Maternal haemoglobin concentrations before and during pregnancy and stillbirth risk: A population-based case-control study

Background: Results of previous studies on the association between maternal haemoglobin concentration during pregnancy and stillbirth risk are inconclusive. It is not clear if haemoglobin concentration before pregnancy has a role. Using prospectively collected information from pre-pregnancy and antenatal visits, we investigated associations of maternal haemoglobin concentrations before and during pregnancy and haemoglobin dilution with stillbirth risk. Methods: In a population-based case-control study from rural Golestan, a province in northern Iran, we identified 495 stillbirths (cases) and randomly selected 2,888 control live births among antenatal health-care visits between 2007 and 2009. Using logistic regression, we estimated associations of maternal haemoglobin concentrations, haemoglobin dilution at different stages of pregnancy, with stillbirth risk. Results: Compared with normal maternal haemoglobin concentration (110-120g/l) at the end of the second trimester, high maternal haemoglobin concentration (≥140g/l) was associated with a more than two-fold increased stillbirth risk (OR = 2.31, 95% CI [1.30-4.10]), while low maternal haemoglobin concentration (<110g/l) was associated with a 37% reduction in stillbirth risk. Haemoglobin concentration before pregnancy was not associated with stillbirth risk. Decreased haemoglobin concentration, as measured during pregnancy (OR = 0.61, 95% CI [0.46, 0.80]), or only during the second trimester (OR = 0.75, 95% CI [0.62, 0.90]), were associated with reduced stillbirth risk. The associations were essentially similar for preterm and term stillbirths. Conclusions: Haemoglobin concentration before pregnancy is not associated with stillbirth risk. High haemoglobin level and absence of haemoglobin dilution during pregnancy could be considered as indicators of a high-risk pregnancy. © 2016 The Author(s)

Placental weight and mortality in premenopausal breast cancer by tumor characteristics

Placental weight may be regarded as an indirect marker of hormone exposures during pregnancy. There is epidemiological evidence that breast cancer mortality in premenopausal women increases with placental weight in the most recent pregnancy. We investigated if this association differs by tumor characteristics, including expression of estrogen and progesterone receptors. In a Swedish population-based cohort, we followed 1,067 women with premenopausal breast cancer diagnosed from 1992 to 2006. Using Cox regression models, we estimated hazard ratios for the association between placental weight and risk of premenopausal breast cancer mortality. In stratified analyses, we estimated mortality risks in subjects with different tumor stages, estrogen receptor (ER) or progesterone receptor (PR) status. Compared with women with placental weight less than 600 g, women with a placental weight between 600 and 699 g were at a 50 % increased risk of mortality, however, not significant change in risk was observed for women with placental weight �700 g. Mortality risks associated with higher placental weight were more pronounced among ER- and PR- breast cancer tumors, where both a placental weight 600-699 g and �700 g were associated with a more than doubled mortality risks compared with tumors among women with placental weight less than 600 g. Moreover, stratified analyses for joint receptor status revealed that a consistent increased mortality risk by placental weight was only apparent in women with ER-/PR- breast cancer. The increased mortality risk in premenopausal breast cancer associated with higher placental weight was most pronounced among ER- and PR- tumors. © 2012 Springer Science+Business Media New York

Consanguineous marriage, prepregnancy maternal characteristics and stillbirth risk: A population-based case-control study

Introduction. Consanguineous marriage is associated with increased risks for congenital anomalies, low birthweight, and other adverse perinatal outcomes. In this population-based, case-control study we investigated the association between consanguineous marriage (first-cousin marriage) and stillbirth risk, using prospectively collected information from prepregnancy visits. Material and methods. From 2007 to 2009, we identified 283 stillbirths (cases) and 2088 randomly selected live control births through prepregnancy visits in rural Golestan, Iran. The associations between consanguinity and prepregnancy maternal characteristics and stillbirth risk were examined using multivariate logistic regression. Results. The rate of consanguineous marriage was 19.4% among cases and 13.6% among controls. Consanguinity was associated with increased stillbirth risk [odds ratio (OR) 1.53; 95% CI 1.10-2.14]. The association was significantly increased for preterm stillbirth (< 37 gestational weeks) (OR 2.43; 95% CI 1.46-4.04) but not for term stillbirth (≥ 37 weeks) (OR 1.14; 95% CI 0.75-1.74). Low and high maternal age, underweight, obesity, nulliparity, a history of infertility or miscarriage, previous obstetric complications (preeclampsia, preterm delivery, and stillbirth in previous pregnancies) were also associated with increased stillbirth risks. Conclusions. Consanguineous marriage is associated with increased risk of stillbirth, particularly preterm stillbirth. Findings for other maternal risk factors for stillbirth in rural Iran are consistent with previously reported findings from high-income countries. © 2015 Nordic Federation of Societies of Obstetrics and Gynecology

Risk of pre-eclampsia in first and subsequent pregnancies: prospective cohort study

Objective To investigate whether pre-eclampsia is more common in first pregnancies solely because fewer affected women, who presumably have a higher risk of recurrence, go on to have subsequent pregnancies

The impact of birth mode of delivery on childhood asthma and allergic diseases : a sibling study

Background: Caesarean section (CS) has been reported to increase the risk of asthma in offspring. This may be due to that infants delivered by CS are unexposed to vaginal flora, according to the ‘hygiene hypothesis’. Objective: Our aim was to investigate if CS increases risk of childhood asthma, and if the risk increase remains after adjustment for familial confounding using sibling design. Methods: A register-based cohort study with 87 500 Swedish sibling pairs was undertaken. Asthma outcome variables were collected from national health registers as diagnosis or asthma medication (ICD-10 J45-J46; ATC code R03) during the 10th or 13th year of life (year of follow-up). Mode of delivery and confounders were retrieved from the Medical Birth Register. The data were analysed both as a cohort and with sibling control analysis which adjusts for unmeasured familial confounding. Results: In the cohort analyses, there was an increased risk of asthma medication and asthma diagnosis during year of follow-up in children born with CS (adjusted ORs, 95% CI 1.13, 1.04–1.24 and 1.10, 1.03–1.18 respectively). When separating between emergency and elective CS the effect on asthma medication remained for emergency CS, but not for elective CS, while both groups had significant effects on asthma diagnosis compared with vaginal delivery. In sibling control analyses, the effect of elective CS on asthma disappeared, while similar but non-significant ORs of medication were obtained for emergency CS. Conclusions and Clinical Relevance: An increased risk of asthma medication in the group born by emergency CS, but not elective, suggests that there is no causal effect due to vaginal microflora. A more probable explanation should be sought in the indications for emergency CS.Swedish Research CouncilCentre for Allergy ResearchStiftelsen Frimurare-Barnhuset i StockholmALF KI/SLLPublishe

Severe asphyxia due to delivery-related malpractice in Sweden 1990–2005

Aim The objective of the thesis was to describe the most common causes of substandard care during labour contributing to severe asphyxia or neonatal death, to study risk factors related to asphyxia associated with substandard care and to explore the occurrence of substandard care during labour. Background There are about 100 000 infants born every year in Sweden. Most infants are born healthy after uncomplicated deliveries. However, 20-50 claims for financial compensation are made annually to the Patients Advisory Committee (PA C) on suspicion that substandard care during labour has contributed to severe asphyxia causing cerebral palsy or death. Even if this group of patients is notably small, asphyxia causes life-long impairment and immeasurable suffering to the patients and their families. In addition, the insurance costs are substantial and amount to 25% of all costs related to substandard care in Sweden. With the exception of this group of patients, and claims to the Health Services Disciplinary Board, the frequency of substandard care in relation to childbirth is fairly unknown. Material and methods Inclusion criteria were pregnancies with a gestational length ≥ 33 weeks, a spontaneous or induced start of labour, a normal CTG at admission for labour, and Apgar score < 7 at 5 minutes of age (Papers I-IV). 472 case records of deliveries from 1990-2005, filed at the PAC were scrutinised. In Paper I and II the deliveries and acts of neonatal resuscitation procedures are described. In Paper III, maternal characteristics, factors related to care and infant characteristics for patients receiving lifelong financial compensation from PAC are compared with all infants with full Apgar score at 5 minutes of age born after a vaginal start during the same time period in Sweden (n=1.141 059). In Paper IV deliveries and risk factors from 313 infants with Apgar score < 7at 5 minutes of age, born in the Stockholm County are compared with 313 infants with full Apgar score at five minutes of age, matched for year of birth. Results One-hundred and seventy-seven infants were considered to have been severely asphyxiated due to substandard care during labour (Paper I-III). The most common occurrences of malpractice in conjunction with labour were neglecting to supervise fetal well-being (98%), neglecting signs of fetal asphyxia (71%), including incautious use of oxytocin (71%) and choosing a non-optimal mode of delivery (52%) (Paper I). Resuscitation of the 177 severely asphyxiated infants was unsatisfactory in 47%. The most important flaw was the defective compliance with the guidelines concerning ventilation and prompt paging for skilled personnel in cases of imminent asphyxia (Paper II). Risk factors associated with asphyxia included maternal age ≥ 30 years, short maternal stature (< 159 cm), previous caesarean delivery, insulin-dependent diabetes, induced deliveries and night deliveries, where the increases in risk were doubled to a four-fold. In addition, dystocia of labour was associated with a five-fold increase in risk, which was further increased if epidural anaesthesia or opioids were used. Small- and large-for-gestational age infants, post-term (> 42 weeks) births, twins and breech deliveries had a three to eight-fold increase in risk of asphyxia when there was substandard care during labour (Paper III). Two thirds of infants born in the Stockholm region 2004-2006, with Apgar score < 7 at 5 minutes but also one third of the healthy controls were subjected to some kind of substandard care during labour (Paper IV). The main causes of substandard care during labour were related to misinterpretation of CTG, not acting timely on abnormal CTG, and incautious use of oxytocin. The risk of asphyxia increased with duration of abnormal CTG and was increased fifteen-fold when this was abnormal for ≥ 90 minutes. Oxytocin was provided without sign of inertia in 20% of cases and controls and the risk of asphyxia was increased more than fivefold in cases of tachysystole. Infants born after a spontaneous vaginal delivery with abnormal CTG for more than 45 minutes had a more than sevenfold risk of low Apgar score. In instrumental deliveries that were considered complex, there was a more than seventeen-fold risk of an Apgar score < 7 at 5 minutes of age. Assuming that substandard care is causative for low Apgar score, we estimate that 42% of the cases could be prevented by avoiding substandard care (Paper IV). Conclusion It is possible to improve patient safety during labour by applying educational efforts on fetal surveillance and increasing awareness of risk factors associated with asphyxia. The main causes of substandard care during labour are related to misinterpretation of CTG, not acting timely on abnormal CTG, misinterpretation of guidelines and misuse of oxytocin. Low Apgar score at 5 minutes of age can substantially, be prevented by avoiding substandard care

Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study

Villamor E, Dekker L, Svensson T, Cnattingius S. Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study. Paediatric and Perinatal Epidemiology 2010.We estimated the accuracy of a non-invasive, inexpensive method (the Chinese lunar calendar, CLC) to predict the sex of a baby from around the time of conception, using 2 840 755 singleton births occurring in Sweden between 1973 and 2006. Maternal lunar age and month of conception were estimated, and used to predict each baby's sex, according to a published algorithm. Kappa statistics were estimated for the actual vs. the CLC-predicted sex of the baby.Overall kappa was 0.0002 [95% CI −0.0009, 0.0014]. Accuracy was not modified by year of conception, maternal age, level of education, body mass index or parity. In a validation subset of 1000 births in which we used a website-customised algorithm to estimate lunar dates, kappa was −0.02 [95% CI −0.08, 0.04]. Simulating the misuse of the method by failing to convert Gregorian dates into lunar did not change the results. We conclude that the CLC method is no better at predicting the sex of a baby than tossing a coin and advise against painting the nursery based on this method's result.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79303/1/j.1365-3016.2010.01129.x.pd