Pregnancy-specific reference intervals for C-reactive protein improve diagnostic accuracy for infection: A longitudinal study

Intimate partner violence during pregnancy: To screen or not to screen?

Intimate partner violence (IPV) during pregnancy emerges as a compelling and urgent concern within the domain of public health, casting a long shadow over a substantial cohort of women. Its pernicious consequences extend beyond the individual, enveloping the well-being of both the mother and the fetus, giving rise to an elevated risk of preterm birth, low birth weight, fetal harm, and maternal psychological distress, including depression, anxiety, post-traumatic stress disorder, and, tragically, maternal mortality. Despite the prevalence of IPV being comparable to other conditions like gestational diabetes and preeclampsia, a universal screening protocol for IPV remains absent globally. We reviewed the clinical guidelines and practices concerning IPV screening, painstakingly scrutinizing their contextual nuances across diverse nations. Our study unveils multifaceted challenges of implementing universal screening. These hurdles encompass impediments to victim awareness and disclosure, limitations in healthcare providers' knowledge and training, and the formidable structural barriers entrenched within healthcare systems. Concurrently, we delve into the potential biomarkers intricately entwined with IPV. These promising markers encompass inflammatory indicators, epigenetic and genetic influences, and a diverse array of chemical compounds and proteins. Lastly, we discussed various criteria for universal screening including (1) valid and reliable screening tool; (2) target population as pregnant women; (3) scientific evidence of screening programme; and (4) integration of education, testing, clinical services, and programme management to minimise the challenges, which are paramount. With the advancement of digital technology and various biomarkers identification, screening and detecting IPV in clinical settings can be conducted systemically. A systems-level interventions with academia-community-indutrial partnerships can help connect pregnant women to desire support services to avoid adverse maternal and child health outcomes.

C-reactive protein across pregnancy in individuals exposed to childhood maltreatment: The role of psychological and physical sequelae of maltreatment

BACKGROUND

Childhood maltreatment (CM) has long-term consequences for the regulation of stress biology which are particularly pronounced when mental and physical health sequelae have manifested. C-reactive protein (CRP) has been shown to be elevated in the non-pregnant state in association with CM as well as in the setting of CM-associated mental and physical health sequelae. In pregnancy, however, the association between CM and CRP is less clear. We sought to examine this association and consider the moderating role of four common health sequelae of CM (maternal depressive symptoms, overweight/obesity, smoking, and hypertensive disorders during pregnancy).

METHODS

A prospective, longitudinal study of 744 healthy pregnant participants was conducted, with analyses focusing on a sample of 643 participants. CM was assessed with the Childhood Trauma Questionnaire (CTQ) and categorized by whether no vs. one or more moderate to severe CM experiences were reported. Blood serum concentrations of CRP, maternal depression severity (continuous scores of the Center for Epidemiologic Studies Depression Scale, CES-D) and smoking during pregnancy were assessed in early (16.52 ± 2.50 weeks gestation) and late (33.65 ± 1.18 weeks gestation) pregnancy. Pre-pregnancy body mass index (BMI) was obtained at the first study visit and hypertensive disorders diagnosed during pregnancy were obtained from the medical record. Linear mixed effects models were employed to assess main effects of CM as well as interactive effects of CM and four common CM-associated sequelae as well as a sum score of these sequelae on repeatedly measured CRP concentration. In secondary analyses, we conducted latent class analyses to classify participants based on their specific experiences of childhood abuse and/or neglect and to assess the association of these CM subgroups with CM sequelae and CRP. All analyses were adjusted for potential confounders (maternal race and ethnicity and education/income).

RESULTS

CRP concentration decreased from early to late pregnancy (B = -0.06, SE = 0.01, p < 0.001). While there was no main effect of CM on CRP (p = 0.49), the interaction of CM and depressive symptoms was associated with CRP concentration (B = 0.08, SE = 0.04, p < 0.05), indicating higher CRP across pregnancy with increasing levels of depressive symptoms during pregnancy in participants with CM experience. This interaction was mainly driven by participants with co-occurring physical and emotional maltreatment. For none of the other CM-associated sequelae a statistically significant interaction with CM on CRP concentration was observed.

CONCLUSIONS

These results add to the growing empirical evidence suggesting higher inflammation during pregnancy in participants exposed to CM who experience depressive symptoms and highlight the detrimental effects of multiple co-occurring experiences of maltreatment. Given the negative consequences of chronic inflammatory state for the mother and the developing fetus, monitoring and treating psychiatric sequelae during pregnancy among participants exposed to CM is potentially an important opportunity to dampen long-term detrimental effects of CM, serving at least two generations.

Adverse perinatal outcomes are strongly associated with degree of abnormality in uterine artery Doppler pulsatility index

OBJECTIVE

To investigate the association between varying degrees of abnormality in the Doppler uterine artery pulsatility index (UtA-PI) and adverse perinatal outcome.

METHODS

This was a prospective study of women with a singleton, non-anomalous pregnancy in whom UtA-PI was measured universally in midpregnancy and who gave birth in Oxford University Hospitals, Oxford, UK, between 2016 and 2023. Relative risk ratios (RRR) for the primary outcomes of extended perinatal mortality and live birth with a severe small-for-gestational-age (SGA) neonate were calculated using multinomial logistic regression, for early preterm birth (before 34 + 0 weeks' gestation) and late preterm/term birth (at or after 34 + 0 weeks). Risks were also investigated for iatrogenic preterm birth and a composite adverse outcome before 34 + 0 weeks.

RESULTS

Overall, 33 364 pregnancies were included in the analysis. Compared to those with a normal UtA-PI, the risk of extended perinatal mortality with delivery before 34 + 0 weeks was higher in women with UtA-PI ≥ 90th percentile (RRR, 4.7 (95% CI, 2.7-8.0); P < 0.001), but this was not demonstrated in births at or after 34 + 0 weeks. The risk of live birth with severe SGA was associated strongly with abnormal UtA-PI for early births (RRR, 26.0 (95% CI, 11.6-58.2); P < 0.001) and later births (RRR, 2.3 (95% CI, 1.8-2.9); P < 0.001). Women with raised UtA-PI were more likely to have an early iatrogenic birth (RRR, 7.8 (95% CI, 5.5-11.2); P < 0.001). For each outcome before 34 + 0 weeks and the composite outcome, the risk increased significantly in association with the degree of abnormality in the UtA-PI (from < 90th, 90-94th, 95-98th to ≥ 99th percentile) (Ptrend < 0.001). When using the 90th percentile as opposed to the 95th, there was a significant improvement in the overall predictive accuracy (as determined by the area under the receiver-operating-characteristics curve) for the composite adverse outcome (χ2 = 6.64, P = 0.01) and iatrogenic preterm birth (χ2 = 4.10, P = 0.04).

CONCLUSIONS

Elevated UtA-PI is a key predictor of iatrogenic preterm birth, severe SGA and perinatal loss up to 34 + 0 weeks' gestation. The 90th percentile for UtA-PI should be used, and management should be tailored according to the degree of abnormality, as pregnancies with very raised UtA-PI measurement constitute a group at extreme risk of adverse outcome. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Correlating maternal and cord-blood inflammatory markers and BDNF with human fetal brain activity recorded by magnetoencephalography: An exploratory study

Background

During gestation, the brain development of the fetus is affected by many biological markers, where inflammatory processes and neurotrophic factors have been of particular interest in the past decade.

Aim

This exploratory study is the first attempt to explore the relationships between biomarker levels in maternal and cord-blood samples and human fetal brain activity measured with non-invasive fetal magnetoencephalography (fMEG).

Method

Twenty-three women were enrolled in this study for collection of maternal serum and fMEG tracings immediately prior to their scheduled cesarean delivery. Twelve of these women had a preexisting diabetic condition. At the time of delivery, umbilical cord blood was also collected. Biomarker levels from both maternal and cord blood were measured and subsequently analyzed for correlations with fetal brain activity in four frequency bands extracted from fMEG power spectral densities.

Results

Relative power in the delta, alpha, and beta frequency bands exhibited moderate-sized correlations with maternal BDNF and cord-blood CRP levels before and after adjusting for confounding diabetic status. These correlations were negative for the delta band, and positive for the alpha and beta bands. Maternal CRP and cord-blood BDNF and IL-6 exhibited negligible correlations with relative power in all four bands. Diabetes did not appear to be a strong confounding factor affecting the studied biomarkers.

Conclusions

Maternal BDNF levels and cord-blood CRP levels appear to have a direct correlation to fetal brain activity. Our findings indicate the potential use of these biomarkers in conjunction with fetal brain electrophysiology to track fetal neurodevelopment.

Maternal pre-pregnancy weight status and gestational weight gain in association with child behavior: The mediating role of prenatal systemic inflammation

BACKGROUND AND AIMS

Maternal pre-pregnancy obesity and excessive gestational weight gain (EGWG) may predispose children to behavioral problems through increased prenatal inflammation. We investigated the association between maternal body mass index (BMI) and gestational weight gain (GWG), and child behavioral problems (primary aim), and the mediating role of prenatal inflammation (secondary aim).

METHODS

We used self-reported pre-pregnancy BMI and estimated-GWG data (N = 1137) from a longitudinal cohort study. Maternal serum C-reactive protein (CRP) was measured in the 3rd-trimester. Parent-reported Child Behavior Checklist (CBCL) was used to assess child internalizing and externalizing behaviors at 3-years-of-age. We used analysis of covariance (ANCOVA), multiple linear regression, and mediation analyses for data analysis.

RESULTS

Maternal obesity (F = 21.98, df 3836), EGWG (F = 6.53, df 2764), and their combination (F = 18.51, df 3764) were associated with the 3rd trimester CRP, but not child behavior in the whole sample. Maternal underweight was associated with withdrawal problems in all children (β = 0.56, 95%CI, 0.11,1.00) and aggressive behaviors in female children (β = 2.59, 95%CI, 0.28,4.91). Obesity had a significant association with externalizing behaviors in female children after controlling for maternal CRP (β = 3.72, 95%CI, 0.12,7.32). Both inadequate and EGWG were associated with somatic complaints in male children (β = 0.50, 95%CI, 0.05,0.95; β = 0.36, 95%CI, 0.01,0.71, respectively). Combined obesity/EGWG was associated with externalizing (β = 6.12, 95%CI, 0.53,11.70) and aggressive (β = 4.23, 95%CI, 0.90,7.56) behaviors in female children. We found no significant effects through CRP.

CONCLUSIONS

Maternal pre-pregnancy BMI and GWG showed sex-specific associations with child behavioral problems. Prenatal CRP, although increased in obesity and EGWG, did not mediate these associations.

Maternal fibrinogen/fibrin degradation products to high density lipoprotein cholesterol ratio for predicting delivery of small and large for gestational age infants: a pilot study

BACKGROUND

The purpose of this pilot study was to investigate associations between fibrinogen/fibrin degradation products (FDP) to high density lipoprotein-cholesterol (HDL-C) ratio (FHR) of mothers and the risk of delivering large/small for gestational age (LGA/SGA) infants and to evaluate the predictive power of FHR on LGA/SGA.

METHODS

This study retrospectively reviewed 11,657 consecutive women whose lipid profiles and FDP levels were investigated at the time of admission for delivery at a specialized hospital. The FHR was calculated, and perinatal outcomes, including clinical parameters, were analyzed.

RESULTS

The prevalence of SGA was 9% (n = 1034), and that of LGA was 15% (n = 1806) in this cohort study. FHR was significantly lower in women who delivered SGA infants (4.0 ± 3.2 vs. 4.7 ± 3.3 mg/mmol, P < 0.01) and higher in women who delivered LGA infants (5.7 ± 3.8 vs. 4.7 ± 3.3 mg/mmol, P < 0.01) compared with those who delivered infants of normal size for their gestational age. Women in the top quartile for FHR (> 5.9 mg/mmol) had a 2.9-fold higher risk of delivering LGA infants [adjusted odds ratio (OR) = 2.9, P < 0.01] and a 47% lower risk of delivering SGA infants (adjusted OR = 0.47, P < 0.01) than those in the bottom quartile (< 2.7 mg/mmol). In addition, adding FHR to the conventional models significantly improved the area under the curve for the prediction of delivering LGA (0.725 vs. 0.739, P < 0.01) and SGA (0.717 vs. 0.727, P < 0.01) infants.

CONCLUSION

These findings suggest that the FHR calculated in late pregnancy is an innovative predictor of delivering LGA and SGA infants. Combining FHR with perinatal parameters could thus enhance the predictive ability for predicting the delivery of LGA/SGA infants.

Elevated levels of renal function tests conferred increased risks of developing various pregnancy complications and adverse perinatal outcomes: insights from a population-based cohort study

OBJECTIVES

Physiological changes during pregnancy can affect the results of renal function tests (RFTs). In this population-based cohort study, we aimed to establish trimester-specific reference intervals (RIs) of RFTs in singleton and twin pregnancies and systematically investigate the relationship between RFTs and adverse pregnancy outcomes.

METHODS

The laboratory results of the first- and third-trimester RFTs, including blood urea nitrogen (BUN), serum uric acid (UA), creatinine (Crea) and cystatin C (Cys C), and the relevant medical records, were retrieved from 29,328 singleton and 840 twin pregnant women who underwent antenatal examinations from November 20, 2017 to January 31, 2021. The trimester-specific RIs of RFTs were estimated with both of the direct observational and the indirect Hoffmann methods. The associations between RTFs and pregnancy complications as well as perinatal outcomes were assessed by logistic regression analysis.

RESULTS

Maternal RFTs showed no significant difference between the direct RIs established with healthy pregnant women and the calculated RIs derived from the Hoffmann method. In addition, elevated levels of RFTs were associated with increased risks of developing various pregnancy complications and adverse perinatal outcomes. Notably, elevated third-trimester RFTs posed strong risks of preterm birth (PTB) and fetal growth restriction (FGR).

CONCLUSIONS

We established the trimester-specific RIs of RFTs in both singleton and twin pregnancies. Our risk analysis findings underscored the importance of RFTs in identifying women at high risks of developing adverse complications or outcomes during pregnancy.

Maternal Iron Status Is Dynamic Throughout Pregnancy and Might Predict Birth Outcomes in a Sex Dependent Manner: Results from the Alberta Pregnancy Outcomes and Nutrition (APrON) Cohort Study

BACKGROUND

Developmental responses to nutrient deprivation may differ by fetal sex. Despite this, relationships between maternal prenatal iron biomarkers and birth outcomes when stratifying by offspring sex are poorly described, especially in healthy cohorts.

OBJECTIVES

This study aimed to determine associations between maternal iron biomarkers and birth weights (BWs) and birth head circumferences (BHCs) among female and male newborns to assess whether the potential predictive ability of iron biomarkers on birth outcomes differs by offspring sex.

METHODS

The Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study recruited 2189 pregnant individuals from Calgary and Edmonton, Canada. Maternal blood was drawn at each trimester and 3 mo postpartum. Maternal serum ferritin (SF) concentrations were measured using chemiluminescent immunoassays and erythropoietin (EPO), hepcidin, and soluble transferrin receptor (sTfR) using enzyme-linked immunosorbent assays. Ratios of sTfR:SF and hepcidin:EPO were calculated and birth outcomes accessed through delivery records. Directed acyclic graphs informed multivariate regression models.

RESULTS

The risk of maternal iron deficiency increased throughout pregnancy because ∼61% showed depleted iron stores (SF < 15 μg/L) by the third trimester. Maternal hepcidin, SF, sTfR, and sTfR:SF concentrations changed across time (P < 0.01), and participants carrying female fetuses consistently (across 6 biomarkers) showed a lower iron status during the third trimester compared with those with male fetuses (P < 0.05). Higher maternal SF and hepcidin:EPO during the third trimester was associated with lower BWs in males (P = 0.006 for SF; P = 0.03 for hepcidin:EPO) and females (P = 0.02 for SF; P = 0.02 for hepcidin:EPO). There were additional inverse associations between BWs and third trimester maternal hepcidin (P = 0.03) and hemoglobin (P = 0.004) and between BHCs and maternal SF (second trimester; P < 0.05) and Hb (third trimester P = 0.02) but only in males.

CONCLUSIONS

Relationships between maternal iron biomarkers and BWs and BHCs may depend on the timing of pregnancy and offpsring sex. There was a high risk of third trimester iron storage depletion among generally healthy pregnant individuals.

Relationship between diet quality and biochemical profile in Brazilian overweight pregnant women

OBJECTIVE

The aim of this study was to evaluate the relationship between the Adapted Diet Quality Index for Pregnant Women (IQDAG) and the biochemical profile of overweight pregnant adult women.

METHODS

This was a cross-sectional study, using baseline data from a randomized controlled clinical trial conducted with 239 pregnant women in Brazil. The usual diet was obtained through two dietary recalls and the Multiple Source Method. Diet quality was assessed using the IQDAG, which has nine components: eight for adequacy and one for moderation. Fasting blood glucose, insulin, total cholesterol, low-density lipoprotein, high-density lipoprotein, triacylglycerols, and C-reactive protein were measured to evaluate the biochemical profile. Adjusted linear regression models were used to evaluate the association between the score of the IQDAG (and its components) and the biochemical profile. The significance level considered was P ≤ 0.05.

RESULTS

The mean index score was 75.4 points. An inverse association was observed between the consumption of legumes and total cholesterol level (β = -4.76; 95% confidence interval [CI], -9.16 to -0.35; P = 0.03) and low-density lipoprotein (β = -4.13; 95% CI, -7.56 to -0.69; P = 0.02), and a direct association between calcium intake and total cholesterol (β = 0.02; 95% CI, 0.002-0.41; P = 0.03). No other associations were observed between the investigated variables.

CONCLUSIONS

The data from the present study suggest that higher consumption of legumes is associated with lower levels of total cholesterol and low-density lipoprotein. A higher intake of calcium was directly associated with total cholesterol . Further research is required to fully understand how diet quality affects pregnant women's biochemical profiles and what that means for the health of the mother and the fetus.

Reference intervals for glycated albumin during physiological pregnancy of Europid women: Evidences from a prospective observational study

BACKGROUND AND AIMS

Glycated albumin (GA) may assess glycometabolic control over a short period of time respect to HbA_1c, and its use to screen for gestational diabetes in pregnancy has been suggested. To this regard few data on reference intervals (RI) for GA on Europid women have been collected, only from cross-sectional investigations. Aim of this work has been to collect trimester-specific RI for GA in physiological pregnancies, following a longitudinal prospective study.

METHODS

Forty-five healthy pregnant Europid women have been enrolled for whom a GDM screening test was scheduled at 24-28 weeks, in 5 different Italian centers. Only those negative to the OGTT were included. The women had 4 successive visits at 6-10 weeks of gestation, at 16-18 weeks, at 24-28 weeks and at the end of pregnancy. ALT, AST, total bilirubin, C-reactive protein, cholinesterase, creatinine, GGT, glycated albumin, iron, total serum proteins, transferrin were measured in duplicate on aliquots of serum samples by a central laboratory.

RESULTS

The RI (2.5-97.5 percentiles) for GA were 11.1-14.8 % (I visit), 10.9-15.6 % (II visit), 10.6-14.1 % (III visit) and 10.7-14.3 % (IV visit). The RI of other biomarkers confirmed previously published data. The RI for serum cholinesterase we present are novel, and were 5049-9906 U/L (Iv), 4212-8965 U/L (IIv), 3518-8470 U/L (IIIv) and 3945-8727 U/L (IVv).

CONCLUSIONS

Trimester-specific RI are important for using GA and serum cholinesterase in pregnancy. However, considering the high inter-individual variability of both markers, the use of longitudinal interpretations of the individual variations of both proteins during pregnancy should be preferred.

How should we interpret lactate in labour? A reference study

OBJECTIVE

To investigate maternal lactate concentrations in labour and the puerperium.

DESIGN

Reference study.

SETTING

Tertiary obstetric unit.

POPULATION

1279 pregnant women with good perinatal outcomes at term.

METHODS

Electronic patient records were searched for women who had lactate measured on the day of delivery or in the following 24 hours, but who were subsequently found to have a very low likelihood of sepsis, based on their outcomes.

MAIN OUTCOME MEASURES

The normative distribution of lactate and C-reactive protein (CRP), differences according to the mode of birth, and the proportion of results above the commonly used cut-offs (≥2 and ≥4 mmol/l).

RESULTS

Lactate varied between 0.4-5.4 mmol/l (median 1.8 mmol/l, interquartile range [IQR] 1.3-2.5). It was higher in women who had vaginal deliveries than caesarean sections (median 1.9 vs. 1.6 mmol/l, pdiff  < 0.001), demonstrating the association with labour (particularly active pushing in the second stage). In contrast, CRP was more elevated in women who had caesarean sections (median 71.8 mg/l) than those who had vaginal deliveries (33.4 mg/l, pdiff  < 0.001). In total, 40.8% had a lactate ≥2 mmol/l, but 95.3% were <4 mmol/l.

CONCLUSIONS

Lactate in labour and the puerperium is commonly elevated above the levels expected in healthy pregnant or non-pregnant women. There is a paucity of evidence to support using lactate or CRP to make decisions about antibiotics around the time of delivery but, as lactate is rarely higher than 4 mmol/l, this upper limit may still represent a useful severity marker for the investigation and management of sepsis in labour.

Reference intervals for clinical biochemistry and haematology tests during normal pregnancy

BACKGROUND

Pregnancy induces physiological changes which affect biochemical and haematological parameters. As the significance of laboratory test results change throughout pregnancy, the reference interval (RI) or key result interpretive guide should be specific to pregnancy. This study sought to establish trimester-specific-RIs for routine biochemical and haematological tests in healthy white European women with singleton pregnancies with comparison to RIs for non-pregnant European adults.

METHODS

A retrospective analysis of a prospective longitudinal single-centre study of healthy pregnant women conducted between November 2018 and December 2020 in a tertiary academic hospital with approximately 3000 births annually. Inclusion criteria: signed informed consent, age ≥18 years, white European, body mass index (BMI) <25 kg/m2, blood pressure <140/90mmHg, non-smoker, no previous pathology or gestational diabetes. Trimester defined as T1: up to 13 weeks + 6 days, T2: 14-27 weeks + 6 days and T3: ≥28-41 weeks + 6 days. Baseline demographics, anthropometric and laboratory measurements were recorded. In total, 31 biochemical and 10 haematological ISO15189:2012 accredited tests were measured using Roche Cobas® and Sysmex XN-9100™ analysers, respectively. RIs were established according to the International Federation of Clinical Chemistry (IFCC) recommended method.

RESULTS

Apparently healthy pregnant women (n = 124) with bio-banked serum samples in each trimester were recruited. At the booking visit, 49.2% (n = 61) of participants were nulliparous, with median age of 34.4 (IQR: 31.3-37.3) years, gestational age of 89 (IQR: 84-93) days, BMI of 22.5 (IQR: 21.0-23.7) kg/m² and systolic and diastolic blood pressure of 116 (110-125) mmHg and 67 (61-75) mmHg, respectively.

CONCLUSIONS

Normative trimester-specific biological intervals for routinely requested biochemical and haematological medical laboratory tests were established. These RIs will be invaluable to result interpretation and the management of pregnant women.

White blood cells in pregnancy: reference intervals for before and after delivery

BACKGROUND

White blood cells (WBC) are commonly measured to investigate suspected infection and inflammation in pregnant women, but the pregnancy-specific reference interval is variably reported, increasing diagnostic uncertainty in this high-risk population. It is essential that clinicians can interpret WBC results in the context of normal pregnant physiology, given the huge global burden of infection on maternal mortality.

METHODS

We performed a longitudinal, repeated measures population study of 24,318 pregnant women in Oxford, UK, to map the trajectory of WBC between 8-40 weeks of gestation. We defined 95% reference intervals (RI) for total WBC, neutrophils, lymphocytes, eosinophils, basophils, and monocytes for the antenatal and postnatal periods.

FINDINGS

WBC were measured 80,637 times over five years. The upper reference limit for total WBC was elevated by 36% in pregnancy (RI 5.7-15.0×109/L), driven by a 55% increase in neutrophils (3.7-11.6×109/L) and 38% increase in monocytes (0.3-1.1×109/L), which remained stable between 8-40 weeks. Lymphocytes were reduced by 36% (1.0-2.9×109/L), while eosinophils and basophils were unchanged. Total WBC was elevated significantly further from the first day after birth (similar regardless of the mode of delivery), which resolved to pre-delivery levels by an average of seven days, and to pre-pregnancy levels by day 21.

INTERPRETATION

There are marked changes in WBC in pregnancy, with substantial differences between cell subtypes. WBC are measured frequently in pregnant women in obstetric and non-obstetric settings, and results should be interpreted using a pregnancy-specific RI until delivery, and between days 7-21 after childbirth.

FUNDING

None.

Plasma C-Reactive Protein and Pentraxin-3 Reference Intervals During Normal Pregnancy

Although several biomarkers are available to monitor the acute phase response, the short pentraxin C-reactive protein (CRP) is dominating in clinical practice. The long pentraxin 3 (PTX3) is structurally and functionally related to CRP, but not liver-derived. In addition, increased levels of PTX3 have been linked to preeclampsia. Reference intervals are usually based on healthy blood donors. Several physiological and immunological alterations occur during normal pregnancy with subsequent potential effects on blood analytes. Hence, this study aims to determine pregnancy-specific reference intervals for CRP and PTX3. Longitudinal clinical data and blood plasma samples from the 1^st, 2^nd and 3^rd trimester of 100 healthy, non-medicating, females aged 18–40 at the time-point of conception were available to us. High‐sensitivity CRP measurements were performed by turbidimetry and enzyme-linked immunosorbent assay (ELISA) was used to quantify PTX3. CRP and PTX3 levels followed each other during the first two trimesters and both increased during the third trimester. CRP showed a median of 4.12 mg/L in the third trimester, and were significantly higher compared to the first (median 2.39 mg/L, p<0.0001) and the second (median 2.44 mg/L, p=0.0006) trimesters. In the third trimester PTX3 levels reached a median of 7.70 µg/L, and were significantly higher compared to the first (median 3.33 µg/L, p<0.0001) and the second (median 3.70 µg/L, p<0.0001) trimesters. Plasma albumin was inversely correlated with CRP (rho=-0.27, p<0.0001), but not with PTX3. In conclusion, it is important to consider pregnancy-specific reference values as elevations of CRP and PTX3 during the later phase may occur in absence of infection.