Altered Serum IL-10 Levels in Preeclamptic Women with Periodontitis: A Cross-Sectional Study

ABSTRACT

Objective:

Preeclampsia (PE) affects 2%–8% of pregnancies globally and represents a significant maternal health challenge, characterized by new-onset hypertension and proteinuria after 20 weeks of gestation. Periodontal disease, defined as chronic inflammation affecting tooth-supporting structures, demonstrates a notably high prevalence among pregnant women. The objective of the present study was to compare serum inflammatory markers and periodontal status between preeclamptic and normotensive pregnant women in a cross-sectional design.

Methods:

Sixty pregnant women were recruited—30 preeclamptic and 30 normotensive—from the Department of Obstetrics and Gynecology, K.S. Hegde Hospital, Mangalore. Oral health evaluations were performed during hospital admission for delivery or 48 h before planned delivery to assess periodontal status. Following the examination of oral health status, the normotensive and preeclamptic pregnant women were grouped as preeclamptic women with healthy periodontium (PH), preeclamptic women with periodontitis (PP), normotensive women with healthy periodontium (NH), and normotensive women with periodontitis (NP) to compare the serum cytokine levels and periodontal status among the subgroups. Periodontitis was defined as a clinical attachment level ≥3 mm in ≥30% of examined sites, assessed by a single calibrated examiner. Serum levels of interleukin (IL)-10, IL-4, tumor necrosis factor-alpha (TNF-α), and IL-2 were quantified using enzyme-linked immunosorbent assay. Group comparisons were performed using the Kruskal–Wallis test with post hoc Bonferroni correction for cytokine data and one-way analysis of variance for periodontal parameters.

Results:

Periodontitis was significantly more prevalent in preeclamptic women (63.3%) compared to normotensive women (30%; P = 0.010). Serum IL-10 levels were significantly lower in the PP group (3.36 [3.06, 5.61] pg/mL) compared to the NH group (7.61 [3.52, 10.03] pg/mL) (P = 0.010, post hoc Bonferroni correction). Serum levels of TNF-α, IL-2, and IL-4 showed no statistically significant differences across subgroups.

Conclusion:

In this cross-sectional study, periodontitis was associated with lower serum IL-10 levels in preeclamptic women, suggesting a possible immune dysregulation between periodontal disease and PE. A causal relationship cannot be established from the present observational data. These findings warrant further investigation through larger prospective longitudinal studies to establish temporality and causation.

INTRODUCTION

Preeclampsia (PE), affecting 2%–8% of pregnancies globally, represents a significant maternal health challenge, characterized by new-onset hypertension and proteinuria after 20 weeks of gestation. The condition’s impact varies markedly between regions, with developing nations experiencing a substantially higher incidence (2.8% of live births) compared to developed countries (0.4%), according to the World Health Organization data.[1] PE and its severe manifestations contribute significantly to maternal–fetal morbidity and mortality, accounting for approximately 50,000 maternal and 500,000 fetal deaths annually worldwide.[2] The condition manifests through multiple systemic effects, including sustained hypertension exceeding 140/90 mm Hg accompanied by either proteinuria (>300 mg/24 h) or evidence of end-organ dysfunction in the renal, hepatic, or neurological systems.[3]

The immunological adaptation during pregnancy involves complex interactions between the placental and maternal systems. Recent research has highlighted fluctuations in various immune mediators throughout gestation, particularly in women who develop PE. Studies have documented elevated levels of proinflammatory markers, including tumor necrosis factor-alpha (TNF-α), interleukin-8 (IL-8), IL-1β, and interferon-gamma during the third trimester in preeclamptic pregnancies. Additionally, variations in regulatory cytokines such as IL-6, IL-2, IL-4, and the anti-inflammatory mediator IL-10 have been associated with PE development, though some studies report conflicting results regarding anti-inflammatory cytokine patterns.[4,5]

Periodontal disease, defined as chronic inflammation affecting tooth-supporting structures, demonstrates a notably high prevalence among pregnant women, with recent meta-analyses indicating rates approaching 40%.[6] This condition’s systemic impact extends beyond oral health, potentially influencing cardiovascular health and pregnancy outcomes. The pathophysiological mechanism involves host inflammatory responses to periodontal pathogens, triggering the release of proinflammatory mediators, including IL-6, IL-1, and TNF-α. These inflammatory cascades may subsequently affect vascular function in pregnant women, potentially contributing to adverse pregnancy outcomes such as PE, preterm labor, and low-birth-weight infants.[7]

Given these interconnected inflammatory pathways, this study aims to investigate the relationship between serum inflammatory markers and periodontal disease status in preeclamptic and normotensive pregnant women.

MATERIALS AND METHODS

STUDY DESIGN AND SETTING

The study population consisted of 60 pregnant women receiving care at the antenatal clinics of our University Hospital’s Department of Obstetrics and Gynecology. The study proceeded after obtaining institutional ethics committee approval. After obtaining informed consent, we documented maternal demographic and obstetric data through comprehensive questionnaires.

SAMPLE SIZE CALCULATION

Sample size was calculated using nMaster software version 2.0 [Department of Biostatistics, KS Hegde Medical Academy, Nitte (Deemed to be University), Mangaluru], based on a 5% level of significance and 80% power, using clinical attachment level (CAL) as the primary variable (standard deviation [SD]: 0.5 mm normotensive, 0.3 mm preeclamptic; effect size 0.75), yielding 30 normotensive pregnant women and 30 preeclamptic pregnant women (total sample size, n = 60).[8]

The sample size of 30 per obstetric group (normotensive/preeclamptic) was subsequently subdivided into four subgroups based on periodontal status, preeclamptic women with healthy periodontium (PH), preeclamptic women with periodontitis (PP), normotensive women with healthy periodontium (NH), and normotensive women with periodontitis (NP) for exploratory subgroup analysis; the study was not powered for subgroup comparisons.

INCLUSION AND EXCLUSION CRITERIA

The inclusion criteria for the study were gestational age ≥26 weeks, planned delivery at the study site, and absence of preexisting medical conditions. Women with preexisting hypertension, other systemic medical conditions, or antibiotic use within the preceding six months were excluded.

STUDY GROUPS AND DEFINITIONS

PE was defined as blood pressure ≥140/90 mm Hg recorded on more than two occasions, separated by at least 4 h, accompanied by proteinuria ≥1+ using dipstick examination (Multistix®, SG Reagent Strips, Bayer Diagnostics India Ltd., Mumbai, Maharashtra, India) of random urine samples. Control participants were recruited from the same hospital setting and matched for demographics; they had consistently normal blood pressure readings throughout pregnancy.

PERIODONTAL EXAMINATION

Oral health evaluations were performed during hospital admission for delivery or 48 h before planned delivery to assess periodontal status. Following the examination of oral health status, the normotensive and preeclamptic pregnant women were grouped as PH, PP, NH, and NP to compare the serum cytokine levels and periodontal status among the subgroups.

A single calibrated examiner conducted all periodontal assessments using a UNC-15 periodontal probe (Hu-Friedy®, Chicago, IL, USA). The examination protocol included evaluation of six sites per tooth (mesiobuccal, mid-buccal, distobuccal, mesiolingual, mid-lingual, and distolingual), and recording of maximum probing depth for each tooth. CAL measurements were performed using the cementoenamel junction as the reference point, recorded to the nearest 0.5 mm. Following modified criteria based on the 1999 International Workshop Classification, periodontitis was defined as CAL ≥3 mm in ≥30% of examined sites.[9,10] Additionally, periodontitis cases were further classified according to the 2017 AAP/EFP classification system for staging only.[10] Staging was determined based on CAL and probing depth measurements: Stage II was defined as CAL of 3–4 mm and probing depth ≤5 mm, and Stage III as CAL ≥5 mm and probing depth ≥6 mm. Formal grading was not performed, as grading requires longitudinal evidence of disease progression rate, which cannot be determined from a single cross-sectional examination. PE status was not used as a grade modifier, as it is not a recognized criterion in the 2017 AAP/EFP grading system.[10]

Plaque scores were recorded using the Silness and Löe Index (scores 0–3), while bleeding on probing (BOP) was documented as present or absent within 30 s of probing and expressed as a percentage of bleeding sites.[11]

BLOOD SAMPLE COLLECTION AND CYTOKINE ANALYSIS

Blood samples were collected to measure serum cytokine levels of IL-2, TNF-α, IL-4, and IL-10. For serum preparation, blood samples were processed in plain vacutainer tubes and centrifuged at 3500g for 5 min. Cytokine analysis was performed using enzyme-linked immunosorbent assay kits (GENLISA, Krishgen Biosystems) to quantify TNF-α, IL-2, IL-10, and IL-4 according to the manufacturer’s protocols in both normotensive and preeclamptic samples. Hospital records provided information regarding the infant’s birth weight and maternal gestational age at delivery.

PATIENT CARE AND FOLLOW-UP

All participants received oral hygiene instructions for maintaining optimal oral health, and when indicated, we explained the necessity for post-delivery periodontal therapy.

STATISTICAL ANALYSIS

Statistical analysis was performed using IBM’s SPSS version 29 software (IBM Corp., Armonk, NY, USA). Quantitative data were expressed as mean ± SD, and qualitative data as frequency and percentage. Normality was assessed using the Shapiro–Wilk test; normally distributed data were analyzed using the unpaired t-test and one-way analysis of variance (ANOVA). Skewed data were analyzed using the Kruskal–Wallis test with Bonferroni correction. Fisher’s Exact test analyzed categorical data, while the unpaired t-test evaluated quantitative measurements between normotensive and preeclamptic pregnant women. Multivariable logistic regression was used to assess the association between obstetric status and demographic variables. One-way ANOVA was used to analyze periodontal parameters, including BOP (percentage of sites), CAL, probing pocket depth, and plaque index between the PH, PP, NH, and NP groups. Cytokine values were expressed as median (interquartile range) and compared between the PH, PP, NH, and NP groups using the Kruskal–Wallis test. Significant findings underwent post hoc pairwise comparisons with Bonferroni correction. These revealed significantly higher IL-10 levels in the NH group compared to the PP group (P = 0.010). All other pairwise comparisons (NH vs. NP [P = 0.803], NH vs. PH [P = 0.099], NP vs. PH [P = 0.196], NP vs. PP [P = 0.061], PH vs. PP [P = 0.333]) were not statistically significant.

The unpaired t-test evaluated newborn weight and gestational age differences between normotensive and preeclamptic groups. We considered P < 0.05 statistically significant.

RESULTS

In the present study of 60 pregnant women, the preeclamptic (n = 30) and normotensive (n = 30) groups demonstrated comparable demographic characteristics. Participants’ mean age was 25.7 ± 1.5 years. Mean gestational age varied between groups, with normotensive women delivering at 37.7 ± 1.28 weeks compared to 36.5 ± 1.19 weeks in preeclamptic women. A notable finding was the higher prevalence of periodontal disease in preeclamptic women (n = 19, 63.3%) versus normotensive women (n = 9, 30%), which was statistically significant (P = 0.010).

Demographic and obstetric characteristics analysis revealed no significant differences between preeclamptic and normotensive groups regarding age distribution, urban/rural residence patterns, or educational background. However, occupational status differed significantly between groups (P < 0.05) [Table 1].

Table 1.

Sociodemographic traits in normotensive and preeclamptic pregnant women

Variable	Normotensive pregnant women (n = 30)	Preeclamptic pregnant women (n = 30)	P values
Maternal age (years)	25.7 ± 1.5	25.7 ± 1.2	0.926
Education			0.337
Primary school	9 (30.0%)	7 (23.3%)
Pre-university	16 (53.3%)	21 (70.0%)
Degree	5 (16.7%)	2 (6.7%)
Occupation			0.004*
Employed	20 (66.7%)	9 (30.0%)
Housewife	10 (33.3%)	21 (70.0%)
Area of residence			0.426
Rural	13 (43.3%)	10 (33.3%)
Urban	17 (56.7%)	20 (66.7%)
Parity			0.194
Primigravida	25 (83.3%)	29 (96.7%)
Multigravida	5 (16.7%)	1 (3.3%)

Demographic and obstetric characteristics analysis revealed no significant differences between preeclamptic and normotensive groups regarding age distribution, urban/rural residence patterns, or educational background. However, occupational status differed significantly between groups (P < 0.05).

^*Statistically significant at P < 0.05

Table 2 shows that the overall logistic regression model was statistically significant (χ² = 18.6, df = 7, P = 0.010). Homemakers had significantly higher odds of being preeclamptic compared to employed women, indicating that homemakers were approximately five times more likely to develop PE than employed women (adjusted odds ratio [AOR] = 4.77; 95% confidence interval [CI]: 1.28–17.69; P = 0.019). Age was not significantly associated with PE (AOR =1.29; 95% CI: 0.77–2.14; P = 0.334). With respect to education, neither women with pre-university education (AOR = 2.48; 95% CI: 0.37–16.36; P = 0.345) nor those with primary school education (AOR = 2.15; 95% CI: 0.23–19.95; P = 0.50) showed a statistically significant association with PE when compared to women with degree-level education. Area of residence was not significantly associated with PE (AOR = 2.98; 95% CI: 0.70–12.59; P = 0.138); however, women residing in urban areas had higher odds of PE compared to rural areas. Parity was not significantly associated with PE (AOR = 7.22; 95% CI: 0.57–91.03; P = 0.126); however, primigravida women showed increased odds of PE compared to multigravida women. Women with periodontitis had higher odds of PE than those with a healthy periodontium (AOR =2.75; 95% CI: 0.74–10.16; P = 0.129), but the association was not statistically significant.

Table 2.

Logistic regression model showing the association of demographic variables with obstetrics status

95% Confidence Interval
Predictor	Estimate	SE	Z	p	Odds ratio		Lower	Upper
Intercept	−10.93	7.087	−1.542	0.123	1.80e-5	1.67e-11		19.40
Age	0.251	0.260	0.966	0.334	1.29	0.77		2.14
Occupation:
Housewife—employed	1.563	0.669	2.338	0.019	4.77	1.28		17.69
Education:
Pre-university—degree	0.909	0.962	0.945	0.345	2.48	0.37		16.36
Primary school—degree	0.766	1.136	0.675	0.500	2.15	0.23		19.95
Area of residence:
Urban—rural	1.091	0.736	1.482	0.138	2.98	0.70		12.59
Parity:
Primigravida—multigravida	1.977	1.293	1.528	0.126	7.22	0.57		91.03
Periodontal status
Periodontitis healthy periodontium	1.013	0.666	1.520	0.129	2.75	0.74		10.16

Obstetrics status—preeclamptic vs. normotensive

Table 3 shows the comparison of periodontal parameters among normotensive and preeclamptic women with and without periodontitis.

Table 3.

Comparison of periodontal parameters among normotensive and preeclamptic women with and without periodontitis

Variable	NH (n = 21)	NP (n = 9)	PH (n = 11)	PP (n = 19)	P value
Periodontitis stage (2017 AAP/EFP)	-	Stage II	-	Stage III
PPD (mm)	1.20 ± 0.10	4.80 ± 0.60	1.30 ± 0.10	5.20 ± 0.70	<0.001*
CAL (mm)	0.10 ± 0.10	3.50 ± 0.50	0.20 ± 0.10	4.20 ± 0.60	<0.001*
PI score	1.20 ± 0.50	1.60 ± 0.40	1.70 ± 0.20	2.50 ± 0.30	<0.001*
BOP (%)	11.40 ± 2.90	12.00 ± 2.90	10.40 ± 2.80	13.30 ± 1.70	<0.001*

Values are presented as mean ± standard deviation. NH = normotensive women with healthy periodontium, NP = normotensive women with periodontitis, PH = preeclamptic women with healthy periodontium, PP = preeclamptic women with periodontitis, PPD = Probing pocket depth; CAL = clinical attachment level; PI = plaque index[11]; BOP = bleeding on probing. Periodontitis staging was based on the 2017 AAP/EFP classification.[10] Formal grading was not assigned as the cross-sectional study design does not permit assessment of the disease progression rate required for grading; preeclampsia status was not used as a grade modifier.

^*Statistically significant at P < 0.05 using one-way ANOVA. Marked differences in mean CAL, mean PPD, PI scores, and BOP percentages (P < 0.001) among these subgroups

Table 4 shows the comparison of serum cytokine levels across pregnant women groups. Serum cytokine analysis demonstrated notable variations between groups. The most significant finding was a statistically significant difference in IL-10 levels across subgroups (Kruskal–Wallis test, P =0.036). While other measured cytokines (TNF-α, IL-2, and IL-4) showed varying patterns across groups, these differences did not achieve statistical significance. Post hoc analysis revealed significantly higher IL-10 levels in the NH group compared to the PP group (P = 0.010), with all other pairwise comparisons (NH vs. NP; P = 0.803), NH versus PH (P = 0.099), NP versus PH (P = 0.196), NP versus PP (P = 0.061), and PH versus PP (P = 0.333) being nonsignificant.

Table 4.

Comparison of serum cytokine levels across pregnant women groups

Cytokines (pg/mL)	NH (n = 21) Median (QI, Q3)	NP (n = 9) Median (QI, Q3)	PH (n = 11) Median (QI, Q3)	PP (n = 19) Median (QI, Q3)	P value
IL-2	219.22 (38.11, 1341.44)	179.22 (6.72, 629.50)	147.56 (13.11, 611.44)	323.67 (39.78,718.67)	0.569
TNF-α	28.02 (17.09, 165.55)	30.48 (15.09, 125.25)	31.55 (18.48, 334.94)	93.09 (31.09, 337.86)	0.323
IL-4	500.56 (159.44, 770.56)	398.33 (213.89, 841.67)	253.89 (119.44, 618.89)	176.11 (96.11, 708.89)	0.287
IL-10	7.61 (3.52,10.03)	3.36 (2.15, 5.94)	6.70 (3.21, 7.70)	3.36 (3.06, 5.61)	0.036*

Values are presented as median (interquartile range). NH = normotensive women with healthy periodontium, NP = normotensive women with periodontitis, PH = preeclamptic women with healthy periodontium, PP = preeclamptic women with periodontitis.

^*Statistically significant at P < 0.05, Kruskal–Wallis test.

Spearman’s correlation between mean CAL and serum IL-10 levels across the full cohort demonstrated a statistically significant positive association (ρ = 0.302, P = 0.019). This finding appears inconsistent with the lower IL-10 levels observed in the PP group, which had the highest mean CAL. This apparent paradox is likely explained by the confounding effect of PE status on the pooled dataset: since PE independently alters serum IL-10 levels regardless of periodontal status, combining both preeclamptic and normotensive women in a single correlation analysis may distort the direction of the observed association [Table 5].

Table 5.

Correlation of severity of periodontitis: Mean CAL and IL-10 levels

Mean CAL (clinical attachment level)
IL-10 (pg/mL)	Spearman’s ρ	0.302
	df	58
	P value	0.019

There is a moderate positive correlation (ρ=0.302) between mean CAL and IL-10, and it is statistically significant (P = 0.019). This pooled correlation should be interpreted with caution, as preeclampsia status independently modifies serum IL-10 levels and may confound the direction of the association when data from all subgroups are combined.

The box plot shows the distribution of IL-10 across pregnant women groups [Figure 1].

Figure 1.

Box plot showing the distribution of IL-10 serum cytokine levels across the pregnant women groups (NH, NP, PH, and PP). x-axis shows NH = normotensive women with healthy periodontium, NP = normotensive women with periodontitis, PH = preeclamptic women with healthy periodontium, PP = preeclamptic women with periodontitis, y-axis shows cytokine IL-10 (pg/mL). IL = interleukin

Birth outcomes analysis revealed significant differences between groups. Infants born to preeclamptic mothers had lower birth weights (2280 ± 374.53 g) compared to those born to normotensive mothers (2576.67 ± 263.51 g; P =0.001). Gestational age at delivery differed significantly between preeclamptic (36.50 ± 1.196 weeks) and normotensive (37.73 ± 1.285 weeks) groups (P = 0.001), reflecting the often-necessary earlier delivery in preeclamptic pregnancies due to maternal risk considerations.

DISCUSSION

The present study investigated the relationship between serum cytokine levels in normotensive and preeclamptic pregnant women with or without periodontal disease. The clinical periodontal examination protocol, executed by a single calibrated examiner, enhanced data quality by eliminating inter-examiner variability. In our study population, 63.3% of preeclamptic women exhibited features of periodontal disease compared to 30% of normotensive pregnant women, which was statistically significant. Previous studies have reported an association between periodontal disease in pregnancy and adverse pregnancy outcomes such as PE, preterm birth, and fetal growth restriction.[12,13] However, a detailed assessment of pregnancy outcomes was beyond the scope of the present study.

Our primary finding revealed lower serum levels of IL-10 in PP compared to NH, suggesting possible dysregulation of anti-inflammatory mechanisms. The placental-oral axis hypothesis suggests that periodontal pathogens, particularly Porphyromonas gingivalis and Fusobacterium nucleatum, can translocate systemically through bacteremia or trigger systemic inflammatory cascades. It has been proposed that gram-negative bacteria release lipopolysaccharides that activate toll-like receptors on immune cells and placental trophoblasts, potentially increasing proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and suppressing IL-10 production. However, whether this proposed mechanism explains the lower IL-10 levels observed in our cross-sectional study cannot be established from the present data alone. Previous studies have documented that, in healthy pregnancies, maternal serum IL-10 concentrations change across trimesters, though these changes are subtle. The current literature presents varying findings regarding IL-10 concentrations across pregnancy trimesters.[5]

The analysis of other inflammatory markers revealed elevated maternal serum levels of TNF-α and IL-2 in PP compared to NH, though these differences did not achieve statistical significance. The other anti-inflammatory cytokine examined, IL-4, demonstrated higher levels in normotensive women compared to PP, but this difference also did not reach statistical significance. The lack of statistical significance for TNF-α, IL-2, and IL-4 may be attributed to the inherent biological variability of cytokine measurements and the limited sample size of the present study.

Our findings regarding serum cytokine levels should be interpreted within the context of current literature on inflammatory markers in pregnancy. While we observed lower IL-10 levels in PP at the time of delivery, the cross-sectional nature of our study limits temporal interpretations. Previous systematic reviews have examined IL-10 concentrations throughout pregnancy, but our single-time-point measurement at delivery cannot address earlier gestational changes. In our study, we observed elevated serum TNF-α levels in preeclamptic subjects with periodontitis, though the difference was not statistically significant; this is consistent with prior evidence demonstrating increased TNF-α concentrations in PE, particularly in the third trimester.[14]

Study design variations may explain certain inconsistencies between our findings and previous research. As demonstrated in recent reviews, factors such as sample size, methodological approaches to cytokine measurement, and exclusion criteria significantly impact results. Studies with larger cohorts (≥40 participants) have more consistently demonstrated elevated TNF-α in PE, while smaller studies often show nonsignificant differences.[14,15]

The immunological interactions observed in our study merit careful consideration. While our investigation focused on serum markers, research examining gingival crevicular fluid (GCF) has shown different patterns, with some studies finding no strong association between GCF and serum cytokine levels.[16] This suggests that systemic inflammatory responses may provide additional insights into these conditions. In periodontal inflammation, IL-10 and IL-4 cytokines act to downregulate the excessive immune response and promote tissue healing; disruption of this equilibrium may contribute to periodontal disease progression.[17,18]

The enhanced proinflammatory environment observed in our preeclamptic subjects, characterized by elevated TNF-α and IL-2, alongside reduced anti-inflammatory IL-10, warrants further investigation regarding its potential influence on both periodontal health and pregnancy outcomes. Poor maternal oral health has been associated with systemic inflammation and adverse gestational outcomes, though causality cannot be established from observational data.[19,20]

Limitations of the present cross-sectional study include its single-center design and small sample size, which have limited our statistical power to detect significant differences in certain cytokine markers, particularly TNF-α, IL-2, and IL-4, despite observed trends. Despite these limitations, the present study possesses notable strengths. The use of a single calibrated examiner for all periodontal assessments eliminated inter-examiner variability and enhanced the reliability of clinical measurements. The matched-control design minimized confounding from demographic factors, thereby strengthening the validity of comparisons between preeclamptic and normotensive groups. The observed reduction in IL-10 levels in the PP group warrants further investigation into whether periodontal disease and PE share immunological pathways. Whether IL-10 could serve as a biomarker in this context requires prospective validation in larger cohorts before any clinical recommendations can be made. Future research directions arising from this study include prospective longitudinal evaluation of periodontal status and cytokine profiles across pregnancy trimesters, validation of IL-10 as a potential immune marker in larger cohorts, and interventional studies examining whether periodontal treatment modifies cytokine profiles in at-risk pregnant women.

CONCLUSION

In this cross-sectional study, periodontitis was associated with lower serum IL-10 levels in preeclamptic women. While other inflammatory markers (TNF-α, IL-2, and IL-4) showed alterations that did not reach statistical significance, the observed cytokine profile, particularly the reduction in IL-10, is consistent with immune dysregulation that warrants further investigation. A causal relationship cannot be established from the present observational data. Larger prospective longitudinal studies are needed to confirm these associations and to establish the temporal and causal relationships between periodontal disease and PE.

CONFLICTS OF INTEREST

There are no conflicts of interest.

ETHICAL POLICY AND INSTITUTIONAL REVIEW BOARD STATEMENT

Ethical approval was obtained from the institutional review board statement. Ethical approval was obtained from the board of the Central Ethics Committee, Nitte University, with reference number NU/CEC/2020/0271.

AUTHOR CONTRIBUTIONS

All authors contributed equally.

DECLARATION OF PATIENT CONSENT

Informed consents were taken from the participants.

DATA AVAILABILITY STATEMENT

Not applicable.

LIST OF ABBREVIATIONS

• CAL - Clinical attachment level

• GI - Gingival index

• NH - Normotensive women with healthy periodontium

• NP - Normotensive with periodontitis

• PH - Preeclamptic women with healthy periodontium

• PI - Plaque index

• PP - Preeclamptic women with periodontitis

• PPD - Probing pocket depth

• TNF - Tumour necrosis factor

Funding Statement

Nil.