Normal Body Mass Index Women Research Articles

Increasing pre-pregnancy body mass index is predictive of a progressive escalation in adverse pregnancy outcomes

Objective: To evaluate the association between pre-pregnancy body mass index (BMI) and adverse pregnancy outcomes using a large administrative database. Methods: Retrospective cohort study of California women delivering singletons in 2007. The association between pre-pregnancy BMI category and adverse outcomes were evaluated using multivariate logistic regression. Results: Among 436,414 women, increasing BMI was associated with increasing odds of adverse outcomes. Obese women (BMI = 30–39.9) were nearly 3x more likely to have gestational diabetes (OR = 2.83, 95% CI = 2.74–2.92) and gestational hypertension/preeclampsia (2.68, 2.59–2.77) and nearly twice as likely to undergo cesarean (1.82, 1.78–1.87), when compared to normal BMI women (BMI = 18.5–24.9). Morbidly obese women (BMI ≥ 40) were 4x more likely to have gestational diabetes (4.72, 4.46–4.99) and gestational hypertension/preeclampsia (4.22, 3.97–4.49) and nearly 3x as likely to undergo cesarean (2.60, 2.46–2.74). Conclusion: There is a strong association between increasing maternal BMI and adverse pregnancy outcomes. This information is important for counseling women regarding the risks of obesity in pregnancy.

P08.07: Duration and number of second trimester screening fetal ultrasound examinations in women with normal and elevated body‐mass‐index

It was analysed if there is a difference in the duration of fetal ultrasound examination and number of visits in women with normal and elevated body-mass-index (BMI). We evaluated 652 women in the year 2003 (ATL HDI 5000) and 562 women in the year 2009 (Voluson 730/E8) with a singleton pregnancy and completed second trimester screening at our tertiary referral center. Duration of examination was routinely measured by the ultrasound machine. We evaluated the BMI, gestational age, former pregnancies, location of the placenta, and position of the fetus as well as the type of the ultrasound machine. We saw 460 (2003) and 393 (2009) women with a normal BMI and 192 (2003) and 169 (2009) women with a BMI above 30.0 kg/m2. The groups differed by a higher count of transverse lie in the obese patients (P < 0.001) causing additional examinations (P = 0.03). Duration of examination in normal BMI women was 37 min. (2003) and 29 min. (2009). In the obesity subgroup with patients having a BMI > 40 duration was 95 min. (2003) and 45 min. (2009), P = 0.001. The number of examinations was significantly higher in 2009 between all stages of obesity compared with normal BMI. In 2003 there was a significant longer duration only in patients with an BMI above 35. There is a significant longer duration of the ultrasound examination in second trimester screening in women with normal and elevated BMI. We also verified the significantly higher numbers of repetitive examinations reflecting the challenge in successful visualisation of fetal and materno-fetal structures. Obese pregnant women need more resources in diagnostic (and therapeutic) procedures and even then successful detection of anomalies is a challenging problem.

Impact of morbid obesity on the mode of delivery and obstetric outcome in nulliparous singleton pregnancy and the implications for rural maternity services

Obesity represents a rapidly emerging epidemic amongst pregnant women. Our study looks at the impact of morbid obesity on pregnant singleton nulliparous women in comparison with normal body mass index women. We conclude that morbid obesity is associated with a significantly higher risk of pre-existing medical conditions, developing antenatal complications, induction of labour, caesarean section and greater birth weight. However, there was no significant difference in caesarean section rates when adjusted for induction of labour. We also found no significant difference in length of hospital stay, postnatal complications and neonatal morbidity.

Abstract P3-11-01: Longitudinal Changes in Mammographic Features and Subsequent Risk of Breast Cancer in Pre-Menopausal Women: Studies Nested within the Age Trial

Abstract Background: Mammographic percent density (PD) is one of the strongest known risk factors for breast cancer, with women with 75% or more density having approximately 4 times greater risk of developing breast cancer than those with little density (&amp;lt;5%). Most studies have been conducted in peri-and post-menopausal women with very few studies of density in younger pre-menopausal women. Mammographic features change throughout a woman's lifetime, with the amount of stromal and epithelial tissue decreasing with age, parity and the menopause. As some of the greatest changes in density occur during the menopause, it would be very informative to know whether PD measured at a younger age or the rate of change in PD could be better predictors of subsequent breast cancer risk. Methods: A nested case-control study of 350 cases and 450 controls was conducted within the intervention arm of the Age Trial of mammographic screening in young women, in which about 54,000 women wererandomised to receive yearly mammographic screening from ages 40 to 48. Women diagnosed with breast cancer were invited to participate in the study, and for each case, healthy controls were randomly selected matched to the cases on screening centre, age and date of mammogram. We are investigating how changes in PD over time in pre-menopausal women, measured on digitised films using a computer-assisted threshold method, relate to subsequent risk of breast cancer. Additionally, we are looking at associations of risk factor variables with baseline PD and changes in PD, investigated in longitudinal analyses in a sample of over 500 breast cancer-free women. Logistic regression models were used to estimate the effect of baseline mammographic density on subsequent breast cancer risk and multilevel linear models to assess the association between longitudinal changes in percent density and risk of breast cancer. Results: Over a 10 year period between ages 40 and 50, the mean reduction in percent density was 10.9% in our sample of breast cancer-free women. Change in percent density was greatest in the women's early forties, with a decrease of 1.9% per year, which reduced to about 0.2% in their late forties/early fifties. Baseline levels and rate of change of percent density were both associated with current and past anthropometric, reproductive and lifestyle factors. Change in percent density was associated with parity, with women who had three or more children experiencing a slower rate of change (P&amp;lt;0.01), and with body mass index (BMI), with extremely overweight women at baseline (&amp;gt;28 kg/m2) having a slower decline in PD than women of normal BMI (22-24 kg/m2). The analysis of the case-control data is currently in progress. Conclusion: We demonstrated that change in PD was associated with known breast cancer risk factors in pre-menopausal women. The results from the nested case-control study will further our understanding of the life-course trajectory of mammographic density and its role as a mediator of breast cancer risk. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-11-01.

Cardiorespiratory Fitness, Adiposity, and All-Cause Mortality in Women

To determine the prospective associations among cardiorespiratory fitness (CRF), different measures of adiposity, and all-cause mortality in women. A total of 11,335 women completed a comprehensive baseline examination between 1970 and 2005. Clinical measures included body mass index (BMI), waist circumference (WC), waist-to-height ratio (W/HT), waist-to-hip ratio (W/Hip), percent body fat (%BF), and CRF quantified as duration of a maximal exercise test. Participants were classified by CRF as low (lowest 20%), moderate (middle 40%), and high (highest 40%) as well as by standard clinical cut points for adiposity measures. Hazard ratios (HR) were computed using Cox regression analysis. During a mean follow-up of 12.3 ± 8.2 yr, 292 deaths occurred. HR for all-cause mortality were 1.0, 0.60, and 0.54 for low, moderate, and high fit groups, respectively (P for trend G0.01). Adjusted death rates of overweight/obese women within each adiposity exposure were somewhat higher compared with normal-weight women and approached statistical significance for BMI, %BF, and W/HT (P = 0.08, P = 0.08, and P = 0.07, respectively). When grouped for joint analyses into categories of fit and unfit (upper 80% and lower 20% of CRF distribution, respectively), HR were significantly higher in unfit women within each stratum of BMI compared with fit–normal BMI women. Fit women with high %BF (HR = 1.0), high WC (HR = 0.9), and high W/HT (HR = 1.2) had no greater risk of death compared with fit–normal-weight women (referent). Low CRF in women was a significant independent predictor of all-cause mortality. Higher CRF was associated with lower mortality within each category of each adiposity exposure. Using adiposity measures as predictors of all-cause mortality in women may be misleading unless CRF is also considered.

The risk of adverse pregnancy outcomes in women who are overweight or obese

BackgroundThe prevalence of obesity amongst women bearing children in Australia is rising and has important implications for obstetric care. The aim of this study was to assess the prevalence and impact of mothers being overweight and obese in early to mid-pregnancy on maternal, peripartum and neonatal outcomes.MethodsA secondary analysis was performed on data collected from nulliparous women with a singleton pregnancy enrolled in the Australian Collaborative Trial of Supplements with antioxidants Vitamin C and Vitamin E to pregnant women for the prevention of pre-eclampsia (ACTS). Women were categorized into three groups according to their body mass index (BMI): normal (BMI 18.5-24.9 kg/m2); overweight (BMI 25-29.9 kg/m2) and; obese (BMI 30-34.9 kg/m2). Obstetric and perinatal outcomes were compared by univariate and multivariate analyses.ResultsOf the 1661 women included, 43% were overweight or obese. Obese women were at increased risk of pre-eclampsia (relative risk (RR) 2.99 [95% confidence intervals (CI) 1.88, 4.73], p < 0.0001) and gestational diabetes (RR 2.10 [95%CI 1.17, 3.79], p = 0.01) compared with women with a normal BMI. Obese and overweight women were more likely to be induced and require a caesarean section compared with women of normal BMI (induction - RR 1.33 [95%CI 1.13, 1.57], p = 0.001 and 1.78 [95%CI 1.51, 2.09], p < 0.0001, caesarean section - RR 1.42 [95%CI 1.18, 1.70], p = 0.0002 and 1.63 [95%CI 1.34, 1.99], p < 0.0001). Babies of women who were obese were more likely to be large for gestational age (LFGA) (RR 2.08 [95%CI 1.47, 2.93], p < 0.0001) and macrosomic (RR 4.54 [95%CI 2.01, 10.24], p = 0.0003) compared with those of women with a normal BMI.ConclusionThe rate of overweight and obesity is increasing amongst the Australian obstetric population. Women who are overweight and obese have an increased risk of adverse pregnancy outcomes. In particular, obese women are at increased risk of gestational diabetes, pregnancy induced hypertension and pre-eclampsia. Effective preventative strategies are urgently needed.Trial RegistrationCurrent Controlled Trials ISRCTN00416244

Association of body mass index with hip and thigh pain following transobturator midurethral sling placement

We sought to investigate the incidence of hip and proximal lower extremity pain following transobturator midurethral sling and evaluate the association between pain and body mass index (BMI). This was a retrospective cohort study of all transobturator midurethral sling procedures from July 2008 through June 2009. The primary outcome was postoperative hip or proximal lower extremity pain. Four urogynecologists performed 226 procedures. The incidence of postoperative hip or proximal lower extremity pain was 15.5%. Women of normal BMI had a higher risk of developing pain than obese women (risk ratio, 2.51; 95% confidence interval, 1.01-6.22). While not statistically significant, overweight women were twice as likely as obese women to develop the primary outcome (risk ratio, 1.99; 95% confidence interval, 0.79-4.99). Women of normal BMI have an increased risk of hip and proximal lower extremity pain following transobturator midurethral sling compared with obese women.

Increased risk of orofacial clefts associated with maternal obesity: case-control study and Monte Carlo-based bias analysis

Our objective was to evaluate whether infants born to obese or diabetic women are at higher risk of non-syndromic orofacial clefting. We conducted a population-based case-control study using Washington State birth certificate and hospitalisation data for the years 1987-2005. Cases were infants born with orofacial clefts (n = 2153) and controls infants without orofacial clefts (n = 18 070). The primary exposures were maternal obesity (body mass index > or =30) and diabetes (either pre-existing or gestational). We estimated adjusted odds ratios (ORs) to compare, for mothers of cases and controls, the proportions of obese vs. normal-weight women and diabetic vs. non-diabetic women. We additionally performed Monte Carlo-based simulation analysis to explore possible influences of biases. Obese women had a small increased risk of isolated orofacial clefts in their offspring compared with normal-body mass index women [adjusted OR 1.26; 95% confidence interval 1.03, 1.55]. Results were similar regardless of type of cleft. Bias analyses suggest that estimates may represent underlying ORs of stronger magnitude. Results for diabetic women were highly imprecise and inconsistent. We and others have observed weak associations of similar magnitude between maternal obesity and risk of non-syndromic orofacial clefts. These results could be due to bias or residual confounding. However, it is also possible that these results represent a stronger underlying association. More precise exposure measurement could help distinguish between these two possibilities.

The influence of body mass index (BMI) on pregnancy rates and outcomes among infertile Japanese women

OBJECTIVE: The World Health Organization defines obesity as BMI ≥ 30 kg/m. The Japan Society for the Study of Obesity (JASSO) defines obesity as BMI ≥ 25 kg/m. The objective of this study was to examine the effect of BMI on infertility treatment in Japanese women based on JASSO criteria.DESIGN: Retrospective studyMATERIALS AND METHODS: 616 patients undergoing infertility treatment from June 2006 to June 2007 were allocated into 3 main groups according to the JASSO criteria: low (n= 112), normal (n= 460), and high (n= 44) BMI. They were further subdivided by treatment into 2 subgroups: no in vitro fertilization (IVF) (n= 302) and IVF (n= 314). The main outcome measures were pregnancy rate (PR), ongoing pregnancy rate (OPR), and miscarriage rate (MR). Statistical testing included Student's t-test, Pearson's chi square test, and Fisher's exact test.RESULTS: PR was significantly lower in the high BMI group (22/44, 50%) than in the normal BMI group (318/460, 69.1%; P<0.05). Low BMI had no significant impact on fertility. Compared to IVF patients with normal BMI (n= 238), IVF patients with high BMI (n = 25) had: a tendency towards lower PR (5/25, 20% vs. 55/238, 23.1%), OPR (3/5, 60% vs. 41/55, 74.5%.), MR (2/5, 40% vs. 14/55, 25.5%), and fertilization rate (115/219, 52.5% vs. 1658/2832, 58.5%); a significant reduction in the number of oocytes retrieved (8.8±5.7 vs. 11.9±8.8; P<0.05) and the number of good quality embryos (33/90, 36.7% vs. 656/1118, 58.7%; P<0.05); and a significant increase in the cancellation rate due to poor response or lack of fertilization (5/25, 20% vs. 18/238, 7.6%; p<0.05).CONCLUSIONS: Obesity has a deleterious effect on fertility. This is clearly obvious among high BMI women seeking IVF, who showed fewer retrieved oocytes, a deterioration in embryo quality. No significant difference was observed in the implantation rate between normal BMI and high BMI women. However, the low fertilization and cleavage rates, possibly due to the bad quality embryos, may explain the poor outcomes in high BMI women. OBJECTIVE: The World Health Organization defines obesity as BMI ≥ 30 kg/m. The Japan Society for the Study of Obesity (JASSO) defines obesity as BMI ≥ 25 kg/m. The objective of this study was to examine the effect of BMI on infertility treatment in Japanese women based on JASSO criteria. DESIGN: Retrospective study MATERIALS AND METHODS: 616 patients undergoing infertility treatment from June 2006 to June 2007 were allocated into 3 main groups according to the JASSO criteria: low (n= 112), normal (n= 460), and high (n= 44) BMI. They were further subdivided by treatment into 2 subgroups: no in vitro fertilization (IVF) (n= 302) and IVF (n= 314). The main outcome measures were pregnancy rate (PR), ongoing pregnancy rate (OPR), and miscarriage rate (MR). Statistical testing included Student's t-test, Pearson's chi square test, and Fisher's exact test. RESULTS: PR was significantly lower in the high BMI group (22/44, 50%) than in the normal BMI group (318/460, 69.1%; P<0.05). Low BMI had no significant impact on fertility. Compared to IVF patients with normal BMI (n= 238), IVF patients with high BMI (n = 25) had: a tendency towards lower PR (5/25, 20% vs. 55/238, 23.1%), OPR (3/5, 60% vs. 41/55, 74.5%.), MR (2/5, 40% vs. 14/55, 25.5%), and fertilization rate (115/219, 52.5% vs. 1658/2832, 58.5%); a significant reduction in the number of oocytes retrieved (8.8±5.7 vs. 11.9±8.8; P<0.05) and the number of good quality embryos (33/90, 36.7% vs. 656/1118, 58.7%; P<0.05); and a significant increase in the cancellation rate due to poor response or lack of fertilization (5/25, 20% vs. 18/238, 7.6%; p<0.05). CONCLUSIONS: Obesity has a deleterious effect on fertility. This is clearly obvious among high BMI women seeking IVF, who showed fewer retrieved oocytes, a deterioration in embryo quality. No significant difference was observed in the implantation rate between normal BMI and high BMI women. However, the low fertilization and cleavage rates, possibly due to the bad quality embryos, may explain the poor outcomes in high BMI women.

Effect of Maternal Obesity on the Ultrasound Detection of Anomalous Fetuses

To estimate the effect of maternal habitus on detection of fetuses with major structural anomalies during second-trimester standard and targeted ultrasound examinations. This was a retrospective cohort study of pregnancies 18 to 24 weeks that underwent ultrasonography over a 5-year period. An anomalous fetus was considered detected if a major abnormality of the relevant organ system was identified, regardless of the anticipated ultrasound detection. Anomalies were verified using a prospectively maintained database. Body mass index (BMI) was based on weight at first prenatal visit. There were 10,112 standard examinations in low-risk pregnancies and 1,098 targeted examinations in pregnancies with either high-risk indications or with an abnormality detected during standard ultrasonography. Detection of anomalous fetuses decreased with increasing BMI. For normal BMI, overweight, and class I, II, and III obesity, detection with standard ultrasonography was 66%, 49%, 48%, 42%, and 25%, respectively, and with targeted ultrasonography, 97%, 91%, 75%, 88%, and 75%, respectively, both P< or =.03. Residual anomaly risk after a normal ultrasound examination increased with increasing BMI, from 0.4% among women of normal BMI to 1.0% among obese women, P=.001. Anomaly detection was lower among women with pregestational diabetes than in those with other high-risk indications, 38% compared with 88% respectively, P<.001. With increasing maternal BMI, we found decreased detection of anomalous fetuses with either standard or targeted ultrasonography, a difference of at least 20% when women of normal BMI were compared with obese women. Anomaly detection was even less in pregnancies complicated by pregestational diabetes. Counseling may need to be modified to reflect the limitations of ultrasonography in obese women.

Umbilical artery tone in maternal obesity

BackgroundThe increasing prevalence of obesity constitutes a major health problem in obstetrics with implications for feto-maternal growth and wellbeing. This study investigated and compared the contractile properties of umbilical arteries excised from obese women, with those excised from women with a normal body mass index (BMI).MethodsSections of umbilical artery were obtained from umbilical cord samples immediately after delivery and mounted for isometric recording in organ tissue baths under physiological conditions. Cumulative additions of 5-Hydroxytryptamine (5-HT) and Prostaglandin F-2alpha (PgF2alpha) were added in the concentration range of 1 nmol/L to 10 micromol/L. Control vessels were exposed to Krebs physiological salt solution (PSS) only. The resultant effects of each drug addition were measured using the Powerlab hardware unit.Results5-HT exerted a significant effect on human umbilical artery tone at concentrations of 100 nmol/L, 1 micromol/L, and 10 micromol/L in normal (n = 5; P < 0.05) and obese (n = 5; P < 0.05) women. The contractile effect was significantly greater in vessels from obese women {Mean Maximum Tension (MMT) = 4.2532 g} than in those from women of normal BMI (MMT = 2.97 g; P < 0.05). PgF2alpha exerted a significant contractile effect on vessels at 1 micromol/L and 10 micromol/L concentrations when compared with controls (n = 5; P < 0.05). There was a non-significant trend towards an enhanced tone response in vessels from obese women (MMT = 3.02 g; n = 5), in comparison to vessels from women of a normal BMI (MMT = 2.358 g; n = 5; P > 0.05).ConclusionThese findings support the hypothesis that endogenous regulation of umbilical artery tone is altered in association with maternal obesity. This may be linked to the cardiovascular effects of secretory products of adipose tissue, with implications for the feto-maternal circulation.

Prepregnancy body mass index and the length of gestation at term

The purpose of this study was to examine the relationship between prepregnancy body mass index (BMI) and length of gestation at term. This was a retrospective study of 9336 births at the University of California, San Francisco, at > or = 37 weeks' gestation. We performed univariate and multivariable analyses of the associations between prepregnancy BMI and length of gestation (> or = 40, > or = 41, and > or = 42 weeks' gestation). Overweight women were more likely to deliver at > or = 40, > or = 41, and > or = 42 weeks' gestation than were women who were underweight or normal weight. In multivariable analyses, higher prepregnancy BMI was associated with higher risk of progressing past 40 weeks. Obese women had 69% higher adjusted odds of reaching 42 weeks' gestation, compared with women of normal prepregnancy BMI (adjusted odds ratio, 1.69; 95% confidence interval, 1.23-2.31). Higher BMI is associated with prolonged gestation at term. Achieving optimal BMI before conception may reduce the risk of postterm pregnancy and its associated complications.

Impact of obesity on oral contraceptive pharmacokinetics and hypothalamic-pituitary-ovarian activity: a mechanism for contraceptive failure?

To determine whether increased body mass index (BMI) affects oral contraceptive (OC) pharmacokinetics and suppression of hypothalamic-pituitary-ovarian axis (HPO) activity. Prospective cohort. Reproductive-age women of normal (<25 kg/m2; n = 10) and obese (>30 kg/m2; n = 7) BMI received a very-low dose OC [20 mcg ethinyl estradiol/100 mcg levonorgestrel (LNG)] for two cycles (C1, C2). Evidence of ovulatory cycles (luteal progesterone ≥3 ng/mL) and percent body fat by air displacement were obtained prior to enrollment. Subjects were admitted for two 48-hour inpatient stays at the beginning (first inpatient stay: C1, Day 21–22) and end (second inpatient stay: C1, Day 28-C2, Day 1) of their OC hormone free interval (HFI). Luteinizing hormone (LH) samples were obtained every 15 minutes from 0900–1700 hours during the second inpatient stay. The deconvolution method was used to analyze each LH series. Estradiol (E2) and progesterone (P) were measured daily during each inpatient stay and bi-weekly in C2. LNG samples were collected during each inpatient stay from which pharmacokinetics were calculated. Mean BMI and percent body fat were greater in the obese BMI group [21.9 kg/m2 (SD 1.6) and 27.6% (SD 7.2) vs. 36.2 kg/m2 (SD 4.1) and 49.3% (SD 3.6); P<0.05]. A trend toward a longer LNG half-life (45.7 ± 8.9 hrs vs. 26.0 ± 7.8 hrs) and an increased volume of distribution (13.1 ± 4.9 L vs. 8.9 ± 4.3 L) was observed in obese compared to normal BMI women. Calculated time to achieve LNG steady state was twice as long in obese women (obese BMI 12 days; normal BMI 6 days). Although not statistically significant, the LNG maximum concentration on C2, Day 1 was lower in obese women [1.79 ng/mL (SD 0.35) vs. 2.53 (SD 0.67); P=0.06]. LH pulsatility was consistent with HPO reactivation at the end of the OC HFI in both BMI groups, with no significant differences in LH pulse parameters (baseline, half-life, pulse numbers, and average pulse mass). While no subject had evidence of ovulation (e.g. P>3 ng/mL), two obese and one normal woman exhibited E2 levels consistent with development of a dominant follicle (>200 pg/mL) during C2. Evidence of HPO reactivation is present in both obese and normal BMI women at the end of the OC HFI. However, the increased time to reach steady state in obese OC users may lengthen the interval for continued HPO activity placing them at risk for ovulation.

Disentangling causal paths between obesity and in vitro fertilization outcomes: an intractable problem?

Research questions should be appropriate for the available data. Disentangling causal paths between obesity and in vitro fertilization outcomes may be an intractable problem, but other research questions of clinical importance can be addressed through appropriate study designs and analytic methods.

Pre-pregnancy body mass index and length of gestation at term

ObjectiveTo examine the relationship between pre-pregnancy body mass index (BMI) and length of gestation at term.Study designThis was a retrospective study of 10,878 parturients. We excluded preterm births, multiple gestations, and elective cesareans without labor. We performed univariate and multivariate analyses of the associations between pre-pregnancy BMI and length of gestation (>40 weeks, >41 weeks, and >42 weeks).ResultsOverweight women were more likely to deliver at >40 weeks, >41 weeks, and >42 weeks than women who were underweight or normal weight (Table 1). In multivariate analyses, higher pre-pregnancy BMI (as a continuous variable) was associated with longer length of gestation at term. Obese women had a 30% higher adjusted odds of reaching 42 weeks gestation compared to women of normal pre-pregnancy BMI (adjusted odds ratio 1.30, 95% CI 1.08-1.57) (Table 2).ConclusionHigher BMI is associated with longer gestation at term. Despite the fact that higher BMI is associated with gestational diabetes and hypertension, conditions that frequently require delivery prior to 40 weeks gestation, overweight women were more likely to go past their estimated due date. Achieving a healthy BMI prior to conception may reduce the risk of postterm pregnancy and its associated complications.Table 1Pre-pregnancy BMI and length of gestation at termLow BMINormal BMIHigh BMIObese BMIp-valueGA >40 weeks50.9%52.5%53.0%57.0%GA >41 weeks19.8%23.1%24.75%29.0%GA >42 weeks3.4%4.7%6.1%5.7% Open table in a new tab Table 2Multivariate analysis of pre-pregnancy BMI and length of term gestationLow BMINormal BMIHigh BMIObese BMIGA >40 weeks0.95 (0.89-1.01)Reference1.08 (0.99-1.18)1.31 (1.19-1.46)GA >41 weeks0.83 (0.77-0.89)Reference1.19 (1.08-1.32)1.39 (1.24-1.57)GA >42 weeks0.77 (0.68-0.87)Reference1.24 (1.06-1.46)1.30 (1.08-1.57) Open table in a new tab ObjectiveTo examine the relationship between pre-pregnancy body mass index (BMI) and length of gestation at term. To examine the relationship between pre-pregnancy body mass index (BMI) and length of gestation at term. Study designThis was a retrospective study of 10,878 parturients. We excluded preterm births, multiple gestations, and elective cesareans without labor. We performed univariate and multivariate analyses of the associations between pre-pregnancy BMI and length of gestation (>40 weeks, >41 weeks, and >42 weeks). This was a retrospective study of 10,878 parturients. We excluded preterm births, multiple gestations, and elective cesareans without labor. We performed univariate and multivariate analyses of the associations between pre-pregnancy BMI and length of gestation (>40 weeks, >41 weeks, and >42 weeks). ResultsOverweight women were more likely to deliver at >40 weeks, >41 weeks, and >42 weeks than women who were underweight or normal weight (Table 1). In multivariate analyses, higher pre-pregnancy BMI (as a continuous variable) was associated with longer length of gestation at term. Obese women had a 30% higher adjusted odds of reaching 42 weeks gestation compared to women of normal pre-pregnancy BMI (adjusted odds ratio 1.30, 95% CI 1.08-1.57) (Table 2). Overweight women were more likely to deliver at >40 weeks, >41 weeks, and >42 weeks than women who were underweight or normal weight (Table 1). In multivariate analyses, higher pre-pregnancy BMI (as a continuous variable) was associated with longer length of gestation at term. Obese women had a 30% higher adjusted odds of reaching 42 weeks gestation compared to women of normal pre-pregnancy BMI (adjusted odds ratio 1.30, 95% CI 1.08-1.57) (Table 2). ConclusionHigher BMI is associated with longer gestation at term. Despite the fact that higher BMI is associated with gestational diabetes and hypertension, conditions that frequently require delivery prior to 40 weeks gestation, overweight women were more likely to go past their estimated due date. Achieving a healthy BMI prior to conception may reduce the risk of postterm pregnancy and its associated complications.Table 1Pre-pregnancy BMI and length of gestation at termLow BMINormal BMIHigh BMIObese BMIp-valueGA >40 weeks50.9%52.5%53.0%57.0%GA >41 weeks19.8%23.1%24.75%29.0%GA >42 weeks3.4%4.7%6.1%5.7% Open table in a new tab Table 2Multivariate analysis of pre-pregnancy BMI and length of term gestationLow BMINormal BMIHigh BMIObese BMIGA >40 weeks0.95 (0.89-1.01)Reference1.08 (0.99-1.18)1.31 (1.19-1.46)GA >41 weeks0.83 (0.77-0.89)Reference1.19 (1.08-1.32)1.39 (1.24-1.57)GA >42 weeks0.77 (0.68-0.87)Reference1.24 (1.06-1.46)1.30 (1.08-1.57) Open table in a new tab Higher BMI is associated with longer gestation at term. Despite the fact that higher BMI is associated with gestational diabetes and hypertension, conditions that frequently require delivery prior to 40 weeks gestation, overweight women were more likely to go past their estimated due date. Achieving a healthy BMI prior to conception may reduce the risk of postterm pregnancy and its associated complications.

Audit of the influence of body mass index on the performance of epidural analgesia in labour and the subsequent mode of delivery

To assess the influence of body mass index (BMI) on the performance of epidural analgesia in labour and the subsequent mode of delivery. A retrospective audit of prospectively collected quality assurance data. The delivery suite of Leeds General Infirmary, Leeds, UK. This is a 4500-delivery teaching hospital unit. All women receiving epidural analgesia during labour in our unit between April 1997 and December 2005. Epidural recipients were divided into BMI groups according to World Health Organization (WHO) categories and compared for indices of epidural performance and mode of delivery. Midwife and patient satisfaction scores with epidural analgesia, epidural resite rates, and mode of delivery. Data from 13 299 epidural recipients were analysed. Using WHO definitions, 22.8% were of normal body mass, 41.9% were overweight, 31.9% obese, and 3.4% morbidly obese. Epidurals were more likely to fail as BMI increased, as judged by midwife satisfaction scores (P < 0.001) and epidural resite rates (P < 0.01). This trend was not seen for maternal satisfaction scores using the WHO BMI categories. However, if women with BMI below 30 kg/m2 were grouped together, a significant trend was found (P < 0.01). BMI had no influence on vaginal instrumental deliveries, but caesarean section rates rose from 11.5% in women of normal BMI to 29.2% in the morbidly obese women (P < 0.001). Obesity increases the incidence of analgesic failure and the need for resite of epidurals. The caesarean section rate among epidural recipients increases dramatically as BMI rises.

Obesity, Recreational Physical Activity, and Risk of Pancreatic Cancer In a Large U.S. Cohort

Obesity and physical activity, in part through their effects on insulin sensitivity, may be modifiable risk factors for pancreatic cancer. The authors analyzed data from the American Cancer Society Cancer Prevention Study II Nutrition Cohort to examine the association between measures of adiposity, recreational physical activity, and pancreatic cancer risk. Information on current weight and weight at age 18, location of weight gain, and recreational physical activity were obtained at baseline in 1992 via a self-administered questionnaire for 145,627 men and women who were cancer-free at enrollment. During the 7 years of follow-up, 242 incident pancreatic cancer cases were identified among these participants. Cox proportional hazards modeling was used to compute hazard rate ratios (RR) and to adjust for potential confounding factors including personal history of diabetes and smoking. We observed an increased risk of pancreatic cancer among obese [body mass index (BMI) >/= 30] men and women compared with men and women of normal BMI [<25; RR, 2.08; 95% confidence interval (95% CI), 1.48-2.93, P(trend) = 0.0001]. After adjustment for between BMI, risk of pancreatic cancer was independently increased among men and women who reported a tendency for central weight gain compared with men and women reporting a tendency for peripheral weight gain (RR, 1.45; 95% CI, 1.02-2.07). We observed no difference in pancreatic cancer incidence rates between men and women who were most active (>31.5 metabolic equivalent hours per week) at baseline compared with men and women who reported no recreational physical activity (RR, 1.20; 95% CI, 0.63-2.27). This study, along with several recent studies, supports the hypothesis that obesity and central adiposity are associated with pancreatic cancer risk.

The impact of maternal obesity and weight gain on vaginal birth after cesarean section success

This study was undertaken to determine the impact of maternal obesity on success of a trial of labor (vaginal birth after cesarean section [VBAC]) after a single low transverse cesarean delivery. Individual charts of women with low transverse cesarean delivery in their first viable pregnancy who underwent a VBAC in their second viable pregnancy at our urban tertiary care institution were reviewed. Maternal body mass index (BMI) was classified as underweight (<19.8 kg/m2), normal (19.8-24.9 kg/m2), overweight (25-29.9 kg/m2), or obese (> or =30 kg/m2). Clinical characteristics and labor outcomes were assessed. Factors potentially affecting VBAC success were analyzed by univariate analysis. Logistic regressions were performed to determine the impact of maternal pregravid BMI on VBAC success after controlling for confounding factors. Of 510 women attempting a trial of labor, 337 (66%) were successful and 173 (34%) failed VBAC. Decreased VBAC success was seen in obese (54.6%) but not overweight (65.5%) women compared with women of normal BMI (70.5%), P = .003 and .36, respectively. Underweight women had more VBAC success than women of normal BMI (84.7% vs 70.5%, P = .04). Controlling for other factors, the association between increasing pregravid BMI and BMI > or =30 kg/m 2 with decreased VBAC success persisted, P = .03 and .006, respectively. Normal BMI women who became overweight before the second pregnancy had decreased VBAC success compared with those whose BMI remained normal (56.6% vs 74.2%, P = .006). However, overweight women who decreased their BMI to normal before the second pregnancy did not significantly improve VBAC success (64.0% vs 58.4%, P = .67). Increasing pregravid BMI and weight gain between pregnancies reduce VBAC success after a single low transverse cesarean delivery.

The impact of adjustment for parity and mid‐upper‐arm circumference on sensitivity of symphysis‐fundus height measurements to predict SGA foetuses in Mozambique

With a new symphysis-fundus height (SFH) growth chart, based on Mozambican women with ultrasound-dated singleton pregnancies, the aim was to examine the possibility to enhance sensitivity of predicting small for gestational age (SGA) newborns by attempts to adjust the chart for parity and for mid-upper-arm circumference (MUAC). Two antenatal clinics were chosen in the suburban area of Maputo City. A cohort of 904 consecutively recruited antenatal clients was followed until birth. Gestational age was determined by ultrasound at enrolment. The growth of the SFH was measured every 2-3 weeks. Women with multiple pregnancy or with gestational age >21 weeks at enrolment were excluded. Attempts were made to adjust SFH measurements for parity and MUAC by developing a mathematical model to increase sensitivity of the SFH method to predict a foetus being SGA. Parous women had on average 0.5-1 cm higher SFH readings than nulliparous women. Women with a body mass index (BMI) <19 and women with BMI >27 had approximately 1 cm lower and 1 cm higher readings, respectively, compared with women of normal BMI. There was a significant correlation between BMI and MUAC (r = 0.621; P < 0.001). The usefulness of SFH measurements to predict SGA newborns was analysed. The sensitivity was 49%, the specificity was 66%, the positive predictive value was 14% and the negative predictive value, 93%. By using the correlation between BMI and MUAC we tried to find a simple and useful method to improve the sensitivity of SFH to detect SGA foetuses. By reducing the SFH measurement by 1 cm for women with MUAC >29 and by 1 cm for multiparous women the sensitivity raised to 65% at the expense of reducing the specificity to 51%. Using a linear function of BMI, MUAC and parity to adjust the SFH measurement for each individual woman, it was possible to get a sensitivity of 70% with a corresponding specificity of 56%. By using BMI, MUAC and parity, it might be possible to improve the sensitivity of the SFH growth chart in predicting newborn being SGA but mostly at the expense of specificity.