The effect of first trimester hemoglobin levels on pregnancy outcomes

Hemostatic biomarkers associated with postpartum hemorrhage: a systematic review and meta-analysis

Postpartum hemorrhage (PPH) is a leading cause of maternal morbi-mortality. Although obstetric risk factors are well described, the impact of predelivery hematologic and hemostatic biomarkers remains incompletely understood. In this systematic review, we aimed to summarize the available literature on the association between predelivery hemostatic biomarkers and PPH/severe PPH. Searching MEDLINE, EMBASE, and CENTRAL databases from inception to October 2022, we included observational studies on unselected pregnant women without bleeding disorder reporting on PPH and on predelivery hemostatic biomarkers. Two review authors independently performed title, abstract and full-text screening, upon which quantitative syntheses of studies reporting on the same hemostatic biomarker were conducted, calculating the mean difference (MD) between women with PPH/severe PPH and controls. A search on 18 October 2022 yielded 81 articles fitting our inclusion criteria. The heterogeneity between studies was considerable. With regard to PPH, the estimated average MD in the investigated biomarkers (platelets, fibrinogen, hemoglobin, Ddimer, activated partial thromboplastin time, and prothrombin time) were not statistically significant. Women who developed severe PPH had lower predelivery platelets than controls (MD = -26.0 109/L; 95% confidence interval, -35.8 to -16.1), whereas differences in predelivery fibrinogen concentration (MD = -0.31 g/L; 95% confidence interval, -0.75 to 0.13) and levels of factor XIII or hemoglobin were not statistically significant in women with and without severe PPH. Predelivery platelet counts were, on average, lower in women with severe PPH compared with controls, suggesting the potential usefulness of this biomarker for predicting severe PPH. This trial was registered at the International Prospective Register of Systematic Reviews as CRD42022368075.

Prepartum Anemia and Risk of Postpartum Hemorrhage: A Meta-Analysis and Brief Review

Postpartum hemorrhage (PPH) is responsible for 30% to 50% of maternal deaths. There is conflicting evidence if prepartum anemia facilitates PPH. A comprehensive analysis of studies describing their relation is missing. An extensive database search was conducted applying the terms "anemia" OR "hemoglobin" AND "postpartum hemorrhage." We used a random-effects meta-analysis model to estimate an overall odds ratio (OR) for PPH and prepartum anemia, separating studies that were conformant and non-conformant with the World Health Organization (WHO) definitions for anemia. The search yielded 2519 studies, and 46 were appropriate for analysis. The meta-analyses of WHO-conformant (n = 22) and non-conformant (n = 24) studies showed that the risk of PPH was increased when anemia was present. The ORs were 1.45 (CL: 1.23-1.71) for WHO-conformant studies, 2.88 (CL: 1.38-6.02) for studies applying lower thresholds for anemia, and 3.28 (CL: 2.08-5.19) for undefined anemia thresholds. PPH risk appeared to increase with lower anemia thresholds. Prepartum anemia is associated with an increased risk of PPH, an observation that is important regarding improved anemia correction strategies such as iron supplementation.

Evaluation of the association between haemoglobin levels and preterm birth at Khartoum, Sudan: A hospital-based study

Objective

The objective of this study was to determine the association between haemoglobin level and PB.

Methods

A cross-sectional study was conducted in Khartoum, Sudan. Questionnaires on demographics and medical and obstetric factors were completed. A logistic regression analysis was performed.

Results

Of the 1,716 pregnant women, approximately two-thirds (65.7%) had anaemia (haemoglobin < 11 g/dl) and six (0.3%) had severe anaemia (haemoglobin < 8 g/dl). Of the 1,716 women, 283 (16.5%) had a PB. In multivariable logistic regression, parity (AOR = 1.15, 95% CI = 1.09–1.21, P < 0.001) was positively associated with PB. Compared to those with haemoglobin levels of 10–10.9 g/dl, pregnant women with haemoglobin levels of 8–8.9 (AOR = 0.41, 95% CI = 0.22–0.77), 9–9.9 (AOR = 0.59, 95% CI = 0.38–0.91), and 11–11.9 g/dl (AOR = 0.53, 95% CI = 0.36–0.77) were at a lower risk of PB. Women with haemoglobin levels of 12–13 g/dl were at a higher risk of PB (AOR = 1.62, 95% CI = 1.06–2.45). There was no significant association between women with haemoglobin levels < 8 g/dl and > 13 g/dl and PB.

Conclusion

This study showed different levels of association between haemoglobin levels and PB.

Association of haemoglobin levels in the first trimester and at 26-30 weeks with fetal and neonatal outcomes: a secondary analysis of the Global Network for Women's and Children's Health's ASPIRIN Trial

OBJECTIVE

Limited data are available from low- and middle-income countries (LMICs) on the relationship of haemoglobin levels to adverse outcomes at different times during pregnancy. We evaluated the association of haemoglobin levels in nulliparous women at two times in pregnancy with pregnancy outcomes.

DESIGN

ASPIRIN Trial data were used to study the association between haemoglobin levels measured at 6⁺⁰ -13⁺⁶  weeks and 26⁺⁰ -30⁺⁰  weeks of gestation with fetal and neonatal outcomes.

SETTING

Obstetric care facilities in Pakistan, India, Kenya, Zambia, The Democratic Republic of the Congo and Guatemala.

POPULATION

A total of 11 976 pregnant women.

METHODS

Generalised linear models were used to obtain adjusted relative risks and 95% CI for adverse outcomes.

MAIN OUTCOME MEASURES

Preterm birth, stillbirth, neonatal death, small for gestational age (SGA) and birthweight <2500 g.

RESULTS

The mean haemoglobin levels at 6⁺⁰ -13⁺⁶  weeks and at 26-30 weeks of gestation were 116 g/l (SD 17) and 107 g/l (SD 15), respectively. In general, pregnancy outcomes were better with increasing haemoglobin. At 6⁺⁰ -13⁺⁶  weeks of gestation, stillbirth, SGA and birthweight <2500 g, were significantly associated with haemoglobin of 70-89 g/l compared with haemoglobin of 110-129 g/l The relationships of adverse pregnancy outcomes with various haemoglobin levels were more marked at 26-30 weeks of gestation.

CONCLUSIONS

Both lower and some higher haemoglobin concentrations are associated with adverse fetal and neonatal outcomes at 6⁺⁰ -13⁺⁶  weeks and at 26-30 weeks of gestation, although the relationship with low haemoglobin levels appears more consistent and generally stronger.

TWEETABLE ABSTRACT

Both lower and some higher haemoglobin concentrations were associated with adverse fetal and neonatal outcomes at 6-13 weeks and 26-30 weeks of gestation.