Effect of interpregnancy interval on adverse perinatal outcomes — a national study

doi:10.1016/j.contraception.2009.06.006

Contraception

Volume 80, Issue 6, December 2009, Pages 512-518

https://doi.org/10.1016/j.contraception.2009.06.006 Get rights and content

Abstract

Background

The interpregnancy interval (IPI) has been reported to influence the outcome of pregnancy and birth. We performed a national study in Israel to determine the impact of IPI on multiple adverse perinatal outcomes.

Study Design

This longitudinal cohort study used birth certificates of siblings born to the same biological mother, with at least one previous birth and a subsequent singleton pregnancy. Adverse pregnancy outcomes included preterm delivery, very preterm birth, small for gestational age (SGA), very SGA (VSGA), early neonatal death and major congenital malformations. Multivariate logistic regression was performed for each outcome.

Results

The study included 440,838 of a total of 846,845 reported live births in Israel over 5 years; excluded were primiparas (32%), multifetal births (4.9%) and those with incomplete data (10.9%). For IPIs shorter than 6 months, there were significantly increased risks for preterm birth (OR=1.23), SGA (OR=1.14), VSGA (OR=1.15), early neonatal death (OR=1.62) and congenital malformations (OR=1.14). Intervals of 60 months or longer had higher risks for preterm birth (OR=1.39) and VSGA (OR=1.16).

Conclusion

Optimal IPI recommendation of >11 months is an accessible and low-cost means to improve multiple adverse perinatal outcomes.

Introduction

The interpregnancy interval (IPI) has been reported to influence the outcome of pregnancy and birth: short interpregancy intervals have been linked to increased risk for preterm birth, low birth weight, small for gestational age (SGA), labor dystocia and maternal morbidity and mortality [1], [2], [3]. The increased risk of adverse pregnancy outcomes due to short IPI has been attributed to a number of mechanisms including maternal nutritional status and folate depletion [4], hormonal imbalance in the postpartum period and lactation stress [5], [6]. The various putative mechanisms suggested to explain this association, the multifaceted nature of pregnancy outcomes [2], [7] and racial and socioeconomic heterogenicity of sampled populations [8], [9] have undoubtedly led to several as yet unproven hypotheses [10]. Therefore, we designed a population-based cohort study to investigate the impact of the IPI on adverse perinatal outcomes, in the hope of both ascertaining if indeed IPI impacts neonatal and maternal outcome and assessing possible mechanisms.

Section snippets

Materials and methods

Data for this study were prospectively obtained through longitudinal collection of birth certificate records for singletons born in Israel to the same biological mother in the years 2000–2005 and who had a previous live birth in Israel between the years 1993 and 2005. The IPI was computed as the interval between two consecutive deliveries minus the gestational age of the second infant, that is, between live births ending with the subsequent conception. All pairs of live birth intervals are

Results

During the years 2000–2005, there were 846,845 live births in Israel. We excluded 271,545 primiparous mothers, 41,974 multifetal pregnancies and 92,488 births with missing information. These resulted in a study population of 440,838 live births out of a potential cohort of 533,206 (83%).

Fig. 1 shows the percentage of preterm and very preterm births as a function of the IPI. There is a significant increase in the rates when the interval is less than 6 months. Fig. 2 shows the percentage of

Discussion

This national study is the first attempt to determine the impact of IPI on several adverse perinatal outcomes. We found that very short IPI and prolonged IPI are related to increased risk of preterm birth, low birth weight, early neonatal death and major congenital malformations. The linkage between short IPI and preterm delivery has been noted in cohorts of European, American and Asian populations [7], [8], [9], [11], [12], [13]. The IPI per se was designated as an independent marker for SGA

Acknowledgment

The authors would like to acknowledge Prof. Arthur I Eidelman, Former Chairman of the Department of Pediatrics, and Dr. Deborah Elstein of the Gaucher Clinic, Shaare Zedek Medical Center, for reviewing the manuscript.

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During the study period, 2,079 women had an index singleton delivery followed by a twin gestation in their next pregnancy recorded at our medical center; 116 (5.9 %) had a history of short IPI, and 1,057 (50.8 %) had a history of optimal IPI. Women with a history of short IPI had higher rates of preterm labor < 37 weeks and < 34 weeks, NICU admissions and prolonged hospital stay of the first and second fetuses, mechanical ventilation of the first fetus, 1 and 5 Minute Apgar score lower than 7 of the second fetus and lower rates of elective cesarean delivery. An adjusted multivariate analysis showed that a history of short IPI was not an independent risk factor for preterm birth either < 34 weeks or < 37 weeks or for composite adverse neonatal outcome of the first and second twin.
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Original research articleEffect of interpregnancy interval on adverse perinatal outcomes — a national study

Abstract

Background

Study Design

Results

Conclusion

Introduction

Section snippets

Materials and methods

Results

Discussion

Acknowledgment

Maternal morbidity and mortality associated with interpregnancy interval: cross sectional study

BMJ

Interpregnancy interval and risk of preterm labor

Am J Epidemiol

Labor dystocia and its association with interpregnancy interval

Am J Obstet Gynecol

A new definition of maternal depletion syndrome

Am J Public Health

Low birth weight and preterm birth after short interpregnancy intervals

Am J Obstet Gynecol

The relationship of interpregnancy interval to the risk of preterm births to black and white women

Int J Epidemiol

The impact of interpregnancy interval and previous preterm birth on the subsequent risk of preterm birth

J Soc Gynecol Investig

Interpregnancy interval and the risk of premature infants

Obstet Gynecol

Effect of interpregnancy interval on birth outcomes: findings from three recent US studies

Int J Gynaecol Obstet

The influence of interpregnancy interval on the subsequent risk of stillbirth and early neonatal death

Obstet Gynecol

Effect of the interpregnancy interval after an abortion on maternal and perinatal health in Latin America

Int J Gynaecol Obstet

Short interpregnancy intervals and unfavourable pregnancy outcome: role of folate depletion

Lancet

Short interpregnancy interval and risk of spontaneous preterm delivery

Eur J Obstet Gynecol Reprod Biol

Short interpregnancy interval: a risk factor for low birthweight

Am J Perinatol

Short interpregnancy interval and the risk of low birthweight

Am J Public Health

Original research article
Effect of interpregnancy interval on adverse perinatal outcomes — a national study