Influence of oligohydramnios on preterm premature rupture of the membranes at 30 to 36 weeks' gestation.

OBJECTIVE: to evaluate the influence of initial oligohydramnios on the prognosis of women with preterm premature rupture of the membranes (PPROM) at 30 to 36 weeks' gestation. METHODS: the Royal Alexandra Hospital ultrasound database was used to identify singleton pregnancies at 30 to 36 weeks' gestation with an ultrasound performed for confirmed PPROM from January 1992 to December 2006. Records were linked to the electronic provincial delivery record to perform a retrospective cohort study comparing the outcomes of pregnancies with an initial amniotic fluid index (AFI) < 5 cm with the outcomes of pregnancies with an AFI of 5 to 10 cm. Logistic and linear regression were used to analyze the association between binary outcome and explanatory variables. RESULTS: the maternal and perinatal outcomes of 438 pregnancies were analyzed. Univariate analysis suggested statistically significant associations between initial oligohydramnios and decreased latency (P < 0.001), increased histologically proven chorioamnionitis (P = 0.01), neonatal length of stay in hospital (P = 0.002), and NICU (P = 0.003); however, after controlling for confounding variables (gestational age at delivery, parity, presentation, and antenatal antibiotic and corticosteroid administration), only latency remained significant (P = 0.004). No association was found between initial oligohydramnios and any other outcomes assessed, including mode of delivery, postpartum endometritis, maternal length of stay, non-reassuring fetal status, and neonatal morbidity and mortality. CONCLUSION: initial oligohydramnios is associated with decreased latency in singleton pregnancies complicated by PPROM at 30 to 36 weeks' gestation; however, it does not appear to influence maternal or neonatal infectious morbidity, and it may not be useful to determine candidacy for expectant management or intentional delivery.

Outcomes of maternity care services in Alberta, 1999 and 2000: a population-based analysis.

OBJECTIVE: To evaluate the maternal and perinatal outcomes of Alberta's regionalized system of care. In particular, to compare the outcomes of communities with limited or no local intrapartum care with those of regional and tertiary care centres. METHODS: We conducted a population-based retrospective study of all Alberta deliveries in 1999 and 2000. Maternal outcome measures were rates of patient outflow, induction of labour, Caesarean section (CS), and participation in vaginal birth after Caesarean section (VBAC). The perinatal outcome measure was the perinatal loss rate (mortality rate plus stillbirth rate). Rural maternity care programs were categorized as follows: no elective local maternity care (level 0), local maternity care without local CS capabilities (level IA), and local maternity care with local CS capabilities (level IC). RESULTS: Communities offering intrapartum care without local CS capability delivered 22.1% of their maternity population. This proportion increased to 70.1% if the communities had local CS capabilities. Although patient outflow was associated with parity, risk, local services, and distance to an urban centre, there was a large unexplained outflow difference between communities with similar service levels. More limited local maternity care services and higher outflow rates were associated with higher rates of induction of labour. Rates for CS, participation in VBAC, and perinatal loss were not significantly different for different types of maternity care programs other than a lower CS rate for residents in type IA communities compared with other communities (18% vs. 20%). CONCLUSION: The principal consequences of a limited scope of local maternity care services for rural women is an increased rate of induction of labour and, if they live in a community that delivers babies without local CS capability (IA), a lower CS rate. These category IA communities, with patient outflows of 78%, are largely unsuccessful in having women deliver locally, but women from these communities have a lower rate of CS wherever they deliver. The 18 rural Alberta maternity care programs where patient outflow is over 67% may not be sustainable.

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.