Prevalence of Iodine Deficiency, Associated Factors, and Perinatal Outcomes in Pregnant Women With Hypertensive Disorders

doi:10.21203/rs.3.rs-4888805/v1

Download PDF

Research Article

Prevalence of Iodine Deficiency, Associated Factors, and Perinatal Outcomes in Pregnant Women With Hypertensive Disorders

https://doi.org/10.21203/rs.3.rs-4888805/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Objectives

this study aimed to determine the prevalence of iodine deficiency, associated factors, and perinatal outcomes in pregnant women with hypertensive disorders.

Methods

a prospective cohort study was conducted in a reference maternity hospital in the state of Paraíba, Brazil, from June 2022 to April 2023. Pregnant women (n = 250) in the third trimester, aged 18 years or older, and with hypertensive disorders were included. Clinical-epidemiological data and urinary samples for iodine concentration were collected; concentrations < 150 µg/L were considered iodine deficiency. A multivariate logistic regression model determined variables associated with iodine deficiency, showing their odds ratio (OR) and 95% confidence interval (CI).

Results

the prevalence of iodine deficiency was 74.8% (n = 187). Women with chronic arterial hypertension and gestational hypertension showed the highest frequencies of iodine deficiency (27.6% and 26.9%, respectively). Twinning (OR = 3.26; 95%CI 1.79 to 5.96; p < 0.001) and superimposed preeclampsia (OR = 0.37; 95%CI 0.15 to 0.93; p < 0.001) were statistically associated with iodine deficiency. Regarding evaluated outcomes, chorioamnionitis (OR = 1.32; 95%CI 1.23 to 1.42; p < 0.001) and neonatal jaundice (OR = 1.25; 95%CI 1.07 to 1.44; p = 0.004) were associated with a high risk of iodine deficiency.

Conclusion

a high prevalence of iodine deficiency was observed in women with chronic arterial hypertension and gestational hypertension, associated with twinning, chorioamnionitis, and neonatal jaundice, which suggest a need for investigation in these patients. Superimposed preeclampsia was a protective factor for iodine deficiency compared with other hypertensive disorders.

Eclampsia

Gestational hypertension

Iodine deficiency

Iodine

Preeclampsia

Iodine is an essential micronutrient present in the soil and seawater and obtained from dietary sources (e.g., iodized salt, seafood, and plants from iodine-rich soils) [1]. After digestion, most iodides are quickly removed by the kidneys (80%), with the remaining stored in the thyroid gland to synthesize thyroid hormones [1]. Iodine deficiency disorders are distributed worldwide and a main preventable cause of mental illness and developmental delay in newborns. According to the International Council for the Control of Iodine Deficiency Disorders, approximately two billion people are exposed to iodine deficiency [2]. In addition, the United Nations International Children's Emergency Fund estimates that 46 million newborns are at risk of iodine deficiency [3].

The urinary iodine concentration (UIC) is a method to evaluate the iodine status of an individual [4]. The World Health Organization advocates adequate iodine levels between 100 and 199 µg/L, and for pregnant women, between 150 and 250 µg/L [4]. Although Brazil is considered an iodine-sufficient country [5–7], national analyses indicate a high prevalence of iodine deficiency in pregnant women [8, 9]. Moreover, pregnant women with hypertensive disorders may have a higher prevalence of iodine deficiency than normotensive women [10–12].

The higher prevalence of iodine deficiency in pregnant women is related to the physiological changes during pregnancy, such as greater demand for iodine by the fetus, lower levels of plasma creatinine, and greater urinary excretion of iodine secondary to increased glomerular filtration rate [13]. Additionally, changes in maternal thyroid function and iodine metabolism lead to increased production of thyroid hormones and iodine requirements of almost 50% [14].

Iodine has an antioxidant function, and its deficiency may increase oxidative stress, leading to complications during pregnancy, such as hypertensive disorders. Furthermore, pregnant women with hypertensive disorders and iodine deficiency show markers of oxidative stress and low antioxidant status [11, 12].

The consequences of iodine deficiency vary according to the trimester of pregnancy; however, findings on maternal-perinatal outcomes are conflicting [15–18].

Thus, considering the scarcity of studies conducted on pregnant women with hypertensive disorders and the higher prevalence of iodine deficiency in these patients. This study aimed to determine the iodine status, perinatal outcomes, and factors associated with iodine deficiency in pregnant women with hypertensive disorders admitted to a reference maternity hospital located in northeastern Brazil.

A prospective cohort study with a cross-sectional design was conducted at the maternity ward of the Elpídio de Almeida Health Institute at Campina Grande (Paraíba, Brazil) from June 2022 to April 2023. The human research ethics committee of the Instituto de Medicina Integral Prof. Fernando Figueira approved this study (no. 58309422.7.0000.5201, opinion nº. 5.443.633). Eligible patients were included after signing the informed consent form.

The sample was non-probabilistic by convenience and included pregnant women in the third trimester, aged 18 years or older, and with hypertensive disorders. Exclusion criteria were gastric malabsorptive disorders, thyroid, psychiatric, and chronic infectious diseases. In addition, vegan pregnant women, under use of levothyroxine, antithyroid drugs, multivitamins, medications containing iodine, or undergone exams with iodinated contrast in the last three months were excluded.

The sample size was calculated using StatCalc version 7.2 (EpiInfo®, CDC, Atlanta, USA) based on a pilot study with the first 100 patients (unpublished data). The prevalence of iodine deficiency was 80%, with a confidence level of 95% and an expected margin of error of 5%, requiring 250 pregnant women with hypertensive disorders.

Variables analyzed were maternal age (years), gestational age at UIC (weeks), skin color (white, mixed race, or black), presence of a partner (yes or no), mesoregion (Agreste, Borborema, or Sertão), educational level (illiteracy/elementary education, secondary education, or higher education), income (yes or no), gestational nutritional classification (underweight, adequate, overweight, or obesity) [19], smoking (yes or no), alcohol consumption (yes or no), use of illicit drugs (yes or no), presence of previous or gestational diabetes mellitus (DM) (yes or no) [20], number of pregnancies, parity and abortions, current twinning (yes or no), and types of hypertensive disorders [21].

Pre-gestational DM was considered for women who had type 1 or 2 DM before conception or fasting blood glucose ˃ 126 mg/dL during pregnancy. Gestational DM was defined as an alteration in fasting blood glucose or abnormal glucose tolerance during pregnancy. In the first trimester, a normal fasting blood glucose was considered < 92 mg/dL, with a recommendation to perform the oral glucose tolerance test between 24 and 28 weeks. Gestational DM was considered if the fasting blood glucose was between 92 mg/dL and 126 mg/dL. In the second trimester, gestational DM was diagnosed when the oral glucose tolerance test (75 g) showed fasting blood glucose ˃ 92 mg/dL, one-hour blood glucose ≥ 180 mg/dL, or two-hour blood glucose ≥ 153 mg/dL [20].

Gestational hypertensive disorders were defined according to the International Society for the Study of Hypertension in Pregnancy [21]: chronic arterial hypertension (CAH), preeclampsia (PE), eclampsia, hemolysis with a microangiopathic blood smear, elevated liver enzymes, and low platelet count (HELLP) syndrome, superimposed PE on CAH, and gestational hypertension (GH).

The perinatal outcomes analyzed were prematurity (yes or no), newborn weight at birth (grams), newborn classification according to birth weight and gestational age (small, appropriate, or large) [22], maternal complications in the perinatal period (peripartumhemorrhage [23], chorioamnionitis [24], or maternal death), and neonatal complications (hypoglycemia [glucose level < 54 mg/dL [25], acute respiratory distress [respiratory rate ≥ 60 or < 30 rpm [22], neonatal jaundice [26], sepsis [27], and perinatal death).

Iodine deficiency was determined using the UIC (µg/L), which was evaluated using an isolated urine sample (approximately 30 mL) collected in the morning or afternoon, preferably after two hours without urinating and vaginal bleeding at collection. Samples were collected in a universal collector and stored in Monovette® (Nümbrecht, Germany) devices for transport and storage at 2°C to 8°C until analysis. Measurements were performed using an inductively coupled plasma mass spectrometry of the Thermo ICAP-RQ (Bremen, Germany) in a single laboratory (Cerba - LCA, São Paulo, Brazil). The UIC was categorized based on international criteria as iodine deficiency (< 150 µg/L), iodine sufficiency (between 150 and 250 µg/L), and excessive iodine (> 250 µg/L) [4].

The statistical software Epi-Info® version 7.2 (CDC, Atlanta, USA) and SPSS version 20.0 (IBM, Chicago, USA) were used for data analysis. Frequency distribution tables with absolute and relative values were created for categorical variables. The chi-square test of association (Pearson) was used to assess differences between proportions of variables according to groups with and without iodine deficiency. The relative risk (RR) and confidence interval of 95% (CI 95%) were calculated; for variables with a significance level < 0.20, multivariate and hierarchical logistic regression analysis was performed. Odds ratio (OR) and CI were calculated to determine variables associated with iodine deficiency. A significance level of 5% (α = 0.05) was considered.

From 313 pregnant women, 7 did not meet the eligible criteria, and 56 refused to participate; therefore, 250 women had their UIC analyzed. After 15 losses, the final sample was 235 pregnant women for analysis of perinatal outcomes (Fig. 1).

The mean age of pregnant women was 29 ± 6.9 years, with a mean gestational age at UIC of 34 ± 3.8 weeks. Most pregnant women declared to be mixed-race (57.6%), living in urban areas (76.8%) from the Agreste mesoregion (85.2%), had a partner (81.6%) and financial income (52.1%), and were obese (51.6%). Regarding educational level, 48.7% were illiterate or had elementary education. Use of illicit drugs was not reported; however, 0.8% were smokers, and 1.2% had alcohol consumption during pregnancy (Table 1).

Previous and gestational DM was prevalent in 39.6% of pregnant women. The most frequent hypertensive disorders were PE (32%), GH (31.2%), superimposed PE (16%), CAH (11.6%), eclampsia (6%), and HELLP syndrome (3.2%) (Table 1).

Table 1

– Clinical and sociodemographic characteristics of patients.
Variable	n	%
Mesoregion
Agreste	213	85.2
Borborema	35	14.0
Sertão	2	0.8
Zone
Urban	192	76.8
Rural	58	23.2
Color
Mixed-race	144	57.6
White	105	42.0
Black	1	0.4
Presence of a partner
Yes (married or common-law)	204	81.6
No (single or divorced)	46	18.4
Educational level
Illiterate or elementary school	115	48.7
High school	108	45.7
Higher education	13	5.6
Income
With income	109	52.1
Without income	100	47.9
Gestational hypertensive disorders
Preeclampsia	80	32.0
Gestational hypertension	78	31.2
Superimposed preeclampsia	40	16.0
Chronic arterial hypertension	29	11.6
Eclampsia	15	6.0
HELLP syndrome	8	3.2
Previous or gestational diabetes mellitus
No	151	60.4
Yes	99	39.6
Gestational nutritional classification
Underweight	2	0.8
Adequate	62	24.8
Overweight	57	22.8
Obesity	129	51.6

HELLP: Hemolysis, Elevated Liver enzymes, Low Platelets.

The prevalence of iodine deficiency in pregnant women with hypertensive disorders was 74.8%, 6% had excessive iodine, and 19.2% had iodine sufficiency. Among the hypertensive disorders, those with CAH (27.6%) and GH (26.9%) presented the highest prevalence of iodine deficiency, while pregnant women with PE (15%) and superimposed PE (10%) had the lowest prevalence (Table 2).

Twinning and type of hypertensive disorder were significantly associated with iodine deficiency in the multi- and bivariate- analysis (Table 2). Twinning was associated with a 3.2-fold increased risk of iodine deficiency in pregnant women with hypertensive disorders (CI 95% = 1.79 to 5.96) (Table 3). However, a significant protective factor for iodine deficiency was observed with superimposed PE (RR 0.37; CI 95%: 0.15 to 0.93) than other hypertensive disorders (Table 3).

Table 2

Bivariate analysis of factors associated with iodine deficiency.
	Sample	Iodine deficiency
Variables	n	n (%)	PR (CI 95%)	p*
Mesoregion Agreste Borborema and Sertão Zone	213 37	38 (17.8) 10 (27.0)	1.0 1.51 (0.83 to 2.77)	0.178 0.249
Urban	192	40 (20.8)	1.51 (0.75 to 3.05)
Rural	58	8 (13.8)	1.0
Skin color				0.550
White	105	22 (21.0)	1.0
Mixed-race and black	145	26 (17.9)	0.86 (0.51 to 1.43)
Presence of a partner				0.625
Yes (married or common-law)	46	10 (21.7)	1.0
No (single or divorced)	204	38 (18.6)	0.86 (0.46 to 1.59)
Educational level				0.622
Illiterate or elementary school	115	23 (20.0)	1.0
High school	108	21 (19.4)	0.97 (0.57 to 1.65)
Higher education	13	1 (7.7)	0.38 (0.06 to 2.63)
Income				0.349
With income	100	16 (16.0)	1.0
Without income	109	23 (21.1)	1.32 (0.74 to 2.35)
Twinship				< 0.001
Yes	9	6 (66.7)	3.83 (2.23 to 6.56)
No	241	42 (17.4)	1.0
Gestational hypertensive disorders**				< 0.001
Gestational hypertension	78	21 (26.9)	1.0
Preeclampsia	80	12 (15.0)	0.56 (0.29 to 1.05)
Superimposed preeclampsia	40	4 (10.0)	0.37 (0.14 to 1.01)
Chronic arterial hypertension	29	8 (27.6)	1.02 (0.51 to 2.05)
Eclampsia	15	3 (20.0)	0.74 (0.25 to 2.18)
Diabetes mellitus				0.285
Gestational	90	20 (22.2)	1.0
Diabetes mellitus prior to pregnancy	9	3 (33.3)	1.50 (0.55 to 4.09)
No	151	25 (16.6)	0.75 (0.44 to 1.26)
Gestational nutritional classification***				0.157
Adequate	62	8 (12.9)	1.0
Overweight	57	9 (15.8)	1.22 (0.51 to 2.96)
Obesity	129	31 (24.0)	1.86 (0.91 to 3.82)
PR: prevalence ratio
*Wald test

**HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome was diagnosed in eight patients who were removed from the analysis since they did not have diagnosis of iodine deficiency.

***Two patients classified as underweight were removed from the analysis because none of them had been diagnosed with iododeficiency.

Table 3

Initial and final multivariable models of factors associated with iodine deficiency.
	Initial multivariate model		Final multivariate model
Variables	RR (CI 95%)	p	RR adjusted (CI 95%)		p*
Mesoregion		0.314
Agreste	1.0
Borborema and Sertão	1.38 (0.74 to 2.56)
Twinship		< 0.001		< 0.001
Yes	3.40 (1.87 to 6.18)		3.26 (1.79 to 5.96)
No	1.0		1.0
Gestational hypertensive disorders		< 0.001		< 0.001
Gestational hypertension	1.0		1.0
Preeclampsia	0.58 (0.31 to 1.09)		0.57 (0.31 to 1.06)
Superimposed preeclampsia	0.37 (0.15 to 0.92)		0.37 (0.15 to 0.93)
Chronic hypertension	0.98 (0.48 to 1.98)		0.98 (0.48 to 2.01)
Gestational nutritional classification		0.319	0.63 (0.20 to 2.04)
Adequate	1.0
Overweight	1.31 (0.54 to 3.20)
Obesity	1.75 (0.81 to 3.77)
*Wald test

Among the seventeen (7.2%) cases of maternal complications reported during the perinatal period, only chorioamnionitis showed a statistically significant association with iodine deficiency (RR 1.32; CI 95% 1.23 to 1.42) (Table 4). No maternal deaths were reported.

Regarding neonatal complications, neonatal jaundice showed a significant association with iodine deficiency (RR 1.25; CI 95% = 1.07 to 1.44). Prematurity and newborn classification did not have a significant association between birth weight, gestational age, and iodine deficiency (Table 4).

Table 4

Univariate analysis of perinatal complications associated with iodine deficiency.
	Sample	Iodine deficiency
Variable	n	n (%)	RR (CI 95%)	p*
Compound maternal complication				0.976
Yes	17	13 (76.5)	1.00 (0.76 to 1.32)
No	218	166 (76.1)	1.0
Peripartum hemorrhage				0.912
Yes	16	12 (75.0)	0.98 (0.73 to 1.32)
No	219	167 (76.3)	1.0
Chorioamnionitis				< 0.001
Yes	1	1 (100.0)	1.32 (1.23 to 1.42)
No	234	178 (75.7)	1.0
Compound neonatal complications				0.272
Yes	91	73 (80.2)	1.08 (0.94 to 1.25)
No	144	106 (74.1)	1.0
Neonatal hypoglycemia				0.580
Yes	21	17 (81.0)	1.06 (0.85 to 1.33)
No	214	162 (76.1)	1.0
Neonatal respiratory distress				0.316
Yes	58	47 (81.0)	1.08 (0.93 to 1.26)
No	177	132 (75.0)	1.0
Neonatal jaundice				0.004
Yes	16	15 (93.8)	1.25 (1.07 to 1.44)
No	219	164 (75.2)	1.0
Neonatal sepsis				0.501
Yes	5	3 (60.0)	0.78 (0.38 to 1.61)
No	230	176 (76.9)	1.0
Perinatal death				0.779
Yes	11	8 (72.7)	0.95 (0.66 to 1.37)
No	224	171 (76.7)	1.0
Prematurity				0.485
Yes	106	83 (78.3)	1.05 (0.91 to 1.21)
No	129	96 (74.4)	1.0
Newborn classification				0.809
SGA	23	17 (73.9)	0.95 (0.74 to 1.23)
AGA	186	144 (77.4)	1,0
LGA	17	12 (70.6)	0.91 (0.66 to 1.25)
SGA: small for gestational age; AGA: adequate for gestational age; LGA: large for gestational age; RR: relative risk
*Wald test

This study observed a high prevalence of iodine deficiency in pregnant women with hypertensive disorders, especially CAH and GH. Twinning was the leading risk factor for iodine deficiency, while superimposed PE was a protective factor compared with other hypertensive disorders. Chorioamnionitis and neonatal jaundice were the perinatal outcomes associated with iodine deficiency.

Previous studies corroborate our findings on the high prevalence of iodine deficiency in pregnant women with hypertensive disorders [10, 28, 29]. Souza et al. [10] showed that hypertensive pregnant women who adhered to a salt-restricted diet increased 112% the risk of iodine deficiency, suggesting the need for iodine supplementation. Oxidative damage in the developing placenta could be a risk factor for PE, and iodine may have a protective effect as an antioxidant [28]. However, our results and two previous studies did not confirm this hypothesis [18, 30], highlighting that this study did not include pregnant women without hypertensive disorders.

Pregnant women with CAH and GH had the highest frequency of iodine deficiency, while those with PE and superimposed PE had the lowest frequencies. These findings could be explained by the divergent pathophysiology of these hypertensive disorders.

When pregnant women with CAH reduce salt consumption from the beginning of pregnancy, this may result in low UIC. Hypertensive disorders associated with pregnancy manifest pathophysiological changes from the 12th week onwards [31] (cases of PE) and in the 20th week [21] (cases of GH). Therefore, data collection in the third trimester may not reflect the iodine status when conditions arise. Although the iodine levels of pregnant women with PE may seem lower than normotensive women, further studies are needed to confirm that iodine deficiency is associated with an increased risk of PE [11, 32].

Iodine demand increases during pregnancy [14], and consequences related to its deficiency may vary according to the trimester of pregnancy [15]. A study showed that iodine deficiency peaked in the second trimester, increasing the risk of preeclampsia, fetal growth restriction, low birth weight, and prematurity [16]. Moreover, pregnant women from Spain with iodine deficiency in the third trimester were more likely to have newborns with low birth weight and small for gestational age [17]. In contrast, an English study analyzing the impact of iodine deficiency in all trimesters of pregnancy did not observe a difference between the incidence of PE, hypertension, gestational diabetes, prematurity, small newborns for gestational age, or postpartum hemorrhage [18]. Therefore, measuring UIC in all gestational trimesters would be better to assess the association between iodine deficiency and its outcomes.

Since iodine is an essential element of thyroid hormones, maternal thyroid dysfunction may cause maternal-perinatal adverse effects of severe iodine deficiency. Hypothyroidism during pregnancy has been associated with an increased risk of miscarriage, prematurity, PE, pregnancy-induced hypertension, low birth weight, and postpartum hemorrhage [4]. Among the perinatal complications evaluated, chorioamnionitis and neonatal jaundice were associated with iodine deficiency. However, this result requires caution, as our study did not evaluate maternal thyroid function, among 235 pregnant women, only one presented chorioamnionitis and iodine deficiency.

Hypothyroidism is the main cause of prolonged jaundice during the neonatal period. A study with 55 full-term newborns with prolonged jaundice showed that 45% of patients had subclinical hypothyroidism and the mean maternal UIC was 137.74 ± 135 µg/L. Although maternal UIC levels were similar (groups with and without hypothyroidism), newborns with subclinical hypothyroidism had higher UIC than euthyroid [26].

This study did not assess the duration of jaundice and thyroid function in newborns. Moreover, since this was a sample with a significant percentage of prematurity, this finding was possibly not only related to maternal UIC levels. Further studies with a specific design would be necessary to assess this association. In addition, twinning was associated with iodine deficiency due to an increased physiological demand for iodine. However, further studies with a larger sample are needed to confirm this association since only 3.7% were twinning in our study.

Conditions described as potential complications [16, 17], such as low birth weight, prematurity, and neonatal death were not associated with iodine deficiency in this study. Confounding factors may justify the divergent findings: UIC evaluation only in the third trimester (the pathophysiological mechanism of eclampsia would already be established), single and isolated measurement of UIC, lack of dietary assessment, and maternal and neonatal thyroid function. An early UIC evaluation and monitoring during all trimesters, associated with maternal and neonatal evaluation of thyroid function could provide consistent data for clinical parameters and maternal-perinatal outcomes.

The strengths of this study are the relevant number of pregnant women for UIC evaluation and its outcomes, a non-probabilistic convenience sample (representing the patients who attended the service), assessment of all pregnant women who had hypertensive disorders (categorizing and comparing them), and the prospective nature of the study, which allowed greater analytical power to detect an association. Detecting iodine deficiency during pregnancy is important to guide iodine intake. However, supplementation should be cautiously conducted, assessing the iodine status of the region of living and individual clinical characteristics, such as gestational hypertension with salt restriction.

Iodine deficiency was more prevalent in GH, CAH, and twinning. Neonatal jaundice was the perinatal complication associated with iodine deficiency, suggesting the need for investigation in this group of patients.

Author Contribution

All authors contributed to the conception and design of the study. Material preparation and data collection were performed by Adriana Duarte Miranda Queiroz, Maria Roseneide dos Santos Torres, Luana Cristina Fernandes Ratis, Maria Clara Vieira Morais, and Alex Sandro Rolland Souza. Data analysis was performed by Adriana Duarte Miranda Queiroz and Alex Sandro Rolland Souza.The first draft of the manuscript was written by Adriana Duarte Miranda Queiroz and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Acknowledgement

Special thanks to Prof. José Natal Figueiroa for perfoming and providing guidance on the statistical analysis.

Hatch-McChesney A, Lieberman HR (2022) Iodine and Iodine Deficiency: A Comprehensive Review of a Re-Emerging Issue. Nutrients14(17). doi:10.3390/nu14173474
The International Council for the Control of iodine Deficiency Disorders (ICCIDD). National iodine status in 2014 [online]. Ottawa, Ontario: ICCIDD Global Network. Published 2014. http://www.ign.org/. Accessed October 9, 2021.
United Nations Children’s Fund (UNICEF). Iodine deficiency still leaves millions of children atrisk of mental retardation [online]. New York: UNICEF. Published 2004. https://www.unicef.org/rosa/press-releases/nearly-19-million-newborns-risk-brain-damage-every-year-due-iodine-deficiency. Accessed February 9, 2022.
World Health Organization (WHO). Assessment of iodine deficiency disorders and monitoring their elimination: a guide for programme managers. Genebra, WHO. Published 2007. https://apps.who.int/iris/bitstream/handle/10665/43781/97 89241595827_eng.pdf. Accessed September 18, 2021.
Universidade Federal de Pelotas, Universidade Federal do Rio Grande (2020) Pesquisa Nacional para Avaliação do Impacto da Iodação do Sal (PNAISAL). Relatório Técnico Final. Published online 2016. http://189.28.128.100/dab/docs/portaldab/docu mentos/pnaisal_relatorio_final.pdf . Accessed June 2, 2021.
Cesar JA, Santos IS, Black RE, Chrestani MAD, Duarte FA, Nilson EAF (2020) Iodine Status of Brazilian School-Age Children: A National Cross-Sectional Survey. Nutrients 12(4):1-13. doi:10.3390/NU12041077
IODINE Global Network. Global Scorecard of Iodine Nutrition in 2021. https://ign.org/app/uploads/2023/04/IGN_Global_Scorecard_MAP_2021_SAC_-_7_May_2021.pdf. Accessed March 17, 2024.
Barca MF, Knobel M, Tomimori E, Cárdia MS, Zugaib M, Medeiros-Neto G (2001) Aspectos ultra-sonográficos e prevalência da tireoidite pós-parto em gestantes sem disfunção tireóidea atendidas em hospital público de São Paulo. Arquivos Brasileiros de Endocrinologia & Metabologia 45(2):180-189. doi:10.1590/S0004-27302001000200010
Soares R, Vanacor R, Manica D, et al (2008) Thyroid volume is associated with family history of thyroid disease in pregnant women with adequate iodine intake: a cross-sectional study in southern Brazil. J Endocrinol Invest 31(7):614-617. doi:10.1007/BF03345612
Sant’Ana Leone de Souza L, de Oliveira Campos R, dos Santos Alves V, et al (2020) Hypertension and Salt-Restrictive Diet Promotes Low Urinary Iodine Concentration in High-Risk Pregnant Women: Results from a Cross-Sectional Study Conducted After Salt Iodination Reduction in Brazil. Biol Trace Elem Res 197(2):445-453. doi:10.1007/S12011-020-02028-8
Cuellar-Rufino S, Navarro-Meza M, García-Solís P, Xochihua-Rosas I, Arroyo-Helguera OE (2017). Iodine levels are associated with oxidative stress and antioxidant status in pregnant women with hypertensive disease. Nutr Hosp 34(3):661-666. doi:10.20960/NH.460
Elind AHO, Brazdova A (2016). Trace Elements as Potential Biomarkers of Preeclampsia. Annu Res Rev Biol 9(1):1-10. doi:10.9734/ARRB/2016/20342
Soldin OP (2002). Controversies in urinary iodine determinations. Clin Biochem 35(8):575-579. doi:10.1016/S0009-9120(02)00406-X
Alexander EK, Pearce EN, Brent GA, et al (2017) 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid 27(3):315-389. doi:10.1089/THY.2016.0457
Candido AC, Azevedo FM, Machamba AAL, et al (2021) Implications of iodine deficiency by gestational trimester: a systematic review. Arch Endocrinol Metab 64(5):507-513. doi:10.20945/2359-3997000000289
Charoenratana C, Leelapat P, Traisrisilp K, Tongsong T (2016) Maternal iodine insufficiency and adverse pregnancy outcomes. Matern Child Nutr 12(4):680-687. doi:10.1111/MCN.12211
Alvarez-Pedrerol M, Guxens M, Mendez M, et al (2009) Iodine levels and thyroid hormones in healthy pregnant women and birth weight of their offspring. Eur J Endocrinol 160(3):423-429. doi:10.1530/EJE-08-0716
Torlinska B, Bath SC, Janjua A, Boelaert K, Chan SY (2018) Iodine status during pregnancy in a region of mild-to-moderate iodine deficiency is not associated with adverse obstetric outcomes; Results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Nutrients 10(3). doi:10.3390/nu10030291
Atalah Samur E, Castillo LC, Castro Santoro R, Aldea PA (1997) Propuesta de un nuevo estándar de evaluación nutricional en embarazadas. Rev méd Chile 1429-1436.
American Diabetes Association (ADA) (2024) Management of Diabetes in Pregnancy: Standards of Care in Diabetes—2024. Diabetes Care 47:S282-S294. doi:10.2337/dc24-S015
Magee LA, Brown MA, Hall DR, et al (2022) The 2021 International Society for the Study of Hypertension in Pregnancy classification, diagnosis & management recommendations for international practice. Pregnancy Hypertens 27:148-169. doi:10.1016/j.preghy.2021.09.008
Brasil. Ministério da Saúde. Manual AIDPI neonatal, 3^a Ed. Brasília. Published 2012. https://bvsms.saude.gov.br/bvs/publicacoes/maual_aidpi_neonatal_quadro_procedimentos.pdf. Accessed January 10, 2022.
American College of Obstetrician and Gynecologists (ACOG) (2017) Postpartum Hemorrhage _ ACOG. Practice bulletin n^o 183 Summary 130(4):923-925.
Carter SWD, Neubronner S, Su LL, et al (2023) Chorioamnionitis: An Update on Diagnostic Evaluation. Biomedicines 11(11). doi:10.3390/biomedicines11112922
Roeper M, Hoermann H, Kummer S, Meissner T (2023) Neonatal hypoglycemia: lack of evidence for a safe management. Front Endocrinol (Lausanne) 14. doi:10.3389/fendo.2023.1179102
Şiklar Z, Öçal G, Bilir P, Ergur A, Berberoǧlu M (2009) “Maternal/neonatal” iodine status in patients with prolonged physiological jaundice. Experimental and Clinical Endocrinology and Diabetes 117(7):312-315. doi:10.1055/s-0028-1086001
Celik IH, Hanna M, Canpolat FE, Mohan Pammi (2022) Diagnosis of neonatal sepsis: the past, present and future. Pediatr Res 91(2):337-350. doi:10.1038/s41390-021-01696-z
Cuellar-Rufino S, Navarro-Meza M, García-Solís P, Xochihua-Rosas I, Arroyo-Helguera OE (2017) Los niveles de yodo están asociados con estrés oxidativo y estado antioxidante en mujeres embarazadas con enfermedad hipertensiva. Nutr Hosp 34(3):661-666. doi:10.20960/nh.460
Businge CB, Longo-Mbenza B, Kengne AP (2022) Iodine deficiency in pregnancy along a concentration gradient is associated with increased severity of preeclampsia in rural Eastern Cape, South Africa. BMC Pregnancy Childbirth 22(1). doi:10.1186/s12884-021-04356-6
Reische EC, Männistö T, Purdue-Smithe A, et al (2021) The Joint Role of Iodine Status and Thyroid Function on Risk for Preeclampsia in Finnish Women: a Population-Based Nested Case-Control Study (199):2131-2137. doi:10.1007/s12011-020-02341-2
Burton GJ, Redman CW, Roberts JM, Moffett A (2019) Pre-eclampsia: pathophysiology and clinical implications. The BMJ 15:366:l2381. doi:10.1136/bmj.l2381
Businge CB, Usenbo A, Longo-Mbenza B, Kengne AP (2021) Insufficient iodine nutrition status and the risk of pre-eclampsia: a systemic review and meta-analysis. BMJ Open 11(2):e043505. doi:10.1136/BMJOPEN-2020-043505

No competing interests reported.

Download PDF

Version 1

posted

You are reading this latest preprint version

Prevalence of Iodine Deficiency, Associated Factors, and Perinatal Outcomes in Pregnant Women With Hypertensive Disorders

Status:

Version 1

Abstract

Objectives

Methods

Results

Conclusion

Figures

Introduction

Methods

Results

Discussion

Conclusion

Declarations

Author Contribution

Acknowledgement

References

Additional Declarations

Status:

Version 1