Interpregnancy Interval and Congenital Anomalies: A Record-Linkage Study Using the Manitoba Population Research Data Repository.

Congenital anomalies are a serious public health issue, and relatively few modifiable risk factors have been identified. Our objective was to investigate one such potential risk factor, the interpregnancy interval (IPI). We conducted a secondary analysis of data housed at the Manitoba Centre for Health Policy. In-hospital live births and stillbirths of at least 20 weeks' gestation were identified, and consecutive births to the same mother were grouped into sibling pairs to calculate the IPI for the younger siblings of each pair. Logistic regression models were fit to examine the association between the IPI and any congenital anomaly, as well as CNS and chromosomal anomalies, while controlling for potentially confounding sociodemographic and clinical factors. Among 172 909 live births and stillbirths, the IPI was not significantly associated with congenital anomalies overall or with chromosomal anomalies. Short IPIs were associated with significantly increased odds of CNS anomalies relative to IPIs of 18-23 months (adjusted OR [aOR] for IPIs <6 months 2.15; 95% CI 1.48-3.12), whereas the aOR for IPIs ≥60 months was elevated but not statistically significant (aOR 1.50; 95% CI 0.96-2.34). In a sensitivity analysis in which the cohort was restricted to births from 2003 onwards (which yielded more complete data on health-related behaviours), the observed effect for IPIs shorter than 6 months and CNS anomalies was attenuated and no longer significant, but it remained elevated (aOR 1.65; 95% CI 0.85-3.24). The findings for CNS anomalies warrant further investigation.

Coo H ，Brownell MD ，Ruth C ，Flavin M ，Au W ，Day AG ... -  《-》

Interpregnancy Interval and Adverse Perinatal Outcomes: A Record-Linkage Study Using the Manitoba Population Research Data Repository.

To examine the association between the interpregnancy interval (IPI) and preterm birth, low birth weight, and SGA birth in a developed country with universal health coverage. We conducted a secondary analysis of data housed at the Manitoba Centre for Health Policy. All live births in Manitoba hospitals over a 29-year period were identified and consecutive births to the same mother were grouped into sibling pairs to calculate the IPI for the younger siblings. Logistic regression models were fit to examine the association between the IPI and adverse perinatal outcomes, adjusted for potentially confounding sociodemographic and clinical factors. In a cohort of more than 171 000 births and relative to IPIs of 18 to 23 months, IPIs shorter than 12 and longer than 23 months were associated with significantly increased odds of preterm birth overall and both medically indicated and spontaneous preterm births, low birth weight, and SGA birth. The strongest association observed was for intervals shorter than 6 months and spontaneous preterm birth (adjusted OR 1.83, 95% CI 1.65-2.03). When the outcome was modelled as GA categories, the strongest association observed was for intervals shorter than 6 months and early preterm birth (<34 weeks' GA; adjusted OR 2.47, 95% CI 2.07-2.94). If the associations observed between the IPI and adverse perinatal outcomes in this large, population-based cohort are causal, birth spacing could form an important target of public health messaging in Canada.

Coo H ，Brownell MD ，Ruth C ，Flavin M ，Au W ，Day AG ... -  《-》

Interpregnancy Intervals in a Contemporary Manitoba Cohort: Prevalence of So-Called Suboptimal Intervals and Associated Maternal Characteristics.

Short and long interpregnancy intervals (IPIs) have been associated with various adverse outcomes, and a 2016 American College of Obstetricians and Gynecologists' Committee Opinion recommends an optimal IPI of 18 months to 5 years. Descriptive data on the IPI in Canada are lacking. The objective of this study was to examine IPIs in a Manitoba cohort. The study analyzed a subset of records from a larger dataset used to examine the IPI and adverse perinatal outcomes. For that study, Manitoba's Hospital Abstracts data were searched to identify births from 1985 to 2014. Each two consecutive live births to the same mother formed a sibling pair. The IPI was calculated as the interval between the two siblings' births, minus the younger sibling's GA. Information on maternal characteristics was extracted from various datasets housed in the Manitoba Population Research Data Repository. The current analysis examined second and higher-order births between 2010 and 2014. The proportion of suboptimal IPIs was determined and IPIs were cross-tabulated with birth year and maternal subgroups. More than half of pregnancies were conceived following a suboptimal interval. IPIs of less than 6 months - which have been associated with the highest risk of adverse outcomes - were more prevalent among certain subgroups. These included younger women as well as women who received inadequate prenatal care, smoked or drank alcohol during pregnancy, were low income, or did not graduate from high school. Suboptimal IPIs were common in this Manitoba cohort. Stakeholders should consider whether greater efforts to promote appropriate birth spacing are warranted.

Coo H ，Brownell MD ，Ruth C ，Flavin M ，Au W ，Day AG ... -  《-》

Interpregnancy interval after live birth or pregnancy termination and estimated risk of preterm birth: a retrospective cohort study.

We assessed whether interpregnancy interval (IPI) length after live birth and after pregnancy termination was associated with preterm birth (PTB). Multiyear birth cohort. Fetal death, birth and infant death certificates in California merged with Office of Statewide Health Planning and Development. One million California live births (2007-10) after live birth and after pregnancy termination. Logistic regression was used to estimate odds ratios (ORs) of PTB of 20-36 weeks of gestation and its subcategories for IPIs after a live birth and after a pregnancy termination. We used conditional logistic regression (two IPIs/mother) to investigate associations within mothers. PTB relative to gestations of ≥ 37 weeks. Analyses included 971 211 women with IPI after live birth, and 138 405 women with IPI after pregnancy termination with 30.6% and 74.6% having intervals of <18 months, respectively. IPIs of <6 months or 6-11 months after live birth showed increased odds of PTB adjusted ORs for PTB of 1.71 (95% CI 1.65-1.78) and 1.20 (95% CI 1.16-1.24), respectively compared with intervals of 18-23 months. An IPI >36 months (versus 18-23 months) was associated with increased odds for PTB. Short IPI after pregnancy termination showed a decreased OR of 0.87 (95% CI 0.81-0.94). The within-mother analysis showed the association of increased odds of PTB for short IPI, but not for long IPI. Women with IPI <1 or >3 years after a live birth were at increased odds of PTB-an important group for intervention to reduce PTB. Short IPI after pregnancy termination was associated with reduced odds for PTB and needs to be further explored. Short and long IPI after live birth, but not after pregnancy termination, showed increased odds for PTB.

Shachar BZ ，Mayo JA ，Lyell DJ ，Baer RJ ，Jeliffe-Pawlowski LL ，Stevenson DK ，Shaw GM ... -  《-》

Interpregnancy interval and birth defects.

Interpregnancy interval is a risk factor for various adverse birth outcomes including birth defects. We investigated the relationship between interpregnancy interval and birth defects. We conducted a retrospective cohort study using linked data from Nevada Birth Outcomes Monitoring System and birth certificate data for 124,341 singleton live births, of which 4641 infants had 7192 birth defects, among Nevada resident women between 2006 and 2011. We used logistic regression to assess factors independently associated with birth defects. Women who had an interpregnancy interval of 36 months or more, adjusted odds ratio (AOR) = 1.16, 95% confidence interval [CI], 1.01-1.33, were more likely to have an infant with a birth defect compared with women with an interpregnancy interval of 18 to 23 months. Other independent risk factors for birth defects included male infants, AOR = 1.34, 95% CI, 1.26-1.42; maternal age (30-34 years) and advanced maternal age (35 years and older), AOR = 1.10, 95% CI, 1.01-1.19 and AOR = 1.29, 95% CI, 1.18-1.42, respectively; being a Black woman, AOR = 1.46, 95% CI, 1.32-1.61; three and four or more previous births, AOR = 1.12, 95% CI, 1.02-1.23 and AOR = 1.24, 95% CI, 1.11-1.38, respectively; smoking, AOR = 1.23, 95% CI, 1.10-1.38; and prescription drug use, AOR = 1.14, 95% CI, 1.07-1.21. A long interpregnancy interval is an independent risk factor for birth defects. It may be helpful for maternal and child health programs and health care providers to highlight the deleterious effects of a long interpregnancy interval.

Mburia-Mwalili A ，Yang W 《-》