Maternal and neonatal urinary iodine excretion and neonatal TSH in relation to use of antiseptic during caesarean section in an iodine sufficient area

Iodine Metabolism and Thyroid Function During the Perinatal Period: Maternal-Neonatal Correlation and Effects of Topical Povidone-Iodine Skin Disinfectants

An adequate maternal iodine intake during pregnancy and lactation is essential for growth and mental development in fetuses and newborns. There are limited data on perinatal iodine metabolism in mothers and infants, as well as the effect of povidone-iodine (PVP-I) antiseptics used in cesarean delivery. The urinary iodine concentration (UIC), serum iodine, thyrotropin (TSH), free thyroxine (FT4), and breast milk iodine concentration (BMIC) were measured consecutively in a total of 327 mothers and 249 term-infants in two prospective studies. The maternal median UIC was 164 μg/L in the third trimester, increased to 256 μg/L at 44 h after birth, and then decreased to 116 μg/L 1 month later. The BMIC on the 4th and 32th postpartum days was 17.6 and 13.5 μg/100 g, respectively. In neonatal infants born to the mothers unexposed to PVP-I, the median UIC was 131 μg/L in the first voiding urine and increased to 272 μg/L on day 4 and then slightly decreased to 265 μg/L on day 28 suggesting sufficient iodine reserve at birth. PVP-I antiseptics containing 1 g of iodine for skin preparation at cesarean delivery transiently increased maternal serum iodine concentration (1.9-fold), UIC (7.8-fold) at 41 h after surgery and BMIC, while it had little effect on maternal TSH, FT4, and neonatal UIC, TSH, or FT4. The iodine status of pregnant women and their infants was adequate in this population; however, the UIC in lactating mothers at one postpartum month was low enough to suggest iodine deficiency or near iodine deficiency. Further studies are necessary.

Vaginal cleansing before unscheduled cesarean delivery to reduce infection: a randomized clinical trial

BACKGROUND

Cesarean delivery is the most performed major surgery among women, and surgical-site infections following a cesarean delivery are a significant source of postoperative morbidity. It is unclear if vaginal cleansing before a cesarean delivery decreases post-cesarean delivery infectious morbidity.

OBJECTIVE

This study aimed to evaluate if preoperative vaginal cleansing with povidone-iodine among women undergoing a cesarean delivery after labor decreases postoperative infectious morbidity.

STUDY DESIGN

This randomized clinical trial was conducted from August 3, 2015 to January 28, 2021, with 30 days of follow-up and the final follow-up completed on February 27, 2021. Patients met the inclusion criteria if they underwent a cesarean delivery after regular contractions with cervical dilation, rupture of membranes, or any cesarean delivery performed at >4 cm dilation. Participants were randomly assigned in a 1:1 ratio to either abdominal cleansing plus vaginal cleansing with 1% povidone-iodine or abdominal cleansing alone. The primary outcome was composite infectious morbidity including surgical-site infection, fever, endometritis, and wound complications within 30 days after the cesarean delivery. Secondary outcomes included individual components of the composite, length of hospital stay, postoperative hospitalization or outpatient treatment related to infectious morbidity, and empirical treatment for neonatal sepsis.

RESULTS

A total of 608 subjects (304 vaginal cleansing group, 304 control group) were included in the intention-to-treat analysis. Patient characteristics were similar between groups. There was no significant difference in the primary composite outcome between the 2 groups (11.8% vs 11.5%; P=.90; relative risk, 1.0; 95% confidence interval, 0.7-1.6). Individual components of the composite and secondary outcomes were also not significantly different between the groups. Similar findings were observed in the as-treated analysis (11.3% vs 11.8%; P=.9; relative risk, 1.0; 95% confidence interval, 0.7-1.6).

CONCLUSION

Vaginal cleansing with povidone-iodine before an unscheduled cesarean delivery occurring after labor did not reduce the postoperative infectious morbidity. These findings do not support the routine use of vaginal cleansing for women undergoing a cesarean delivery after labor.

Is There an Ideal Diet to Protect against Iodine Deficiency?

Iodine deficiency is a global issue and affects around 2 billion people worldwide, with pregnant women as a high-risk group. Iodine-deficiency prevention began in the 20th century and started with global salt iodination programmes, which aimed to improve the iodine intake status globally. Although it resulted in the effective eradication of the endemic goitre, it seems that salt iodination did not resolve all the issues. Currently, it is recommended to limit the consumption of salt, which is the main source of iodine, as a preventive measure of non-communicable diseases, such as hypertension or cancer the prevalence of which is increasing. In spite of the fact that there are other sources of iodine, such as fish, seafood, dairy products, water, and vegetables, the high consumption of processed food with a high content of unionised salt, alternative diets or limited salt intake can still lead to iodine deficiency. Thus, iodine deficiency remains a relevant issue, with new, preventive solutions necessary. However, it appears that there is no diet which would fully cover the iodine requirements, and iodine food supplementation is still required.

Povidone-Iodine Use in Sinonasal and Oral Cavities: A Review of Safety in the COVID-19 Era

OBJECTIVES

Approaches to nasal and oral decontamination with povidone-iodine (PVP-I) have been published to reduce nosocomial spread of Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2). The safety of PVP-I topically applied to the nasal and oral cavity is addressed by a literature review. The specific efficacy of PVP-I against coronaviruses and its potential efficacy against SARS-CoV-2 is discussed.

METHODS

A review was performed utilizing PubMed and Cochrane Databases. All citations in protocols for nasal and oral PVP-I use regarding COVID-19 were independently reviewed.

RESULTS

Povidone-iodine has been safely administered for up to 5 months in the nasal cavity and 6 months in the oral cavity. Concentrations less than 2.5% in vitro do not reduce ciliary beat frequency or cause pathological changes in ciliated nasal epithelium, upper respiratory, or mucosal cells. Adverse events with oral use have not been reported in conscious adults or children. Allergy and contact sensitivity is rare. Chronic mucosal use up to 5% has not been shown to result in clinical thyroid disease. PVP-I is rapidly virucidal and inactivates coronaviruses, including SARS-CoV and Middle East Respiratory Syndrome (MERS).

CONCLUSIONS

Povidone-iodine can safely be used in the nose at concentrations up to 1.25% and in the mouth at concentrations up to 2.5% for up to 5 months. Povidone-iodine rapidly inactivates coronaviruses, including SARS and MERS, when applied for as little as 15 seconds. There is optimism that PVP-I can inactivate SARS-CoV-2, but in vitro efficacy has not yet been demonstrated.

Neonatal thyrotropin concentration and iodine nutrition status of mothers: a systematic review and meta-analysis

BACKGROUND

Low maternal iodine intake disturbs the thyroid function of neonates transiently or permanently.

OBJECTIVE

To our knowledge, we conducted one of the first systematic reviews and meta-analyses aimed at exploring the association of neonatal thyrotropin concentrations and iodine status of mothers during pregnancy and early postpartum periods.

DESIGN

Data were collected through literature searches for studies published between 1969 and 2015 with the use of electronic databases. Mean or median maternal urinary iodine and neonatal thyrotropin concentrations, along with other relevant data, were extracted from eligible studies. The quality and risk of bias of each study was assessed.

RESULTS

A random-effects model was used for the analysis. Of 110 studies identified, 25 trials were shown to be eligible for inclusion in the meta-analysis. Mean (95% CI) thyrotropin concentrations of neonates born to mothers with iodine deficiency were higher than in neonates born to mothers with iodine sufficiency during pregnancy in both heel blood samples [1.79 mIU/L (95% CI: 1.61, 1.97 mIU/L) compared with 1.75 mIU/L (95% CI: 1.68, 1.82 mIU/L), respectively] and cord blood samples [11.91 mIU/L (95% CI: 6.67, 17.14 mIU/L) compared with 6.15 mIU/L (95% CI: 4.30, 8.01 mIU/L), respectively]. There were no significant differences in neonatal thyrotropin concentrations of heel samples between mothers with iodine deficiency and those with sufficiency during the early postpartum period; however, the values of thyrotropin in cord samples of neonates born to mothers with iodine deficiency were significantly higher than in neonates born to mothers with iodine sufficiency [11.62 mIU/L (95% CI: 10.47, 12.77 mIU/L) compared with 7.40 mIU/L (95% CI: 6.21, 8.59 mIU/L)].

CONCLUSION

Our findings reveal that, compared with heel blood samples, neonatal thyrotropin in samples collected from the cord are more sensitive to the iodine status of mothers; however, further investigations are required in this regard.

Iodine-containing disinfectants in preparation for caesarean section: impact on thyroid profile in cord blood

BACKGROUND

Iodine-containing disinfectants are widely used for skin preparation before caesarean section. Current evidence suggests that maternal exposure to these disinfectants results in thyroid dysfunction in the newborns, but its extent is not known.

OBJECTIVES

The purpose of this study was to explain the quality of the effect of these disinfectants on the thyroid function of newborns.

METHODS

This cohort study was performed on all the healthy mothers with a term pregnancy who underwent caesarean section in the obstetrics emergency department of an educational hospital affiliated with Tehran University of Medical Sciences from December 2013 to December 2014. We divided this 12-month period into two consecutive 6 months. Povidone-iodine 10% (PVP-I) and chlorhexidine gluconate 4% (CHX) were used in the first and second 6 months, respectively, for skin preparation before caesarean section and also for umbilical cord disinfection. Cord blood thyroid stimulating hormone (TSH) and thyroxine (T4) were assayed by the ELISA method.

RESULTS

We included 326 cases in this study, 153 in the PVP-I group and 173 in the CHX group. The incidence of cord blood TSH ≥ 10 mIU/L and T4 ≤ 7.3 µg/dL was significantly higher in the PVP-I than the CHX group. Cord blood TSH concentration showed a significant positive correlation with cord blood T4 concentration in the CHX group. Through selection of cases with cord blood T4 < 13 µg/dL, we found a negative correlation between cord blood TSH and T4 concentration in the PVP-I group.

CONCLUSIONS

It seems that PVP-I has the potential to cause false-positive screening-test results and increase recall rates, which should be evaluated in further studies.

TRIAL REGISTRATION NUMBER

Iranian Registry of Clinical Trials (IRCT) number IRCT201204289568N1.

Maternal and neonatal urinary iodine status and its effect on neonatal TSH levels in a mildly iodine-deficient area

OBJECTIVE

Iodine deficiency and excess are the most important factors that affect screening and recall rates of congenital hypothyroidism. The purpose of this study was to investigate the urinary iodine status in newborns and their mothers and its effects on neonatal thyroid-stimulating hormone (TSH) levels in a mildly iodine-deficient area.

METHODS

A total of 116 newborns and their mothers were included in the study. Urinary iodine levels were measured from healthy mothers and their babies on the 5th day following birth. Neonatal TSH levels were screened, and TSH and free thyroxine (fT4) levels were measured on the 15th day in the recall cases. T4 treatment was started in infants with high TSH and low fT4 levels. These measurements were repeated on the 30th day in these newborns.

RESULTS

Ninety-nine percent of the mothers included in the study were using iodized salt. The median urinary iodine level in the newborns was 279 µg/L, while it was 84 µg/L in their mothers. The rate of iodine deficiency among the mothers was 56.8%, and the rate of iodine excess was 8.6%. This rate was 10.3% for iodine deficiency and 61.2% for iodine excess in the newborns. The recall rate at the screening was 9.5% (n=11). The urinary iodine levels were above 200 µg/L in three newborns who had transient hyperthyrotropinemia.

CONCLUSIONS

Iodine deficiency was more frequently observed in nursing mothers, and iodine excess was more frequently seen in their newborns. The iodine excess noted in the newborns was attributed to the use of antiseptics containing iodine. The iodine excess leads to increases in recall rates, screening costs, and frequency of transient hyperthyrotropinemia.

Myth: babies would choose prelabour caesarean section

Interest in rising caesarean section (CS) rates focuses on the putative relative effects on maternal health and perinatal mortality, especially in 'non-medical', 'request' or 'repeat' planned prelabour CS (PLCS). Shortening pregnancy and avoiding labour affect fetal maturity. Babies who do not experience labour have significantly increased respiratory and other morbidities that may have profound effects on development, determining immediate and potentially life-long disease. It is thus surprising that obstetricians do not advocate awaiting or inducing labour even in women considering CS. Mothers must be fully informed of all the evidence before they can give valid consent and make decisions on their baby's behalf. New evidence about immunological and metabolic differences induced by obstetric interventions continues to emerge, but large knowledge gaps exist. Although all modes of delivery carry potential risk of neonatal morbidity or mortality, we conclude that normal babies would indeed 'choose' labour.