Factors influencing delivery mode for nulliparous women with a singleton pregnancy and cephalic presentation during a 17-year period
ABSTRACT To evaluate the effects of maternal age, induction of labour, epidural analgesia and birth weight on mode of delivery in nulliparous women with a singleton pregnancy and cephalic presentation at > or =36 weeks gestation, and to describe how these factors and their influence have changed over a 17-year period from 1989 to 2005.
The study was conducted in the obstetric department of a university teaching hospital in Ireland. Of 45,647 women delivered, 14,867 were nulliparous with a singleton pregnancy and cephalic presentation and undergoing labour at > or =36 weeks gestation, and were included in the study. The main outcome measures were the influence of maternal age, induction of labour, epidural analgesia and birth weight on the mode of delivery. Multinomial logistic regression analysis for type of delivery and the associated explanatory variables and trend analysis of these variables were performed.
There was a significant progressive increase in both unplanned abdominal delivery and instrumental vaginal delivery, with advancing maternal age. Induction of labour increased the risk of unplanned abdominal delivery (OR 1.92; 95% CI 1.73-2.14). Epidural analgesia was associated with an increased risk of instrumental vaginal delivery (OR 4.68; 95% CI 4.18-5.25), and unplanned abdominal delivery (OR 2.29; 95% CI 1.98-2.66). Mothers of infants with birth weight > or =4.5 kg were less likely to be delivered by instrumental vaginal delivery (OR 0.60; 95% CI 0.41-0.88), than mothers delivering infants in the 2.50-4.49 kg birth weight category. Between 1989 and 2005 there was a significant increase in maternal age (P=0.0001), birth weight (P=0.042) and unplanned abdominal delivery rates (P=0.0004), and a reduction in instrumental vaginal delivery rates (P=0.0013).
These data demonstrate that the increasing trend of unplanned abdominal delivery in nulliparous women with a singleton pregnancy and cephalic presentation may be partially explained by advancing maternal age, and other obstetric factors also play a significant role.
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ABSTRACT: QUESTION: Can differences in Australian birth intervention rates be explained by women's residence at the time of childbearing?. METHODS: Data were collected prospectively via surveys in 1996, 2000, 2003, 2006 and 2009 from women, born between 1973 and 1978, of the Australian Longitudinal Study on Women's Health. Analysis included data from 5886 women who had given birth to their first child between 1994 and 2009. Outcome measures were self-report of birth interventions: pharmacological pain relief (epidural and spinal block analgesia, inhalational analgesia and intramuscular injections), surgical births (an elective or emergency caesarean section) and instrumental births (forceps and ventouse). FINDINGS: Primiparous women residing in non-metropolitan areas of Australia experienced fewer birth interventions than women residing in metropolitan areas: 43% versus 56% received epidural analgesia; 8% versus 11% had elective caesarean sections; and 16% versus 18% had emergency caesarean sections. Differences in maternal age and private health insurance status at first birth accounted for differences in surgical birth rates but did not fully explain differences in epidural analgesia. CONCLUSION: Non-metropolitan women had fewer birth interventions, particularly epidural analgesia, than metropolitan women. Differences in maternal age and private health insurance do not fully explain the differences in epidural analgesia rates, suggesting care provided to labouring women may differ by area of residence. The difference in epidural analgesia rates may be due to lack of choice in maternity services, however it could also be due to differing expectations leading to differences in birth interventions for primiparous women living in metropolitan and non-metropolitan areas.Women and Birth 12/2012; 26(2). DOI:10.1016/j.wombi.2012.12.001 · 1.70 Impact Factor
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ABSTRACT: To determine the association between fetal position at labor onset and mode of delivery, specifically left occipito-anterior (LOA) fetal position and spontaneous vaginal delivery (SVD). All nulliparous women who were booked at the Birmingham Women's NHS Foundation Trust (BWH) with a singleton live fetus without structural anomalies at term gestation were invited to take part in the study. Women recruited to the study were given a trans-abdominal ultrasound scan to determine fetal occiput position at the onset of labor. Women were then followed up until birth to determine outcomes. The primary outcome measure was mode of delivery, categorised into spontaneous vaginal delivery, instrumental delivery and caesarean section. One-thousand-two-hundred-and-fifty valid scans were obtained from 1,647 eligible women at onset of labor of whom 155 (12.4%) had fetuses in the LOA position. Analysis showed no evidence of difference in odds of SVD for fetuses in the LOA position compared with all other positions (OR 0.864; 95% CI 0.617-1.209; p-value 0.394). No difference remained with adjustment for confounding effects of variables known to influence mode of delivery (OR 0.837; 95% CI 0.551-1.272; p-value 0.405). No other occipital position showed significant association with SVD. There was also no evidence of the LOA position being associated with Cesarean section, ventouse or forceps delivery. There is no evidence of association between the fetal occipital position LOA at labor onset and SVD. This finding challenges the theory of LOA as the optimum fetal position at labor onset and suggests antenatal practices encouraging an LOA fetal position through maternal posturing are unnecessary.Ultrasound in Obstetrics and Gynecology 02/2014; 43(2). DOI:10.1002/uog.13189 · 3.14 Impact Factor
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ABSTRACT: To evaluate risk factors for unsuccessful instrumental delivery when variability between individual obstetricians is taken into account. We conducted a retrospective cohort study of attempted instrumental deliveries over a 5-year period (2008-2012 inclusive) in a tertiary United Kingdom center. To account for interobstetrician variability, we matched unsuccessful deliveries (case group) with successful deliveries (control group) by the same operators. Multivariate logistic regression was used to compare successful and unsuccessful instrumental deliveries. Three thousand seven hundred ninety-eight instrumental deliveries of vertex-presenting, single, term newborns were attempted, of which 246 were unsuccessful (6.5%). Increased birth weight (odds ratio [OR] 1.11; P<.001), second-stage labor duration (OR 1.01; P<.001), rotational delivery (OR 1.52; P<.05), and use of ventouse compared with forceps (OR 1.33; P<.05) were associated with unsuccessful outcome. When interobstetrician variability was controlled for, instrument selection and decision to rotate were no longer associated with instrumental delivery success. More senior obstetricians had higher rates of unsuccessful deliveries (12% compared with 5%; P<.05) but were used to undertake more complicated cases. Cesarean delivery during the second stage of labor without previous attempt at instrumental delivery was associated with higher birth weight (OR 1.07; P<.001), increased maternal age (OR 1.03; P<.01), and epidural analgesia (OR 1.46; P<.001). Results suggest that birth weight and head position are the most important factors in successful instrumental delivery, whereas the influence of instrument selection and rotational delivery appear to be operator-dependent. Risk factors for lack of instrumental delivery success are distinct from risk factors for requiring instrumental delivery, and these should not be conflated in clinical practice. LEVEL OF EVIDENCE:: II.Obstetrics and Gynecology 04/2014; 123(4):796-803. DOI:10.1097/AOG.0000000000000188 · 4.37 Impact Factor