Who is at risk for prolonged and postterm pregnancy?

Department of Obstetrics and Gynecology, University of California, San Francisco, CA, USA.
American journal of obstetrics and gynecology (Impact Factor: 4.7). 05/2009; 200(6):683.e1-5. DOI: 10.1016/j.ajog.2009.02.034
Source: PubMed


The objective of the study was to examine risk factors for postterm (gestational age >or= 42 weeks) or prolonged (gestational age >or= 41 weeks) pregnancy.
We conducted a retrospective cohort study of all term, singleton pregnancies delivered at a mature, managed care organization. The primary outcome measures were the rates of pregnancies greater than 41 or 42 weeks' gestation. Multivariable logistic regression models were used to control for potential confounding and interaction.
Specific risk factors for pregnancy beyond 41 weeks of gestation include obesity (adjusted odds ratio [aOR], 1.26; 95% confidence interval [CI], 1.16-1.37), nulliparity (aOR, 1.46; 95% CI 1.42-1.51), and maternal age 30-39 years (aOR, 1.06; 95% CI, 1.02-1.10) and 40 years or older (aOR, 1.07; 95% CI, 1.02-1.12). Additionally, African American, Latina, and Asian race/ethnicity were all associated with a lower risk of reaching 41 or 42 weeks of gestation.
Our findings suggest that there may be biological differences that underlie the risk for women to progress to 41 or 42 weeks of gestation. In particular, obesity is a modifiable risk factor and could potentially be prevented with prepregnancy or interpregnancy interventions.

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    • "Axmon et al. also reported a significant relationship between longer TTP, and EP and abortion.[7] Our results are similar to those of Henriksen et al.[8] Henriksen et al. also reported the correlation between shorter TTP and increase in the prevalence of multiple pregnancy,[9] but we did not have any case with multiple pregnancy in the current study. "
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    ABSTRACT: Background: Studies have shown significant correlation between time to pregnancy (TTP) and pregnancy outcomes. But understanding of these mechanisms may not be facilitated. The aim of this study was to determine the relation between TTP and pregnancy outcome. Materials and Methods: This study was a case cohort study that was done in Shahid Beheshti Educational Hospital during 2006-2007. Women aged 18-35 years, who had only one pregnancy without using any contraception method before pregnancy and delivered their first child, were enrolled in this study. Thus, 801 women were selected and followed up for pregnancy outcome and TTP until the end of pregnancy. All the participants filled in a special questionnaire. Finally the collected data were entered into computer and analyzed by SPSS ver. 20 software. Results: The frequency distribution of TTP-based pregnancy outcome showed that TTP >48 weeks was higher in normal delivery than in abnormal delivery (5.6% vs. 19.4%). According to Chi-square test, the frequency distribution of pregnancy outcome was related to TTP (P < 0.001). Conclusion: According to the results of this study, there is a significant relationship between TTP and pregnancy outcome, and TTP may lead to unwanted complications such as ectopic pregnancy, preterm labor, and abortion. Thus, all women with a long time of contraception, especially in the rural areas, mast be controlled.
    08/2014; 3:175. DOI:10.4103/2277-9175.139411
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    • "Post-term pregnancy is defined by the World Health Organization and the International Federation of Obstetrics and Gynecology as a pregnancy proceeding to and beyond 294 days of gestation i.e. 42 weeks + 0 days [1-3]. The term prolonged pregnancy has commonly been used about pregnancies proceeding to or beyond 287 days of gestation, corresponding to 41 weeks + 0 days [4]. Both conditions have been associated with numerous maternal and neonatal adverse outcomes [4-10]. "
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    ABSTRACT: Background Whether gestational age per se increases perinatal mortality in post-term pregnancy is unclear. We aimed at assessing gestational week specific perinatal mortality in small-for-gestational-age (SGA) and non-SGA term and post-term gestations, and specifically to evaluate whether the relation between post-term gestation and perinatal mortality differed before and after ultrasound was introduced as the standard method of gestational age estimation. Methods A population-based cohort study, using data from the Medical Birth Registry of Norway (MBRN), 1967–2006, was designed. Singleton births at 37 through 44 gestational weeks (n = 1 855 682), excluding preeclampsia, diabetes and fetal anomalies, were included. Odds ratios (OR) with 95% confidence intervals (CI) for perinatal mortality and stillbirth in SGA and non-SGA births by gestational week were calculated. Results SGA infants judged post-term by LMP had significantly higher perinatal mortality than post-term non-SGA infants at 40 weeks, independent of time period (highest during 1999–2006 [OR 9.8, 95% CI: 5.7-17.0]). When comparing years before (1967–1986) versus after (1987–2006) ultrasound was introduced, there was no decrease in the excess mortality for post-term SGA versus non-SGA births (ORs from 6.1 [95% CI: 5.2-7.1] to 6.7 [5.2-8.5]), while mortality at 40 weeks decreased significantly (ORs from 4.6, [4.0-5.3] to 3.2 [2.5-3.9]). When assessing stillbirth risk (1999–2006), more than 40% of SGA stillbirths (11/26) judged to be ≥41 weeks by LMP were shifted to lower gestational ages using ultrasound estimation. Conclusions Mortality risk in post-term infants was strongly associated with growth restriction. Such infants may erroneously be judged younger than they are when using ultrasound estimation, so that the routine assessment for fetal wellbeing in the prolonged gestation may be given too late.
    BMC Pregnancy and Childbirth 05/2014; 14(1):172. DOI:10.1186/1471-2393-14-172 · 2.19 Impact Factor
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    • "Obese women tend to have a longer gestation and are more likely to deliver beyond 41 weeks of pregnancy, especially when BMI reaches 35 kg/m 2 or more (Usha Kiran et al., 2005; Graves et al., 2006; Bhattacharya et al., 2007; Stotland et al., 2007; Denison et al., 2008; Caughey et al., 2009; Nohr et al., 2009). "
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    ABSTRACT: BACKGROUND: the incidence of obesity increases in all developed countries to frightful percentages, also in women of reproductive age. Maternal obesity is associated with important obstetrical complications; and this group also exhibits a higher incidence of prolonged pregnancies and labours. OBJECTIVE: to review the literature on the pathophysiology of onset and progression of labour in obese woman and translate this knowledge into practical recommendations for clinical management. METHODS: a literature review, in particular a critical summary of research, in order to determine associations, gaps or inconsistencies in this specific but limited body of research. FINDINGS: the combination of a higher incidence of post-term childbirths and increased inadequate contraction pattern during the first stage of labour suggests an influence of obesity on myometrial activity. A pathophysiologic pathway for altered onset and progression of labour in obese pregnant women is proposed. CONCLUSIONS: analysis of the literature shows that obesity is associated with an increased duration of pregnancy and prolonged duration of first stage of labour. IMPLICATIONS FOR PRACTICE: an adapted clinical approach is suggested in these patients.
    Midwifery 02/2013; 29(12). DOI:10.1016/j.midw.2012.12.013 · 1.57 Impact Factor
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