Discrepancy between pregnancy dating methods – correlates and outcomes

With the introduction of obstetric ultrasound there has been a shift from last menstrual period-based to ultrasound-based estimation of gestational age. The choice of the method and timing of pregnancy dating is important because it can affect dating precision and perinatal outcomes. First, when comparing two large population-based cohorts from the Medical Birth Register, from before and after the introduction of ultrasound-based pregnancy dating, male infants on the edge of prematurity did not benefit from progress in medical care as much as female infants in terms of prematurity-related outcomes. This might reflect a bias introduced by the ultrasound-based pregnancy dating method, because of a tendency to overestimate gestational age in pregnancies with a male fetus. Second, in a large population-based cross-sectional study, the associations of discrepancies between last menstrual period-based and ultrasound-based estimates with variables such as fetal sex and maternal height, indicated that ultrasound-based pregnancy dating introduced systematic errors presumably related to the method’s use of fetal size as a proxy for gestational age. The largest effect estimates were found for maternal obesity in cases of large negative discrepancies. Third, in a large population-based cohort study, discrepancies between last menstrual period-based and ultrasound-based estimates were associated with several adverse pregnancy, delivery, and neonatal outcomes. Most importantly, a large negative discrepancy was associated with higher odds for neonatal and intrauterine fetal death, as well as for an infant being small for gestational age. Fourth, in a survey study there was overall good adherence to national guidelines, except for early pregnancy dating. However, the management of discrepancies between methods for pregnancy dating varied widely in clinical practice, which may be due to the lack of national guidelines. In summary, ultrasound-based dating can be biased by maternal or fetal characteristics. Discrepancies between methods for pregnancy dating may indicate a need for closer monitoring to optimize perinatal care during pregnancy and childbirth

Discrepancy between pregnancy dating methods – correlates and outcomes

With the introduction of obstetric ultrasound there has been a shift from last menstrual period-based to ultrasound-based estimation of gestational age. The choice of the method and timing of pregnancy dating is important because it can affect dating precision and perinatal outcomes. First, when comparing two large population-based cohorts from the Medical Birth Register, from before and after the introduction of ultrasound-based pregnancy dating, male infants on the edge of prematurity did not benefit from progress in medical care as much as female infants in terms of prematurity-related outcomes. This might reflect a bias introduced by the ultrasound-based pregnancy dating method, because of a tendency to overestimate gestational age in pregnancies with a male fetus. Second, in a large population-based cross-sectional study, the associations of discrepancies between last menstrual period-based and ultrasound-based estimates with variables such as fetal sex and maternal height, indicated that ultrasound-based pregnancy dating introduced systematic errors presumably related to the method’s use of fetal size as a proxy for gestational age. The largest effect estimates were found for maternal obesity in cases of large negative discrepancies. Third, in a large population-based cohort study, discrepancies between last menstrual period-based and ultrasound-based estimates were associated with several adverse pregnancy, delivery, and neonatal outcomes. Most importantly, a large negative discrepancy was associated with higher odds for neonatal and intrauterine fetal death, as well as for an infant being small for gestational age. Fourth, in a survey study there was overall good adherence to national guidelines, except for early pregnancy dating. However, the management of discrepancies between methods for pregnancy dating varied widely in clinical practice, which may be due to the lack of national guidelines. In summary, ultrasound-based dating can be biased by maternal or fetal characteristics. Discrepancies between methods for pregnancy dating may indicate a need for closer monitoring to optimize perinatal care during pregnancy and childbirth

Maternal and fetal characteristics affect discrepancies between pregnancy-dating methods : a population-based cross-sectional register study

IntroductionGestational age is estimated by ultrasound using fetal size as a proxy for age, although variance in early growth affects reliability. The aim of this study was to identify characteristics associated with discrepancies between last menstrual period-based (EDD-LMP) and ultrasound-based (EDD-US) estimated delivery dates. Material and methodsWe identified all singleton births (n=1201679) recorded in the Swedish Medical Birth Register in 1995-2010, to assess the association between maternal/fetal characteristics and large negative and large positive discrepancies (EDD-LMP earlier than EDD-US and 10th percentile in the discrepancy distribution vs. EDD-LMP later than EDD-US and 90th percentile). Analyses were adjusted for age, parity, height, body mass index, smoking, and employment status. ResultsWomen with a body mass index >40kg/m(2) had the highest odds for large negative discrepancies (-9 to -20days) [odds ratio (OR) 2.16, 95% CI 2.01-2.33]. Other factors associated with large negative discrepancies were: diabetes, young maternal age, multiparity, body mass index between 30 and 39.9kg/m(2) or <18.5kg/m(2), a history of gestational diabetes, female fetus, shorter stature (<-1SD), a history of preeclampsia, smoking or snuff use, and unemployment. Large positive discrepancies (+4 to +20days) were associated with male fetus (OR 1.80, 95% CI 1.77-1.83), age 30years, multiparity, not living with a partner, taller stature (>+1 SD), and unemployment. ConclusionsSeveral maternal and fetal characteristics were associated with discrepancies between dating methods. Systematic associations of discrepancies with maternal height, fetal sex, and partly obesity, may reflect an influence on the precision of the ultrasound estimate due to variance in early growth

Discrepancy between pregnancy dating methods affects obstetric and neonatal outcomes : a population-based register cohort study

To assess associations between discrepancy of pregnancy dating methods and adverse pregnancy, delivery, and neonatal outcomes, odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for discrepancy categories among all singleton births from the Medical Birth Register (1995–2010) with estimated date of delivery (EDD) by last menstrual period (LMP) minus EDD by ultrasound (US) -20 to +20 days. Negative/positive discrepancy was a fetus smaller/larger than expected when dated by US (EDD postponed/changed to an earlier date). Large discrepancy was <10th or >90th percentile. Reference was median discrepancy ± 2 days. Odds for diabetes and preeclampsia were higher in pregnancies with negative discrepancy, and for most delivery outcomes in case of large positive discrepancy (+9 to +20 days): shoulder dystocia [OR 1.16 (95% CI 1.01–1.33)] and sphincter injuries [OR 1.13 (95% CI 1.09–1.17)]. Odds for adverse neonatal outcomes were higher in large negative discrepancy (–4 to –20 days): low Apgar score [OR 1.18 (95% CI 1.09–1.27)], asphyxia [OR 1.18 (95% CI 1.11–1.25)], fetal death [OR 1.47 (95% CI 1.32–1.64)], and neonatal death [OR 2.19 (95% CI 1.91–2.50)]. In conclusion, especially, large negative discrepancy was associated with increased risks of adverse perinatal outcomes. Discrepancy between pregnancy dating methods – correlates and outcome

Adherence to Swedish national pregnancy dating guidelines and management of discrepancies between pregnancy dating methods : a survey study

Background. Swedish national guidelines for pregnancy dating were published in 2010. Follow-up is needed to assess adherence and to identify whether any clinical topics are not covered in the guidelines. Methods. All units in Sweden that performed ultrasound-based pregnancy dating were asked to complete a web-based questionnaire comprising multiple-response questions and commentary fields. Information was collected regarding baseline information, current and previous clinical practice, and management of discrepancies between last-menstrual-period- and ultrasound-based methods for pregnancy dating. Results. The response rate was 88% (38/43 units). Half of the units offered first-trimester ultrasound to all pregnant women. However, contrary to the guidelines, the crown–rump length was not used for ultrasound-based pregnancy dating in most units. Ultrasound-based pregnancy dating was performed only if the biparietal diameter was between 21 and 55 mm. The methods for management of discrepancies between methods for pregnancy dating varied widely. Conclusions. The units reported high adherence to national guidelines, except for early pregnancy dating, for which many units followed unwritten or informal guidelines. The management of discrepancies between last-menstrual-period-based and ultrasound-based estimated day of delivery varied widely. These findings emphasize the need for regular updating of national written guidelines and efforts to improve their implementation in all units.Discrepancy between pregnancy dating methods – correlates and outcome

Effects of ultrasound pregnancy dating on neonatal morbidity in late preterm and early term male infants : a register-based cohort study

Background: Assessing gestational age by ultrasound can introduce a systematic bias due to sex differences in early growth. Methods: This cohort study included data on 1,314,602 births recorded in the Swedish Medical Birth Register. We compared rates of prematurity-related adverse outcomes in male infants born early term (gestational week 37-38) or late preterm (gestational week 35-36), in relation to female infants, between a time period when pregnancy dating was based on the last menstrual period (1973-1978), and a time period when ultrasound was used for pregnancy dating (1995-2010), in order to assess the method's influence on outcome by fetal sex. Results: As expected, adverse outcomes were lower in the later time period, but the reduction in prematurity-related morbidity was less marked for male than for female infants. After changing the pregnancy dating method, male infants born early term had, in relation to female infants, higher odds for pneumothorax (Cohort ratio [CR] 2. 05; 95 % confidence interval [CI] 1.33-3.16), respiratory distress syndrome of the newborn (CR 1.99; 95 % CI 1.33-2. 98), low Apgar score (CR 1.26; 5 % CI 1.08-1.47), and hyperbilirubinemia (CR 1.12; 95 % CI 1.06-1.19), when outcome was compared between the two time periods. A similar trend was seen for late preterm male infants. Conclusion: Misclassification of gestational age by ultrasound, due to size differences, can partially explain currently reported sex differences in early term and late preterm infants' adverse neonatal outcomes, and should be taken into account in clinical decisions and when interpreting study results related to fetal sex

Pregnancy planning and neonatal outcome : a retrospective cohort study

Background Unplanned pregnancy is common, and although some research indicates adverse outcomes for the neonate, such as death, low birth weight, and preterm birth, results are inconsistent. The purpose of the present study was to investigate associated neonatal outcomes of an unplanned pregnancy in a Swedish setting. Methods We conducted a retrospective cohort study in which data from 2953 women were retrieved from the Swedish Pregnancy Planning Study, covering ten Swedish counties from September 2012 through July 2013. Pregnancy intention was measured using the London Measurement of Unplanned Pregnancy. Women with unplanned pregnancies and pregnancies of ambivalent intention were combined and referred to as unplanned. Data on neonatal outcomes: small for gestational age, low birth weight, preterm birth, Apgar score < 7 at 5 min, and severe adverse neonatal outcome defined as death or need for resuscitation at birth, were retrieved from the Swedish Medical Birth Register. Results The prevalence of unplanned pregnancies was 30.4%. Compared with women who had planned pregnancies, those with unplanned pregnancies were more likely to give birth to neonates small for gestational age: 3.6% vs. 1.7% (aOR 2.1, 95% CI 1.2–3.7). There were no significant differences in preterm birth, Apgar score < 7 at 5 min, or severe adverse neonatal outcome. Conclusions In a Swedish setting, an unplanned pregnancy might increase the risk for birth of an infant small for gestational age

Additional file 1: of Effects of ultrasound pregnancy dating on neonatal morbidity in late preterm and early term male infants: a register-based cohort study

Results from the stratified analysis by mode of delivery. (DOCX 101 kb

Unplanned pregnancy and the association with maternal health and pregnancy outcomes: A Swedish cohort study.

ObjectivesUnplanned pregnancies are common and associated with late initiation and inadequate antenatal care attendance, which may pose health risks to mother and child. How pregnancy planning relates to maternal health and delivery in Sweden, a country with free antenatal care and free abortion, has not been studied previously. Our aims were to study whether pregnancy planning was associated with antenatal care utilization and pregnancy outcomes in a Swedish setting.MethodsData for 2953 women, who answered a questionnaire when recruited at antenatal clinics in Sweden and later gave birth, was linked to the Swedish Medical Birth Register. The degree of pregnancy planning was estimated using the London Measure of Unplanned Pregnancy. Unplanned (comprising unplanned and ambivalent intention to pregnancy) was compared to planned pregnancy. Differences between women with unplanned and planned pregnancy intention and associated pregnancy outcomes were analyzed using Fisher's exact test and logistic regression.ResultsThere were 31% unplanned (2% unplanned and 29% ambivalent) pregnancies, whereas most woman (69%) reported their pregnancy to be planned. Women with an unplanned pregnancy enrolled later to antenatal care, but there was no difference in number of visits compared with planned pregnancy. Women with an unplanned pregnancy had higher odds to have induced labor (17% versus 13%; aOR 1.33 95% CI 1.06-1.67) and a longer hospital stay (41% versus 37%; aOR 1.21 95% CI 1.02-1.44). No associations were found between pregnancy planning and pregnancy-induced hypertension, gestational diabetes mellitus, preeclampsia, epidural analgesia use, vacuum extraction delivery, Caesarean section or sphincter rupture.ConclusionsUnplanned pregnancy was associated with delayed initiation of antenatal care, higher odds for induction of labor and longer hospital stay, but not with any severe pregnancy outcomes. These findings suggest that women with an unplanned pregnancy cope well in a setting with free abortion and free health care