratio (RR) 0.30, 95% confidence interval (CI) 0.20 to 0.47; 14 trials, 13,543 women; low-certainty evidence) and iron deficiency at term (44.0% versus 66.0%; RR 0.51, 95% CI 0.38 to 0.68; 8 trials, 2873 women; low-certainty evidence), and probably reduces maternal iron-deficiency anaemia at term (5.0% versus 18.4%; RR 0.41, 95% CI 0.26 to 0.63; 7 trials, 2704 women; moderate-certainty evidence), compared to placebo or no iron supplementation. There is probably little to no difference in maternal death (2 versus 4 events, RR 0.57, 95% CI 0.12 to 2.69; 3 trials, 14,060 women; moderate-certainty evidence). The evidence is very uncertain for adverse effects (21.6% versus 18.0%; RR 1.29, 95% CI 0.83 to 2.02; 12 trials, 2423 women; very low-certainty evidence) and severe anaemia (Hb < 70 g/L) in the second/third trimester (< 1% versus 3.6%; RR 0.22, 95% CI 0.01 to 3.20; 8 trials, 1398 women; very low-certainty evidence). No trials reported clinical malaria or infection during pregnancy. Infant outcomes: Women taking iron supplements are probably less likely to have infants with low birthweight (5.2% versus 6.1%; RR 0.84, 95% CI 0.72 to 0.99; 12 trials, 18,290 infants; moderate-certainty evidence), compared to placebo or no iron supplementation. However, the evidence is very uncertain for infant birthweight (MD 24.9 g, 95% CI -125.81 to 175.60; 16 trials, 18,554 infants; very low-certainty evidence). There is probably little to no difference in preterm birth (7.6% versus 8.2%; RR 0.93, 95% CI 0.84 to 1.02; 11 trials, 18,827 infants; moderate-certainty evidence) and there may be little to no difference in neonatal death (1.4% versus 1.5%, RR 0.98, 95% CI 0.77 to 1.24; 4 trials, 17,243 infants; low-certainty evidence) or congenital anomalies, including neural tube defects (41 versus 48 events; RR 0.88, 95% CI 0.58 to 1.33; 4 trials, 14,377 infants; low-certainty evidence). Iron + folic supplementation compared to placebo or no iron + folic acid Maternal outcomes: Daily oral supplementation with iron + folic acid probably reduces maternal anaemia at term (12.1% versus 25.5%; RR 0.44, 95% CI 0.30 to 0.64; 4 trials, 1962 women; moderate-certainty evidence), and may reduce maternal iron deficiency at term (3.6% versus 15%; RR 0.24, 95% CI 0.06 to 0.99; 1 trial, 131 women; low-certainty evidence), compared to placebo or no iron + folic acid. The evidence is very uncertain about the effects of iron + folic acid on maternal iron-deficiency anaemia (10.8% versus 25%; RR 0.43, 95% CI 0.17 to 1.09; 1 trial, 131 women; very low-certainty evidence), or maternal deaths (no events; 1 trial; very low-certainty evidence). The evidence is uncertain for adverse effects (21.0% versus 0.0%; RR 44.32, 95% CI 2.77 to 709.09; 1 trial, 456 women; low-certainty evidence), and the evidence is very uncertain for severe anaemia in the second or third trimester (< 1% versus 5.6%; RR 0.12, 95% CI 0.02 to 0.63; 4 trials, 506 women; very low-certainty evidence), compared to placebo or no iron + folic acid. Infant outcomes: There may be little to no difference in infant low birthweight (33.4% versus 40.2%; RR 1.07, 95% CI 0.31 to 3.74; 2 trials, 1311 infants; low-certainty evidence), comparing iron + folic acid supplementation to placebo or no iron + folic acid. Infants born to women who received iron + folic acid during pregnancy probably had higher birthweight (MD 57.73 g, 95% CI 7.66 to 107.79; 2 trials, 1365 infants; moderate-certainty evidence), compared to placebo or no iron + folic acid. There may be little to no difference in other infant outcomes, including preterm birth (19.4% versus 19.2%; RR 1.55, 95% CI 0.40 to 6.00; 3 trials, 1497 infants; low-certainty evidence), neonatal death (3.4% versus 4.2%; RR 0.81, 95% CI 0.51 to 1.30; 1 trial, 1793 infants; low-certainty evidence), or congenital anomalies (1.7% versus 2.4; RR 0.70, 95% CI 0.35 to 1.40; 1 trial, 1652 infants; low-certainty evidence), comparing iron + folic acid supplementation to placebo or no iron + folic acid. A total of 19 trials were conducted in malaria-endemic countries, or in settings with some malaria risk. No studies reported maternal clinical malaria; one study reported data on placental malaria. Daily oral iron supplementation during pregnancy may reduce maternal anaemia and iron deficiency at term. For other maternal and infant outcomes, there was little to no difference between groups or the evidence was uncertain. Future research is needed to examine the effects of iron supplementation on other maternal and infant health outcomes, including infant iron status, growth, and development.

Finkelstein JL ，Cuthbert A ，Weeks J ，Venkatramanan S ，Larvie DY ，De-Regil LM ，Garcia-Casal MN ... -  《Cochrane Database of Systematic Reviews》

Cell salvage for the management of postpartum haemorrhage.

Postpartum haemorrhage (PPH), defined as a blood loss of 500 mL or more within 24 hours of birth, is the leading global cause of maternal morbidity and mortality. Allogenic blood transfusions are a critical component of PPH management, yet are often unfeasible, particularly in resource-poor settings where maternal morbidity is highest. Autologous cell salvage in the management of PPH has been proposed to combat limitations in access to allogenic blood and potential transfusion-related risks. This review examines the benefits and harms of using cell salvage for pregnant women during birth. To assess the benefits and harms of cell salvage when used during birth. We searched the CENTRAL, MEDLINE, Ovid Embase, and Global Index Medicus databases and the ICTRP and ClinicalTrials.gov trials registers. We also carried out reference checking and citation searching, and contacted study authors to identify all relevant studies. The latest search date was 8 February 2024. We included randomised controlled trials (RCTs) in pregnant women (24 weeks or more gestation) comparing use of cell salvage following caesarean or vaginal birth with routine care (defined as no cell salvage). We did not place any restrictions on mode of birth, ethnicity, race, socioeconomic status, education level, or place of residence. Critical outcomes for this review were risk of allogenic blood transfusion, risk of transfusion-related adverse reactions, risk of haemorrhage, transfer to higher level of care, length of hospitalisation, length of operation, and risk of sepsis. Important outcomes were estimated blood loss, blood loss ≥ 500 mL, blood loss ≥ 1000 mL, use of additional uterotonics or tranexamic acid, maternal death, postpartum haemoglobin concentration, change in haemoglobin, major surgery including hysterectomy, future major surgery, end-organ dysfunction or failure, amniotic fluid embolism, side effects, clotting abnormalities, maternal experience/satisfaction, maternal well-being, and breastfeeding. We assessed risk of bias using the Cochrane risk of bias tool (RoB 1) for each critical outcome from each RCT. We conducted a meta-analysis for each outcome where data were available from more than one study using a random-effects model. If data could not be analysed using meta-analysis, we synthesised results narratively using the Synthesis Without Meta-analysis (SWiM) guidance. We used GRADE to assess the certainty of evidence for each outcome. We included six RCTs with 3476 participants. All trials involved pregnant women having a caesarean birth. Three trials were conducted in high-income countries, and three were conducted in an upper-middle-income country. Allogenic blood transfusion Intraoperative cell salvage at caesarean birth may reduce the need for allogenic transfusions received by participants, although the 95% confidence interval (CI) includes the possibility of an increase in effect. Low-certainty evidence from three studies found the risk of donor transfusions was possibly lower in participants with cell salvage (risk ratio (RR) 0.45, 95% CI 0.15 to 1.33; P = 0.15, I2 = 33%; 3 RCTs, 3115 women; low-certainty evidence). The absolute risk of transfusion was very low in the studies (4% in women not treated with cell salvage and 2% in women treated with cell salvage). Transfusion-related adverse reactions The evidence is very uncertain about the risk of transfusion-related adverse reactions in participants with intraoperative cell salvage (RR 0.48, 95% CI 0.09 to 2.62; P = 0.39; 4 RCTs, 3304 women; very low-certainty evidence). Haemorrhage Two studies reported risk of haemorrhage and found that there was probably no difference between arms (RR 0.88, 95% CI 0.67 to 1.15; P = 0.36, I² = 0%; 2 RCTs, 3077 women; moderate-certainty evidence). Length of hospitalisation The evidence is very uncertain about whether interoperative cell salvage at caesarean birth affects length of hospitalisation. Three studies reported length of hospitalisation (MD -2.02 days, 95% CI -4.73 to 0.70; P = 0.15, I2 = 100%; 3 RCTs, 3174 women; very low-certainty evidence). Length of operation Two studies reported on length of operation. However, meta-analysis was not possible due to statistical heterogeneity and divergence of study findings; the direction of effect could not be determined. We evaluated the evidence as very low certainty. Sepsis One study reported risk of sepsis, finding that there was possibly no difference between arms (RR 1.00, 95% CI 0.43 to 2.29; P = 0.99; 1 RCT, 2990 women; low-certainty evidence). Estimated blood loss Cell salvage at caesarean birth may reduce blood loss. Two studies reported that estimated blood loss was possibly lower in women who had cell salvage compared to those who did not (MD -113.59 mL, 95% CI -130.41 to -96.77; P < 0.00001, I2 = 0%; 2 RCTs, 246 women; low-certainty evidence). Postpartum haemoglobin concentration Cell salvage at caesarean birth may increase day one postpartum haemoglobin. Three studies reported day one postpartum haemoglobin levels (MD 6.14 g/L, 95% CI 1.62 to 10.65; P = 0.008, I2 = 97%; 3 RCTs, 3070 women; low-certainty evidence). Amniotic fluid embolism Three trials reported risk of amniotic fluid embolism and no cases were observed (n = 3226 women). Cell salvage may reduce the need for allogenic blood transfusion, may reduce blood loss, and may increase day one postpartum haemoglobin in pregnant women having caesarean birth (low certainty). Cell salvage may make little to no difference to the risk of sepsis (low certainty) and probably makes little to no difference to the risk of haemorrhage (moderate certainty). The effect of cell salvage on risk of transfusion-related adverse reactions is very uncertain. The effect of cell salvage on the length of hospital stay was both clinically and statistically heterogenous, with a very low certainty of evidence. The effect of cell salvage on length of operation is divergent and meta-analysis was not possible due to significant statistical heterogeneity; the evidence is of very low certainty. No cases of amniotic fluid embolism were reported among the included trials. Studies in low- and middle-income settings are needed. This review had no dedicated funding. This review was registered with PROSPERO (CRD42024554204).

Dey T ，Brown D ，Cole MG ，Hill RA ，Chaplin M ，Huffstetler HE ，Curtis F ... -  《Cochrane Database of Systematic Reviews》