Short interpregnancy intervals and associated risk of preterm birth in Asians and Pacific Islanders

Birth spacing and risk of adverse pregnancy and birth outcomes: A systematic review and dose-response meta-analysis

INTRODUCTION

The association between extreme birth spacing and adverse outcomes is controversial, and available evidence is fragmented into different classifications of birth spacing.

MATERIAL AND METHODS

We conducted a systematic review of observational studies to evaluate the association between birth spacing (i.e., interpregnancy interval and interoutcome interval) and adverse outcomes (i.e., pregnancy complications, adverse birth outcomes). Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using a random-effects model, and the dose-response relationships were evaluated using generalized least squares trend estimation.

RESULTS

A total of 129 studies involving 46 874 843 pregnancies were included. In the general population, compared with an interpregnancy interval of 18-23 months, extreme intervals (<6 months and ≥ 60 months) were associated with an increased risk of adverse outcomes, including preterm birth, small for gestational age, low birthweight, fetal death, birth defects, early neonatal death, and premature rupture of fetal membranes (pooled OR range: 1.08-1.56; p < 0.05). The dose-response analyses further confirmed these J-shaped relationships (pnon-linear  < 0.001-0.009). Long interpregnancy interval was only associated with an increased risk of preeclampsia and gestational diabetes (pnon-linear  < 0.005 and pnon-linear  < 0.001, respectively). Similar associations were observed between interoutcome interval and risk of low birthweight and preterm birth (pnon-linear  < 0.001). Moreover, interoutcome interval of ≥60 months was associated with an increased risk of cesarean delivery (pooled OR 1.72, 95% CI 1.04-2.83). For pregnancies following preterm births, an interpregnancy interval of 9 months was not associated with an increased risk of preterm birth, according to dose-response analyses (pnon-linear  = 0.008). Based on limited evidence, we did not observe significant associations between interpregnancy interval or interoutcome interval after pregnancy losses and risk of small for gestational age, fetal death, miscarriage, or preeclampsia (pooled OR range: 0.76-1.21; p > 0.05).

CONCLUSIONS

Extreme birth spacing has extensive adverse effects on maternal and infant health. In the general population, interpregnancy interval of 18-23 months may be associated with potential benefits for both mothers and infants. For women with previous preterm birth, the optimal birth spacing may be 9 months.

Association between inter-pregnancy interval and risk of adverse birth outcomes in subsequent pregnancy: A retrospective study from Jordan

BACKGROUND

Adverse birth outcomes, such as preterm birth and low birth weight (LBW), are leading causes of neonatal morbidity and mortality. In this study, we aimed to estimate the association between inter-pregnancy interval (IPI) and the risks of adverse birth outcomes in a subsequent pregnancy.

METHODS

We conducted a retrospective analysis involving 630 mothers who delivered a singleton live infant at a leading tertiary hospital in northern Jordan from March to August 2021. Outcome variables were preterm birth (<37 weeks of gestation) and LBW (<2.5 kg). Using multivariable logistic regression, the association between IPI and these two adverse birth outcomes was investigated.

RESULTS

The rates of preterm birth and LBW were 12.4% and 16.8%, respectively. Compared with an optimal IPI (24-36 months), a short IPI (<24 months) was positively associated with preterm birth (aOR: 4.09; 95% CI: 1.48-6.55) and LBW (aOR: 3.58; 95% CI: 1.57-5.15). Infants conceived after a long IPI (≥ 60 months) had increased odds of preterm birth (aOR: 3.78; 95% CI: 1.12-5.78) and LBW (aOR: 2.65; 95% CI: 1.67-4.03). Preterm delivery was also significantly associated with the mother's age (aOR: 1.10; 95% CI: 1.04-1.17), history of multiple cesarean births (aOR: 2.67; 95% CI: 1.14-4.29), prolonged rupture of membranes (aOR: 2.46; 95% CI: 1.10-5.52), and perinatal death (aOR: 3.42; 95% CI: 1.10-5.49). A mother's history of prior LBW (aOR: 4.39; 95% CI: 1.08-6.80), hypertensive disorders (aOR: 1.95; 95% CI: 1.03-3.89), and multiple cesarean births (aOR: 4.35; 95% CI: 2.10-6.99) was associated with LBW.

CONCLUSIONS

Both short and long IPIs were related to preterm delivery and LBW. Optimal birth spacing is recommended to improve birth outcomes and must be considered when designing effective family planning programs.

Preterm birth among Pacific Islanders in the United States and the US-affiliated Pacific Islands: A systematic review and meta-analysis

OBJECTIVE

To better understand the epidemiology of preterm birth among Pacific Islanders in the United States and the US-Affiliated Pacific Islands.

METHODS

Systematic searches of MEDLINE, Embase, CINAHL, PsycINFO, two nonindexed regional journals, and gray literature were conducted and finalized in September 2021. Observational studies published since January 2010 that documented preterm birth outcomes among Pacific Islanders in the United States and the US-Affiliated Pacific Islands were eligible for inclusion. Outcomes of interest included preterm birth prevalence, risk compared with white women, and risk factors for preterm birth among Pacific Islanders.

RESULTS

Fourteen of the 3183 screened articles were included in meta-analyses. Random-effects models were used for pooled estimates with 95% confidence intervals. The pooled prevalence of preterm birth among Pacific Islanders was 11.2%, 95% CI: 9.3%-13.6%. Marshallese women had the highest pooled prevalence (20.7%, 95% CI 18.6%-23.0%) among Pacific Islander subgroups. Compared with white women, Pacific Islander women had higher odds of experiencing preterm birth (OR = 1.40, 95% CI: 1.28-1.53). Four risk factors for preterm birth could be explored with the data available: hypertension, diabetes, smoking, and pre-pregnancy body mass index; hypertension and diabetes significantly increased the odds of preterm birth.

CONCLUSIONS

Existing literature suggests that United States Pacific Islanders were more likely to experience preterm birth than white women, although the pooled prevalence varied by Pacific Islander subgroup. Data support the need for disaggregation of Pacific Islanders in future research and argue for examination of subgroup-specific outcomes to address perinatal health disparities.

Short interpregnancy interval can lead to adverse pregnancy outcomes: A meta-analysis

BACKGROUND

The evidence of some previous papers was insufficient in studying the causal association between interpregnancy interval (IPI) and adverse pregnancy outcomes. In addition, more literature have been updated worldwide during the last 10 years.

METHODS

English and Chinese articles published from January 1980 to August 2021 in the databases of PubMed, Cochrane Library, Ovid, Embase, China Biology Medicine disc (CBM), and China National Knowledge Infrastructure (CNKI) were searched. Then following the inclusion and exclusion criteria, we screened the articles. Utilizing the Newcastle-Ottawa Scale (NOS), we evaluated the quality of the included articles. The literature information extraction table was set up in Excel, and the meta-analysis was performed with Stata 16.0 software (Texas, USA).

RESULTS

A total of 41 articles were included in the meta-analysis, and NOS scores were four to eight. The short IPI after delivery was the risk factor of preterm birth (pooled odds ratio 1.49, 95% confidence interval 1.42-1.57), very preterm birth (pooled OR: 1.82, 95% CI: 1.55-2.14), low birth weight (pooled OR: 1.33, 95% CI: 1.24-1.43), and small for gestational age (pooled OR: 1.14, 95% CI: 1.07-1.21), offspring death (pooled OR: 1.60, 95% CI: 1.51-1.69), NICU (pooled OR: 1.26, 95% CI: 1.01-1.57), and congenital abnormality (pooled OR: 1.10, 95% CI: 1.05-1.16), while was not the risk factor of gestational hypertension (pooled OR: 0.95, 95% CI: 0.93-0.98) or gestational diabetes (pooled OR: 1.06, 95% CI: 0.93-1.20).

CONCLUSION

Short IPI (IPI < 6 months) can lead to adverse perinatal outcomes, while it is not a risk factor for gestational diabetes and gestational hypertension. Therefore, more high-quality studies covering more comprehensive indicators of maternal and perinatal pregnancy outcomes are needed to ameliorate the pregnancy policy for women of childbearing age.

Pregnancy health and perinatal outcomes among Pacific Islander women in the United States and US Affiliated Pacific Islands: Protocol for a scoping review

This scoping review examines the literature on pregnancy and perinatal outcomes among Pacific Islander women in the United States (U.S.) and U.S.-affiliated Pacific Islands. Our aim was to identify research that disaggregated Pacific Islanders from other population groups. We conducted a systematic search of MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCO), and PsycINFO (Ovid) databases and a hand-search of grey literature. Forty-eight articles published between January 2010 and June 2020 were included. The majority of studies were conducted in Hawaii and utilized clinical record data. Infant outcomes were more commonly reported than maternal outcomes. We highlighted several limitations of the existing literature that included aggregation of Pacific Islanders with Asian American and other ethnic groups; limited comparison between Pacific Islander sub-groups; inadequate definitions of the nationality and ethnic composition of Pacific Islander groups; a lack of hypothesis-driven primary data collection and clinical trials; and underrepresentation of Pacific Islanders in population-based studies. Researchers should address these limitations to improve pregnancy and perinatal outcomes among Pacific Islanders, who comprise the second fastest growing ethnic minority in the U.S.