Maternal obesity classes, preterm and post-term birth: a retrospective analysis of 479,864 births in England.

BACKGROUND: Preterm (< 37 weeks gestation) and post-term birth (≥42 weeks gestation) are associated with increased morbidity and mortality for mother and infant. Obesity (body mass index (BMI) ≥30 kg/m2) is increasing in women of reproductive age. Maternal obesity has been associated with adverse pregnancy outcomes including preterm and post-term birth. However, the effect sizes vary according to the subgroups of both maternal BMI and gestational age considered. The aim of this retrospective analysis was to determine the association between maternal obesity classes and gestational age at delivery. METHODS: A secondary data analysis of 13 maternity units in England with information on 479,864 singleton live births between 1990 and 2007. BMI categories were: underweight (< 18.5 kg/m2), recommended weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2) and obesity classes I (30.0-34.9 kg/m2), II (35.0-39.9 kg/m2), IIIa (40-49.9 kg/m2) and IIIb (≥50 kg/m2). Gestational age at delivery categories were: Gestational age at delivery (weeks): extreme preterm (20-27), very preterm (28-31), moderately preterm (32-36), early term (37, 38), full term (39-40), late term (41) and post-term (≥42). The adjusted odds of births in each gestational age category (compared to full-term birth), according to maternal BMI categories were estimated using multinomial logistic regression. Missing data were estimated using multiple imputation with chained equations. RESULTS: There was a J-shaped association between the absolute risk of extreme, very and moderate preterm birth and BMI category, with the greatest effect size for extreme preterm. The absolute risk of post-term birth increased monotonically as BMI category increased. The largest effect sizes were observed for class IIIb obesity and extreme preterm birth (adjusted OR 2.80, 95% CI 1.31-5.98). CONCLUSION: Women with class IIIb obesity have the greatest risks for inadequate gestational age. Combining obesity classes does not accurately represent risks for many women as it overestimates the risk of all preterm and post-term categories for women with class I obesity, and underestimates the risk for women in all other obesity classes.

[Posterm pregnancy]. / Potermínové tehotenství.

UNLABELLED: This review presents the up-to-date information from published resources on the issue of Posterm pregnancy (Medline, Cochrane Database, ACOG, RCOG, SOGC) and complements the presented guidelines. The most of resources are using the term "postterm pregnancy" for pregnancy reaching or exceeding 42+0 weeks and days of gestation, while late pregnancy is defined as a period in between 41+0 and 41+6.The exact determination of gestational age is necessary for exact diagnosis and appropriate management of late and postterm pregnancy, because these pregnancies have increased risk of perinatal morbidity and mortality. DESIGN: Review.

Common questions about late-term and postterm pregnancy.

Pregnancy is considered late term from 41 weeks, 0 days' to 41 weeks, 6 days' gestation, and postterm at 42 weeks' gestation. Early dating of the pregnancy is important for accurately determining when a pregnancy is late- or postterm, and first-trimester ultrasonography should be performed if clinical dating is uncertain. Optimal management of a low-risk, late-term pregnancy should consider maternal preference and balance the benefits and risks of induction vs. waiting for spontaneous labor. Compared with expectant management, induction at 41 weeks' gestation is associated with a small absolute decrease in perinatal mortality and decreases in other fetal and maternal risks without an increased risk of cesarean delivery. Although there is no clear evidence that antenatal testing beginning at 41 weeks' gestation prevents intrauterine fetal demise, it is often performed because the risks are low. When expectant management is chosen, most experts recommend beginning twice-weekly antenatal surveillance at 41 weeks with biophysical profile or nonstress testing plus amniotic fluid index (modified biophysical profile); induction may be deferred until 42 weeks if this surveillance is reassuring.

Low 3rd trimester haemoglobin level and the risk of post-term pregnancy.

The aim of this study was to examine the association between haemoglobin (Hb) concentration during pregnancy and the risk of post-term pregnancy (PTP). Based on data from a population-based prenatal care programme in South China, a total of 102,484 women who delivered during 1995-2000 were identified. Haemoglobin concentration was determined by using standard methods. Risk of PTP was analysed according to severity of anaemia and multiple Hb categories. Multivariable logistic regression models were used to control potential confounding factors. Results showed that the overall prevalence rate of PTP in the population was 4.8% (4,947/102,484). The rate was 5.0%, 4.7% and 4.8% for women who were anaemic, while it was 4.5%, 4.4% and 4.2% for women who were non-anaemic in the 1st, 2nd and 3rd trimester, respectively. Although anaemia in either of the trimesters was not significantly associated with an increased risk of PTP, the risk was two-fold higher (odds ratio, 2.06; 95% CI, 1.18-3.59) for women whose last trimester haemoglobin concentration was lower than 80 g/l, when compared with women whose last trimester haemoglobin concentration was 140 g/l or higher. Our findings suggest that a very low 3rd trimester haemoglobin level is associated with an increased risk of PTP.

Early signs of maternal iron deficiency do not influence the iron status of the newborn, but are associated with higher infant birthweight.

OBJECTIVE: To investigate the associations between maternal iron status, pregnancy outcome and newborn iron status using sensitive and specific red blood cell indices reflecting iron-deficient erythropoiesis. DESIGN AND SETTING: Cross-sectional study in Kuopio University Hospital, Finland. POPULATION: One hundred and ninety-two pregnant women and their full-term newborns (cord blood). METHODS: Quartile analysis and Spearman correlations were used to investigate the associations of the iron status of pregnant women with that of their newborns, and with pregnancy outcome. MAIN OUTCOME MEASURES: Maternal and cord blood analysis including indices reflecting the hemoglobin (Hb) content of red blood cells as well as serum iron, transferrin saturation, transferrin receptor and ferritin. Gestational age, birthweight and placental weight. RESULTS: The highest quartile of the maternal percentage of hypochromic red blood cells (%HYPOm) indicating the lowest iron status was associated with a high birthweight and a long duration of pregnancy. The newborns in this group did not show any signs of iron deficiency even though the maternal %HYPOm was elevated. CONCLUSIONS: In a well-nourished maternal population, lower maternal iron status did not affect the iron accumulation on the fetal side. However, longer duration of pregnancy and growth of the fetus appeared to be associated with a lower amount of iron for Hb synthesis in maternal red blood cells, as reflected by the increased maternal %HYPOm, birthweight and length of gestation.

Maternal obesity, length of gestation, risk of postdates pregnancy and spontaneous onset of labour at term.

OBJECTIVE: To investigate the effect of maternal body mass index (BMI) on postdates pregnancy, length of gestation and likelihood of spontaneous onset of labour at term. DESIGN: Retrospective cohort study. SETTING: Swedish Medical Birth Register. POPULATION: A total of 186 087 primiparous women (of whom 143 519 had spontaneous onset of labour at term) who gave birth between 1998 and 2002. METHODS: Mann-Whitney test, one-way analysis of variance, linear regression and single variable logistic regression. MAIN OUTCOME MEASURES: Postdates pregnancy (>/=294 days or 42(+0) weeks), length of gestation and likelihood of spontaneous onset of labour at term. RESULTS: About 6.8% of pregnancies delivered postdates. Higher maternal BMI (kg/m(2)) during the first trimester was associated with longer gestation (P < 0.001) as was a greater change in BMI between the first and third trimesters (BMI measured on admission prior to delivery) with mean (SD) gestation at delivery of 280.7 (8.6) and 283.2 (8.6) days for increases in BMI of <2 and >/=10 kg/m(2), respectively. Higher BMI during the first trimester was associated with a lower chance of spontaneous onset of labour at term. Compared with BMI 20 to <25 kg/m(2), the odds ratios (95% CI) for spontaneous onset of labour at term were 1.21 (1.15-1.27) for BMI of <20 kg/m(2), 0.71 (0.69-0.74) for BMI of 25 to <30 kg/m(2), 0.57 (0.54-0.60) for BMI of 30 to <35 kg/m(2) and 0.43 (0.40-0.47) for BMI of >/=35 kg/m(2). Higher BMI during the first trimester (BMI of >/=35 kg/m(2) compared with BMI of 20 to <25 kg/m(2)) was also associated with an increased risk of complications including stillbirth (OR 3.90, 95% CI 2.44-6.22), gestational diabetes (OR 5.61, 95% CI 4.61-6.83) and caesarean section (OR 2.39; 95% CI 2.20-2.59). CONCLUSIONS: Higher maternal BMI in the first trimester and a greater change in BMI during pregnancy were associated with longer gestation and an increased risk of postdates pregnancy. Higher maternal BMI during the first trimester was also associated with decreased likelihood of spontaneous onset of labour at term and increased likelihood of complications.

Anterior placental location influences onset and progress of labor and postpartum outcome.

INTRODUCTION: The aim of the study is to evaluate whether placental location at term is associated with delivery outcome. METHODS: A prospective study including 2354 patients with singleton pregnancy at term admitted for vaginal delivery was conducted. Placental position was determined before delivery by ultrasonographic examination performed transabdominally with women in the supine position. Maternal characteristics and delivery outcome such as premature rupture of membranes, induction of labor, mode and gestational age at delivery, indication for cesarean section, duration of the third stage, postpartum hemorrhage (PPH) and manual removal of placenta were correlated with anterior, posterior or fundal placental locations. RESULTS: Among women enrolled: i) 1164 had an anterior placenta, ii) 1087 a posterior placenta, iii) 103 a fundal placenta. Women with anterior placenta showed: i) a higher incidence of induction of labor (p = 0.0001), especially for postdate pregnancies and prolonged prelabor rupture of membranes (p < 0.0001), ii) a higher rate of cesarean section rate for failure to progress in labor (p = 0.02), iii) a prolonged third stage (p = 0.01), iv) a higher incidence of manual removal of placenta (p = 0.003) and a higher rate of PPH in vaginal deliveries (p = 0.02). DISCUSSION: The present study showed the influence of anterior placental location on the course of labor, with a later onset of labor, a higher rate of induction and cesarean section and postpartum complications. The reason for this influence on labor and delivery complications remains to be elucidated.

Practice bulletin no. 146: Management of late-term and postterm pregnancies.

Postterm pregnancy refers to a pregnancy that has reached or extended beyond 42 0/7 weeks of gestation from the last menstrual period (LMP), whereas a late-term pregnancy is defined as one that has reached between 41 0/7 weeks and 41 6/7 weeks of gestation (). In 2011, the overall incidence of postterm pregnancy in the United States was 5.5% (). The incidence of postterm pregnancies may vary by population, in part as a result of differences in regional management practices for pregnancies that go beyond the estimated date of delivery. Accurate determination of gestational age is essential to accurate diagnosis and appropriate management of late-term and postterm pregnancies. Antepartum fetal surveillance and induction of labor have been evaluated as strategies to decrease the risks of perinatal morbidity and mortality associated with late-term and postterm pregnancies. The purpose of this document is to review the current understanding of late-term and postterm pregnancies and provide guidelines for management that have been validated by appropriately conducted outcome-based research when available. Additional guidelines on the basis of consensus and expert opinion also are presented.

Fetal gender effects on induction of labor in postdate pregnancies.

OBJECTIVE: To determine delivery outcome in women undergoing induction of labor for postdate pregnancy in relation to fetal gender. STUDY DESIGN: A total of 365 nulliparous and 127 multiparous women carrying singleton postdate pregnancies with unfavorable cervix were enrolled. Clinical characteristics and delivery outcome were analyzed in relation to fetal gender. RESULTS: Women carrying male fetuses showed higher rate of caesarean section than those carrying females, in both nulliparous and multiparous women. Moreover, women carrying male fetuses presented more frequently with (i) interval between induction of labor and delivery >24 hours (P < .0002); (ii) augmentation of labor after cervical ripening (P < .0391); (iii) meconium-stained liquor (P< .0126); and (iv) higher neonatal weight (P < .0011) than those carrying females. CONCLUSION: Male fetuses are more likely to be associated with higher rates of cesarean section. In maternal fetal medicine, gender differences may add prognostic information on the delivery outcome in women induced for postdate pregnancy.

Weight gain regardless of pre-pregnancy BMI and influence of fetal gender in response to labor induction in postdate pregnancy.

OBJECTIVE: To evaluate whether maternal weight and body mass index (BMI) and their increase throughout pregnancy are associated with the response to labor induction in postdate pregnancies. METHODS: A total of 376 nulliparous women carrying singleton postdate pregnancies with unfavorable cervix were enrolled. We considered as primary outcome vaginal delivery within 24 h after induction, and outcomes were divided into responders (n = 258) and non-responders (n = 107) to the induction of labor to perform the statistical analyses. RESULTS: In the total population of study, women who successfully delivered within 24 h differed significantly from the remaining patients in terms of maternal weight gain (p = 0.009) and BMI increase (p = 0.02) during pregnancy. In addition, males were significantly more (p = 0.005) than females among newborns of women not responding to induction of labor. In the multivariate analysis, maternal weight gain and fetal sex significantly influenced the induction response. The occurrence of a failed induction of labor was more likely in patients presenting a greater maternal weight gain (cut-off 12 kg) and male fetus. CONCLUSION: Weight gain over 12 kg regardless of pre-pregnancy weight and male fetal gender are two novel potential risk factors for the prediction of failure to induction of labor in postdate pregnancy.

Low-risk pregnancy at 41 weeks: when should we induce labor?

OBJECTIVE: To study the perinatal outcome according to whether labor was induced or not, when a low-risk pregnancy reached 41 weeks of gestation. METHODS: A quasi-experimental study of 11492 low-risk singleton pregnancies was designed. A total of 1,721 patients (15.0%) women met the study criteria, were informed about the risks and benefits and gave their informed consent, of whom 629 (36.5%) were planned for induction soon after the 41 weeks (287-289 days). RESULTS: An intention-to-treat analysis was performed. The proportion of small-for-gestational age babies was lower in the early-induced labor cohort (10.5% versus 15%; p = 0.008). This cohort showed an increased hospital stay (4.54 versus 3.80 days; p < 0.001), and a higher rate of requiring delivery by caesarean section (31.1% versus 19.8%;p < 0.001), including the need for caesarean section for failed induction (21.8% versus 11%;p < 0.001). Three stillbirths occurred in the group followed expectantly, whereas no stillbirths were seen in the early induction group. CONCLUSIONS: Induction of labor for prolonged pregnancy in low-risk patients soon after the 41 weeks, reduces the proportion of small-for-gestational age babies, but increases the mean hospital stay as well as the need for delivery by caesarean section, including that for failed induction.

Adverse perinatal outcomes after the February 27th 2010 Chilean earthquake.

OBJECTIVE: To investigate whether the February 27th earthquake exposition was associated to adverse perinatal outcomes in Chilean pregnant women. METHODS: We analyzed all deliveries occurred in 2009 (n = 3,609) and 2010 (n = 3,279) in a reference hospital in the area of the earthquake. Furthermore, we investigated pregnant women who gave birth between March 1st and December 31st 2010 (n = 2,553) and we classified them according to timing of exposition. RESULTS: We found a 9% reduction in birth rate, but an increase in the rate of early preterm deliveries (<34 weeks), premature rupture of membranes (PROM), macrosomia, small for gestational age, and intrauterine growth restriction (IUGR) after the earthquake, in contrast to the previous year. Women exposed to the earthquake during her first trimester delivered smaller newborns (3,340 ± 712 g v/s 3,426 ± 576 g respectively, p = 0.007) and were more likely diagnosed with early preterm delivery, preterm delivery (<37 weeks) and PROM but were less likely diagnosed with IUGR and late delivery (42 weeks, p < 0.05) compared to those exposed at third trimester. Accordingly, IUGR and preterm deliveries presented elevated healthcare costs. CONCLUSION: Natural disasters such as earthquakes are associated to adverse perinatal outcomes that impact negatively the entire maternal-neonatal healthcare system.

[Fetal and neonatal complications related to prolonged pregnancy]. / Complications fœtales et néonatales des grossesses prolongées.

OBJECTIVE: To evaluate fetal and neonatal outcomes related to prolonged pregnancy. METHODS: This study is based on Pubmed search, Cochrane library and HAS recommendations. RESULTS: The risk of fetal complications including macrosomia (6 %), oligohydramnios (10 %-15 %), abnormal fetal heart rate pattern and meconium-stained fluid is increased in prolonged pregnancy (≥ 41(+0) weeks). The rate of stillbirth was estimated between 1.6 ‰ and 3.0 ‰ live births according to countries in post-term pregnancies (≥ 42(+0) weeks). The risk of umbilical cord pH less than 7.10, Apgar score at five minutes inferior to 7, ICU admissions and perinatal asphyxia is increased in post-term infants (≥ 42(+0) weeks) compared with term infants. The risk of neurologic complications including neonatal convulsion, hypoxic ischemic encephalopathy, cerebral palsy, developmental deviations and epilepsy in childhood is increased in post-term infants. The risk of meconium aspiration syndrome, neonatal sepsis, and birth trauma including shoulder dystocia and bone fracture is increased in post-term infants. The rate of perinatal mortality increases in post-term infants. The perinatal mortality in post-term infants could be explained by perinatal asphyxia and meconium aspiration syndrome. CONCLUSIONS: The risk of perinatal complications and mortality are increased in prolonged pregnancy.

Prenatal risk indicators of a prolonged pregnancy. The Danish Birth Cohort 1998-2001.

BACKGROUND: Few prenatal risk factors of prolonged pregnancy, a pregnancy of 42 weeks or more, are known. The objective was to examine whether sociodemographic, reproductive, toxicologic, or medical health conditions were associated with the risk of prolonged pregnancy. METHODS: Data from the Danish Birth Cohort in Denmark were used. Interview data from 53,392 participants with live-born singleton deliveries in the period 1998-2001 were available at the time of this study. The participants were interviewed by telephone at 12 and 30 weeks' gestation, and 6 and 18 months after delivery. Statistical analyses were done using logistic regression. RESULTS: Women with a pre-pregnancy body mass index of 25 kg/m2 or more had a high risk of prolonged pregnancy. If the pre-pregnancy body mass index was 35 kg/m2 or more the odds ratio was 1.52 (95% CI 1.28-1.82). Nulliparity also increased the risk of prolonged pregnancy (OR (95% CI) = 1.35 (1.27-1.44)). CONCLUSIONS: The risk of post-term delivery was high in women with a pre-pregnancy body mass index of 25 kg/m2 or more, and in nulliparous women.

Obstetric outcome in post-term pregnancies: time for reappraisal in clinical management.

BACKGROUND: The objective of this study was to determine the outcome of pregnancy in post-term cases compared with term cases in a well defined population receiving modern obstetric care. METHODS: We utilized the population-based birth registry data of the Kuopio University Hospital (1990-2000) to investigate pregnancy outcome in 1,678 post-term singleton pregnancies. The general obstetric population (n=22,712) was used as a reference group in logistic regression analysis. RESULTS: The overall frequency of post-term pregnancies was 6.9% and the incidence of post-term pregnancies was found to be increased in obese, primiparous, and smoking women, whereas in women with chronic diseases and obstetric risks deliveries were induced earlier. The risks of macrosomia, maternal complications, and operative deliveries were increased in post-term pregnancies. Post-term infants experienced meconium passage (21.2% versus 12.8%) (p<0.01) and intrapartum asphyxia (3.4% versus 2.1%) (p<0.01) significantly more often than the controls. However, the stillbirth rate was low, probably due to careful monitoring of these pregnancies. CONCLUSIONS: Although high-risk pregnancies were not allowed to come post-term, postmaturity per se is a moderate risk state compromising fetal well-being with regard to meconium passage and acid-base status at birth. We conclude that simple antenatal monitoring beyond 42 weeks reduces perinatal mortality but is inefficient in reducing meconium-stained liquor seen with increasing gestation.