The Effect of Gestational Weight Gain by Body Mass Index on Maternal and Neonatal Outcomes

ObjectiveTo evaluate the effects of gestational weight gain on maternal and neonatal outcomes in different body mass index (BMI) classes.MethodsWe compared maternal and neonatal outcomes based on gestational weight gain in underweight, normal weight, overweight, obese, and morbidly obese (BMI ≥ 40.00) women. The study group was a population-based cohort of women with singleton gestations who delivered between April 1, 2001, and March 31, 2007, drawn from the Newfoundland and Labrador Provincial Perinatal Program Database. Univariate analyses and multivariate logistic regression analyses (controlling for maternal age, parity, smoking status, partnered status, and gestational age) were performed and odds ratios (ORs) were calculated.ResultsOnly 30.6% of women gained the recommended amount of weight during pregnancy; 52.3% of women gained more than recommended, and 17.1% gained less than recommended. In women with normal pre-pregnancy BMI, excess weight gain was associated with increased rates of gestational hypertension (OR 1.27; 95% CI 1.08–1.49), augmentation of labour (OR 1.09; 95% CI 1.01–1.18), and birth weight ≥ 4000 g (OR 1.21; 95% CI 1.10–1.34). In overweight women, excess weight gain was associated with increased rates of gestational hypertension (OR 1.31; 95% CI 1.10–1.55) and birth weight ≥4000 g (OR 1.30; 95% CI 1.15–1.47). In women who were obese or morbidly obese, excess weight gain was associated with increased rates of birth weight ≥4000 g (OR 1.20; 95% CI 1.07–1.34) and neonatal metabolic abnormality (OR 1.31; 95% CI 1.00–1.70). In morbidly obese women, poor weight gain was associated with less use of epidural analgesia (OR 0.34; 95% CI 0.12–0.95). In women who were of normal weight, overweight, or obese, the rate of adverse outcome (Caesarean section, gestational hypertension, birth weight < 2500 g or birth weight ≥4000 g) was lower in women with recommended weight gain than in those with excess weight gain. Adverse outcomes were reduced in nulliparous morbidly obese women who had poor weight gain (OR 0.18; 95% CI 0.04–0.83).ConclusionThe effects of gestational weight gain on pregnancy outcome depend on the woman’s pre-pregnancy BMI. Pregnancy weight gains of 6.7–11.2 kg (15–25lb) in overweight and obese women, and less than 6.7 kg (15lb) in morbidly obese women are associated with a reduction in the risk of adverse outcome.     

Maternal and Perinatal Outcomes of Extreme Obesity in Pregnancy

ObjectiveTo evaluate the effects of extreme obesity (pre-pregnancy BMI ≥ 50.0 kg/m²) in pregnancy on maternal and perinatal outcomes.MethodsWe conducted a population-based cohort study using the Newfoundland and Labrador Perinatal Database to compare obstetric outcomes in women with extreme obesity and those with a normal BMI (pre-pregnancy BMI 18.50 to 24.99 kg/m²). We included women with singleton gestations who gave birth between January 1, 2002, and December 31, 2011. Maternal outcomes of interest included gestational hypertension, gestational diabetes, Caesarean section, shoulder dystocia, length of hospital stay, maternal ICU admission, postpartum hemorrhage, and death. Perinatal outcomes included birth weight, preterm birth, Apgar score, neonatal metabolic abnormality, NICU admission, stillbirth, and neonatal death. A composite morbidity outcome was developed including at least one of Caesarean section, gestational hypertension, birth weight ≥ 4000 g, birth weight < 2500 g, or NICU admission. Univariate analyses and multivariate logistic regression analyses (controlling for maternal age, parity, smoking, partner status, and gestational age) were performed, and adjusted odds ratios (aORs) and 95% confidence intervals were calculated.ResultsA total of 5788 women were included in the study: 71 with extreme obesity and 5717 with a normal BMI. Extremely obese women were more likely to have gestational hypertension (19.7% vs.4.8%) (aOR 1.56; 95% CI 1.33 to 1.82), gestational diabetes (21.1% vs.1.5%) (aOR 2.04; 95% CI 1.74 to 2.38), shoulder dystocia (7.1% vs.1.4%) (aOR 1.51; 95% CI 1.05 to 2.19), Caesarean section (60.6% vs.25.0%) (aOR 1.46; 95% CI 1.29 to 1.65), length of hospital stay more than five days (excluding Caesarean section) (14.3% vs.4.7%) (aOR 1.42; 95% CI 1.07 to 1.89), birth weight ≥ 4000 g (38.0% vs. 11.9%) (aOR 1.58; 95% CI 1.38 to 1.80), birth weight ≥ 4500 g (16.9% vs.2.1%) (aOR 1.87; 95% CI 1.57 to 2.23), neonatal metabolic abnormality (8.5% vs.2.0%) (aOR 1.50; 95% CI 1.20 to 1.86), NICU admission (16.9% vs.7.8%) (aOR 1.28; 95% CI 1.07 to 1.52), stillbirth (1.4% vs.0.2%) (aOR 1.68; 95% CI 1.00 to 2.82) and composite adverse outcome (81.7% vs.41.5%) (aOR 1.57; 95% CI 1.35 to 1.83).ConclusionWomen with extreme obesity have increased risks of a variety of adverse maternal and perinatal outcomes. As approximately 6 per 1000 women giving birth in our population have extreme obesity, it is important to address these risks pre-conceptually and encourage a healthier BMI before pregnancy.     

The Combined Effect of Maternal Obesity and Fetal Macrosomia on Pregnancy Outcomes

ObjectiveTo examine the combined effect of macrosomia and maternal obesity on adverse pregnancy outcomes using a retrospective cohort.MethodsInfants with a birth weight of ≥ 4000g (macrosomia) were identified from an institutional birth cohort. Demographic characteristics and maternal, fetal, neonatal, and pregnancy outcomes of macrosomic infants whose mothers were obese were compared with those whose mothers were non-obese.ResultsPregnancies in obese women resulting in macrosomic infants are more likely to be complicated by gestational diabetes, gestational hypertension, and smoking than pregnancies in non-obese women with macrosomic infants. Mothers whose infants are macrosomic are significantly more likely to require induction of labour (OR 1.42; 95% CI 1.10 to 1.98) and delivery by Caesarean section (OR 1.45; 95% CI 1.04 to 2.01), particularly for maternal indications (OR 3.7; 95% CI 1.47 to 9.34), if they are obese. Finally, macrosomic infants of obese mothers are significantly more likely to require neonatal resuscitation in the form of free flow oxygen (OR 1.57; 95% CI 1.03 to 2.42) than macrosomic infants of non-obese mothers.ConclusionWhen both maternal obesity and macrosomia are present, adverse pregnancy outcomes are more common than when fetal macrosomia occurs in a woman of normal weight.     

Performance de l’estimation échographique du poids fœtal réalisée par les internes de spécialité le jour du terme

ObjectivesThe aim of this study was to evaluate the accuracy of ultrasound fetal weight prediction at due date and to find parameters that may affect this prediction.Patients and methodsWe retrospectively studied 201 patients at due date in a university hospital in 2006, the fetal weight estimation being performed by Obstetric-gynecology (OB-Gyn). Estimated fetal weight was calculated with the Hadlock's formula, including biparietal diameter, cephalic circumference, abdominal perimeter and femoral length and was compared with birth weight.ResultsThe mean birth weight was 3561 ± 415 g. The mean absolute weight difference was 261 ± 190 g (absolute range: 0 to 1183 g, actual range: −935 to 1183 g). Body mass index >30 kg/m² was associated with greater fetal weight inaccuracy (p = 0,013). Fetal weight estimation was not influenced by fetal macrosomia, oligoanamnios or maternal weight gain during pregnancy.Discussion and conclusionThe sonographic estimated fetal weight and birth weight are correlated with a mean absolute percentage error of 7%. However, clinicians should be aware of the risk of inaccuracy in obese women.     

Following the 2009 American Institute of Medicine recommendations for normal body mass index and overweight women led to an increased risk of fetal macrosomia among Taiwanese women

ObjectiveThis study aimed to investigate the risk of birth weights over 4000 g (macrosomia) in association with following the 2009 American Institute of Medicine (AIOM) recommendations.Materials and MethodsSeventy-six nondiabetic women who delivered a singleton, term macrosomic fetus and 82 women who delivered a singleton, term fetus weighing <4000 g were analyzed retrospectively. The relationship between the risk of macrosomia and gestational weight gain in different periods of pregnancy was investigated using logistic regression.ResultsThe incidence of macrosomia from January 2008 to December 2009 was 1.8% among the Taiwanese women. The incidences of cesarean delivery (54.5% vs. 18.2%, p < 0.001) and blood loss >1000 mL at delivery (35.5% vs. 6.1%, p < 0.0001) were associated with macrosomia. The risk of macrosomia among normal weight women with gestational weight gain greater than 13 kg increased four-fold [odds ratio (OR) = 4.88; 95% confidence interval (CI) 1.84–12.90]. For overweight women with total gestational weight gain >11.5 kg, the risk of macrosomia increased nine-fold (OR = 9.63; 95% CI 1.76–52.74).ConclusionMacrosomia resulted in more cesarean deliveries and greater maternal blood loss at birth. In Taiwan, to prevent macrosomia, we suggest that the total gestational weight gain should be <11.5 kg among normal weight women and within 10 kg for overweight women.     

Using Estimated Fetal Weight From Ultrasonography at 18 to 22 Weeks to Predict Gestational Diabetes Mellitus and Newborn Macrosomia

ObjectivesTo determine if fetal macrosomia in the second trimester predicts the onset of gestational diabetes mellitus (GDM) or large for gestational age (LGA) birth weight.MethodsWe performed a case–control study using data from the Diabetes in Pregnancy Clinic in our tertiary care hospital. Cases were women with GDM requiring insulin (n = 65) or controlled with diet (n = 65). Control subjects were women who screened negative for GDM at 24 to 28 weeks’ gestation (n = 131). Estimated fetal weight (EFW) was determined by ultrasound at 18 to 22 weeks.ResultsEstimated fetal weight that was one standard deviation (70 g) higher at 18 to 22 weeks was not associated with subsequent GDM (adjusted OR [aOR] 1.00, 95% confidence intervals 0.61 to 1.66), but was associated with a 231 g (95% CI 128 g to 334 g) increase in birth weight and increased odds of LGA (aOR 4.02, 95% CI 1.76 to 9.19) after adjusting for gestational age at the time of estimating fetal weight, maternal age, parity, BMI and GDM treatment.ConclusionEFW at 18 to 22 weeks did not predict the onset of GDM, but did predict LGA.     

La dystocie des épaules : analyse descriptive sur dix années dans une maternité de niveau III

ObjectiveShoulder dystocia is one of the most dreadful complications of vaginal deliveries. The aim of this observational study was to evaluate risk factors of dystocia, maternal and neonatal complications and recurrent risk factors.Patients and methodsSixty-six cases of shoulder dystocia occurring between January 1998 and August 2008 in our university hospital were identified. Demographic data, labor management, management of the shoulder dystocia and neonatal outcome were recorded.ResultsThe incidence of shoulder dystocia was 0.3%. Multiparity, weight gain greater than 12 kg, and post-term delivery were more present in our study group. McRoberts’ manoeuver and symphyseal pressure were first realised. Brachial plexus injuries affected 9% of neonates with skeletal fractures in 7.5% of cases. Maternal morbidity was evaluated at about 8%. Twenty per cent had a recurrent shoulder dystocia.Discussion and conclusionShoulder dystocia is an obstetric emergency which requires a prompt management of trained personnel. Despite the difficulty of being able to prevent shoulder dystocia, training the obstetric staff could probably improve management of shoulder dystocia.     

Valores extremos del IMC materno: factores determinantes de peores resultados obstétricos y perinatales

ObjectiveTo study the influence of maternal body mass index (BMI) at the beginning of pregnancy on obstetric-perinatal outcomes.Material and methodsObservational-ambispective study. We recruited 1407 patients with singleton gestations and deliveries of foetuses > 24 weeks between 01/12/2017 and 31/07/2019. The sample was stratified according to their BMI following the WHO classification. Variables on pre-pregnancy, gestational disease, obstetric care, and maternal-perinatal outcomes were analysed and compared between the studied groups. The statistical program has been R Core Team 2020, version 3.6.3. P ≤ .05 was considered significant.ResultsClass II-III (BMI 35-39 and BMI ≥ 40 respectively) obese women have a higher risk of chronic arterial hypertension (OR 53.54, 95% CI 18.21-229.02), gestational diabetes (OR 5.24, 95% CI 2.87-9.51) and preeclampsia (OR 2.38, 95% CI 0.95-5.51 with P = .049). The underweight women had more intrauterine growth restriction diagnoses (OR 3.09, 95% CI 1.46-6.17). Inductions of labour and caesarean sections increase as BMI increases (P = .006). Low weight patients also had a higher risk of caesarean section (OR 2.46, 95% CI 1.06-5.20). Neonatal admissions were more frequent in obese and underweight women (OR 2.68, 95% CI 1.39-5.00 and OR 2.56, 95% CI 1.10-5.44 respectively). Obese women had a higher risk of neonatal weight > 4000 g (OR 3.06, 95% CI 1.57-5.77) and low weight pregnant women had a higher risk of neonatal weight < 2500 g (OR 2.94, 95% CI 1.54-5.41).ConclusionExtreme values of maternal BMI at the beginning of gestation are determining factors for an adverse obstetric-perinatal outcome.     

Maternal risks for newborn macrosomia, incidence of a shoulder dystocia and of damages of the plexus brachialis

PATIENTS RESPECTIVELY AND METHODS: In the HEPE 619 242 births have been analysed (1990 - 2000) to calculate the incidence of a birthweight between 4000 and 4499 g and of a weight > or = 4500 g in relationship to maternal obesity, high maternal weight gain and of a duration of pregnancy more than 298 days. RESULTS: The risk of a macrosomia > or = 4500 g is in cases of obesity 3.4 times higher, in cases of obesity and prolongation of pregnancy 6.6 times higher and in the presence of all 3 risk factors 10 times higher. Data of the Frauenklinik Wiesbaden (HSK) (n = 6075 births) complete the results, because a correlation between macrosomia, shoulder dystocia and a damage to the plexus brachialis has been found. The incidence of a damage to the plexus brachialis is in case of a shoulder dystocia and a birth weight of < or = 4000 g 6.3%, at a birth weight between 4000-4499 g 25% and in newborns with a weight > or = 4500 g 40%. CONCLUSIONS: Because of the low sensitivity (60%) of the ultrasonic weight measurement the 3 maternal risk factors--if they exist--of a shoulder dystocia and of a damage of the plexus brachialis should be discussed with the pregnant woman to help her about the decision of an alternative cesarean section. Still one third of the newborns weigh more than 4000 g if all 3 maternal risk factors exist.     

Is maternal obesity a predictor of shoulder dystocia?

OBJECTIVE: To explore the relationship between maternal obesity and shoulder dystocia while controlling for the potential confounding effects of other variables associated with obesity. METHODS: We performed a case-control study of provincial delivery records audited by the Northern and Central Alberta Perinatal Outreach Program. Risk factors evaluated were selected based on previously published studies. Cases and controls were drawn from 45,877 live singleton cephalic vaginal deliveries weighing more than 2500 g between January 1995 and December 1997. There were 413 cases of shoulder dystocia (0.9% incidence). Controls (n = 845) were randomly chosen from the remainder of the target population to create a 1:2 case/control ratio. Univariate analysis with calculation of odds ratios (ORs) was used to determine which of the chosen risk factors were significantly related to the incidence of shoulder dystocia. Multivariable regression analyses were then used to determine the independently associated variables, and the adjusted ORs were obtained for each relevant risk factor. RESULTS: Maternal obesity was not significant as an independent risk factor for shoulder dystocia after adjusting for confounding variables (adjusted OR 0.9; 95% confidence interval [CI] 0.5, 1.6). Fetal macrosomia was the single most powerful predictor. The adjusted ORs were 39.5 (95% CI 19.1, 81.4) for birth weight greater than 4500 g and 9.0 (95% CI 6.5, 12.6) for birth weight between 4000 and 4499 g. CONCLUSION: The strongest predictors of shoulder dystocia are related to fetal macrosomia. For obese nondiabetic women carrying fetuses whose weights are estimated to be within normal limits, there is no increased risk of shoulder dystocia.     

Sonographic evaluation of fetal abdominal circumference and cerebroplacental Doppler indices for the prediction of fetal macrosomia in full term pregnant women. Cohort study

ObjectivesThe aim of the study was to explore the relationship between cerebroplacental Doppler ratio and birth weight in cases of suspected fetal macrosomia.MethodsThe pulsatility indices of the umbilical (UA-PI) and middle cerebral (MCA-PI) arteries, the cerebroplacental pulsatility index ratio (CPR) and the estimated fetal weight (EFW) were obtained in a cohort of 150 ultrasound-dated pregnancies at ⩾ 37 weeks’ gestation divided into two groups as follows; large for gestational age (LGA, n = 50) and average for gestational age (AGA, n = 100).ResultsThere is a significant difference between groups in abdominal circumference (AC), head circumference (HC), biparital diameter (BPD), estimated fetal weight (EFW) and actual fetal weight with a mean difference of 92.7 g in the LGA group and 84 g in the AGA group. MCA-RI and PI were significantly lower in the LGA group with no difference in UA-RI, PI and CPR-PI between both groups.ConclusionsCPR-PI could not differentiate between LGA and AGA.     

Macrosomia prediction using ultrasound fetal abdominal circumference of 35 centimeters or more

OBJECTIVE: To determine if birth weights greater than 4000 g can be predicted by ultrasound measurements of abdominal circumferences. METHODS: In 1996, 254 newborns delivered at Tampa General Hospital weighed at least 4000 g, 84 of whom had ultrasound examinations within 2 weeks of delivery. Those were compared with 84 neonates with recent ultrasounds who weighed less than 4000 g. Data were abstracted retrospectively from maternal medical records. RESULTS: The best linear predictor of birth weight was ultrasound measurement of abdominal circumference (AC), which had a correlation coefficient of 0.95. An AC measurement of 35 cm or more predicted 93% of macrosomic infants. Among 177 macrosomic infants born vaginally, 23 (13%) had shoulder dystocia. In that group, induction of labor was associated with a greater than three-fold increase in risk of shoulder dystocia (odds ratio [OR] 3.4, 95% confidence interval [CI] 1.4, 8.2; P < .01). Labor augmentation was not associated with increased risk of shoulder dystocia. CONCLUSION: Abdominal circumference measurements were useful in screening for suspected macrosomia. An AC measurement of 35 cm or more identified more than 90% of macrosomic infants who were at risk for shoulder dystocia. Induction of labor in macrosomic patients increased the risk of shoulder dystocia.     

Prevalence of hyperglycemia during pregnancy according to maternal age and pre-pregnancy body mass index in Japan, 2007–2009

ObjectiveTo assess the prevalence of hyperglycemia according to maternal age and pre-pregnancy body mass index (BMI) among Japanese women before introduction of the current diagnostic criteria.MethodsIn a retrospective study, data were analyzed from women with singleton pregnancies who were registered with the JSOG Successive Pregnancy Birth Registry System and who gave birth at 22 weeks of gestation or more between January 2007 and December 2009.ResultsAmong 138 530 women, 3667 (2.6%) were diagnosed with hyperglycemia including gestational diabetes and diabetes mellitus. The prevalence of hyperglycemia increased with advancing maternal age and increasing BMI. Among women aged ≤ 24, 25–34, 35–39, and ≥ 40 years, the prevalence was 0.4%, 0.8%, 1.5%, and 4.0%, respectively, in lean women (BMI < 18.5); 1.0%, 1.6%, 2.3%, and 3.1%, respectively, in normal weight women (BMI 18.5–24.9); and 5.7%, 9.2%, 12.9%, and 15.2%, respectively, in obese women (BMI ≥ 25.0). Of the 1181 newborns with a birth weight of 4000 g or more, 1046 (88.6%) were born to women not diagnosed with hyperglycemia.ConclusionThe results may reflect the baseline prevalence of hyperglycemia and macrosomic neonates (birth weight ≥ 4000 g) during the era of the old diagnostic criteria in Japan.     

Risk factors for shoulder dystocia

The risk factors associated with the occurrence of shoulder dystocia were examined in the general obstetrical population of women delivering vaginally. An increasing incidence of shoulder dystocia was found as infant birth weight increased. Although one-third of shoulder dystocia occurred in pregnancies at 42 + weeks, except for those resulting in infants weighing 4500 + g, the vast majority was unaffected by shoulder dystocia. The incidence of shoulder dystocia in nondiabetic gravidas delivering an infant weighing 4000 to 4499 and 4500 + g vaginally was 10.0 and 22.6%, respectively. Within the 4000- to 4499-g group, no labor abnormality was clearly predictive; however, in the heaviest birth weight group, an arrest disorder heralded a shoulder dystocia in 55.0% of cases. Diabetics experienced more shoulder dystocia than nondiabetics. Among them, 31% of vaginally delivered neonates weighing 4000 + g experienced shoulder dystocia. Nevertheless, the risk factors of diabetes and large fetus (4000 + g) could predict 73% of shoulder dystocia among diabetics; large fetus along flagged 52% of shoulder dystocia in nondiabetics. Cesarean section is recommended as the delivery method for diabetic gravidas whose estimated fetal weight is 4000 + g. If others confirm the risk, the authors advise serious consideration of cesarean section for gravidas who are carrying fetuses estimated to be 4500 + g and who experience an abnormal labor.     

Serial fetal abdominal circumference measurements in predicting normal birth weight in gestational diabetes mellitus

ObjectivesTo construct a clinical management matrix using serial fetal abdominal circumference measurements (ACMs) that will predict normal birth weight in pregnancies complicated by gestational diabetes (GDM) and reduce unnecessary ultrasound examination in women with GDM.Study designRetrospective cohort study of 144 women with GDM in a specialist obstetric-diabetes clinic. Women with GDM who delivered singleton infants were identified from a clinical register. Regression analysis was used to identify associations between serial ACMs, maternal parameters and normal birth weight (birth weight between the 10th and 90th percentiles). Predictive clinical models were designed with the aim of identifying normal birth weight infants with the lowest number of fetal ultrasound scans.ResultsCompared to mothers of large-for-gestational-age (LGA) infants, mothers of normal weight infants had lower fasting glucose measurements at diagnosis (5.9 mmol/l ± 1.0 vs. 6.6 mmol/l ± 0.7, p < 0.05), lower maternal weight at delivery (90 kg ± 17 vs. 96 kg ± 17, p < 0.05), and a lower rate of prior LGA infants (31% vs. 60%, p < 0.05). Maternal weight and a history of prior LGA delivery were identified as useful predictors of fetal birth weight in predictive models. Serial ACMs below the 50th, 75th and 90th percentiles could predict normal birth weight with 100%, 97% and 96% positive predictive value respectively when used in these risk factor based models. Two measurements sufficed in low-risk pregnancies.ConclusionSerial ACMs can predict normal birth weight in GDM.     

Risk of recurrent shoulder dystocia: are we any closer to prediction?

Objective: To determine the incidence and risk factors for recurrent shoulder dystocia in women.

Methods: We searched Medline, Pubmed, Embase, and CINAHL for relevant articles in English and French from 1980 to February 2018 that described risks of recurrent shoulder dystocia undergoing a trial of labour in subsequent pregnancies. A total of 684 articles were found, of which 13 were included as they met criteria. We extracted data on study characteristics, incidence of recurrent shoulder dystocia, degree of neonatal injury, and presence of known risk factors.

Results: There was a wide variation in the incidence of shoulder dystocia in subsequent pregnancies from 1–25%. The largest cohort reported a risk of 13.5%. The most important risk factor for recurrent shoulder dystocia is an increase in birthweight in the subsequent pregnancy compared to the index pregnancy (OR 7–12). Prolonged second stage, instrumental delivery, maternal diabetes, increased maternal BMI, and severe neonatal morbidity in the index pregnancy were also associated with an increased risk of recurrent shoulder dystocia. However, many of these risk factors were present in women who did not have a recurrent shoulder dystocia. In addition, women with recurrent shoulder dystocia rarely had identifiable risk factors, other than the history of previous shoulder dystocia. Sample sizes were low as most studies are single centre, retrospective cohorts with low rates of subsequent pregnancy and vaginal birth as many women may have elected to have a caesarean section in subsequent pregnancies or were lost to follow up. There was a high rate of reporting bias and heterogeneity, prohibiting formal meta-analyses.

Conclusion: Recurrent shoulder dystocia is an unpredictable obstetric complication with potentially devastating consequences. Individual assessment and thorough counselling should be offered to women contemplating a subsequent planned vaginal birth with specific attention paid to those women where the estimated birthweight is >4000?g or greater than in the index pregnancy.     

超声测量胎儿腹围预测新生儿出生体重的研究

目的探讨超声测量胎儿腹围在预测新生儿出生体重和诊断巨大儿中的价值。方法在孕妇分娩前1周超声测量胎儿腹围,追踪胎儿的出生体重,分析胎儿腹围与出生体重的关系。结果(1)共检测1475例单胎孕妇胎儿,胎儿腹围与出生体重呈直线正相关关系,r为0.85(P<0.01)。(2)胎儿腹围<34cm者中无一例巨大儿;胎儿腹围<35cm有1007例,99.7%的新生儿平均出生体重<4000g;胎儿腹围在35～35.9cm有206例,新生儿平均出生体重为(3691±277)g,其中14.6%(30例)的新生儿出生体重≥4000g;胎儿腹围在36～36.9cm有149例,其中51.0%(76例)的新生儿出生体重≥4000g,新生儿平均出生体重为(3957±256)g;胎儿腹围在37～37.9cm有64例,其中84.4%(54例)的新生儿出生体重≥4000g,平均出生体重(4205±250)g;胎儿腹围≥38cm有44例,新生儿平均出生体重≥4000g者为100%(44例),平均出生体重为(4489±267)g。(3)1475例中有811例孕妇行剖宫产术(55.0%),新生儿出生体重为4000～4500g者,剖宫产率为71.4%(125/175),出生体重≥4500g者,剖宫产率为93.8%(30/32),均显著高于新生儿出生体重<4000g的剖宫产率(P<0.01)。结论超声测量胎儿腹围可以预测新生儿出生体重。胎儿腹围与胎儿体重呈高度直线正相关。胎儿腹围<35cm提示发生巨大儿的可能性极低;≥37cm提示巨大儿的可能性大。     

Prematurity and Low Birth Weight among Brazilian Adolescents and Young Adults

Study ObjectiveTo compare the incidence of preterm birth and low birth weight infants in young and older primiparous adolescents versus young adults.DesignCross-sectional study.SettingMaternity hospital in Vitória, ES, Brazil.ParticipantsDuring a 5-year period, young primiparous women who delivered a singleton liveborn infant over 22 weeks were interviewed while in the postpartum ward.InterventionsA single investigator performed all the individual interviews to collect sociodemographic variables and obtained gestational age and birth weight from the patients' charts before discharge.Main Outcome MeasuresParticipants were divided into 3 groups according to age: young adolescents (10–15 years), older adolescents (16–19 y) and young adults (20–24 y). The χ² test was used to compare the rate of preterm birth and low birth weight between the groups and analyze differences in sociodemographic characteristics between the 3 groups. P < 0.05 was considered significant.ResultsA total of 1124 participants were included: 164 young adolescents, 537 older adolescents and 423 adults. The rate of preterm birth was similar in the 3 groups: 4.3%, 3.5% and 4.5%, for young adolescents, older adolescents and adults, respectively (P = 0.48). The rate of low birth weight was significantly higher among young adolescents (9.7%) compared to older adolescents (6.1%) and young adults (3.5%) (P = 0.012).ConclusionsThe rate of preterm birth was similar in adolescents and young adults. Adolescent mothers under 16 years of age have a significantly higher incidence of low birth weight infants.     

The effect of maternal hypertension on mortality in infants 22, 29 weeks gestation

ObjectiveTo evaluate the effect of maternal hypertension on mortality risk prior to discharge, in infants 22 + 0 to 29 + 6 weeks gestational age.Study designWe evaluated 88,275 North American infants whose births were recorded in Vermont Oxford Network centers between 2008 and 2011 Infants born between 22 + 0 and 29 + 6 weeks gestational age were evaluated in 2-week gestational age cohorts and followed until death or discharge. Logistic regression was used to adjust for birth weight, antenatal steroid exposure, infant sex, maternal race, inborn/outborn, prenatal care and birth year.Results21,896 infants were born to hypertensive mothers; 13% died prior to Neonatal Intensive Care Unit discharge compared to 20% of the 66,379 infants born to mothers without hypertension. After adjustment, infants had significantly lower mortality compared to preterm infants not born to hypertensive mothers, at all gestational ages examined (22/23: odds ratio (OR) = 0.65 (95% Confidence Interval (CI): 0.55, 0.77; 24/25); OR = 0.77 (95% CI: 0.71, 0.84); 26/27: OR = 0.66 (95% CI: 0.59, 0.74); 28/29: OR = 0.58 (95% CI: 0.51, 0.67). Additionally, births associated with maternal hypertension increase dramatically by gestational age, resulting in a larger proportion of births associated with maternal hypertension at later gestational ages.ConclusionsPreterm birth due to any cause carries significant risk of mortality, especially at the earliest of viable gestational ages. Maternal hypertension independently influences mortality, with lower odds of mortality seen in infants born to hypertensive mothers, after adjustment, and should be taken into consideration as an element in counseling parents.