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One of the main reasons for the rising caesarean section rate is labor progression abnormalities. New guidelines were released promoting the changing paradigm from Friedman to Zhang's labor curves. However, the lack of evidence of its safety and the unclear effect on caesarean section rates have been challenging its adoption.Comparison between women with Friedman's criteria of arrested labor and women with Zhang's in terms of maternal and neonatal outcomes.Retrospective, single-center cohort study in a tertiary hospital between January 1st 2015 and December 31st of 2016.preterm or multiple deliveries, women without entering the active stage of labor, scheduled caesarean deliveries. Women were classified into 3 groups: normal progress, labor arrest by Friedman's criteria or by Zhang's criteria. Maternal morbidity included thrombotic, hemorrhagic, traumatic, infectious, and "total" (any of the previous morbidities). Adverse neonatal outcomes were assessed as a composite. Single and multivariable logistic regression was used to obtain the odd ratio (ORs) of each group and by stage of labor. Statistical significance threshold was set at 0,05.From a total number of 5051 deliveries, 3665 deliveries were included in the study, 2839 with normal labor progression, 426 with labor arrest according to Friedman's criteria and 400 according to Zhang's criteria. Regarding neonatal outcomes, no significant differences were observed. Compared to normal labor, labor arrest was significantly associated with higher total maternal morbidity (OR for Friedman's criteria 3.04; 95% confidence interval, 2.26-4.09; OR for Zhang's criteria 3.59; 2.68-4.80), maternal hemorrhagic (OR for Friedman's criteria 2.87; 1.81-4.55; OR for Zhang's criteria 2.80; 1.75-4.49) and infectious morbidity (OR for Friedman's criteria 3.56; 2.44-5.18; OR for Zhang's criteria 4.77; 3.34-6.80). Results were still significant after adjustment for confounders. Comparing Friedman's and Zhang's criteria, no significant differences regarding maternal and neonatal outcomes were verified.Changing criteria of labor arrest from Friedman's to Zhang's was not associated with more maternal morbidity in our study population nor worse neonatal outcomes. Changing labor arrest criteria from Friedman's to Zhang's may reduce caesarean section rates without an important increase in maternal and neonatal morbidities.

Objective To validate the use of placenta accreta risk-antepartum (PAR-A) score as a predictive tool of clinical outcomes of placenta accreta spectrum (PAS). Methods This is a prospective study, conducted in six PAS specialized centers in six different countries. The study was conducted between October 1, 2020 and March 31, 2021. Women who were provisionally diagnosed with PAS during pregnancy were considered eligible. A machine-learning-based PAR-A score was calculated. Diagnostic performance of the PAR-A score was evaluated using a receiver operating characteristic curve, for perioperative massive blood loss and admission to intensive care unit (ClinicalTrials.gov identifier NCT04525001). Results Of 97 eligible women, 86 were included. PAS-associated massive blood loss occurred in 10 patients (11.63%). Median PAR-A scores of massive blood loss in the current cohort were 8.9 (interquartile range 6.9-14.1). In predicting massive blood loss, the area under the curve of PAR-A scores was 0.85 (95% confidence interval [CI] 0.74-0.95), which was not significantly different from the original cohort (P = 0.2). PAR-A score prediction of intensive care unit admission was slightly higher compared with the original cohort (0.88, 95% CI 0.81-0.95; P = 0.06). Conclusion PAR-A score is a novel scoring system of PAS outcomes, which showed external validity based on current data.

Pregnant women may be at higher risk of severe complications associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may lead to obstetrical complications. We performed a case control study comparing pregnant women with severe coronavirus disease 19 (cases) to pregnant women with a milder form (controls) enrolled in the COVI-Preg international registry cohort between March 24 and July 26, 2020. Risk factors for severity, obstetrical and immediate neonatal outcomes were assessed. A total of 926 pregnant women with a positive test for SARS-CoV-2 were included, among which 92 (9.9%) presented with severe COVID-19 disease. Risk factors for severe maternal outcomes were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. Pregnant women with severe maternal outcomes were at higher risk of caesarean section [70.7% (n = 53/75)], preterm delivery [62.7% (n = 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n = 31/75)]. In this study, several risk factors for developing severe complications of SARS-CoV-2 infection among pregnant women were identified including pulmonary comorbidities, hypertensive disorders and diabetes. Obstetrical and neonatal outcomes appear to be influenced by the severity of maternal disease. ispartof: SCIENTIFIC REPORTS vol:11 issue:1 ispartof: location:England status: published

Objectives To evaluate the strength of association between maternal and pregnancy characteristics and the risk of adverse perinatal outcomes in pregnancies with laboratory confirmed COVID-19. Methods Secondary analysis of a multinational, cohort study on all consecutive pregnant women with laboratory-confirmed COVID-19 from February 1, 2020 to April 30, 2020 from 73 centers from 22 different countries. A confirmed case of COVID-19 was defined as a positive result on real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay of nasal and pharyngeal swab specimens. The primary outcome was a composite adverse fetal outcome, defined as the presence of either abortion (pregnancy loss before 22 weeks of gestations), stillbirth (intrauterine fetal death after 22 weeks of gestation), neonatal death (death of a live-born infant within the first 28 days of life), and perinatal death (either stillbirth or neonatal death). Logistic regression analysis was performed to evaluate parameters independently associated with the primary outcome. Logistic regression was reported as odds ratio (OR) with 95% confidence interval (CI). Results Mean gestational age at diagnosis was 30.6±9.5 weeks, with 8.0% of women being diagnosed in the first, 22.2% in the second and 69.8% in the third trimester of pregnancy. There were six miscarriage (2.3%), six intrauterine device (IUD) (2.3) and 5 (2.0%) neonatal deaths, with an overall rate of perinatal death of 4.2% (11/265), thus resulting into 17 cases experiencing and 226 not experiencing composite adverse fetal outcome. Neither stillbirths nor neonatal deaths had congenital anomalies found at antenatal or postnatal evaluation. Furthermore, none of the cases experiencing IUD had signs of impending demise at arterial or venous Doppler. Neonatal deaths were all considered as prematurity-related adverse events. Of the 250 live-born neonates, one (0.4%) was found positive at RT-PCR pharyngeal swabs performed after delivery. The mother was tested positive during the third trimester of pregnancy. The newborn was asymptomatic and had negative RT-PCR test after 14 days of life. At logistic regression analysis, gestational age at diagnosis (OR: 0.85, 95% CI 0.8–0.9 per week increase; p Conclusions Early gestational age at infection, maternal ventilatory supports and low birthweight are the main determinants of adverse perinatal outcomes in fetuses with maternal COVID-19 infection. Conversely, the risk of vertical transmission seems negligible.

Objective: To compare maternal and neonatal outcomes of immediate versus delayed cord clamping in women with placenta accreta spectrum (PAS). Study Design: PAS-ID is an international retrospective multicenter database originating from 11 centers (9 countries), which included women with confirmed PAS between January 1st, 2010 and December 31st, 2019. Women were considered eligible to this study if diagnosis of PAS was confirmed, women were adequately followed ante- and postpartum. Women with intrauterine fetal death were excluded. Primary outcome was massive PAS-associated perioperative blood loss (intraoperative blood loss ≥ 2500 ml, bleeding associated massive transfusion protocol, or complicated by disseminated intravascular coagulopathy). Secondary outcomes include 1-minute, 5-minute APGAR scores, and admission to neonatal intensive care unit (NICU). Multivariable logistic regression was used for analysis and results were presented as adjusted odds ratios (aOR) and 95% confidence interval (CI). Results: Out of 797 women, 716 met our inclusion criteria. Of these women, 120 underwent delayed cord clamping (16.76%). After adjustment for potential confounders, delayed cord clamping was associated with lower risk of massive blood loss (aOR 0.26, 95% CI 0.11 – 0.63) and admission to NICU (aOR 0.45, 95% CI 0.29 - 0.87). It was not associated with lower risk of 1 minute APGAR < 7 (aOR 1.88, 95% CI 0.92 - 3.85) or 5-minute APGAR < 7 (aOR 0.67, 95% CI 0.21 - 2.10). Conclusion: Delayed cord clamping does not seem to increase risk of PAS-associated massive blood loss. However, maternal, and neonatal stability should be considered before a decision can be made. Funding Information: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Declaration of Interests: The authors have no conflicts of interest. Ethics Approval Statement: Ethical approval was obtained in each contributing center from their receptive institutional review board before the study was conducted. This includes Aswan University, Egypt (Ethics Committee on Feb 11th, 2020, reference N; Aswu/439/2/20), Inonu University (reference number: 2020/476, dated 3/3/2020), Yuzuncu yil University (reference number: 55163642-100-E.36909, dated 09/06/2020), and Ege University (reference number: 20-4.1 T/3, dated 14/4/2020) in Turkey, Fatima memorial hospital/College of Medicine, and Dentistry, Pakistan (reference number: FMH-03-2020-IRB747-M, dated 5/12/2020), Kazan State University, Russia (reference number: 1765, dated 30/6/2020), Centro Hospitalar Sao Joao, Portugal (reference number: 76/2020, dated 21/5/2020), National Taiwan University College of Medicine, Taiwan (reference number: 202003007RINC, dated 30/3/2020), Faculty of Medicine of University of Yaounde I, Cameroon (reference numbers: 1019/CIERSH/DM/2020, dated 25/2/2020). Both Peking University Shenzhen Hospital and Universitas Padjadjaran Bandung were waived for the minimal risk per their local hospital policies. All data were anonymized and authorized for use before submission for analysis.

Introduction Placenta accreta spectrum is a major obstetric disorder that is associated with significant morbidity and mortality. The objective of this study is to establish a prediction model of clinical outcomes in these women Materials and methods PAS-ID is an international multicenter study that comprises 11 centers from 9 countries. Women who were diagnosed with PAS and were managed in the recruiting centers between 1 January 2010 and 31 December 2019 were included. Data were reanalyzed using machine learning (ML) models, and 2 models were created to predict outcomes using antepartum and perioperative features. ML model was conducted using python(R) programing language. The primary outcome was massive PAS-associated perioperative blood loss (intraoperative blood loss >= 2500 ml, triggering massive transfusion protocol, or complicated by disseminated intravascular coagulopathy). Other outcomes include prolonged hospitalization >7 days and admission to the intensive care unit (ICU). Results 727 women with PAS were included. The area under curve (AUC) for ML antepartum prediction model was 0.84, 0.81, and 0.82 for massive blood loss, prolonged hospitalization, and admission to ICU, respectively. Significant contributors to this model were parity, placental site, method of diagnosis, and antepartum hemoglobin. Combining baseline and perioperative variables, the ML model performed at 0.86, 0.90, and 0.86 for study outcomes, respectively. Ethnicity, pelvic invasion, and uterine incision were the most predictive factors in this model. Discussion ML models can be used to calculate the individualized risk of morbidity in women with PAS. Model-based risk assessment facilitates a priori delineation of management.

Objective To create a model for prediction of success of uterine preserving procedures in women with placenta accreta spectrum (PAS) METHODS: PAS-ID is a multicenter study that included 11 centers from 9 countries. Women with PAS, who were managed between January 1st, 2010 and December 31st, 2019, were retrospectively included. Data were split into model development and validation cohorts, and a prediction model was created using logistic regression. Main outcome was success of uterine preservation. Results Out of 797 women with PAS, 587 were eligible. Uterus preserving procedures were successful in 469 patients (79.9%). Number of previous cesarean sections (CS) was inversely associated with management success (adjusted odds ratio "aOR" 0.02; 95% confidence interval "CI", 0.001-3.63 with 5 previous CSs). Other variables were complete placental invasion (aOR 0.14; 95%CI, 0.05-0.43), type of CS incision (aOR 0.04; 95%CI, 0.01-0.25 for classical incision), compression sutures (aOR 2.48; 95%CI, 1.00-6.16), accreta type (aOR 3.76; 95%CI, 1.13-12.53), incising away from placenta (aOR 5.09; 95%CI, 1.52-16.97), and uterine resection (aOR 102.57, 95%CI, 3.97-2652.74). Conclusion This current study provides a prediction model for success of uterine preservation, which may assist preoperative and intraoperative decisions, and promote incorporation of uterine preservation procedures in comprehensive PAS protocols.

Post-partum hemorrhage is one of the leading causes of maternal mortality and it's etiology needs to be identified in order for adequate treatment to be provided. We report a case of a post-partum hemorrhage in a multiparous woman treated with selective coil packing embolization after identification of laceration of the right uterine artery's ascending branch. The patient was admitted to an intensive care unit in hemorrhagic hypovolemic shock and disseminated intravascular coagulation and underwent total hysterectomy due to infectious complications.A hemorragia pós-parto é uma das principais causas de mortalidade materna e a sua etiologia deve ser identificada para um tratamento adequado. Descrevemos um caso de hemorragia pós parto numa multípara tratada com embolização selectiva após identificação de uma laceração total do ramo ascendente da artéria uterina direita. A puérpera foi admitida na unidade de cuidados intensivos em choque hipovolémico hemorrágico e coagulação intravascular disseminada que culminou numa histerectomia abdominal por complicações infeciosas.

Background: Pregnant women represent a vulnerable population at higher risk of complications of infectious diseases. Data regarding the consequences of the emerging pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy are scarce. Recent evidence suggests that pregnant women might be at higher risk of severe disease, while exposed fetuses and newborns could suffer from preterm birth, growth restriction and neonatal infections. Methods: We developed an international web registry to allow structured data collection. Pregnant women at any stage during gestation tested for SARS-CoV-2 infection were enrolled. Maternal, obstetrical and neonatal outcomes were recorded. Findings: 1033 pregnant women tested for SARS-CoV-2 were included, among which 926 tested positive and 107 tested negative. Positive pregnant women were at higher risk of severe maternal outcomes compared to negative women [aRR 5.6, 95% CI 1.4-22.7]. Risk factors for severe maternal outcomes among positive women were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. No difference in term of obstetrical and neonatal outcomes were observed between positive and negative women. Positive pregnant women with severe maternal outcomes were at higher risk of cesarean sections [70.7% (n=53/75)], preterm deliveries [62.7% (n= 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n=31/75)]. A positive neonatal SARS-CoV-2 test was observed in 2.9% (n=11/384) of newborns with an available test at birth. Interpretation: Pregnant women, particularly those with associated comorbidities, seem to be at higher risk of severe complications of SARS-CoV-2 infection. Preliminary data regarding obstetrical and neonatal outcomes among women with a mild disease are reassuring. Funding Statement: None. Declaration of Interests: The authors declare that we have no conflicts of interest. Ethics Approval Statement: The study was approved by both the Swiss Ethical Board (CER-VD-2020-00548) and the local ethics boards at each participating center.

Background: Recent evidence suggests that pregnant women might be at higher risk of severe disease associated with the emerging pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while exposed fetuses/newborns could suffer from preterm birth, growth restriction and neonatal infections. The magnitude of this increased risk and specific risk factors for severity remains unclear. Methods: We performed a case control study comparing pregnant women with severe coronavirus disease 19 (case) to pregnant women with a milder form (controls) enrolled in COVI-Preg international registry cohort between from March 24 to July 26, 2020. Risk factors for severity, obstetrical, fetal and neonatal outcomes were assessed. Findings: A total of 926 pregnant women with a positive test for SARS-CoV-2 were included, among which 92 (9.9%) presented a severe COVID-19 disease. Risk factors for severe maternal outcomes were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. Pregnant women with severe maternal outcomes were at higher risk of cesarean sections [70.7% (n=53/75)], preterm deliveries [62.7% (n= 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n=31/75)]. Interpretation: Pregnant women, particularly those with associated comorbidities, seem to be at higher risk of severe complications of SARS-CoV-2 infection. Obstetrical and neonatal outcomes appear to be influenced by the severity of maternal disease; complications include cesarean sections, prematurity and neonatal admission to the intensive care unit. Funding Statement: None. Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: The study was approved by both the Swiss Ethical Board (CER-VD- 2020-00548) and the local ethics boards at each participating center.

Objective To determine the rate of therapeutic hypothermia (TH) use, current practices, and long-term follow-up. Study Design Prospective cross-sectional national survey with 19 questions related to the assessment of hypoxic–ischemic encephalopathy (HIE) and TH practices. An online questionnaire was made available to health care professionals working in neonatal care in Brazil. Results A total of 1,092 professionals replied, of which 681 (62%) reported using TH in their units. Of these, 624 (92%) provided TH practices details: 136 (20%) did not use any neurologic score or amplitude-integrated electroencephalogram (aEEG) to assess encephalopathy and 81(13%) did not answer this question. Any specific training for encephalopathy assessment was provided to only 81/407 (19%) professionals. Infants with mild HIE are cooled according to 184 (29%) of the respondents. Significant variations in practice were noticed concerning time of initiation and cooling methods, site of temperature measurements and monitoring, and access to aEEG, electroencephalogram (EEG), and neurology consultation. Only 19% could perform a brain magnetic resonance imaging (MRI), and 31% reported having a well-established follow-up program for these infants. Conclusion TH has been implemented in Brazil but with significant heterogeneity for most aspects of hypothermia practices, which may affect safety or efficacy of the therapy. A step forward toward quality improvement is important.

Severe hemorrhage is a major concern during operative procedures for abnormally invasive placenta (AIP). We reviewed published literature with the objective to provide evidence of blood loss with the most common treatment options for AIP. We selected 54 articles that fulfilled the inclusion criteria. Cesarean hysterectomy, with or without occlusion balloons in the internal iliac arteries, was the treatment associated with the greatest blood loss. Major blood loss was also associated with the placenta left in situ (reported in 3 of 10 articles), and with uterine artery embolization (reported in 3 of 15 articles). The best outcomes were seen for cesarean hysterectomy with balloon occlusion of the common iliac arteries (CIA; 9 patients, including 1 with major blood loss), balloon occlusion of the abdominal aorta (27 patients, no major blood loss) and conservative surgery (99 patients, including one with major blood loss). In conclusion, cesarean hysterectomy with balloon occlusion of the CIA or abdominal aorta, and conservative treatments seem to have the best outcomes. However, our results are based on a small number of articles. Hence, it is necessary to have available more reports on the outcomes of these treatments, to arrive at a more definitive conclusion.

Background Visual analysis of cardiotocographic (CTG) tracings has been shown to be prone to poor intra- and interobserver agreement when several interpretation guidelines are used, and this may have an important impact on the technology’s performance. Objectives The aim of this study was to evaluate agreement in CTG interpretation using the new 2015 FIGO guidelines on intrapartum fetal monitoring. Study design A pre-existing database of intrapartum CTG tracings was used to sequentially select 151 cases acquired with a fetal electrode, with duration exceeding 60 minutes, and signal loss less than 15%. These tracings were presented to six clinicians, three with more than 5 years’ experience in the labor ward, and three with 5 or less years’ experience. Observers were asked to evaluate tracings independently, to assess basic CTG features: baseline, variability, accelerations, decelerations, sinusoidal pattern, tachysystole, and to classify each tracing as normal, suspicious or pathologic, according to the 2015 FIGO guidelines on intrapartum fetal monitoring. Agreement between observers was evaluated using the proportions of agreement (Pa), with 95% confidence intervals (95%CI). Results A good interobserver agreement was found in the evaluation of most CTG features, but not bradycardia, reduced variability, saltatory pattern, absence of accelerations and absence of decelerations. For baseline classification Pa was 0.85 [0.82–0.90], for variability 0.82 [0.78–0.85], for accelerations 0.72 [0.68–0.75], for tachysystole 0.77 [0.74–0.81], for decelerations 0.92 [0.90–0.95], for variable decelerations 0.62 [0.58–0.65], for late decelerations 0.63 [0.59–0.66], for repetitive decelerations 0.73 [0.69–0.78], and for prolonged decelerations 0.81 [0.77–0.85]. For overall CTG classification, Pa were 0.60 [0.56–0.64], for classification as normal 0.67 [0.61–0.72], for suspicious 0.54 [0.48–0.60] and for pathologic 0.59 [0.51–0.66]. No differences in agreement according to the level of expertise were observed, except in the identification of accelerations, where it was better in the more experienced group. Conclusions A good interobserver agreement was found in evaluation of most CTG features and in overall tracing classification. Results were better than those reported in previous studies evaluating agreement in overall tracing classification. Observer experience did not appear to play a role in agreement.

Ulipristal acetate (UPA) is an oral selective progesterone receptor modulator. It is one of the most recent alternatives in the management of symptomatic fibroids and its safety and effectiveness have already been demonstrated in several studies. Nevertheless, there is few evidence regarding its use in the subgroup of women who experience fertility issues and desire to conceive. The authors report a case of a 39- years-old woman with abnormal uterine bleeding and anemia. She had had an uncomplicated pregnancy some years before and was trying to have a second child. She was treated for 3 months with UPA, at a daily dose of 5 mg, per os, followed by a ressectoscopic myomectomy. After five months, she conceived spontaneously and had an uneventful pregnancy. She then remained asymptomatic and almost two years after she was pregnant again. This case supports the idea that UPA is a valid alternative in patients still have a desire to conceive and thus want to avoid surgery. Even tough larger studies on the subject are required, UPA may become very important role in the management of fibroids in the infertility context.

ResumoOBJETIVOA ministração antenatal de um ciclo único de corticoterapia está recomendada a mulheres grávidas entre a 24 e a 34 semanas com risco de parto prematuro. O efeito máximo é atingido quando os corticosteroides ministrados entre 24 horas e 7 dias antes do parto. O objetivo deste estudo foi avaliar a ocorrência de parto nos sete dias após corticoterapia nas principais situações obstétricas com risco de parto pré-termoMÉTODOSEstudo de coorte retrospectivo incluindo 209 grávidas internadas em risco de parto pré-termo submetidas a tratamento com corticosteroides para maturação pulmonar fetal. O estudo foi realizado entre janeiro de 2012 e março de 2014 e um hospital universitário. O desfecho principal avaliado foi o número de mulheres que tiveram parto no prazo de 7 dias após a ministração antenatal de corticosteroides. Foram definidos dois grupos de acordo com o motivo para iniciar corticosteroides: ameaça de parto pré-termo (Grupo APPT) e outras indicações para corticoterapia (Grupo RPPT). Foi efetuada uma análise de sobrevivência de Kaplan-Meier e um valor p

Objective. To evaluate the impact of preeclampsia in the modification of lifestyle habits and decreasing cardiovascular risk factors in a population of women at least 6 months after having the diagnosis of preeclampsia.Methods. Cross-sectional observational study. Data included 141 cases of preeclampsia and chronic hypertension with superimposed preeclampsia on singleton births diagnosed in our institution between January 2010 and December 2013. From the cases diagnosed over 6 months a standardized questionnaire evaluating lifestyle changes was applied.Results. We reviewed 141 cases, of which 120 were diagnosed for more than 6 months. An overall participation rate in the questionnaire of 65% was yielded. A slight increase from the mean BMI before pregnancy was found. No statistical significant association was established between postpregnancy mean BMI, weight variation, and the frequency of aerobic exercise with the severity of preeclampsia. Only 28% of our cases were practising aerobic exercise at least weekly. The majority of women assessed blood pressure at least monthly (45/78), but only 25 assessed glycaemia at least once/year.Conclusion. This study shows that the majority of our patients and general practitioners do not take into consideration a previous pregnancy affected by preeclampsia as a risk factor for future cardiovascular disease.

We have studied the development of the adrenal gland in the rat comprising the ages ranging from 0 to 90 days after birth. The weight of the animals and that of the adrenal glands demonstrated a linear growth with time until 75 days, both in males and females. The area of the zona glomerulosa (ZG) increased in size from birth until approximately 40 days of age. After that, growth had a much smaller slope (females, r=0.84, P0.001; males, r=0.81, P0.001). Aldosterone secretion had a marked increase until 20 days of age and thereafter demonstrated a tendency for a decrease (females, r=-0.19, P0.02: males r=-0.26, P0.001). Plasma renin activity followed a trend parallel to that of aldosterone. The steroid precursor 18-OH-deoxycorticosterone (18-OH-DOC) demonstrated a different course as it increased progressively with age especially in the females (females, r=0.57, P0.001; males, r=0.40, P0.001). The expression of the enzyme 3-beta-hydroxysteroid dehydrogenase (3-beta-HSD) was also studied by immunohistochemistry and it was shown to be very low at birth and starting to increase by 10 days of age. After 30/40 days of age the amount of this enzyme existing in the ZG was comparable with that of the outer zona fasciculata (ZF). We conclude that the development of the ZG in the rat has particularities that make it different from that of the rest of the cortex.

The Inner Zone Antibody (IZAb) is a monoclonal antibody which interacts with an antigen found predominantly in rat adrenal inner cortical zones. Since its expression increases after ACTH treatment the antigen may have a role in steroidogenesis although, so far, this has not yet been fully characterised. Due to its molecular weight, it cannot be any of the known cytochrome P450 proteins. In this study we examined the expression of IZAb in male and female rats throughout their postnatal development and in aged animals. In a different set of animals, blood was collected for hormonal assays and the adrenals stained with classical methods. The staining with IZAb was clear from the first post-natal day. The zona glomerulosa which was always present at birth, was easily distinguished and unstained. The staining in the inner zone cells was fainter at birth and increased progressively until postnatal day 20. Afterwards these cells were remarkably stained at all ages. Medullary cells were also present from birth although they were generally found in clusters instead of constituting a well defined zone. Cortical cells appeared in the medullary zone at all ages after its complete development. The zona glomerulosa increased in size until approximately postnatal day 40 while the inner zones increased until day 70. The area of the cortex was significantly different between the two sexes from day 50 onwards and this was predominantly due to differences in the zona fasciculata. Corticosterone levels increased until approximately day 25 in the male rat and until day 45 in the female.(ABSTRACT TRUNCATED AT 250 WORDS)