Iodine Status over Two Decades: Influence of Seaweed Exposure.

Iodine deficiency is known to result in deficits in neuropsychological development in children born to iodine deficient mothers. However, a remedy in terms of iodisation of table salt as is the norm in most countries, has not been embraced by Ireland. The borderline iodine status of the Irish population persists unchanged over the past 20 years with the annual median urinary iodine (UI) varying from 62.9 to 105 µg/L; overall median 72.4 µg/L (WHO recommended 100 µg/L). Exposure to a seaweed rich environment allowing for intake by respiration of seaweed derived gaseous iodine, rather than simple proximity to the sea, confers advantages in terms of iodine intake with 21/46 (45.6%) of schoolchildren in seaweed rich coastal areas having UI values > 150 µg/L compared to 1/28 (3.6 %) and 2/93 (2.2%) in low seaweed abundant coastal and inland areas respectively. The corresponding values for adult females were 31/72 (43%), 7/60 (11.6%) and 21/132 (16.0%). The findings support introduction of iodine prophylaxis through Universal Salt Iodisation (USI), to ensure that women of child bearing age have access to sufficient dietary iodine.

Does anal sphincter injury preclude subsequent vaginal delivery?

OBJECTIVE: To assess continence and anal sphincter integrity during a subsequent pregnancy and delivery in women known to have a previous anal sphincter injury. DESIGN: Prospective observational study. SETTING: The National Maternity Hospital, Dublin, Ireland. POPULATION: Antenatal patients with a documented obstetric anal sphincter injury at a previous delivery. METHODS: Women underwent symptom scoring, endoanal ultrasound and manometry. MAIN OUTCOME MEASURES: Recommended and actual mode of delivery, continence scores and endoanal ultrasound findings after index delivery. RESULTS: 557 women were studied. 293 (53%) had no symptoms of faecal incontinence, 189 (34%) had mild symptoms and 75 (13%) moderate or severe symptoms. 408 (73%) had an endoanal ultrasound. 383(94%) had a normal or small (<1 quadrant) defect in the internal anal sphincter and 390 (96%) had a scar or small (<1e quadrant) defect in the external anal sphincter. 393 (70%) delivered vaginally. 164 (30%) were delivered by caesarean section. 197/557 (35%) returned for follow-up. There was no significant change in continence following either vaginal or caesarean delivery. 20 (5.1%) women had a recognised second anal sphincter tear during vaginal delivery. CONCLUSIONS: The majority of women who sustain a third degree tear have minimal or no symptoms of faecal incontinence when assessed antenatally in a subsequent pregnancy. 70% go on to have a vaginal delivery, with little impact on faecal continence. These findings provide reassurance for patients and clinicians about the safety of vaginal delivery following anal sphincter injury in appropriately selected patients.

Umbilical cord prolapse--changing patterns and improved outcomes: a retrospective cohort study.

OBJECTIVE: Umbilical cord prolapse is an acute obstetrical emergency requiring rapid identification and intervention. Its management has undergone significant changes over the past century. This study aims to document the changes in incidence, morbidity, and perinatal mortality over a 69-year period. DESIGN: A retrospective review of the annual clinical reports of the National Maternity Hospital, Dublin, Ireland, was performed. SETTING: The National Maternity hospital was founded in 1894 and has nearly 10,000 deliveries each year. POPULATION: All deliveries in the hospital for each year are included in each annual report. METHODS: We reviewed the reports from a 69-year period (1940-2009). Information from the reports was collated into a database and analysed using Microsoft excel 2007. MAIN OUTCOME MEASURES: Incidence and outcome of all cases of umbilical cord prolapse were recorded, along with the neurological outcome of all neonatal survivors (available since 1970). RESULTS: The incidence of cord prolapse has decreased from 6.4/1000 live births in the 1940s to 1.7/1000 [corrected] live births in the last decade. Perinatal survival increased from 46 to 94% in the same period of time. This is inversely related to the use of caesarean section as the recommended method of delivery in this emergency. Short- and long-term neurological impairment remains rare. CONCLUSIONS: There has been a large reduction in the incidence of cord prolapse over a period of 69 years. A reduction in grand multiparity and use of caesarean section as the gold standard for delivery are likely to have accounted for the changes seen. Neurological impairment remains unusual.

Are women having a vaginal birth after a previous caesarean delivery at increased risk of anal sphincter injury?

OBJECTIVE: To examine the incidence of obstetric anal sphincter injury in women who had a successful vaginal birth after a previous caesarean delivery (VBAC). DESIGN: Retrospective analysis of prospectively gathered data. SETTING: A tertiary referral university institution. POPULATION: All secundiparous women with a previous caesarean delivery who had a VBAC from 2001 to 2011. METHODS: Details of maternal demographics, intrapartum characteristics and outcomes were examined in cases of VBAC with accompanying anal sphincter injury. MAIN OUTCOME MEASURES: Rates of obstetric anal sphincter injury and associated risk factors. RESULTS: During the study period there were 3071 trials of labour in secundiparous women with a previous caesarean delivery; 65% (1981/3071) of these had a successful VBAC. Women having a VBAC were at greater risk of anal sphincter injury than nulliparous women having a vaginal delivery over the same period (5% [98/1981] versus 3.5% [1216/34,496], P = 0.001, odds ratio 1.4, 95% CI 1.15-1.75). The rate of instrumental delivery in woman having a VBAC was 39% (771/1981). On multiple logistic regression analysis an increased rate of instrumental delivery was a strong predictor of sphincter injury (P = 0.03, odds ratio 1.15, 95% CI 1.01-1.3). When the first labours of women with sphincter injury in the VBAC group were examined, 70% (60/86) had been in labour before undergoing their caesarean delivery. CONCLUSION: The incidence of anal sphincter injury in women undergoing VBAC is 5% and birthweight is the strongest predictor of this. The rate of instrumental delivery in this group was also increased.

Randomised controlled trial comparing early home biofeedback physiotherapy with pelvic floor exercises for the treatment of third-degree tears (EBAPT Trial).

OBJECTIVE: To compare early home biofeedback physiotherapy with pelvic floor exercises (PFEs) for the initial management of women sustaining a primary third-degree tear. DESIGN: Single centre, randomised trial. SETTING: National Maternity Hospital, Dublin, Ireland. POPULATION: A total of 120 women sustaining a primary third-degree tear. METHODS: Women were randomised in a one to three ratio: 30 to early postpartum home biofeedback physiotherapy and 90 to PFEs. MAIN OUTCOME MEASURES: Differences in anorectal manometry results, Cleveland Clinic continence scores and Rockwood faecal incontinence quality of life scale scores after 3 months of postpartum treatment. RESULTS: The mean anal resting pressure was 39 ± 13 mmHg in the early biofeedback physiotherapy group and 43 ± 17 mmHg in the PFE group. The mean anal squeeze pressure was 64 ± 17 mmHg in the biofeedback group and 62 ± 23 mmHg in the PFE group. There was no significant difference in anal resting and squeeze pressure values between the groups (P = 0.123 and P = 0.68, respectively). There were no differences in symptom score and quality of life measurements between the groups. CONCLUSIONS: This study demonstrates no added value in using early home biofeedback physiotherapy in the management of women sustaining third-degree tears. Poor compliance may have contributed because women found it difficult to designate time to using biofeedback.

Regulation of iodide uptake in placental primary cultures.

BACKGROUND: Maintenance of adequate iodide supply to the developing fetus is dependent not only on maternal dietary iodine intake but also on placental iodide transport. The objective of this study was to examine the effects of different pregnancy-associated hormones on the uptake of radioiodide by the placenta and to determine if iodide transporter expression is affected by hormone incubation. METHODS: Primary cultures of placental trophoblast cells were established from placentas obtained at term from pre-labor caesarean sections. They were pre-incubated with 17ß-estradiol, prolactin, oxytocin, human chorionic gonadotropin (hCG) and progesterone either singly or in combination over 12 h with (125)I uptake being measured after 6 h. RNA was isolated from placental trophoblasts and real-time RT-PCR performed using sodium iodide symporter (NIS) and pendrin (PDS) probes. RESULTS: Significant dose response increments in (125)I uptake by trophoblast cells (p < 0.01) were observed following incubation with hCG (60% increase), oxytocin (45% increase) and prolactin (32% increase). Although progesterone (50-200 ng/ml) and 17ß-estradiol (1,000-15,000 pg/ml) alone produced no significant differences in uptake, they facilitated increased uptake when combined with prolactin or oxytocin, with a combination of all four hormones producing the greatest increase (82%). Increased (125)I uptake was accompanied by corresponding increments in NIS mRNA (ratio 1.52) compared to untreated control cells. No significantly increased expression levels of PDS were observed. CONCLUSIONS: Pregnancy-associated hormones, particularly oxytocin and hCG, have a role in promoting placental iodide uptake which may protect the fetus against iodine deficiency.

Comparison of the motor discharge to the voluntary sphincters of continence in the rat.

BACKGROUND: The rat external anal sphincter (EAS) and external urethral sphincter (EUS) are voluntary muscles of continence that can display similar synchronous electromyographic (EMG) activity patterns. However, the two sphincters are quite different in structure and function. The EUS is a fast twitch muscle and contains fibers expressing type 2B myosin. In contrast, the EAS exhibits slower kinetics and lacks type 2B fibers. This striking contrast in kinetics and fiber type profiles may be shaped by differences in the basal motor drive that each sphincter receives. METHODS: A double EMG approach was used to obtain spontaneously active single motor unit action potentials from the EUS and EAS simultaneously and compare their basal discharge frequencies in urethane anaesthetized rats. KEY RESULTS: The basal firing rates of motor units of the EUS and EAS were not significantly different (3.9 ± 0.9 Hz vs. 3.1 ± 1.6 Hz, respectively, n = 7 animals, P = 0.32, paired Student's t-test). However, auto-correlogram analysis showed that EUS is driven by neurons with faster instantaneous firing frequencies: 30.5 ± 2.4 Hz vs 14.3 ± 0.9 Hz in the EAS (P = 0.03, paired Student's t-test). CONCLUSIONS & INFERENCES: The oscillator(s) driving the EUS operate(s) at a frequency twice that of the EAS. This may explain the presence of type 2B fibers in the EUS. In the inter-micturition periods no cross correlation was found in motor discharge to the sphincters suggesting that the two muscles do not share a common central drive to sustain the continent tonus of the two outlet tracts.

Combined ischemic and neuropathic insult to the anal canal in an animal model of obstetric-related trauma.

BACKGROUND: Childbirth, in particular, when it involves instrumental vaginal delivery, can result in direct trauma to the external anal sphincter muscle. In addition, a global injury to the pelvic floor, including neurovascular injury to the anal sphincter complex, may occur. OBJECTIVE: The aims of this study were to determine whether sensory drive from the anal canal and oxygenation of the external anal sphincter were compromised during simulated labor in a validated animal model of obstetric trauma. DESIGN: Fifteen female Wister rats were operated on. Group 1 (n = 5) underwent pelvic balloon compression for 1 hour to simulate increased pelvic pressure during childbirth. Somatosensory cortical potentials, evoked by electrically stimulating the anal canal, were tracked. In group 2 (sham), the balloons were not inflated. In group 3, tissue PO2 values of the external anal sphincter and femoral arterial blood flow were measured simultaneously during the period of balloon inflation. RESULTS: The peak amplitude of cortical evoked potentials was reduced (from 11.8 ± 1.5 µV to 3.1 ± 1.1 µV) during pelvic compression (p = 0.002, ANOVA). During this period, arterial blood flow to the hindlimb and the external anal sphincter tissue PO2 decreased by 20% (p < 0.001) and 60% (p < 0.001). CONCLUSION: Pelvic compression that mimics obstetric trauma is associated with diminished anocortical drive. This neural insult may be compounded by concomitant ischemia of the external anal sphincter.

Sacral nerve stimulation increases activation of the primary somatosensory cortex by anal canal stimulation in an experimental model.

BACKGROUND: Sacral and posterior tibial nerve stimulation may be used to treat faecal incontinence; however, the mechanism of action is unknown. The aim of this study was to establish whether sensory activation of the cerebral cortex by anal canal stimulation was increased by peripheral neuromodulation. METHODS: A multielectrode array was positioned over the right primary somatosensory cortex of anaesthetized rats. A brief burst of electrical stimulation was applied to either the left sacral root or the left posterior tibial nerve, and evoked potentials from anal canal stimulation were signal-averaged at intervals over 1 h. At the end of the experiment, the cerebral cortex was removed and probed for polysialylated neural cell adhesion molecule (PSA-NCAM). RESULTS: Sacral nerve root and posterior tibial nerve stimulation significantly increased the peak amplitude of primary cortical evoked potentials by 54.0 and 45.1 per cent respectively. This change persisted throughout the period of observation. The density of PSA-NCAM-positive cells in the somatosensory cortex underlying the electrode array was increased by approximately 50 per cent in the sacral nerve-stimulated group. CONCLUSION: Brief sacral neuromodulation induces profound changes in anal canal representation on the primary somatosensory cortex, providing a plausible hypothesis concerning the mechanism of action of neuromodulation in the treatment of faecal incontinence.

Effect of injury on S1 dorsal root ganglia in an experimental model of neuropathic faecal incontinence.

BACKGROUND: An experimental model of neuropathic faecal incontinence has recently been established. This study aimed to quantify and compare the effect of crush and compression injury on first-order sensory neurones of the inferior rectal nerve (IRN) using a nuclear marker of axonal injury, activating transcription factor (ATF) 3. METHODS: Eighteen Wistar rats were allocated to three groups: an unoperated control group, an IRN crush group (positive control) and a retrouterine balloon compression group. Five days after surgery, all animals were anaesthetized and perfused with fixative, and S1 dorsal root ganglia (DRG) were harvested. The tissue was sampled and neuronal nuclear ATF-3 expression calculated. RESULTS: Estimated total S1 DRG ATF-3 nuclear labelling was higher in the nerve crush (median (interquartile range) 171 (60-824) cells) and balloon compression (59 (20-274) cells) groups, compared with that in the unoperated control group (9 (3-24) cells) (P = 0.001 and P = 0.008 respectively). In all groups, most neurones displaying the marker of injury were of the C-fibre class. CONCLUSION: This study confirmed the presence of axonal injury in a pelvic compression model of obstetric injury. C-fibre afferent pathways appeared to be most vulnerable. Neuromodulation may function through augmentation of residual C-fibre pathways.

Is placental iodine content related to dietary iodine intake?

OBJECTIVE: Delivery of iodine to the foetus depends not only on maternal dietary iodine intake but also on the presence of a functioning placental transport system. A role for the placenta as an iodine storage organ has been suggested, and this study compares the iodine content of placentas from women giving birth at term in Ireland and Iran, areas with median urinary iodine of 79 and 206 µg/l respectively. DESIGN: Placental cotyledon iodine was measured using an alkaline ashing technique with Sandell-Kolthoff kinetic colorimetry. Samples were taken from six sites from the centre and periphery of each cotyledon. Placentas (Ireland n = 58; Iran n = 45) were obtained from consecutive euthyroid women delivering at term. RESULTS: The median placental iodine (µg/g wet weight) was significantly higher in Iranian than in Irish women (187·2 µg/g vs 34·3 µg/g; P < 0·001). The distribution of individual placental iodine values showed that values >50µg/g were found in 71·0% of Iranian and in only 21·0% of Irish samples. In Irish subjects, the relationship of placental iodine to pregnant population urinary iodine (UI) (ng/g:µg/l) was 1:2 (40:79), while in Iranians this ratio is closer to 1:1 (211:206). CONCLUSIONS: These findings, by demonstrating an apparent ability of the placenta to store iodine in a concentration-dependent manner, suggest a hitherto undetected role for the placenta. Whether placental iodine has a role in protecting the foetus from inadequacies in maternal dietary iodine intake is as yet unknown.

Ethnic variation between white European women in labour outcomes in a setting in which the management of labour is standardised-a healthy migrant effect?

OBJECTIVE: To test the hypothesis that women from Eastern European countries have lower caesarean delivery rates and higher spontaneous labour rates relative to Irish women in a setting in which the management of labour is standardised. DESIGN: A retrospective review of prospectively collected data. SETTING: Tertiary referral centre, Dublin, Ireland. POPULATION: All Irish and Eastern European term nulliparous women who laboured and delivered in 2008. METHODS: A comparison of labour outcomes between women from Ireland and women from Eastern European countries. MAIN OUTCOME MEASURES: The principal outcomes measured were the gestational age at onset of labour, whether labour was spontaneous or induced, the need for oxytocin augmentation, duration of labour, mode of delivery, epidural use and birthweight. RESULTS: Of 2556 Irish (n = 2041) and Eastern European (n = 511) term cephalic singleton labours in the calendar year 2008, women from Eastern Europe were significantly more likely to labour spontaneously (74.6% versus 65.9%, P < 0.001), required less epidural analgesia (68.4% versus 59.7%) and were significantly less likely to require delivery by caesarean section (8.6% versus 15.7%, P < 0.001) than Irish women. This is despite no significant difference between the two groups with regard to mean birthweight (3581 g versus 3569 g, P = 0.6) or macrosomia (birthweight over 4000 g) (18% versus 16%, P = 0.4). There were significant differences in maternal age at delivery (27.2 years versus 29.2 years, P < 0.001) and body mass index (BMI) (24.1 kg/m² versus 25.4 kg/m², P < 0.001) between the two groups. CONCLUSION: These findings confirm our hypothesis that economic migrants from Eastern European countries exhibit a so-called 'healthy migrant effect' in terms of obstetric outcomes.

Current trends in Irish perinatal mortality.

This was a retrospective review of normally formed perinatal deaths among 176,620 births at the National Maternity Hospital (1984-2007). Prelabor stillbirths were categorised by presumed cause of death including unexplained, intrauterine growth retardation (IUGR), placental abruption, red cell alloimmunisation (RCA) and deaths related to prematurity. Peripartum deaths included intrapartum and first week neonatal deaths. The post-mortem rate, initially almost 100%, fell to 60%. Data were analysed using the Mantel-Haenszel chi square test for trends. In the study period there was a significant reduction in the PNM, largely because of a fall in death related to prematurity, term peripartum death, death at 42 weeks or greater, placental abruption, death related to IUGR and RCA (P < 0.01). Overall the unexplained still birth rate was unchanged throughout the study period (p = 0.8) despite a highly significant (p < 0.001) increase in obstetric intervention particularly induction of labor and caesarean section.

Appropriate antenatal corticosteroid use in women at risk for preterm birth before 34 weeks of gestation.

OBJECTIVE: To determine the utilisation of antenatal corticosteroid administration in women presenting at risk of preterm birth (PTB) in a centre where tocolytics are not prescribed. DESIGN: A prospective cohort study. SETTING: Tertiary referral centre, Dublin, Ireland. POPULATION: Four hundred and fourteen consecutive women presenting at risk of PTB. METHODS: Clinical details were collated prospectively on all booked patients who presented at risk of PTB (i.e. at <34 weeks of gestation) during 2008. MAIN OUTCOME MEASURE: Rate of administration of antenatal corticosteroids in PTB. RESULTS: Of 8985 deliveries, 414 women (5%) presented at <34 weeks of gestation with a clinical potential for PTB, of whom 277 (67%) received antenatal corticosteroids. Amongst women delivering at <34 weeks of gestation, 93% (80/86) received any corticosteroids and 76% (65/86) received a complete course. The ratio of women given a complete course of corticosteroids to the number who actually delivered before 34 weeks of gestation was 4:1 overall. Analysis by indication for PTB revealed this ratio to be 15:1 in suspected preterm labour (PTL), 8:1 in antepartum haemorrhage (APH), and 2:1 in both preterm prelabour rupture of membranes (PPROM) and medically indicated PTB (MIPTB). Seven of ten multiparae (70%) who delivered prematurely during the study period following PTL had a history of previous PTL before 34 weeks of gestation. CONCLUSION: The ratio of maternal antenatal corticosteroid administration for potential versus actual PTB at <34 weeks of gestation was high in categories such as PTL and substantial APH, whereas selection in PPROM and MIPTB approached 100%. There should be a low threshold for single course therapy for women with prior PTL before 34 weeks of gestation.

Atrophy of the sphincters of continence in an experimental model.

BACKGROUND: Pudendal nerve injury during childbirth may result in external anal sphincter (EAS) atrophy. Recently, balloon compression of the pelvic side wall has been shown to result in EAS atrophy in an experimental model. The aim of this study was to determine whether other sphincters of continence are similarly affected. METHOD: Sixteen adult female virgin Wistar rats (eight controls) were studied 4 weeks after surgery. Anal and urethral canals were dissected, snap frozen and sectioned using a cryostat (100 microm thickness). Masses of EAS, internal anal sphincter (IAS) and external urethral sphincter (EUS) were calculated stereologically and stained with succinate dehydrogenase histochemistry to differentiate striated from smooth muscle. Sphincter length was determined and total sphincter mass calculated. Data were analysed with an unpaired Student's t-test. RESULTS: Atrophy of EAS (30.9 +/- 1.7 to 21.3 +/- 1.7 mg/ kg, P = 0.001), IAS (98.1 +/- 11.3 to 67.1 +/- 5.0 mg/kg, P = 0.01) and EUS (9.6 +/- 0.98 to 7.4 +/- 0.8 mg/kg, P = 0.05) was found 4 weeks after the injury. CONCLUSION: In an experimental model of obstetric pudendal nerve injury, significant atrophy of striated and smooth muscle sphincters of continence occurs and may contribute to altered continence following vaginal childbirth.

Cerebral palsy following neonatal hypoxic seizures in singleton term infants: the influence of parity.

This was a retrospective review of term singleton neonates (> 37 weeks) with early onset seizures, with and without encephalopathy, from 1989 through 2000. Our aim was to examine the relationship between antepartum and intrapartum obstetric events, neonatal hypoxic seizures and subsequent neurological impairment of 77,838 infants, the incidence of seizures was significantly higher among primiparas (2.4/1000; 67/31,729) compared with multiparas (0.35/1000; 16/46,109)(p < 0.001). Compared with multiparas, seizures with encephalopathy occurred more frequently among primiparas (0.8/1000; 26/31,729) vs. multiparas (0.2/1000; 8/46,109), were more commonly associated with unexplained intrapartum hypoxia (0.6/1000, n = 20 vs.0.04/ 1000, n = 2) and the incidence of cerebral palsy, 45% (9/20) vs. 0% (0/2) was significantly higher(p < 0.001). Seizures with encephalopathy (0.2/1000 vs.0.13/1000) and cerebral palsy (33%) had a similar incidence in primiparas and multiparas following a sentinel event. Neonatal seizures with encephalopathy, related to intrapartum events, were 4 times more common following first delivery and associated with a 9 fold higher incidence of cerebral palsy, implicating primiparous labor in the development of cerebral palsy.

Experimental models of neuropathic fecal incontinence: an animal model of childbirth injury to the pudendal nerve and external anal sphincter.

PURPOSE: Childbirth is the most common cause of fecal incontinence and damage to the pudendal nerve is a major component of childbirth injury. This study was designed to develop an acute animal model of injury to the innervation of the external anal sphincter. METHODS: Forty-eight female virgin wistar rats were studied. Two models of neuropathic injury were developed. Bilateral inferior rectal nerve crush (Group A) acted as a positive control. Prolonged intrapelvic retrouterine balloon inflation (Group B) simulated the pelvic compressive forces of labor. Quantitative analysis of external anal sphincter muscle function was performed by using electromyography, external anal sphincter specific force production, and stereologic calculation of external anal sphincter mass. RESULTS: Injury in both groups caused significant atrophy of the external anal sphincter (P = 0.002, ANOVA) and electromyographic evidence of reinnervation at one week. Specific force (mN force per mg mass) was not altered. External anal sphincter muscle mass recovered after four weeks in Group B. CONCLUSIONS: Balloon dilation within the boney pelvis results in denervation of the external anal sphincter and offers an experimental model of the effects of childbirth on the continence mechanism in humans.