Asunto(s)

RESUMEN

BACKGROUND: Fetometry dating of gestational age is the gold standard in most developed countries but may have some inborn errors. Dating pregnancies after in vitro fertilization can be used for the evaluation of fetometric studies and for studies of variables which may affect them. METHODS: We compared the actual gestational age of 9543 singleton and 869 twin pregnancies with estimates based on second-trimester fetometry. Mean gestational age, percentage of births classified as preterm, and skewness of the distribution of differences between actual and estimated gestational age were studied. Subanalyses were made of data on singletons for males and females, for infants born to overweight or obese women or to smoking women, for infants judged to be small or large for gestational age, and on twins. RESULTS: In the majority of cases, good agreement was found between actual and estimated gestational age but in singletons there was an excess of positive differences resulting in a moderate over-estimate of the rate of preterm births (8%), more marked for females (11%) than for males (6%) and increased for infants born to overweight (7%) or obese (16%) mothers. Singleton infants born small for gestational age also showed an excess of positive differences (3%). These differences were less marked for twins. CONCLUSIONS: In most IVF pregnancies, routine fetometry correctly predicts gestational age but deviations exist which indicate that ultrasound underestimates the age of fetuses that will be born small for gestational age and when the woman is obese. The differences between actual age and estimates based on fetometry seem to be smaller than those between estimates based on last menstrual period and fetometry.

Asunto(s)

Asunto(s)

RESUMEN

BACKGROUND: The Swedish National Inpatient Register (IPR), also called the Hospital Discharge Register, is a principal source of data for numerous research projects. The IPR is part of the National Patient Register. The Swedish IPR was launched in 1964 (psychiatric diagnoses from 1973) but complete coverage did not begin until 1987. Currently, more than 99% of all somatic (including surgery) and psychiatric hospital discharges are registered in the IPR. A previous validation of the IPR by the National Board of Health and Welfare showed that 85-95% of all diagnoses in the IPR are valid. The current paper describes the history, structure, coverage and quality of the Swedish IPR. METHODS AND RESULTS: In January 2010, we searched the medical databases, Medline and HighWire, using the search algorithm "validat* (inpatient or hospital discharge) Sweden". We also contacted 218 members of the Swedish Society of Epidemiology and an additional 201 medical researchers to identify papers that had validated the IPR. In total, 132 papers were reviewed. The positive predictive value (PPV) was found to differ between diagnoses in the IPR, but is generally 85-95%. CONCLUSIONS: In conclusion, the validity of the Swedish IPR is high for many but not all diagnoses. The long follow-up makes the register particularly suitable for large-scale population-based research, but for certain research areas the use of other health registers, such as the Swedish Cancer Register, may be more suitable.

Asunto(s)

Asunto(s)

RESUMEN

PURPOSE: To compare interview data on drug use during pregnancy with data identified from a register of prescriptions. MATERIALS: We compared information from the Swedish Prescribed Drug Register with the Swedish Medical Birth Register on antidepressant use. In order to evaluate the clinical significance of the difference in ascertainment with the two methods, the rate of preterm births among singletons and of neonatal symptoms were studied. RESULTS: During the year before the last menstrual period, 1.5% of the women filled prescriptions for antidepressants each month. Already before the pregnancy was known, the rate of filled prescriptions decreased and reached 0.5% towards the end of the pregnancy. Twenty-two percent of first-trimester use of antidepressants was unidentified using interview data and prescriptions during the 2nd and 3rd pregnancy months covered only 55% of actual use. When women who filled prescriptions 1 or 3 months before the last menstrual period were included, 17 and 43% respectively of women were included who probably did not use the drugs in the first trimester. Prescriptions gave a more complete ascertainment of drug use after the first trimester than data from antenatal care, which seemed to overestimate drug use. CONCLUSIONS: Interview data seem to give the most valid results on early use. When interview data are not available, prescription data could be used, but should not include prescriptions given earlier than 1 month before the last menstrual period. Studies of drug use later in pregnancy are best based on prescription data in the absence of interview data.

Asunto(s)

RESUMEN

OBJECTIVE: To summarize data on deliveries after in vitro fertilization (IVF) performed in Sweden up to 2006. DESIGN: Cohort study of women and children, conceived after IVF, with comparisons of deliveries after IVF before and after 1 April 2001. SETTING: Study based on Swedish health registers. POPULATION: Births registered in the Swedish Medical Birth Register with information on IVF from all IVF clinics in Sweden. METHODS: Results from the second study period are summarized, and outcomes between the two periods are compared. Long-term follow-up is based on data from both periods. MAIN OUTCOME MEASURES: Maternal and perinatal outcomes, long-term sequels. RESULTS: Some maternal pregnancy complications decreased in rate, notably pre-eclampsia and premature rupture of membranes. The rate of multiple births and preterm births decreased dramatically, with a better neonatal outcome, including reduced neonatal mortality. No difference in outcome existed between IVF and intracytoplasmic sperm injection or between the use of fresh and cryopreserved embryos, but children born after blastocyst transfer had a slightly higher risk for preterm birth and congenital malformations than children born after cleavage stage transfer. An increased risk for cerebral palsy, possibly for attention deficit and hyperactivity disorder, for impaired visual acuity and for childhood cancer was noted, but these outcomes were rare also after IVF. An increased risk for asthma was demonstrated. No effect on maternal cancer risk was seen. CONCLUSION: A marked decrease in multiple births was the main reason for better pregnancy and neonatal outcome and may also have a beneficial effect on long-term results, notably cerebral palsy.

Asunto(s)

RESUMEN

OBJECTIVES: Studies conducted so far have found no statistically significant increased risk for cancer among children who are born after in vitro fertilization (IVF). METHODS: We followed 26,692 children who were born after IVF during the years 1982-2005 by using the Swedish Cancer Register and compared the number of children who had cancer and were born after IVF with children who were not conceived by IVF. Adjustment was made for year of birth. RESULTS: Maternal age, parity, smoking, subfertility, previous miscarriages, BMI, and multiple births did not significantly affect cancer risk in offspring. High birth weight, premature delivery, and the presence of respiratory diagnoses and low Apgar score were risk factors for cancer. We identified 53 cases of cancer in children who were born after IVF against 38 expected cases: 18 of them with hematologic cancer (15 of them acute lymphoblastic leukemia), 17 with eye or central nervous system tumors, and 12 with other solid cancers. There were 6 cases of Langerhans histiocytosis against 1.0 expected. The total cancer risk estimate was 1.42 (95% confidence interval: 1.09-1.87). CONCLUSIONS: We found a moderately increased risk for cancer in children who were conceived by IVF. Putative intermediary factors could be preterm birth and neonatal asphyxia.

Asunto(s)

RESUMEN

PURPOSE: To follow up children born after in vitro fertilization (IVF) with respect to eye malformations and poor visual acuity. DESIGN: Observational cohort study based on Swedish health registers. METHODS: Congenital eye malformations were studied in 32 091 children born from 1982 through 2007 and severe visual impairment was studied in 24 628 children born from 1985 through 2005 after IVF in Sweden. Comparisons were made with all children born in Sweden during corresponding periods with adjustment for various confounders. The main outcome measure was the presence of a congenital eye malformation and poor visual acuity. RESULTS: Thirty-six (1.1 per 1000) IVF infants with ocular malformations were identified, and the risk, compared with non-IVF children, was not increased when adjusted for maternal age, parity, smoking, and body mass index (odds ratio, 1.05; 95% confidence interval, 0.75 to 1.47). Severe visual impairment was identified in 25 cases (1.0 per 1000), and the risk increase was statistically significant (odds ratio, 1.65; 95% confidence interval, 1.12 to 2.45) and was only slightly reduced when adjustment as above was made (odds ratio, 1.55; 95% confidence interval, 1.04 to 2.32). When adjustment was made for known length of unwanted childlessness, the OR decreased to 1.15 (95% confidence interval, 0.61 to 2.16). Only 3 of the 25 children with visual impairment had ocular malformations. CONCLUSIONS: Although there is an increased risk for visual impairment among children born after IVF, the individual risk is small and may be secondary to parental characteristics. No increased risk for eye malformations was found.

Asunto(s)

RESUMEN

OBJECTIVE: To compare neonatal outcome of blastocyst and cleavage stage embryo transfers after IVF. DESIGN: Register study. SETTING: Births recorded in the Swedish Medical Birth Register after IVF performed, 2002-2006. PATIENT(S): Treatments reported from all Swedish IVF clinics. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Some neonatal characteristics were compared in 1,311 infants born after blastocyst-stage transfer and 12,562 infants born after cleavage-stage transfer. Comparisons were also made with all births, 2002-2007 (n = 598,687). RESULT(S): After adjusting for year of birth, maternal age, parity, smoking habits, and body mass index, the risk of preterm birth among singletons was significantly greater after blastocyst-stage transfer than after cleavage-stage transfer. The risk of congenital malformations was also significantly higher. When the analysis was restricted to clinics where blastocyst transfers were made, the risk estimates increased for preterm birth, low birth weight, low APGAR score, and respiratory diagnoses, but did not change for congenital malformations. CONCLUSION(S): The results indicate a small increase in risk associated with blastocyst transfer, perhaps owing to the longer period of in vitro culture. There is a possibility that this effect is due, at least in part, to a selection of women for blastocyst transfers. Further studies are needed either to verify or to refute the found associations.

Asunto(s)

RESUMEN

BACKGROUND: Women with schizophrenia are at increased risk for adverse pregnancy outcomes. It is not known whether offspring born to fathers with schizophrenia also have an increased risk. AIMS: To evaluate paternal and maternal influences on the association between schizophrenia and pregnancy outcomes. METHOD: A record linkage including 2 million births was made using Swedish population-based registers. The risk for adverse pregnancy outcomes was evaluated through logistic regression. RESULTS: Offspring with a mother or father with schizophrenia faced a doubled risk of infant mortality, which could not be explained by maternal behaviour alone during pregnancy. Excess infant death risk was largely attributable to post-neonatal death. Maternal factors (e.g. smoking) explained most of the other risks of adverse pregnancy outcomes among both mothers and fathers with schizophrenia. CONCLUSIONS: The risks to offspring whose fathers had schizophrenia suggest that, in addition to maternal risk behaviour, non-optimal social and/or parenting circumstances are of importance.

Asunto(s)

RESUMEN

In order to evaluate the previously published association between maternal use of selective serotonin re-uptake inhibitors (SSRI) and persistent pulmonary hypertension in the neonate (PPHN), we used data from the Swedish Medical Birth Register for the years 1997-2005. Infants were identified from discharge diagnoses, and maternal exposure to drugs from interviews performed in early pregnancy and from prescriptions from the antenatal care service. Putative confounders were studied: an increased risk for PPHN was indicated for high maternal age, for first parity, for maternal BMI, and possibly for maternal smoking. Adjusting for these variables and year of birth, an association between maternal use of SSRI and PPHN in births after 34 completed weeks was identified with a risk ratio of 2.4, 95%CI 1.2-4.3 when based on women who reported the drug use in early pregnancy. When a subgroup of the women were studied who also had prescriptions for SSRI from the antenatal care later in pregnancy, the risk estimate was 3.6, 95%CI 1.2-8.3. The risk estimates were lower than that described previously in the literature, but both estimates could come from the same about 4-5 times increased risk. The mechanism behind the association between SSRI and PPHN is unclear but an increased risk for respiratory problems after maternal use of SSRI is well known, and PPHN could be a rare part of this association.

Asunto(s)

RESUMEN

BACKGROUND: Various outcomes have been described during pregnancy and among infants born to women after in vitro fertilisation (IVF) treatments. This mini-review summarises recent population-based Swedish studies about the short- and long-term effects of IVF on the infant and child, and also comments on disturbances of pregnancies and deliveries occurring after IVF. METHODS: Data on women who had IVF treatments and gave birth in Sweden during the period 1982-2001 were collected from all clinics performing IVF. By linkage with the Swedish Medical Birth Register, the Swedish Register of Congenital Malformations, the Swedish Hospital Discharge Register, the Swedish Cancer Register, and the Swedish Cause of Death Register, data on short- and long-term complications were retrieved. RESULTS: From 1982 to 2001, a total of 13,261 women gave birth to 16,280 infants after IVF treatment. During the final years of the study, nearly half of the pregnancies occurred after intracytoplasmic sperm injection intracytoplasmic sperm injection (ICSI). Characteristics of women who delivered after IVF were analysed. Various anomalies in pregnancy and delivery outcome were found, but few long-term effects. CONCLUSIONS: Most deviations, except for multiple pregnancies, could be explained by parents characteristics, notably their subfertility status. Little difference was found between pregnancies after standard IVF and pregnancies after ICSI.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

The original report published in 2001 on a possible association between maternal use of loratadine and an increased risk of infant hypospadias, based on data in the Swedish Medical Birth Register 1995-2001, has been followed up by continued surveillance in the same register. The original "signal" was based on 15 infants with hypospadias among 2780 loratadine-exposed infants born, representing an adjusted odd ratio of about 2.3, statistically significant. Since then another 10 cases have been identified, and 12.5 expected. For the period 2001-2004, another 1911 loratadine-exposed infants have been identified and only two had hypospadias (4 expected). Our present position is that the primary finding was a "signal" which had occurred by chance and the follow-up agrees with independent studies which indicate an absence of an association. This illustrates the care with which apparent statistically significant increases have to be handled when no prior hypothesis exists.

RESUMEN

OBJECTIVE: The purpose of this study was to evaluate delivery outcome after maternal use of oral decongestants. STUDY DESIGN: We identified 2474 women who had reported the use of oral decongestants (mainly phenylpropanolamine) during early pregnancy and 1771 women who used prescription oral decongestants later in pregnancy. With Mantel-Haenszel analysis, comparisons were made with all women who gave birth in Sweden. RESULTS: The risk ratio for any congenital malformation after the use of oral decongestants was 0.96 (95% CI, 0.80-1.16). Women who were prescribed decongestants after the first antenatal visit less often than expected had infants who were born preterm (odds ratio, 0.68; 95% CI, 0.52-0.88), of low birth weight (odds ratio, 0.53; 95% CI, 0.37-0.77), small-for-date (odds ratio, 0.71; 95% CI, 0.47-1.08), or perinatally dead (odds ratio, 0.53; 95% CI, 0.22-12.5). CONCLUSION: No teratogenic effect of oral decongestants was found. An association found between the late pregnancy use of such drugs and a favorable neonatal outcome can be explained hypothetically by the postulated association between pregnancy rhinitis and placental hormones.

Asunto(s)

RESUMEN

BACKGROUND: The median age at first childbirth has increased dramatically in many high-income countries during the past decades. The psychiatric consequences of this demographic change are insufficiently described on a population level. This study aimed to investigate whether parental age at childbearing is related to psychiatric morbidity among Swedish youths. METHOD: This was a cohort study based on Swedish national registers. A national cohort of 292129 children born to primiparas women during 1973-1979 was followed prospectively from 1987 to 2002 in registers. Multivariate Cox analyses of proportional hazards were used to estimate the relative risk of hospital admission for schizophrenia, alcohol and illicit drug abuse, suicide attempts and deaths. RESULTS: Youths born of teenage mothers had a high risk for suicide death [relative risk (RR) 1.9, 95% confidence interval (CI) 1.3-2.7] and hospital admissions because of suicide attempt (RR 2.0, 95% CI 1.7-2.3) and substance abuse (alcohol: RR 1.6, 95% CI 1.4-1.8; illicit drug: RR 2.2, 95% CI 1.9-2.5) after adjustments for major sociodemographic confounders, compared with children of mothers aged 25-29 years. Offspring of older parents (>34 years) had the highest risk for schizophrenia (RR 1.8, 95% CI 1.0-3.0). CONCLUSIONS: Parental age is related to psychiatric morbidity.

Asunto(s)

RESUMEN

OBJECTIVES: To investigate the association between epidural analgesia for labour-pain relief and mode of delivery. STUDY DESIGN: The Swedish medical birth register covers 99% of all births and contains prospectively collected information from all delivery units in Sweden. The present population-based cohort study includes singleton births among nulliparae during 1998-2000, excluding deliveries with elective caesarean section, giving study population of n=94,217. The frequencies of epidural block in this population were estimated for each delivery unit. The outcomes studied were non-elective caesarean section and instrumental delivery. RESULTS: There was no clear association between frequency of epidural block and caesarean section and instrumental delivery, respectively. Delivery units with the lowest (20-29%) and the highest (60-64%) relative frequencies of epidural block had the lowest proportion of caesarean section (9.1%). For the other groups the proportion varied between 10.3 and 10.6%. Instrumental deliveries were most common, 18.8%, in delivery units with 50-59% frequency of epidural block use. The lowest incidence (14.1%) was in units using epidurals in 30-39% of cases. In the other groups (20-29, 40-49 and 60-64%) the proportion varied between 15.3 and 15.7%. CONCLUSIONS: This investigation shows no clear association between epidural use and caesarean section or instrumental delivery, indicating that there is no reason to restrict the epidural rate to improve obstetric outcome.

Asunto(s)

RESUMEN

Obstetric complications increase the risk of schizophrenia. However, it is not known whether there is a causal relation or whether the association is mediated by genetic and/or shared environmental effects. The aim of this study was to investigate the associations between birthweight, other birth characteristics, and schizophrenia. Twin pairs discordant for schizophrenia will also control for unmeasured genetic and shared environmental effects. Prospectively filed obstetric records were used for a cohort analysis of 11,360 same-sexed twins, and within-twin pair analyses were conducted on 90 twin pairs discordant for schizophrenia. The results from the cohort study showed that low birthweight (less than or equal to 1999 grams; odds ratio [OR] 1.67, 95% confidence interval [CI] 0.88-3.14 and 2000-2299 grams; OR 1.79, 95% CI 1.07-3.01) and small head circumference (less than or equal to 31.5 cm; OR 1.61, 95% CI 1.03-2.51) were associated with later development of schizophrenia. The associations remained in the within-pair analyses. The association between low birthweight and schizophrenia is partly a function of reduced fetal growth. Fetal growth restriction seems to be associated with risk of schizophrenia independently of familial factors.

Asunto(s)