Differences in risk factors for incident and recurrent preterm birth: a population-based linkage of 3.5 million births from the CIDACS birth cohort (original) (raw)
Related papers
Risk factors for recurrent preterm delivery
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2004
Objective: To identify risk factors for recurrent preterm delivery among primiparous women with previous preterm delivery. Study design: A retrospective case-control study was designed: 152 primiparous women who delivered preterm (22-36 weeks) were divided into two groups: 81 had a second preterm delivery (study group) and 71 had a second-term delivery (control group). Exclusion criteria were induced preterm delivery, hydramnions and multiple gestations. Results: Comparing second preterm delivery before 34 weeks (n ¼ 36) to the second delivery of the control group, higher rates of hospitalization due to preterm labor were noted in the study versus the control group (52.8% versus 16.9%, P ¼ 0:001). The interval between pregnancies was shorter in the study subgroup, before 34 weeks gestational age, versus the controls (20:1 AE 15:7 months versus 28:9 AE 18:7 months, P ¼ 0:011). Multiple regression analyses, adjusted for confounding variables, found the occurrence of preterm labor and short interval between pregnancies, especially up to 12 months, as independent risk factors for the recurrence of preterm delivery (OR ¼ 4:98; P < 0:001, OR ¼ 5:13; P ¼ 0:007, respectively). Conclusion: When adjusted for confounding variables, short interval between pregnancies is an independent risk factor for recurrent preterm delivery. #
BMC Pregnancy and Childbirth, 2011
Preterm birth (PTB) is a major cause of infant morbidity and mortality, but the relationship between comorbidity and PTB by clinical subtype and severity of gestational age remains poorly understood. We evaluated associations between maternal comorbidities and PTB by clinical subtype and gestational age. We conducted a retrospective cohort study of 1,329,737 singleton births delivered in hospitals in the province of Québec, Canada, 1989-2006. PTB was classified by clinical subtype (medically indicated, preterm premature rupture of membranes (PPROM), spontaneous preterm labour) and gestational age (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 28, 28-31, 32-36 completed weeks). Odds ratios (OR) of PTB by clinical subtype for systemic and localized maternal comorbidities were estimated using polytomous logistic regression, adjusting for maternal age, grand multiparity, and period. Attributable fractions were calculated. PTB rates were higher among mothers with comorbidity (10.9%) compared to those without comorbidity (4.7%). Several comorbidities were associated with greater odds of medically indicated PTB compared with no comorbidity, but only comorbidities localized to the reproductive system were associated with spontaneous PTB. Drug dependence and mental disorders were strongly associated with PPROM and spontaneous PTBs across all gestational ages (OR &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 2.0). At the population level, several major comorbidities (placental abruption, chorioamnionitis, oliogohydramnios, structural abnormality, cervical incompetence) were key contributors to all clinical subtypes of PTB, especially at &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 32 weeks. Major systemic comorbidities (preeclampsia, anemia) were key contributors to PPROM and medically indicated PTBs. The relationship between comorbidity and clinical subtypes of PTB depends on gestational age. Prevention of PPROM and spontaneous PTB may benefit from greater attention to preeclampsia, anemia and comorbidities localized to the reproductive system.
Paediatric and Perinatal Epidemiology, 2010
The prevalence and intractability of preterm birth is known as is its association with reproductive history, but the relationship with sequence of pregnancies is not well studied. The data were from a population-based case-control study, conducted in Victoria, Australia. The study recruited women giving birth between April 2002 and April 2004 from 73 maternity hospitals. Detailed reproductive histories were collected by interview a few weeks after the birth. The cases were 603 women having a singleton birth between 20 and <32 weeks gestation (very preterm births including terminations of pregnancy). The controls were 796 randomly selected women from the population having a singleton birth of at least 37 completed weeks gestation. Unconditional logistic regression was used to assess the association of very preterm birth with sequence of pregnancies defined by their outcome (prior abortion-spontaneous or induced, and prior preterm or term birth) with adjustment for sociodemographic factors. The outcomes of each prior pregnancy, stratified by pregnancy order, and starting with the pregnancy immediately before the index or control pregnancy, were categorised as one of abortion, preterm birth or term birth. We showed that each of these prior pregnancy events was an independent risk of very preterm birth. This finding does not support the hypothesis of a neutralising effect of a term birth after an abortion on the subsequent risk for very preterm birth and is further evidence for the cumulative or increasing risk associated with increasing numbers of prior abortions or preterm births.
Journal of Perinatal Medicine, 2016
To examine the proportion of iatrogenic births among all preterm births over a 26-year period.A registry-based survey of preterm deliveries between 1987 and 2012 analyzed by the onset of labor: spontaneous with intact membranes, preterm premature rupture of membranes (PPROM) or iatrogenic. Stratification into categories by gestation (22 weeks to 27 weeks and 6 days, 28 weeks to 31 weeks and 6 days, 32 weeks to 33 weeks and 6 days, 34 weeks to 36 weeks and 6 days) was performed. Preterm birth rates were analyzed using the Mantel-Haenszel linear-by-linear associationOverall preterm birth rate was 5.9% (31328 deliveries) including 2358 (0.4%) before 28 completed weeks, 3388 (0.6%) between 28 weeks and 31 weeks 6 days, 3970 (0.8%) between 32 weeks and 33 weeks and 6 days, and 21611 (4.1%) between 34 weeks and 36 weeks and 6 days There was an increase in overall preterm birth rate (P<0.001). The rate of iatrogenic preterm births and PPROM increased over time (P<0.001 and P<0.014...
Recurrent preterm birth: data from the study “Birth in Brazil”
Revista de Saúde Pública, 2022
OBJECTIVE Describe and estimate the rate of recurrent preterm birth in Brazil according to the type of delivery, weighted by associated factors. METHODS We obtained data from the national hospital-based study “Birth in Brazil”, conducted in 2011 and 2012, from interviews with 23,894 women. Initially, we used the chi-square test to verify the differences between newborns according to previous prematurity and type of recurrent prematurity. Sequentially, we applied the propensity score method to balance the groups according to the following covariates: maternal age, socio-economic status, smoking during pregnancy, parity, previous cesarean section, previous stillbirth or neonatal death, chronic hypertension and chronic diabetes. Finally, we performed multiple logistic regression to estimate the recorrence. RESULTS We analyzed 6,701 newborns. The rate of recurrence was 42.0%, considering all women with previous prematurity. Among the recurrent premature births, 62.2% were spontaneous an...
A case-control study of preterm delivery risk factors according to clinical subtypes and severity
Journal of Obstetrics and Gynaecology Research, 2010
Aims-To examine risk factors of preterm delivery (PTD) among Thai women. Methods-Our case-control study included 467 term controls and 467 PTD cases. PTD was studied in aggregate and in subgroups (i.e., spontaneous preterm labor and delivery [SPTD], preterm premature rupture of membrane [PPROM], medically indicated preterm delivery [MIPTD], moderate preterm delivery [32-36 weeks], and very preterm delivery [<32 weeks]). We used multivariable logistic regression procedures to estimate odds ratio (OR) and 95% confidence intervals (CI) of potential PTD risk factors. Results-Advanced maternal age (≥35 years) was associated with a 2.27-fold increased PTD risk overall (95%CI: 1.40, 3.68); and with a 3.79-fold increased risk of MIPTD (95%CI: 1.89, 7.59). Young maternal age (<20 years) was associated with a 2.07-fold increased risk of SPTD (95%CI: 1.19, 3.61). Prior history of PTD was associated with a 3.64-fold increased PTD risk overall (95%CI: 1.87, 7.09), and with a 5.69-fold increased risk of MIPTD (95%CI: 2.44, 13.24). No prenatal care was associated with all PTD subtypes. Lean women (BMI<18.5 kg/m 2), compared with normal weight women (18.5-24.9 kg/m 2), had a 1.70-fold increased risk of PTD (95%CI: 1.21, 2.39). Risk of SPTD (OR=2.16, 95%CI: 1.44, 3.24) and very PTD (OR=2.45, 95%CI: 1.35, 4.45) were also elevated in lean women. Conclusions-Maternal age, pre-pregnancy body mass index, prior history of PTD and no utilization of prenatal care were covariates identified in this study as risk factors for PTD. Our findings also suggest heterogeneity in risk factors for clinical subtypes of PTD.
The preterm prediction study: Risk factors for indicated preterm births
American Journal of Obstetrics and Gynecology, 1998
OBJECTIVE: Preterm births occur for many different reasons. Most efforts to identify risk factors for preterm births either ignore cause and consider preterm births as a single entity or examine risk factors for spontaneous preterm births. We performed this study to examine risk factors for indicated preterm births, which constitute more than one quarter of all preterm births. STUDY DESIGN: The study included 2929 women evaluated at 24 weeks' gestation at 10 centers. Information was gathered about demographic factors, socioeconomic status, home and work environments, drug and alcohol use, and medical history. In addition vaginal samples were evaluated for fetal fibronectin and bacterial vaginosis and cervical length was measured by transvaginal ultrasonography. Associations with indicated preterm birth were evaluated by univariate tests and by multivariable analysis with logistic regression. RESULTS: Of the women studied at 24 weeks' gestation 15.3% were delivered of their infants at <37 weeks' gestation. Of these deliveries, 27.7% were indicated preterm births. Risk factors in the final multivariable model were, in order of decreasing odds ratios, müllerian duct abnormality (odds ratio 7.02), proteinuria at <24 weeks' gestation (odds ratio 5.85), history of chronic hypertension (odds ratio 4.06), history of previous indicated preterm birth (odds ratio 2.79), history of lung disease (odds ratio 2.52), previous spontaneous preterm birth (odds ratio 2.45), age >30 years (odds ratio 2.42), black ethnicity (odds ratio 1.56), and working during pregnancy (odds ratio 1.49). Alcohol use in pregnancy was actually associated with a lower risk of indicated preterm birth (odds ratio 0.35). CONCLUSION: The risk factors found in this analysis tend to be different from those associated with spontaneous preterm birth. (Am J Obstet Gynecol 1998;178:562-7) Don't miss a single issue of the journal! To ensure prompt service when you change your address, please photocopy and complete the form below.