Establishment of reference intervals of complete blood count for twin pregnancy

BACKGROUND

Twin pregnancy poses a high risk, and its incidence has increased in recent years. Establishment of reference intervals of complete blood count (CBC) for women with twin pregnancies during pregnancy may aid in the prognosis of adverse outcomes.

METHODS

The incidence of complications and the intensity associated with adverse outcomes were analyzed in 1153 cases of twin pregnancy. A total of 253 cases in the twin pregnancy reference cohort were screened from all candidates after complications and adverse pregnancy outcomes were excluded. Complete blood count data were collected during the mid- and late-term of pregnancy and analyzed using SPSS to establish the reference intervals for peripheral blood in twin pregnancy.

RESULTS

Premature rupture of the membrane and pelvic inflammatory disease were highly positively correlated with adverse outcomes, with OR values of 3.31 and 3.81, respectively. Within the interval population with normal outcomes, red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), and platelet (PLT) values were lower in twin-pregnant women during gestation than in healthy nulligravida women, but the levels of white blood cells (WBC), neutrophils (NEU), and the NEU% increased, especially in the mid-term. The reference intervals of late-term pregnancy were validated using 20 twin pregnancies samples, and then utilized to determine the distinctive CBC characteristics in preterm birth (PTB) pregnancy. Absolute WBC and NEU values increased in PTB pregnancy based on our established reference intervals, which suggests that these may might be prognostic indicators of this adverse outcome.

CONCLUSION

Establishing the reference interval of blood cell-related indicators of normal twin pregnancy is helpful for the monitoring and prognosis of gestation.

Physiological and metabolic adaptations in pregnancy: importance of trimester-specific reference intervals to investigate maternal health and complications

Diagnosis, prognostication, and monitoring of maternal health throughout pregnancy relies on laboratory testing, including but not limited to key markers of thyroid, hepatic, cardiac, hematology, and renal function. Dynamic physiological processes during gestation significantly influence the maternal biochemistry that supports both the mother and fetus. Resultant changes in blood biochemistry alter the expected values of common laboratory tests. However, the importance of pregnancy-specific reference intervals for laboratory test result interpretation and appropriate monitoring of maternal health and complications is underappreciated. Most clinical laboratories continue to use non-pregnant adult reference intervals for laboratory test interpretation in pregnancy. The current review summarizes and critically evaluates the available literature regarding physiological and metabolic adaptations in pregnancy and their influence on common biomarkers of health and disease. The main laboratory parameters discussed include thyroid, hepatic, metabolic, renal, hematology, inflammatory, and cardiac markers. Considering the available data, further studies are urgently needed to establish trimester-specific reference intervals in healthy pregnant women on updated analytical platforms. Without such data, the standard of clinical laboratory service in pregnancy remains compromised and affects the quality of maternal-fetal healthcare.

Evaluating definitions for maternal fever as diagnostic criteria for intraamniotic infection in low-risk pregnancies

BACKGROUND

Conflicting statements by stakeholders in obstetric care have suggested different criteria for defining peripartum fever and suspected intraamniotic infection, which have not been evaluated.

METHODS

A case-control study of pregnancies between 35 and 41 weeks at a single tertiary care center between January 2016 and December 2017. Cases with pathology-confirmed chorioamnionitis were identified, and demographic data, risk factors, and neonatal outcomes were extracted from the medical record. The American College of Gynecology (ACOG) and National Institutes of Health (NIH) Workshop guidelines for identifying isolated maternal fever and suspected intraamniotic infection were applied, retrospectively. Odds ratios, sensitivity/specificity, and predictive value of each guideline for pathology-confirmed chorioamnionitis and for secondary outcomes of interest were determined.

RESULTS

943 mother-infant dyads were evaluated including 41 (4.3%) with pathology-confirmed chorioamnionitis. Among cases, 18 (43.9%) experienced any maternal temperature ≥38°C (100.4°F) with 12 (29.2%) and 8 (19.5%) cases meeting criteria for isolated maternal fever according to the ACOG and Workshop guidelines, respectively. Furthermore, the ACOG and Workshop guidelines correctly identified 6 (14.6%) and 3 (7.3%) of cases of pathology-confirmed chorioamnionitis with high agreement between definitions (κ = 0.63). Laboratory evaluation, antimicrobial exposure, and prolonged length of stay in offspring are substantially higher in cases as compared to controls.

CONCLUSIONS

Guidelines that rely on maternal fever definitions for the diagnosis of suspected intraamniotic infection exhibit high agreement with low sensitivity, but high specificity and negative predictive value for pathology-confirmed chorioamnionitis. Maternal temperature ≥38°C continues to drive clinical decision-making for both mother and offspring.

The maternal leukocyte count at admission for labor is indicative of early maternal postpartum infectious morbidity and adverse neonatal outcome

OBJECTIVES

Investigate the association between maternal leukocyte count at admission for labor and postpartum infectious maternal morbidity (PPIM) following vaginal delivery.

STUDY DESIGN

Retrospective cohort study, 2005-2017. Afebrile women, term, singleton, vaginal delivery included. Maternal leukocyte/differential at admission for labor and 24 h postpartum were analyzed as continuous values and quintiles. Pre/postpartum difference (Δleukocyte) was calculated. The primary outcome was maternal PPIM, early and late. The secondary outcome was adverse neonatal outcomes (ANO).

RESULTS

58,174 eligible deliveries out of168,979 (34.4 %); 1068 (1.8 %) women with PPIM. The rate rose linearly from 1.4 % for the lowest admission for labor leukocyte quantile to 2.7 % for the highest quantile, p for trend <0.001. The women with early PPIM had significantly higher admission levels of leukocytes (mean): 12.04 ± 3.43 vs. 11.18 ± 2.86 × 10^3/μl; neutrophils, 9.48 ± 3.46 vs. 8.40 ± 2.67 × 10^3/μl; and monocytes 0.76 ± 0.25 vs. 0.72 ± 0.23 × 10^3/μl); p < 0.001 for all. The mean leukocyte count for women with PPIM diagnosis, including only postpartum fever, was 12.06 ± 2.64; significantly higher than in the non-PPIM group, p = 0.014. A Δleukocyte value of >3.7 × 10^3/μl is significantly associated with PPIM, aOR 2.10 [1.82-2.41]. No significant association between leukocyte count or Δleukocyte and maternal readmission rate due to infectious complications. 386 neonates (0.7 %) had records of ANO and 64 neonates (0.1 %) had records of neonatal sepsis, positive linear association; p for trend < 0.001. The maternal Δleukocyte value of >3.7 × 10^3/μl was found to be significantly associated with the risk for ANO, aOR 1.5[1.19-1.90].

CONCLUSION

In healthy women, an elevated level of the leukocyte count at admission for labor and the Δleukocyte are significant risk predictors of PPIM and ANO.

Lymphopenia and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection Among Hospitalized Obstetric Patients

Lymphopenia does not identify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among asymptomatic patients admitted to an obstetrics unit or among obstetric patients under investigation for coronavirus disease 2019 (COVID-19).

Immune function during pregnancy varies between ecologically distinct populations

BACKGROUND AND OBJECTIVES

Among placental mammals, females undergo immunological shifts during pregnancy to accommodate the fetus (i.e. fetal tolerance). Fetal tolerance has primarily been characterized within post-industrial populations experiencing evolutionarily novel conditions (e.g. reduced pathogen exposure), which may shape maternal response to fetal antigens. This study investigates how ecological conditions affect maternal immune status during pregnancy by comparing the direction and magnitude of immunological changes associated with each trimester among the Tsimane (a subsistence population subjected to high pathogen load) and women in the USA.

METHODOLOGY

Data from the Tsimane Health and Life History Project (N = 935) and the National Health and Nutrition Examination Survey (N = 1395) were used to estimate population-specific effects of trimester on differential leukocyte count and C-reactive protein (CRP), a marker of systemic inflammation.

RESULTS

In both populations, pregnancy was associated with increased neutrophil prevalence, reduced lymphocyte and eosinophil count and elevated CRP. Compared to their US counterparts, pregnant Tsimane women exhibited elevated lymphocyte and eosinophil counts, fewer neutrophils and monocytes and lower CRP. Total leukocyte count remained high and unchanged among pregnant Tsimane women while pregnant US women exhibited substantially elevated counts, resulting in overlapping leukocyte prevalence among all third-trimester individuals.

CONCLUSIONS AND IMPLICATIONS

Our findings indicate that ecological conditions shape non-pregnant immune baselines and the magnitude of immunological shifts during pregnancy via developmental constraints and current trade-offs. Future research should investigate how such flexibility impacts maternal health and disease susceptibility, particularly the degree to which chronic pathogen exposure might dampen inflammatory response to fetal antigens.

LAY SUMMARY

This study compares immunological changes associated with pregnancy between the Tsimane (an Amazonian subsistence population) and individuals in the USA. Results suggest that while pregnancy enhances non-specific defenses and dampens both antigen-specific immunity and parasite/allergy response, ecological conditions strongly influence immune baselines and the magnitude of shifts during gestation.

Reference values for maternal total and differential leukocyte counts in different trimesters of pregnancy and the initial postpartum period in western Turkey

The aim of this study was to investigate alterations in the leukocyte and differential leukocyte counts in different trimesters of pregnancy and the initial postpartum period. The study population consisted of 40,325 pregnant women. A full blood count and automated differential leukocyte count were performed and all the haemogram results in the different trimesters of pregnancy were recorded. Percentiles were calculated using statistical software. A total of 82,786 complete blood count evaluations were performed in 40,325 subjects from the 6th to 41st week of pregnancy and in the initial postpartum period. The leukocyte counts increased from the 1st to the 3rd trimester and peaked in the initial postpartum period. Our reference values for the total and differential leukocyte counts may assist clinicians in distinguishing between leukocytosis and pathological elevation of the white blood cell count during pregnancy and the initial postpartum period. Impact statement Pregnancy requires profound adaptation by multiple systems to accommodate the demands of the developing foetus. Similar to all other systems, many haematological changes occur during pregnancy. Studies of normal variation in leukocyte counts were insufficient to distinguish normal from abnormal leukocyte counts during pregnancy and in the initial postpartum period, due to small numbers of patients and a lack of differential leukocyte counts. Without reference leukocyte levels, infections may be more difficult to assess during pregnancy and in the postpartum period. In this study, we report the 3rd, 5th, 10th, 50th, 95th and 99th percentile values for the total and differential leukocyte counts according to trimester in normal pregnancy and the initial postpartum period. Our reference values for the total and differential leukocyte counts in each trimester and the initial postpartum period may assist clinicians in distinguishing between normal leukocytosis and pathological elevation of the white blood cell count during pregnancy and the initial postpartum period. Our results may prevent misdiagnosis of physiological elevated leukocytes as bacterial infection that leads to unnecessary medication use that may compromise the foetus.

The effect of labor and delivery on white blood cell count

OBJECTIVE

To explore post-partum white blood cell (WBC) count, and possible factors affecting it.

STUDY DESIGN

Retrospective cohort analysis of 12 079 healthy women, delivering a singleton term fetus with an uncomplicated course of labor, delivery and puerperium. All women delivered in a single tertiary, university-affiliated medical center from 2009 to 2014. Student's t-test, Mann-Whitney's U-test, χ(2) test and ANOVA were used to compare between variables. Multiple variable analyses was performed to allow adjustment for potential covariates and confounders. The main outcome measures included post-partum WBC count and the difference in the post-partum versus ante-partum WBC count, in association to mode of delivery, type of analgesia, timing of cesarean delivery and perineal trauma.

RESULTS

The mean post-partum WBC count was 13.39 ± .24 × 10(9)/L (range 1.20-37.30 × 10(9)/L). There is a significant increase in the WBC after delivery (2.1 9 ± 3.33 × 10(9)/L) with significant differences according to mode of delivery (2.34 ± 3.48, 3.32 ± 3.69 and 1.6 0 ± 2.87 × 10(9)/L for spontaneous, assisted and cesarean deliveries. Multiple variables can affect post-partum leukocytosis, including: age, parity, gestational age, mode of delivery, type of anesthesia, timing of cesarean delivery in relation to labor onset and the extent of perineal trauma.

CONCLUSIONS

Post-partum leukocytosis is a physiological phenomenon with a wide normal variation and multiple contributing factors. As a single parameter, post-partum leukocytosis should not prompt further work up.