Intrauterine Mortality Research Articles

Impact Assessment of Endocrine Disruptors on Sudden Intrauterine and Infant Death Syndromes

Background and Objectives: The endocrine disruptors (EDs) are able to interfere with the endocrine system, mimicking or antagonizing the hormonal activity. They can persist in the environment, due to their degradation resistance. The aim of our research has been to analyze the possible link between unexplained intrauterine and infant mortality and chronic exposure to EDs. Materials and Methods: We have investigated 16 cases of sudden intrauterine unexplained death syndrome (SIUDS) and 8 cases of sudden infant death syndrome (SIDS), collected over a 3-year period (2012-2014). Brain samples were submitted to chemical analysis of 25 EDs, consisting in a liquid-solid extraction procedure, followed by a purification step and by a gas chromatography-mass spectrometry analysis. Results: The analytical method to detect the presence of EDs in brain samples has been successfully applied to SIUDS and SIDS victims. At the level of the brainstem, the frequent association between the hypoplasia of the facial/parafacial complex and the hypoplasia of the raphe system has been ascertained. In particular, the hypodevelopment of the parafacial nucleus, consisting of ‘pre-inspiratory’ neurons with the main function of hierarchical modulation of breathing circuitry, appears an exclusive finding of unexplained stillbirths. Conclusions: The environmental EDs have been found able to cross the placental barrier, reaching also the brain nuclei assigned to the control of vital functions. This is consistent with literature data that report the presence of these selected pollutants in other human tissue. For this reason, environmental EDs should be searched during autopsy in order to establish a possible correlation with unexplained intrauterine and infant deaths.

Antiepileptic drugs and intrauterine death

To compare the risk of spontaneous abortions and stillbirth associated with maternal use of different antiepileptic drugs (AEDs). The EURAP registry is an observational international cohort study primarily designed to determine the risk of major congenital malformations (MCMs) after prenatal AED exposure. Using EURAP data, we prospectively monitored pregnancies exposed to the 6 most common AED monotherapies and to polytherapy. Intrauterine death (spontaneous abortion and stillbirth combined) was the primary endpoint. Of 7,055 pregnancies exposed to monotherapy with lamotrigine (n = 1,910), carbamazepine (n = 1,713), valproic acid (n = 1,171), levetiracetam (n = 324), oxcarbazepine (n = 262), or phenobarbital (n = 260), and to polytherapy (n = 1,415), 632 ended in intrauterine deaths (592 spontaneous abortions and 40 stillbirths). Rates of intrauterine death were similar across the different monotherapies (8.2%; 95% confidence interval [CI] 7.5%-8.9%), higher with polytherapy (12.1%; 95% CI 10.5%-13.9%), but showed no relationship with AED dose in monotherapy at conception. Multivariable analysis including 11 covariates in addition to the different AED exposures showed that the risk was greater with polytherapy vs monotherapy (risk ratio [RR] 1.38; 95% CI 1.14-1.66), parental history of MCMs (RR 1.92; 1.20-3.07), maternal age (RR 1.06; 1.04-1.07), and number of previous intrauterine deaths (RR 1.09; 1.00-1.19). The risk was greater with early enrollment and decreased with later gestational week at enrollment (RR 0.84; 0.82-0.86). The most important risk factors for intrauterine death in pregnancies of women with epilepsy include maternal exposure to AED polytherapy and the presence of MCMs in at least one of the parents.

Clinical risk factors for poor neonatal outcomes in umbilical cord prolapse

Objectives: To clarify the clinical risk factors associated with poor neonatal outcomes due to umbilical cord prolapse (UCP).Methods: A postal questionnaire survey was attempted in Japan. The clinical risk factors and managements associated with poor neonatal outcomes were analyzed in cases of UCP treated in Japan.Results: A total of 267 cases of UCP (out of 2 037 460 total deliveries) were analyzed. The rates of intrauterine death, neonatal death and survival with disability were 3.4%, 5.6% and 7.1%, respectively. The multivariate regression analysis for these poor neonatal outcomes revealed that the significant risk factors included a prolapsed amniotic sac (adjusted odds ratio (aOR), 4.49), preterm labor (aOR, 2.99) and replacement of the prolapsed umbilical cord into the uterus (aOR, 2.87). However, UCP that occurred during labor (aOR, 0.28) and emergency cesarean section (aOR, 0.11) were associated with a reduction in the rates of poor outcomes. The interval between the diagnosis of UCP and delivery was significantly longer in the infants with a poor outcome than intact survival (median 30 versus 24 min, p = 0.048).Conclusion: An emergency cesarean section should be carried out immediately to ensure a better outcome for the infant.

FLUJOMETRÍA DOPPLER PATOLÓGICA Y SU CORRELACIÓN CON EL PRONÓSTICO PERINATAL A CORTO PLAZO

Objetivos: Determinar la morbilidad y mortalidad de fetos con flujometría Doppler patológico y evaluar discapacidades en el corto plazo. Diseño: Estudio tipo retrospectivo, observacional, analítico, correlacional. Lugar: Unidad de vigilancia fetal, Hospital Nacional Edgardo Rebagliati Martins, Red Asistencial Rebagliati, EsSalud, Lima, Perú. Participantes: Gestantes con flujometría Doppler patológicos y sus perinatos. Intervenciones: Se estudió todos los casos de gestantes con flujometría Doppler alterado, entre febrero de 2008 y febrero de 2010. Se agrupó por tipos de flujometría Doppler y se describió la frecuencia de patología y morbimortalidad perinatal, correlacionándolas con la edad gestacional. El análisis se realizó con el paquete estadístico SPSS 11,0, la prueba chi cuadrado para las variables discretas y la de Kruskal-Wallis, para las variables continuas. Se asumió un valor de significancia de p < ,005. Principales medidas de resultados: Morbilidad y mortalidad perinatal, discapacidades motoras, auditivas y psicomotoras a las 6 meses de edad. Resultados: Sesentaitrés gestantes cumplieron con el criterio de inclusión. El peso medio al nacer de sus fetos fue 1 593 g; 24 casos (40%) presentaron peso al nacer menor al percentil 10 para la edad gestacional. La mayor parte mostró flujometría Doppler tipo III, 46 casos con signos de redistribución hemodinámica. La mortalidad global fue 8%. Cuatro fetos murieron intraútero; 59 fetos (94%) llegaron a nacer vivos; de ellos solo un caso falleció durante el periodo de estudio. La tasa global de mortalidad fue significativamente mayor y el peso al nacer más bajo en el grupo de fetos con flujometría Doppler tipo IV, con una media de 937 g. La mortalidad fue significativamente más alta en el grupo de 24 a 27,6 semanas. La estancia en UCI, la necesidad de ventilación asistida (VM) y presión positiva continua, el riesgo de desarrollar retinopatía y hemorragia interventricular y las discapacidades auditivas y trastorno del desarrollo psicomotor estuvieron correlacionados con la prematuridad. Conclusiones: Los casos de flujometría Doppler con compromiso hemodinámico severo presentaron acidemia y tasa alta de mortalidad, independiente del percentil de crecimiento al nacer. La mortalidad intraútero se asoció significativamente a la severidad mostrada por el estudio Doppler, por lo que no se recomienda continuar el embarazo en los tipos III y IV, si hay madurez pulmonar fetal.

Perinatal outcome after first-trimester risk assessment in monochorionic and dichorionic twin pregnancies: a population-based register study.

To evaluate the influence of chorionicity on outcome in twin pregnancies with two live fetuses at the nuchal translucency scan in the first trimester. Population-based register study. Denmark. A cohort of 3621 twin pregnancies, 84.3% dichorionic (DC) pregnancies and 15.7% monochorionic (MC) pregnancies (15% diamniotic [MCDA] and 0.7% monoamniotic [MCMA]). A cohort study based on data collected from the Danish Fetal Medicine Database from July 2008 to July 2011. Fetal loss rate before week 22, intrauterine death rate from week 22 to birth, and neonatal mortality. Significantly more DC than MC pregnancies resulted in at least one live born infant-98.2% versus 92.3% in MCDA (P < 0.05) and 66.7% in MCMA pregnancies (P < 0.05). The rates of spontaneous loss of both fetuses before week 22 were 0.9, 2.4, and 20.8% for DC, MCDA and MCMA twins, respectively (P < 0.05). The rate of intrauterine death of one fetus after week 22 was higher in MCDA twins than DC twins 1.7% versus 0.6% (P < 0.05). We found no significant difference in the rate of neonatal death. The risk of spontaneous loss of both fetuses before week 22 of gestation was significantly higher in MCMA and MCDA pregnancies than in DC pregnancies, and significantly higher in MCMA pregnancies than in MCDA pregnancies. After week 22 the risk of loss of one fetus after week 22 was significantly higher in MCDA pregnancies than in DC pregnancies.

Effects of Subcutaneous LPS Injection on Gestational Length and Intrauterine and Neonatal Mortality in Mice

Background: Infection during pregnancy can predispose offspring to develop various psychiatric disorders such as depression in later life. In order to investigate the potential mechanisms underlying these associations, animal models of maternal infection have been employed. As such, lipopolysaccharide (LPS) has been commonly used to mimic a bacterial infection in pregnant mice. Objective: The original aim of our study was to investigate the effects of different doses of subcutaneous LPS administration on affective behavior in adult mouse offspring. In the present paper, however, we report that subcutaneous LPS administration has a profound impact on gestational length, litter size, and perinatal mortality in the offspring, even at a relatively low dose. Methods: Pregnant mice were randomly divided into 3 groups, receiving either a high (2 mg/kg) or a low (0.5 mg/kg) dose of LPS or phosphate-buffered saline by means of subcutaneous injection. Subsequently, the effects on gestational length, litter size, and perinatal mortality in the offspring were assessed. Results: After subcutaneous injection with a high dose of LPS, we observed a significant decrease in gestational length and an increase in neonatal mortality. When the low dose was administered, a tendency towards a reduced litter size was observed, most likely reflecting increased intrauterine mortality in response to prenatal maternal LPS exposure. Conclusions: We showed that subcutaneous administration of 2 mg/kg LPS to pregnant mice in the last phase of gestation should be avoided because of high offspring mortality rates, whereas subcutaneous injection of 0.5 mg/kg LPS seems to result in reabsorption of the fetuses.

Right atrial cardiac rhabdomyoma with premature foramen ovale restriction: A case report.

Fetal cardiac rhabdomyoma is the most common cardiac tumor in fetuses. However, this benign tumor can cause hemodynamic repercussions and intrauterine fetal mortality. The present study reports a case of rare fetal cardiac rhabdomyoma located in the right atrium, accompanied by premature restriction of the foramen ovale and moderate pericardial effusion, as determined by tomographic ultrasound imaging (TUI). Fetal mortality subsequently occurred late in the second trimester of pregnancy and the diagnosis was confirmed by pathology. The present study discusses the occurrence and diagnosis of this rare abnormality. TUI mode with spatio-temporal image correlation offline imaging provides the physician with clear views of abnormal intracardiac structures in the beating heart. With improvements in sonographic technology, the diagnosis of fetal cardiac rhabdomyoma may be easier and more accurate in the clinical arena.

The placental expression of Human Leukocyte Antigen HLA-F and HLA-E in early normal placentation

The placental expression of Human Leukocyte Antigen HLA-F and HLA-E in early normal placentation

Perinatal outcome of monochorionic diamniotic twins with selective intrauterine growth restriction

To evaluate the perinatal outcome of three types of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR). From January 2005 to June 2012, clinical data of 42 pairs of MCDA twins (84 fetuses) with sIUGR and 71 pairs of normal MCDA twins (142 fetuses) in the same period were analyzed retrospectively in the First Affiliated Hospital of Sun Yat-Sen University. Fetuses with sIUGR were classified into three groups based on umbilical artery Doppler flow.There were 25 cases of type I, 11 cases of type II and 6 cases of type III. The perinatal outcome was compared between sIUGR and normal MCDA twins, and among the three types of sIUGR as well. Perinatal outcomes included gestational age at delivery, rate of intrauterine fetal death (IUFD), birth weight, intertwin discordance of birth weight, neonatal death and survival rate at 6 months. (1) The gestational age of sIUGR at delivery was significantly earlier than the control group [(34±3), (36±2) weeks, respectively], and the rate of IUFD of both fetuses of sIUGR was significantly higher (4.8%, 0, respectively). In the sIUGR group, the average birth weight of large or small twins [(2130±350), (1520±400) g, respectively] was smaller than those in the control group [(2470±500), (2340±460) g, respectively]. The difference was statistically significant (P<0.05, P<0.01, respectively). The intertwin discordance of birth weight in sIUGR group was significantly larger (27.6%) than the control group (4.0%, P<0.01). (2) The gestational age at delivery in type II and type III [(34±5), (34±2) weeks, respectively] was significantly earlier than the control group (P<0.05). The rate of IUFD of both fetuses in type II (18%) was significantly higher than in type I (0) and the control group (0, P<0.05). In sIUGR group, the average birth weight of small twins in type I, type II and type III was (1640±430), (1330±310) and (1500±380) g respectively, all of which were significantly smaller than that in the control group (P<0.05). The average birth weight of small twins in type II was smaller than in type I and the difference was statistically significant (P<0.05). In sIUGR group, the intertwin discordance of birth weight in type I, type II and type III was 24.1%, 34.6%, 31.3% respectively, all of which were significantly larger than that in the control group (4.0%, P<0.05). There were no statistically significant differences of the intertwin discordance of birth weight among the three types of sIUGR (P>0.05). Survival rate at 6 months in type II (64%) was significantly lower than in type I (92%) and the control group (91.5%, P<0.01). The perinatal outcome of MCDA twins with sIUGR is poor. The outcome is different among the three types of sIUGR, and typeIIis the worst. Type II is associated with a high risk of intrauterine fetal demise. It is important to monitor the intrauterine situation closely.

Serum sodium, potassium, calcium and magnesium in women with pregnancy induced hypertension and preeclampsia in Oredo local Government, Benin Metropolis: A pilot study

Background: Pregnancy induced hypertension and preeclampsia (hypertension in pregnancy in association with the excretion of >300 mg of urinary protein per day after 20 weeks of gestation) is one of the most common complications of pregnancy seen in Benin City, Nigeria. It contributes significantly to maternal mortality, premature birth, intrauterine growth retardation and perinatal mortality. Studies have been performed to evaluate the role of electrolytes in etiopathogenesis of pregnancy induced hypertension and preeclampsia. The outcome of the studies has varied ina different environment and population. Objective: The objectiveof this study is to determine the role of serum sodium, potassium, magnesium and calcium in etiopathogenesis of preeclampsia in this environment. Materials and Methods: A total of 60 subjects were involved in the study. 20 were normotensive non-pregnant women, 20 normotensive pregnant women, 20 with preeclampsia. They were of similar age groups, with singleton pregnancies and in the second and third trimester of pregnancy. Serum sodium, potassium, calcium, magnesium was assayed in the three groups. Serum sodium and potassium was assayed using the ion-selective electrode method. Statistical analysis was done using SPSS Student Version 13 for Windows. Results: Mean serum sodium was non-significantly raised in women with preeclampsia above the upper limit of normal reference interval (151 ± 1.5 mmol/l) ( P > 0.05) while it was within normal reference interval of 140 ± 2.3 mmol/L for normotensive pregnant women and 144 ± 4.2 mmol/L for normotensive non-pregnant women. Serum potassium, calcium, magnesium were all within normal reference intervals across the three groups studied. Conclusion: Serum sodium, potassium, calcium, magnesium do not seem to play a vital role in the etiopathogenesis of preeclampsia in this environment as there was no statistically significant difference in the values of the electrolytes assayed across the three groups studied.

Facteurs prédictifs de tolérance fœtale à la cordocentèse : étude rétrospective monocentrique

ObjectivesIndications for fetal blood sampling (FBS) are getting more limited. In this context, we aimed to evaluate fetal loss and morbidity associated with FBS and to precise the predictive parameters for fetal complications. More than a retrospective evaluation of our practices, the final end point of our study was to better inform the patients coming to our centre. Patients and methodsRetrospective monocentric cohort (Canadian Task Force classification II-2) of the 99 FBS performed between April 2004 and June 2010 on 80 fetuses, after excluding the procedures done for termination of pregnancy. The main clinical outcome was a composite outcome criteria for fetal tolerance including cesarean section for abnormal non stress test within the 24hours, or any event responsible of a modified obstetrical management during the 14day following FBS. ResultsMean maternal age at FBS was 30years±5.13 SD and parity was 2.49±1.38SD. FBS was performed by an experienced operator in 86.5% of cases (CI 95%, 78–92.6); with a single insertion in 83.3% of circumstances (CI 95%, 74.4–90.2). The mean duration was 11min±6.37 SD. The total rate of intrauterine death, in our series, was 7.1% (CI 95%, 2.9–14), including all reported fetal demise within the 14 days after FBS, whatever the relation with the procedure. Our study demonstrated a 9.1% occurrence of post-FBS altered CTG fetal testing (CI 95%, 4.2–16.6), half of it with spontaneous resolution. The rate of severe complications (main clinical outcome) was 11.1% (CI 95%, 5.7–19) including one fetal death liable to FBS and 10 emergency caesarean sections: 5.1% for fetal bradycardia (CI 95%, 1.7–11.4), 2% for placental abruption (CI 95%, 0.2–7.1), 2% for premature preterm rupture of membranes (CI 95%, 0.2–7.1) and 1% for significative umbilical cord bleeding (CI 95%, 0–5.5). Univariate factor analysis highlights 4 parameters for impaired fetal tolerance; a prolonged procedure, presence of low fetal platelets (<30.109/L); and FBS performed for fetal anaemia during Parvovirus B19 infection or allo-immune thrombocytopenia. Discussion and conclusionFBS remains a tricky procedure with a substantial risk of fetal loss or complications especially when performed on high-risk fœtuses. The length of the procedure should be shortened as much as possible (trained operator, postponed procedure when all favourable condition are not available). Fetal thrombocytopenia is a meaningful risk factor encouraging carefulness when exploring allo-immune fetal thrombocytopenia.

Development of bovine embryos derived from reproductive techniques

Assisted reproduction techniques have improved agricultural breeding in the bovine. However, important development steps may differ from the situation in vivo and there is a high mortality rate during the first trimester of gestation. To better understand these events, we investigated the development of embryos and fetal membranes following fixed-time AI (FTAI), IVF and nuclear transfer (NT). The onset of yolk-sac development was not normal in cloned embryos. Later steps differed from conditions in vivo in all three groups; the yolk-sac was yellowish and juxtaposed with the amniotic membrane. Vascularisation of the chorioallantoic membrane was relatively late and low in NT gestations, but normal in the others. The overall development of the embryos was normal, as indicated by morphology and regression analysis of growth rate. However, NT conceptuses were significantly smaller, with the livers in some embryos occupying the abdominal cavity and others exhibiting heart abnormalities. In conclusion, the yolk-sac and the cardiovascular system seem to be vulnerable to morphogenetic alterations. Future studies will focus on gene expression and early vascularisation processes to investigate whether these changes may be responsible for the high incidence of intrauterine mortality, especially in clones.

Fetale Lageanomalien und Heterotaxien

Disorders of laterality and heterotaxy syndromes are rare diseases with an incidence of 1-1.5/10,000 live births. They are associated with numerous viscerocardiac anomalies and malformations. In particular, heterotaxy syndromes are associated with complex cardiac and extracardiac malformations that have an important impact on the prenatal and postnatal course. A prenatal differentiation between the 2 main variants of heterotaxy--left and right isomerism--is possible by assessment of cardiac rhythm, anomalies of caval veins and descending aorta and concomittant cardiac and extracardiac anomalies. An exact diagnosis is mandatory for adequate counselling of the parents and planning of postnatal care. Left isomerism has a high intrauterine mortality, caused by early atrioventricular block with subsequent cardiac failure and hydrops. In contrast, right isomerism has a high postnatal mortality due to the more complex type of cardiac defects and splenic disorders. The type of associated cardiac and extracardiac anomalies determines the postnatal morbidity and mortality. Polysplenia and asplenia may be associated with immunological disorders, that cannot be ruled out in the prenatal period, and further complicate the postnatal course.

Evaluation of Reproductive Disorders in Female Rats Exposed to N‐Methyl‐2‐Pyrrolidone

N-methyl-2-pyrrolidone (NMP) is a solvent used in the petrochemical, and electronic industries, in pesticides production, veterinary drugs, and paint removers. The aim of study was to evaluate the relationship between the dose of NMP given orally and its effect on fertility in female rats and early development of their progeny. Females were exposed by gavage 5 days/week to NMP at 150, 450, or 1000mg/kg/day 2 weeks before mating, during mating, gestation, and lactation. On the first postnatal day (PND 1), the live and dead pups were counted, weighed, and gender was determined. On PND 4, the litters were culled to eight animals each and balanced for gender. Young animals were observed during 3 weeks after birth. Fertility index did not significantly differ in the control and the group exposed at 150mg/kg/day but it was significantly lower in the groups exposed at 450 or 1000mg/kg/day. The number of live pups in the group exposed to the highest dose was significantly lower and the number of stillbirths in litters was significantly greater. Survival of the pups from all exposed groups during the 3 weeks after birth was significantly lower than the control animals. The results of our study indicate that intragastric exposure of female rats to NMP before pregnancy during gestation causes significant impairment in female fertility and intrauterine mortality rates. At lower doses, toxic or slightly toxic to the mothers, this substance causes decrease in viability and physical development of progeny.

Prospective risk of fetal death in uncomplicated monochorionic twins

A retrospective cohort study was carried out in a university teaching hospital to determine the prospective risk of unexpected fetal death in uncomplicated monochorionic diamniotic (MCDA) twin pregnancies after viability. All MCDA twins delivered at or after 24 weeks' gestation from July 1999 to July 2007 were included. Pregnancies with twin-twin transfusion syndrome, growth restriction, structural abnormalities, or twin reversed arterial perfusion sequence were excluded. Of the 144 MCDA twin pregnancies included in our analysis, the risk of intrauterine death was 4.9%. The prospective risk of unexpected intrauterine death was 1 in 43 after 32 weeks' gestation and 1 in 37 after 34 weeks' gestation. Our results demonstrate that despite close surveillance, the unexpected intrauterine death rate in uncomplicated MCDA twin pregnancies is high. This rate seems to increase after 34 weeks' gestation, suggesting that a policy of elective preterm delivery warrants evaluation.

Restricting inbreeding while maintaining selection response for weight gain in Mus musculus

An experiment with mice was designed to test the relative efficiency of three selection methods that help to minimize the rate of inbreeding during selection. A common house mice (Mus musculus) population was selected for 17 generations to increase the weight gain between 21 and 42 days. The population was split at random into three lines A, B and C where three selection methods were applied: individual selection and random mating, weighted selection with random mating and individual selection with minimum coancestry mating, respectively. There were three replicates for each line. Cumulated selection response was similar in the three lines, but there were differences in the level of inbreeding attained (in percentage): 31.24 (method A), 24.72 (method B) and 27.88 (method C). As consequence, lines B and C (weighted selection and minimum coancestry) showed a lower value of deterioration of fitness traits (the intrauterine mortality and the mortality at birth) than line A (random mating).

Prenatal Brain Damage in Preeclamptic Animal Model Induced by Gestational Nitric Oxide Synthase Inhibition

Cerebral palsy is a major neonatal handicap with unknown aetiology. There is evidence that prenatal brain injury is the leading cause of CP. Severe placental pathology accounts for a high percentage of cases. Several factors predispose to prenatal brain damage but when and how they act is unclear. The aim of this paper was to determine if hypoxia during pregnancy leads to damage in fetal brain and to evaluate the localization of this injury. An animal model of chronic hypoxia produced by chronic administration of a nitric oxide synthase inhibitor (L-NAME) was used to evaluate apoptotic activity in fetal brains and to localize the most sensitive areas. L-NAME reproduces a preeclamptic-like condition with increased blood pressure, proteinuria, growth restriction and intrauterine mortality. Apoptotic activity was increased in L-NAME brains and the most sensitive areas were the subventricular and pallidum zone. These results may explain the clinical features of CP. Further studies are needed.

Autoimmune processes after long-term low-level exposure to electromagnetic fields (experimental results) part 5. Study of the influence of blood serum from rats exposed to low-level electromagnetic fields on pregnancy and fetal and offspring development

The work evaluates the possible adverse effects on pregnancy and fetal and offspring development arising from the injection of blood serum from rats exposed to microwaves at a power density of 500 μW/cm2 into intact female rats. The study is performed on 59 pregnant Wistar rats. Intrauterine mortality, embryo and fetal body weights, and placenta weight are used for the evaluation of embryo and fetal development. Generally accepted integral and specific parameters are used for the evaluation of the postnatal development of offspring during the first 30 days of life. It is shown that injection of blood serum from rats subjected to long-term RF exposure at 500 μW/cm2 into intact rats on the tenth day of pregnancy results in adverse effects on fetal and offspring development. Higher total in utero and postnatal mortality, as well as delayed offspring development, are recorded.

Reproductive performance of wild boar females in Portugal

Reproductive tracts of 214 female wild boars collected in Central Portugal between October and February over the period 1997 to 2001 were examined. From this material, we were able to determine reproductive phenology (conception and birth periods) as well as age and weight of sows at puberty, ovulation rates of adults, foetal sex ratio, levels of intrauterine mortality, final litter size and postnatal mortality. Differences between year, region, age and body weight were analysed. A total of 66.8% of the females examined were gestating or lactating and 96.3% of these weighed >40 kg. The highest proportions of pregnant sows were found in the adult age/weight classes (74%). None of the juvenile females (1 year old and younger) were lactating and only 7% was pregnant. The average number of foetuses/female (4.1 ± 1.2SD) and that of corpora lutea per female (4.6 ± 1.7SD) increased from lighter and younger to heavier and older wild sows. Foetal sex ratio was biased towards males (1.3:1). Observed intrauterine mortality rate (9.7%) and postnatal mortality (6.3%) were among the lowest recorded in European wild boar populations. The productivity rate of the Central Portuguese wild boar population was calculated as 1.1 young per individual in the population. Conception and birth periods did not differ significantly between the considered 4 years. Birth synchronisation was pronounced in all the years, with a peak of births occurring in March.

Parents’ genetic dissimilarity and offspring sex in a polygynous mammal

Offspring quality may benefit from genetic dissimilarity between parents. However, genetic dissimilarity may trade-off with additive genetic benefits. We hypothesized that when sexual selection produces sex-specific selective scenarios, the relative benefits of additive genetic vs. dissimilarity may differ for sons and daughters. Here we study a sample of 666 red deer (Cervus elaphus) microsatellite genotypes, including males, females and their foetuses, from 20 wild populations in Spain (the main analyses are based on 241 different foetuses and 190 mother-foetus pairs). We found that parental lineages were more dissimilar in daughters than in sons. On average, every mother was less related to her mate than to the sample of fathers in the population when producing daughters not sons. Male foetuses conceived early in the rutting season were much more inbred than any other foetuses. These differences maintained through gestation length, ruling out intrauterine mortality as a cause for the results, and indicating that the potential mechanism producing the association between parents' dissimilarity and offspring sex should operate close to mating or conception time. Our findings highlight the relevance of considering the sex of offspring when studying genetic similarity between parents.