Association between anemia in pregnancy with low birth weight and preterm birth in Ethiopia: A systematic review and meta-analysis.

BACKGROUND: Anemia in pregnancy has been associated with a number of adverse birth outcomes, such as low birth weight (LBW) or preterm birth (PTB). However, the evidence from primary studies on anemia in pregnancy with LBW and PTB is contentious. Moreover, a systematic review and meta-analysis to summarize these findings have not been conducted for Ethiopia. This study aimed to synthesize the best available evidence and quantify the strength and direction of the association of anemia in Ethiopia. METHODS: This review examined women with singleton pregnancies with low birth weight (LBW) and preterm birth (PTB). We retrieved studies from PubMed, Wiley, Cochrane databases, and Google Scholar from inception to February 2, 2024. The World Health Organization (WHO) defines anemia in pregnancy as a low blood haemoglobin (Hgb) concentration below 11 g/dl or a hematocrit level of < 33%. When the newborn's weight was below 2500 g, LBW was considered. Preterm birth refers to the birth of a baby before 37 completed weeks of gestation. Meta-analysis was conducted using fixed and random effects models. The degree of heterogeneity, publication bias, and quality of the evidence of studies was assessed. RESULTS: There were 35 and 8 studies, with 14,319 and 3,265 respondents included in the meta-analysis for LBW and PTB, respectively. Neonates born to women who had normal Hgb levels were less likely to be LBW [pooled odds ratio (POR) = 0.22, 95% CI: (0.17, 0.28); I2 = 80%] (low-quality evidence). Neonates born to women with normal Hgb levels had a lower risk of PTB [POR = 0.22, 95% CI: 0.18, 0.28; I2 = 19%] (very low-quality evidence). The effect size estimate remained significant after sub-group analysis based on study design and province, except in two retrospective cohort studies for LBW. CONCLUSION: The findings suggest major implications for strengthening the implementation of nutrition policies to prevent anemia during pregnancy in Ethiopia. Further research is warranted to assess interventions that are effective in combating maternal anemia to reduce rates of LBW and PTB.

[Management of pregnant women with deficiency of factor VII. Report of one case]. / Manejo de embarazada con deficiencia de factor VII. A propósito de un caso.

Tissue Factor-Factor VII complex is essential in coagulation activation. Congenital factor VII deficiency is a rare disorder that has an autosomal recessive inheritance. Clinical presentations are heterogeneous, ranging from asymptomatic carriers to severe bleeding phenotypes with factor VII replacement therapy requirements. Treatments options are plasma derived and recombinants FVII concentrates or fresh frozen plasma in case that first options are not available. In pregnancy factor VII levels increase in women with mild and moderate deficiencies but not in severe deficiency. The management of pregnant women with factor FVII deficiency must be done by a multidisciplinary team of hematologist, obstetrics and anesthetist and should be guided by the women bleeding history, the coagulations test, levels of factor FVII and rout of delivery. We present the case of a 31-year-old pregnant woman who, due to an alteration in prothrombin time, is diagnosed with Factor VII deficiency and its respective obstetric management.

The effect of dates and honey extracts (phoenix dactylifera and apis mellifera) for increasing pregnant women's haemoglobin.

Objectives: To examine the effect of date fruit extract and honey in increasing haemoglobin levels in pregnant women. METHODS: The quasi-experimental study was conducted from July to August 2022 in Rumbai Pesisir Subdistric, Pekanbaru, Indonesia, and comprised anaemic pregnant women with haemoglobin levels <11gm/dl who were not consuming iron tablets or blood boosters. They were given honey and date extracts 2 tablespoons twice daily for two weeks. Haemoglobin level was checked at baseline and then at the end of each week of intervention. Data was analysed using SPSS version 20 and quantitative method by using bivariate analysis. RESULTS: Of the 50 women, 59(98%) were aged 20-35 years, and 1(2%) was aged >35 years. Besides, 21(42%) women were in the second trimester, 17(34%) in third, and 12(24%) in the first trimester of pregnancy. The increase in haemoglobin levels post-intervention was highly significant (p=0.0001). CONCLUSIONS: Date fruit extract and honey increased haemoglobin level of pregnant women.

Enhancing diagnostic accuracy for iron deficiency in pregnant women through mean reticulocyte volume.

BACKGROUND AND OBJECTIVES: Women are more prone to iron deficiency (ID) anemia when pregnant. The diagnostic use of mean reticulocyte volume (MRV) in identifying ID anemia during pregnancy has not been thoroughly investigated. The objective of this study is to evaluate the effectiveness of MRV in diagnosing ID in pregnant women. METHODS AND STUDY DESIGN: Firstly, MRV of 20 healthy female volunteers (healthy group) was measured on specific days for one month. Subsequently, clinical data from 724 pregnant women were thoroughly examined. These women were divided into two groups: 282 with ID (research group) and 442 without ID (control group). Parameters such as MRV, reticulocyte hemoglobin equivalent (RHE), red blood cell volume distribution width-standard deviation (RDW-SD), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hematocrit (HCT), reticulocyte count (RET), MRV/MCV ratio, and serum ferritin (SF) were analyzed and compared. RESULTS: MRV remained consistent over a period of one month for 20 healthy individuals. In addition, there were significant differences in MRV, RHE, RDW-SD, MCV, MCH, MCHC, HCT, RET, and MRV/MCV between the research group and control group. The receiver operating characteristic (ROC) analysis showed that the areas under the curve (AUCs) for these measures were as follow: 0.840, 0.837, 0.676, 0.654, 0.639, 0.602, 0.571, 0.550, and 0.816, respectively. Ultimately, there was a substantial disparity in MRV prior to and following therapy with oral iron treatments. CONCLUSIONS: In healthy women, MRV remains stable and is a reliable ID marker, which can be used to assess oral iron treatment effectiveness during pregnancy.

Screening for Iron Deficiency and Iron Deficiency Anemia During Pregnancy.

This JAMA Patient Page discusses the pros and cons of screening for iron deficiency and iron deficiency anemia during pregnancy.

Screening and Supplementation for Iron Deficiency and Iron Deficiency Anemia During Pregnancy: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.

Importance: In 2015 the US Preventive Services Task Force (USPSTF) found insufficient evidence to assess the balance of benefits and harms of routine screening and supplementation for iron deficiency anemia during pregnancy. Objective: To update the 2015 review on screening for iron deficiency anemia, in addition to iron deficiency during pregnancy, to inform the USPSTF. Data Sources: Ovid MEDLINE and Cochrane databases through May 24, 2023; surveillance through May 24, 2024. Study Selection: Randomized clinical trials of iron supplementation, screening effectiveness, treatment, and harms; observational studies of screening. Data Extraction and Synthesis: Dual review of abstracts, full-text articles, study quality, and data abstraction. Data were pooled using a random-effects model. Main Outcomes and Measures: Maternal and infant clinical outcomes, hematologic indices, and harms. Results: Seventeen trials (N = 24 023) on maternal iron supplementation were included. Iron supplementation was associated with decreased risk of maternal iron deficiency anemia at term (4 trials, n = 2230; 8.6% vs 19.8%; relative risk, 0.40 [95% CI, 0.26-0.61]; I2 = 20.5%) and maternal iron deficiency at term (6 trials, n = 2361; 46% vs 70%; relative risk, 0.47 [95% CI, 0.33-0.67]; I2 = 81.9%) compared with placebo or no iron supplement. There were no statistically significant differences in maternal quality of life, rates of gestational diabetes, maternal hemorrhage, hypertensive disorders of pregnancy, cesarean delivery, preterm birth, infant low birth weight, or infants small for gestational age for maternal iron supplementation compared with placebo or no supplementation. Harms of iron supplementation included transient gastrointestinal adverse effects. No studies evaluated the benefits or harms of screening for iron deficiency or iron deficiency anemia during pregnancy. Data on the association between iron status and health outcomes, such as hypertensive disorders of pregnancy and preterm birth, were very limited. Conclusions and Relevance: Routine prenatal iron supplementation reduces the incidence of iron deficiency and iron deficiency anemia during pregnancy, but evidence on health outcomes is limited or indicates no benefit. No studies addressed screening for iron deficiency or iron deficiency anemia during pregnancy. Research is needed to understand the association between changes in maternal iron status measures and health outcomes.

Hemostatic management of von Willebrand disease during childbirth with a plasma-derived von Willebrand factor/factor VIII concentrate.

BACKGROUND: Females with von Willebrand disease (VWD) do not show the same increases in von Willebrand factor and factor (F)VIII levels during pregnancy as females without VWD and are at higher risk of excessive bleeding associated with childbirth. Data on hemostatic management for childbirth in VWD patients are limited. OBJECTIVES: To evaluate the dosing, efficacy, and safety of plasma-derived von Willebrand factor/FVIII (wilate) for prevention of excessive bleeding associated with childbirth in females with any type of VWD. METHODS: Data for females with VWD who received wilate for hemostatic coverage for childbirth during 2 prospective clinical studies were analyzed. RESULTS: Ten females with VWD and a mean age at enrolment of 29.6 years were treated with wilate to prevent excessive bleeding associated with childbirth. Two patients had type 1, 4 had type 2 (2 2A, 1 2B, and 1 2M), and 4 had type 3 VWD. Of the 10 deliveries, 5 were by cesarean section. Patients received a mean of 9.5 infusions of wilate over 6.8 exposure days, with a mean total dose of 234 IU/kg per delivery and 25 IU/kg per infusion. Hemostatic management for all deliveries was rated excellent or good, with no excessive bleeding during delivery and no postpartum bleeding during the period of wilate treatment in any patient. Two patients experienced 8 possible or probable treatment-related adverse events; all were mild or moderate and resolved. No thromboembolic events were observed. CONCLUSION: The results of this case series indicate that wilate provided effective hemostatic cover for childbirth in females with VWD during delivery and postpartum.

Rituximab as a treatment for refractory immune thrombocytopenia during pregnancy.

Immune thrombocytopenia (ITP) is most common in women during their reproductive years. When a low platelet count occurs for the first time during pregnancy, the differential diagnosis includes pregnancy-specific conditions. Although ITP is the most common cause of thrombocytopenia early in pregnancy, pregnancy-related thrombocytopenia develops mainly in late gestation. As maternal and neonatal outcomes are usually favourable, ITP per se is not a contraindication for pregnancy. We report the case with a literature review of patient with ITP, whose diagnosis was established in early pregnancy. This condition was refractory to first-line treatments, such as high-dose steroids and intravenous immunoglobulin and other splenectomy-sparing approaches, as rituximab, having the control been reached on the third trimester after splenectomy. Although not effective in this case, we still believe that rituximab should be considered before surgery during pregnancy.

Effectiveness, reliability, and validity of new Japanese diagnostic criteria for obstetrical disseminated intravascular coagulation.

Since July 2022, obstetrical disseminated intravascular coagulation (DIC) in Japan has been diagnosed based on the new criteria (tentative version), which assesses the main underlying disease, fibrinogen level, and fibrin/fibrinogen degradation products or D-dimer level. In June 2024, the tentative version underwent minor revision and the final version was released. The previous Japanese criteria assessed underlying disease, clinical symptoms, and various laboratory findings. This study aimed to prove the effectiveness, reliability, and validity of the new criteria (final version). We analyzed 212 women with singleton pregnancies who delivered after 22 gestational weeks and experienced blood loss ≥ 1000 mL during vaginal delivery or ≥ 2000 mL during cesarean section. Those with missing laboratory findings before receiving blood transfusion at delivery were excluded. In the obstetrical DIC group, the frequency of fibrinogen levels < 150 mg/dL was significantly higher than in the control group (90% vs. 5%, p < 0.0001), as was the frequency of scores ≥ 8 according to the previous Japanese criteria (100% vs. 10%, p < 0.0001). Cronbach alpha was 0.757 and Spearman's rank-order correlation was 0.558 between the new and previous criteria. In conclusion, we proved the effectiveness, reliability, and validity of the Japanese new criteria (final version) to diagnose obstetrical DIC.

Viscoelastic testing guided coagulation management in factor VII deficiency for spinal anaesthesia and caesarean section.

The risks and benefits of spinal anaesthesia must be assessed in patients with coagulation disorders. A woman in her 20s with congenital factor VII (FVII) deficiency (31%) was admitted at 38 weeks for caesarean delivery. A rotational thromboelastometry (ROTEM) analysis showed normal coagulation and spinal anaesthesia was performed safely. A repeated ROTEM analysis after haemostasis and uterine closure showed normal coagulation without fibrinolysis. No prophylactic FVII was administered, resulting in a cost savings of US$12 884. FVII level did not predict bleeding or fibrinolysis and FVII and tranexamic acid were not indicated.

How does maternal anemia affect the levels of umbilical cord brain-derived neurotrophic factor?

OBJECTIVE: In this study, we aimed to evaluate the effect of maternal iron deficiency anemia on the umbilical cord level of brain-derived neurotrophic factor (BDNF), which plays a very important role in the central nervous system. METHODS: Our research was planned as a quantitative, prospective, and analytical type of study. A total of 90 volunteers, term, singleton pregnant hospitalized in the Health Sciences University Ümraniye Training and Research Hospital Gynecology and Obstetrics Clinic between September 2021 and August 2022 were included in this study. While 45 of these pregnants were pregnant women with iron deficiency anemia (hemoglobin ≤ 110 g/L and serum ferritin level ≤ 12 µg/L), 45 cases were in the control group without iron deficiency anemia (hemoglobin > 110 g/L, serum ferritin > 12 µg/L). When pregnant were admitted to the hospital, blood samples were taken to analyze hemoglobin, mean cell volume (MCV), iron, unsaturated iron binding capacity, total iron binding capacity, serum ferritin, transferrin, and CRP levels. Also, we noted the maternal age, gravida, parity, birth weight, head circumference, type of birth, 1. minute Apgar score, and 5. minute Apgar score. During the delivery; after the umbilical cord had been clamped and cut, we took 5 cc of umbilical cord blood. Then, we put it in the serum-separating laboratory tubes. After we centrifuged these blood samples, we put the serum parts in the Eppendorf tubes to be stored at -80 degrees Celsius. At the end of the study, we calculated the level of BDNF using special human brain-derived neurotrophic factor ELISA kits. The umbilical cord BDNF levels of the maternal iron deficiency anemia group and the control group were compared statistically. RESULTS: When we evaluated the fetal umbilical cord BDNF values of 90 participants, the median value BDNF in the babies of 45 anemic mothers was 3.16 (IQR 0.73), and the median BDNF value of the babies of 45 healthy mothers was 5.37 (IQR 1.02). We found a statistical difference between BDNF and hemoglobin, hematocrit, MCV, and iron values between these two groups. CONCLUSION: In conclusion, the BDNF value of the babies of healthy individuals is higher than that of anemic individuals. Our study showed that the amount of BDNF in the umbilical cord blood was significantly affected by maternal iron deficiency anemia.

The influence of hematological profiles on the transfusion management and mortality risk of mothers presenting to the obstetric unit of a South African tertiary medical facility.

BACKGROUND: Laboratory results are frequently abnormal in pregnant mothers. Abnormalities usually relate to pregnancy or associated complications. Hematological abnormalities and age in pregnancy may increase the likelihood for transfusion and mortality. STUDY DESIGN AND METHODS: Hematological profiles and transfusion history of pregnant mothers presenting to a tertiary hospital, were evaluated over 2 years. Age, anemia, leukocytosis and thrombocytopenia were assessed for transfusion likelihood. Iron deficiency and coagulation were assessed in transfused patients. Anemia, leukocytosis, thrombocytopenia, human immunodeficiency virus (HIV) and transfusion were assessed for mortality likelihood. RESULTS: There were 12,889 pregnant mothers included. Mothers <19-years-old had the highest prevalence of anemia (31.5%) and proportion of transfusions (19%). The transfusion likelihood was increased in mothers with anemia (odds ratios [OR] = 6.41; confidence intervals at 95% [95% CI] 5.46-7.71), leukocytosis (OR = 2.35; 95% CI 2.00-2.76) or thrombocytopenia (OR = 2.71; 95% CI 2.21-3.33). Mothers with prolonged prothrombin times received twice as many blood products as their normal counterparts (p = .03) and those with iron deficiency anemia five times more blood products (p < .001). Increased likelihood for mortality was seen in patients with anemia (OR = 4.15, 95% CI 2.03-8.49), leukocytosis (OR = 2.68; 95% CI 1.19-6.04) and those receiving blood transfusion (OR = 3.6, 95% CI 1.75-7.47). DISCUSSION: Adolescence, anemia, leukocytosis and thrombocytopenia expose mothers to a high risk for transfusion and/or mortality. These risk factors should promptly trigger management and referral of patients. Presenting hematological profiles are strong predictors of maternal outcome and transfusion risk.

Is there a correlation between prepartum anaemia and an increased likelihood of developing postpartum depression? A prospective observational study.

PURPOSE: Postpartum depression (PPD) represents a significant challenge to maternal and child health. Early screening for PPD is essential to ensure appropriate treatment and support. The present study aimed to assess whether maternal prepartum anaemia influences the likelihood of developing PPD within 3 days after delivery. METHODS: In collaboration with the Department of Psychiatry, a prospective observational study was carried out at the Gynaecology and Obstetrics Department of the University of Campania "Luigi Vanvitelli" in Naples. A total of 211 full-term pregnant women were enrolled, and their predelivery haemoglobin value was recorded. Women with gestational diabetes, hypertension, pre-eclampsia, intrauterine growth restriction, intellectual disability, or pre-existing diagnosis of psychotic spectrum disorder were excluded. Participants provided written informed consent to fill out the Edinburgh Postnatal Depression Scale (EPDS) 3 days after delivery. EPDS cut-off score of ≥ 10 was used to identify women at risk of developing PPD. Statistical analysis was performed using Student's t test, the Wilcoxon Rank Sum test, and linear regression. RESULTS: The participants were categorized into 2 groups based on EPDS scores: EPDS < 10 (176 patients) or EPDS ≥ 10 (35 patients). The two groups showed homogeneity in terms of socio-demographic and clinical characteristics. The mean haemoglobin values of anaemic pregnant women in the EPDS ≤ 10 group (11.78 ± 1.39 g/dl) and the EPDS > 10 group (11.62 ± 1.27 g/dl) were not significantly different (p = 0.52). There was no significant correlation between the predelivery haemoglobin value and the EPDS postpartum score of < 10 or ≥ 10. The Wilcoxon Rank Sum test and the estimated coefficients of the linear regression model did not show any statistical relationship between continuous and binary haemoglobin values. CONCLUSIONS: Our study found that maternal prepartum anaemia did not negatively impact the likelihood of developing postpartum depressive symptoms, in the first 3 days after delivery.

Management of pregnancy and delivery in congenital fibrinogen disorders: communication from the ISTH SSC Subcommittee on Factor XIII and Fibrinogen.

Congenital fibrinogen disorders (CFDs) are a heterogeneous group of rare congenital quantitative and/or qualitative fibrinogen deficiencies. The spectrum of molecular anomalies is broad, leading to several subtypes of fibrinogen disorders (ie, afibrinogenemia, hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia). Pregnancy in women with CFDs is a high-risk clinical situation, with an increased tendency for miscarriages, bleeding, and thrombosis. Even though it is well established that management of such pregnancies requires a multidisciplinary approach involving specialists (hematologists and maternal/fetal medicine experts with expertise in the management of inherited bleeding disorders), specific guidelines are lacking. In this International Society on Thrombosis and Haemostasis (ISTH) Scientific and Standardization Committee communication, we aim to propose an expert consensus opinion with literature evidence where available on the strategy for management of pregnancy, delivery, and puerperium in CFDs.

Prevalence and aetiologies of anaemia among first trimester pregnant women in Sri Lanka; the need for revisiting the current control strategies.

BACKGROUND: The Sustainable development goals, which focus strongly on equity, aim to end all forms of malnutrition by 2030. However, a significant cause of intergenerational transfer of malnutrition, anaemia in pregnancy, is still a challenge. It is especially so in the low- and middle-income settings where possible context-specific aetiologies leading to anaemia have been poorly explored. This study explores the prevalence of etiological factors significantly contributing to anaemia in pregnancy in Sri Lanka, a lower-middle-income country with a high prevalence of malnutrition albeit robust public health infrastructure. METHODS: All first-trimester pregnant women registered in the public maternal care programme in the Anuradhapura district from July to September 2019 were invited to participate in Rajarata Pregnancy Cohort (RaPCo). After a full blood count analysis, high-performance liquid chromatography, peripheral blood film examination, serum B12 and folate levels were performed in anaemic participants, guided by an algorithm based on the red cell indices in the full blood count. In addition, serum ferritin was tested in a random subsample of 213 participants. Anaemic women in this subsample underwent B12 and folate testing. RESULTS: Among 3127 participants, 14.4% (95%CI 13.2-15.7, n = 451) were anaemic. Haemoglobin ranged between 7.4 to 19.6 g/dl. 331(10.6%) had mild anaemia. Haemoglobin ≥13 g/dl was observed in 39(12.7%). Microcytic, normochromic-normocytic, hypochromic-normocytic and macrocytic anaemia was observed in 243(54%), 114(25.3%), 80(17.8%) and two (0.4%) of full blood counts in anaemic women, respectively. Microcytic anaemia with a red cell count ≥5 * 106 /µl demonstrated a 100% positive predictive value for minor haemoglobinopathies. Minor hemoglobinopathies were present in at least 23.3%(n = 105) of anaemic pregnant women. Prevalence of iron deficiency, B12 deficiency and Southeast Asian ovalocytosis among the anaemic was 41.9% (95%CI 26.4-59.2), 23.8% (95%CI 10.6-45.1) and 0.9% (95%CI 0.3-2.3%), respectively. Folate deficiency was not observed. CONCLUSION: Even though iron deficiency remains the primary cause, minor hemoglobinopathies, B 12 deficiency and other aetiologies substantially contribute to anaemia in pregnancy in this study population. Public health interventions, including screening for minor hemoglobinopathies and multiple micronutrient supplementation in pregnancy, should be considered in the national programme for areas where these problems have been identified.

Effectiveness of Caplacizumab Nanobody in Acquired Thrombotic Thrombocytopenic Purpura Refractory to Conventional Treatment.

Acquired thrombocytopenic thrombotic purpura (aTTP) is an autoantibody-mediated disease against the enzyme A Disintegrin and Metalloprotease domain with ThromboSpondin-1 type motif 13, which until now has been treated with plasma exchange (PEX) and corticosteroids. A 29-year-old female patient, who presented with aTTP in the context of pregnancy, has developed multiple relapses after treatment with PEX, corticosteroids, and rituximab. Recently, caplacizumab, a nanobody against von Willebrand factor, has been approved for the treatment of aTTP. In our patient, caplacizumab achieved better disease control, with a lower platelet count restoration time, days of PEX and hospitalization duration, as compared to standard therapy, reproducing the results of clinical trials. Caplacizumab represents a significant advance in the treatment of aTTP, especially in cases of recurrent relapses.

Pregnancy in special populations: challenges and solutions practical aspects of managing von Willebrand disease in pregnancy.

Pregnancy and childbirth pose an important hemostatic challenge for women with von Willebrand disease (VWD) and can be associated with an increased risk of maternal and neonatal bleeding complications. VWD is a genetically and clinically heterogeneous bleeding disorder caused by a deficiency or an abnormality in the function of von Willebrand factor. Understanding inheritance pattern, hemostatic response to pregnancy, and response to treatment is essential for provision of individualized obstetric care and optimal outcome. A multidisciplinary approach to management with a close liaison between the obstetric team and the hemophilia treatment center is required for continuity of care from preconception counseling through to antenatal, peripartum, and postpartum care. Delivery plan must be coordinated by the multidisciplinary team and include decisions on place and mode of delivery, implementation of safe analgesia/anesthesia, and peripartum hemostasis. In this clinical case-based review, we aim to deliver evidence-based practical guidance for challenges encountered during pregnancy and management of childbirth and puerperium.

Mild Anemia May Affect Thyroid Function in Pregnant Chinese Women During the First Trimester.

Background: Pregnant women are often susceptible to anemia, which can damage the thyroid gland. However, compared with moderate and severe anemia, less attention has been paid to mild anemia. The purpose of this study was to evaluate the effect of mild anemia on the thyroid function in pregnant women during the first trimester. Methods: A total of 1,761 women in the first trimester of their pregnancy were enrolled from Shenyang, China, and divided into mild anemia and normal control groups based on their hemoglobin levels. Thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) levels were compared between the two groups. Results: The TSH levels of pregnant women with mild anemia were higher than those of pregnant women without mild anemia (p < 0.05). Normal control women were selected to set new reference intervals for TSH, FT3, and FT4 levels during the first trimester, which were 0.11-4.13 mIU/l, 3.45-5.47 pmol/l, and 7.96-16.54 pmol/l, respectively. The upper limit of TSH 4.13 mU/l is close to the upper limit 4.0 mU/l recommended in the 2017 American Thyroid Association (ATA) guidelines, indicating that exclusion of mild anemia may reduce the difference in reference values from different regions. Mild anemia was related to 4.40 times odds of abnormally TSH levels (95% CI: 2.84, 6.76) and 5.87 increased odds of abnormal FT3 (95% CI: 3.89, 8.85). The proportion of hypothyroidism and subclinical hypothyroidism in patients with mild anemia was higher than that in those without anemia (0.6% vs. 0, p = 0.009; 12.1% vs. 1.9%, p < 0.001). Mild anemia was related to 7.61 times increased odds of subclinical hypothyroidism (95% CI: 4.53, 12.90). Conclusions: Mild anemia may affect thyroid function during the first trimester, which highlights the importance of excluding mild anemia confounding when establishing a locally derived specific reference interval for early pregnancy.