Fear of childbirth prolongs interpregnancy interval: A nationwide register-based quantile logistic regression analysis

Introduction

It is not well studied how fear of childbirth (FOC) influences the interpregnancy interval (IPI). Thus, we aimed to analyze the association between FOC and the length of the IPI.

Methods

All women having their first and second pregnancies during the study period (2004-2018) were gathered from the Finnish Medical Birth Register. A logistic regression model was used to assess the association between the FOC and subsequent length of the IPI. The length of the IPI was assessed separately for women with FOC in the first pregnancy, and for women who developed the FOC in the second pregnancy. IPIs with a length in the lower quartal were considered short IPIs, and length in the upper quartal as long IPIs. Adjusted odds ratios (aOR) with 95% CIs were compared between the groups.

Results

A total of 52 709 women with short IPI (<1.05 years), 105 604 women with normal IPI, and 52 889 women with long IPI (>2.57 years) were included. A total of 3606 women had FOC in the first pregnancy, and a total of 11 473 had their first FOC diagnosis in the second pregnancy. Women with FOC in the first pregnancy had lower odds for short IPI (aOR 0.88, CI 0.81-0.95) and higher odds for long IPI (aOR 1.30, CI 1.21-1.40). Women with the first FOC diagnosis in the second pregnancy had higher odds for long IPI (aOR 1.68, CI 1.61-1.75), When only vaginal deliveries in the first pregnancy were included, women with FOC in the second pregnancy had lower odds for long IPI (aOR 0.71, CI 0.66-0.75) and higher odds for long IPI (aOR 1.52, CI 1.41-1.62), when only cesarean section was included.

Conclusion

The main finding of this study was that women with FOC had notably higher odds for long IPI. The etiologic and background factors behind FOC should be better recognized and prevented, and FOC should not only be considered as a complicating factor for pregnancy and delivery but also a factor that strongly affects the desire of women to get pregnant again.

Association between interpregnancy interval and risk of autism spectrum disorder: a systematic review and Bayesian network meta-analysis

Although the risk of autism spectrum disorder (ASD) has been reported to be associated with interpregnancy intervals (IPIs), their association remains debatable due to inconsistent findings in existing studies. Therefore, the present study aimed to explore their association. PubMed, Embase, Web of Science, and the Cochrane Library were systematically retrieved up to May 25, 2022. An updated search was performed on May 25, 2023, to encompass recent studies. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Our primary outcome measures were expressed as adjusted odds ratios (ORs). Given various control measures for IPI and diverse IPI thresholds in the included studies, a Bayesian network meta-analysis was performed. Eight studies were included, involving 24,865 children with ASD and 2,890,289 children without ASD. Compared to an IPI of 24 to 35 months, various IPIs were significantly associated with a higher risk of ASD (IPIs < 6 months: OR = 1.63, 95% CI 1.53-1.74, n = 5; IPIs of 6-11 months: OR = 1.50, 95% CI 1.42-1.59, n = 4; IPIs of 12-23 months: OR = 1.19, 95% CI 1.12-1.23, n = 10; IPIs of 36-59 months: OR = 0.96, 95% CI 0.94-0.99, n = 2; IPIs of 60-119 months: OR = 1.15, 95% CI 1.10-1.20, n = 4; IPIs > 120 months: OR = 1.57, 95% CI 1.43-1.72, n = 4). After adjusting confounding variables, our analysis delineated a U-shaped restricted cubic spline curve, underscoring that both substantially short (< 24 months) and excessively long IPIs (> 72 months) are significantly correlated with an increased risk of ASD.  Conclusion: Our analysis indicates that both shorter and longer IPIs might predispose children to a higher risk of ASD. Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months. What is Known: • An association between autism spectrum disorder (ASD) and interpregnancy intervals (IPIs) has been speculated in some reports. • This association remains debatable due to inconsistent findings in available studies. What is New: • Our study delineated a U-shaped restricted cubic spline curve, suggesting that both shorter and longer IPIs predispose children to a higher risk of ASD. • Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months.

Association of interpregnancy interval with adverse pregnancy outcomes according to the outcomes of the preceding pregnancy: a longitudinal study with 4.7 million live births from Brazil

Background

Earlier studies have proposed a link between the Interpregnancy Interval (IPI) and unfavorable birth outcomes. However, it remains unclear if the outcomes of previous births could affect this relationship. We aimed to investigate whether the occurrence of adverse outcomes-small for gestational age (SGA), preterm birth (PTB), and low birth weight (LBW)-at the immediately preceding pregnancy could alter the association between IPI and the same outcomes at the subsequent pregnancy.

Methods

We used a population-based linked cohort from Brazil (2001-2015). IPI was measured as the difference, in months, between the preceding birth and subsequent conception. Outcomes included SGA (<10th birthweight percentile for gestational age and sex), LBW (<2500 g), and PTB (gestational age <37 weeks). We calculated risk ratios (RRs), using the IPI of 18-22 months as the reference IPI category, we also stratified by the number of adverse birth outcomes at the preceding pregnancy.

Findings

Among 4,788,279 births from 3,804,152 mothers, absolute risks for subsequent SGA, PTB, and LBW were higher for women with more adverse outcomes in the preceding delivery. The RR of SGA and LBW for IPIs <6 months were greater for women without previous adverse outcomes (SGA: 1.44 [95% Confidence Interval (CI): 1.41-1.46]; LBW: 1.49 [1.45-1.52]) compared to those with three previous adverse outcomes (SGA: 1.20 [1.10-1.29]; LBW: 1.24 [1.15-1.33]). IPIs ≥120 months were associated with greater increases in risk for LBW and PTB among women without previous birth outcomes (LBW: 1.59; [1.53-1.65]; PTB: 2.45 [2.39-2.52]) compared to women with three adverse outcomes at the index birth (LBW: 0.92 [0.78-1.06]; PTB: 1.66 [1.44-1.88]).

Interpretation

Our study suggests that women with prior adverse outcomes may have higher risks for adverse birth outcomes in subsequent pregnancies. However, risk changes due to differences in IPI length seem to have a lesser impact compared to women without a prior event. Considering maternal obstetric history is essential in birth spacing counseling.

Funding

Wellcome Trust225925/Z/22/Z.

Interpregnancy interval and early infant neurodevelopment: the role of maternal-fetal glucose metabolism

BACKGROUND

Interpregnancy interval (IPI) is associated with a variety of adverse maternal and infant outcomes. However, reports of its associations with early infant neurodevelopment are limited and the mechanisms of this association have not been elucidated. Maternal-fetal glucose metabolism has been shown to be associated with infant neurodevelopmental. The objective of this study was to determine whether this metabolism plays a role in the relationship between IPI and neurodevelopment.

METHODS

This prospective birth cohort study included 2599 mother-infant pairs. The IPI was calculated by subtracting the gestational age of the current pregnancy from the interval at the end of the previous pregnancy. Neurodevelopmental outcomes at 12 months in infants were assessed by the Ages and Stages Questionnaire Edition 3 (ASQ-3). Maternal fasting venous blood was collected at 24-28 weeks and cord blood was collected at delivery. The association between IPI and neurodevelopment was determined by logistic regression. Mediation and sensitivity analyses were also conducted.

RESULTS

In our cohort, 14.0% had an IPI < 12 months. IPI < 12 months increased the failure of the communication domain, fine motor domain, and personal social domain of the ASQ (relative risks (RRs) with 95% confidence interval (CI): 1.73 [1.11,2.70]; 1.73 [1.10,2.72]; 1.51 [1.00,2.29]). Maternal homeostasis model assessment of insulin resistance (HOMA-IR) and cord blood C-peptide was significantly associated with failure in the communication domain [RRs with 95% CI: 1.15 (1.02, 1.31); 2.15 (1.26, 3.67)]. The proportion of the association between IPI and failure of the communication domain risk mediated by maternal HOMA-IR and cord blood C-peptide was 14.4%.

CONCLUSIONS

IPI < 12 months was associated with failing the communication domain in infants. Maternal-fetal glucose metabolism abnormality may partially explain the risk of neurodevelopmental delay caused by short IPI.

Interactions between long interpregnancy interval and advanced maternal age on neonatal outcomes

BACKGROUND

After the implementation of the universal two-child policy in China, it was more frequent to have long interpregnancy intervals (IPIs) and advanced maternal age. However, the interactions between long IPIs and advanced maternal age on neonatal outcomes are unknown.

METHODS

The study subjects of this historical cohort study were multiparas with singleton live births between October 1st, 2015, and October 31st, 2020. IPI was defined as the interval between delivery and conception of the subsequent pregnancy. Logistic regression models were used to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of the risks of preterm birth (PTB), low birth weight (LBW), small for gestation age, and 1-min Apgar score ≤ 7 in different IPI groups. Relative excess risk due to interaction (RERI) was used to evaluate the additive interaction between long IPIs and advanced maternal age.

RESULTS

Compared with the 24 ≤ IPI ≤ 59 months group, the long IPI group (IPI ≥ 60 months) was associated with a higher risk of PTB (aOR, 1.27; 95% CI: 1.07-1.50), LBW (aOR, 1.32; 95% CI 1.08-1.61), and one-minute Apgar score ≤ 7 (aOR, 1.46; 95% CI 1.07-1.98). Negative additive interactions (all RERIs < 0) existed between long IPIs and advanced maternal age for these neonatal outcomes. Meanwhile, IPI < 12 months was also associated with PTB (aOR, 1.51; 95% CI 1.13-2.01), LBW (aOR, 1.50; 95% CI 1.09-2.07), and 1-min Apgar score ≤ 7 (aOR, 1.93; 95% CI 1.23-3.04).

CONCLUSIONS

Both short and long IPIs are associated with an increased risk of adverse neonatal outcomes. Appropriate IPI should be recommended to women planning to become pregnant again. In addition, better antenatal care might be taken to balance the inferiority of advanced maternal age and to improve neonatal outcomes.

Effects of Short Interpregnancy Intervals on Adverse Pregnancy Outcomes - Haidian District, Beijing Municipality, China, 2017-2019

What is already known about this topic?

Interpregnancy intervals (IPIs) that are either excessively long or short have been linked with an elevated risk of adverse perinatal outcomes. Presently, no pertinent guidelines have been established in China to provide clear direction with regard to optimal IPI.

What is added by this report?

A brief interpregnancy interval may elevate the risk of miscarriage, postpartum hemorrhage, and fetal distress among expectant women.

What are the implications for public health practice?

These results could inform prenatal consultations, guiding pregnant women towards an ideal interpregnancy interval of no less than 24 months.

Postpartum long-acting reversible contraception among privately insured: U.S. National analysis 2007-2016, by term and preterm birth

OBJECTIVES

To investigate postpartum long-acting reversible contraception (LARC) use among privately insured women, with specific consideration of use after preterm delivery.

STUDY DESIGN

We used the national IBM MarketScan Commercial Database to identify singleton deliveries from 2007 to 2016, spontaneous preterm birth, and follow-up ≤12 weeks postpartum. We assessed ≤12-week postpartum LARC placement overall and after spontaneous preterm deliveries, across study years. We examined timing of placement, rates of postpartum follow-up, and state-level variation in postpartum LARC.

RESULTS

Among 3,132,107 singleton deliveries, 6.6% were spontaneous preterm. Over the time period, total postpartum LARC use increased 4.8% to 11.7% for intrauterine devices (IUDs), 0.2% to 2.4% for implants. In 2016, those who experienced a spontaneous preterm birth were less likely to initiate postpartum IUDs compared to their peers (10.2% vs 11.8%, p < 0.001), minimally more likely to initiate implants (2.7% vs 2.4%, p = 0.04) and more likely to present for postpartum care (61.7% vs 55.9%, p < 0.001). LARC placement prior to hospital discharge was rare (preterm: 8 per 10,000 deliveries vs all others: 6.3 per 10,000 deliveries, p = 0.002). State-level analysis showed wide variation in postpartum LARC (range 6%-32%).

CONCLUSIONS

While postpartum LARC use increased among the privately insured 2007-2016, few received LARC prior to hospital discharge. Those experiencing preterm birth were no more likely to receive inpatient LARC. Postpartum follow-up remained low and regional variation of LARC was high, highlighting the need for efforts to remove barriers to inpatient postpartum LARC for all who desire it-public and privately insured alike.

IMPLICATIONS

Among the half of U.S. births that are privately insured, postpartum LARC is increasing after both term and preterm births, yet exceedingly few (<0.1%) received LARC prior to hospital discharge.

The influence of birth outcomes and pregnancy complications on interpregnancy interval: a quantile regression analysis

PURPOSE

To ascertain whether adverse pregnancy outcomes at first pregnancy influence subsequent interpregnancy intervals (IPIs) and whether the size of this effect varies with IPI distribution METHODS: We included 251,892 mothers who gave birth to their first two singletons in Western Australia, from 1980 to 2015. Using quantile regression, we investigated whether gestational diabetes, hypertension, or preeclampsia in the first pregnancy influenced IPI to subsequent pregnancy and whether effects were consistent across the IPI distribution. We considered intervals at the 25th centile of the distribution as 'short' and the 75th centile as 'long'.

RESULTS

The average IPI was 26.6 mo. It was 0.56 mo (95% CI: 0.25-0.88 mo) and 1.12 mo (95% CI: 0.56 - 1.68 mo) longer after preeclampsia, and gestational hypertension respectively. There was insufficient evidence to suggest that the association between previous pregnancy complications and IPI differed by the extent of the interval. However, associations with marital status, race/ethnicity and stillbirth contributed to either shortening or prolonging IPIs differently across the distribution of IPI.

CONCLUSION

Mothers with preeclampsia and gestational hypertension had slightly longer subsequent IPIs than mothers whose pregnancies were not complicated by these conditions. However, the extent of the delay was small (<2 mo).

Impact of the interpregnancy interval after cesarean delivery on subsequent perinatal risks: a retrospective study

PURPOSE

To assess the impact of the interpregnancy interval (IPI) after cesarean delivery on the risks of adverse perinatal events during subsequent pregnancies.

METHODS

We retrospectively examined perinatal outcomes of subsequent pregnancies of women whose most recent birth experience involved cesarean delivery at our hospital between January 2014 and December 2019. IPI was defined as the time between live birth and subsequent conception. Three IPI groups: < 18 months, 18-60 months, and > 60 months, were assessed. The risks of preterm birth, preeclampsia, placenta previa, placental abruption, fetal growth restriction, and successful vaginal birth were compared among the three IPI groups using uni- and multivariate analyses.

RESULTS

We registered 592 births after cesarean delivery: 178, 288, and 126 in the IPI < 18 months, 18-60 months, and > 60 months groups, respectively. The groups did not differ significantly regarding perinatal outcomes. The multivariate analysis revealed no significant differences in the risks of adverse perinatal outcomes among all groups. The odds ratios (ORs) for preterm birth at < 37 weeks of gestation were 1.24 and 1.64 for those in the < 18 months and > 60 months groups, respectively (P = 0.362 and P = 0.055, respectively). The groups did not differ significantly regarding vaginal birth success rate (ORs 1.72 for the < 18 months group, 0.49 for the > 60 months group; P = 0.486 and P = 0.446, respectively).

CONCLUSION

After cesarean delivery, IPIs shorter than 18 months and longer than 60 months do not significantly impact the risks of adverse perinatal outcomes or successful vaginal birth compared with IPIs of 18-60 months.

Association between interpregnancy interval and maternal and neonatal adverse outcomes in women with a cesarean delivery: a population-based study

BACKGROUND

Interpregnancy interval (IPI) has been linked with several maternal and neonatal adverse events in the general population. However, the association between IPI and maternal and neonatal outcomes in women whose first delivery was by cesarean delivery is unclear. We aimed to investigate the association between IPI after cesarean delivery and the risk of maternal and neonatal adverse events.

METHODS

Women (aged ≥ 18 years) whose first delivery was cesarean delivery with 2 consecutive singleton pregnancies from the National Vital Statistics System (NVSS) database between 2017 and 2019 were included in this retrospective cohort study. In this post-hoc analysis, logistic regression analyses were used to examine IPI (≤ 11, 12-17, 18-23 [reference], 24-35, 36-59, and ≥ 60 months) in relation to the risk of repeat cesarean delivery, maternal adverse events (maternal transfusion, ruptured uterus, unplanned hysterectomy, and admission to an intensive care unit), and neonatal adverse events (low birthweight, premature birth, Apgar score at 5 min < 7, and abnormal conditions of the newborn). Stratified analysis based on age (< 35 and ≥ 35 years) and previous preterm birth.

RESULTS

We included 792,094 maternities, 704,244 (88.91%) of which underwent a repeat cesarean delivery, 5,246 (0.66%) women had adverse events, and 144,423 (18.23%) neonates had adverse events. After adjusting for confounders, compared to an IPI of 18-23 months, the IPI of ≤ 11 months [odds ratio (OR) = 1.55, 95% confidence interval (CI): 1.44-1.66], 12-17 months (OR = 1.38, 95%CI: 1.33-1.43), 36-59 months (OR = 1.12, 95%CI: 1.10-1.15), and ≥ 60 months (OR = 1.19, 95%CI: 1.16-1.22) were associated with an increased risk of repeat cesarean delivery. In terms of maternal adverse events, only IPI of ≥ 60 months (OR = 0.85, 95%CI: 0.76-0.95) was observed to be associated with decreased risk of maternal adverse events in women aged < 35 years. In analysis of neonatal adverse events, IPI of ≤ 11 months (OR = 1.14, 95%CI: 1.07-1.21), 12-17 months (OR = 1.07, 95%CI: 1.03-1.10), and ≥ 60 months (OR = 1.05, 95%CI: 1.02-1.08) were related to an increased risk of neonatal adverse events.

CONCLUSION

Both short and long IPI were associated with an increased risk of repeat cesarean delivery and neonatal adverse events, and women < 35 years may benefit from a longer IPI.

Association of interpregnancy interval and gestational diabetes mellitus

OBJECTIVE

To evaluate the association between interpregnancy interval (IPI) and risk for gestational diabetes mellitus (GDM).

METHODS

We conducted a retrospective cohort study among singleton, non-anomalous, live birth pregnancies of 5,705,812 pregnant individuals in the United States from 2016 to 2018. We examined IPI of 4-<6 months, 6-11 months, 12-17 months, 24-35 months, 36-47 months, 48-59 months, 60-71 months, and ≥72 months in comparison to the reference interval of 18-23 months in relation to risk for GDM. We used logistic regression to evaluate the association between IPI and risk for GDM.

RESULTS

There is a significantly increased risk for GDM associated with IPIs of 6-11 months and 12-17 months compared to the reference of 18-23 months (adjusted Odds Ratio [aOR] 1.05, 95% CI: 1.03-1.07; aOR 1.02, 95% CI: 1.01-1.03). The risk for GDM is greater for longer IPIs (36-47 months aOR 1.10, 95% CI: 1.05-1.08; 48-59 months aOR 1.11, 95% CI: 1.09-1.13; 60-71 months aOR 1.14, 95% CI: 1.12-1.16; ≥72 months aOR 1.31, 95% CI: 1.30-1.33).

CONCLUSION

Our findings support the growing evidence that shorter and longer IPI increase the risk of GDM in pregnant individuals. Screening guidelines for detection of GDM may need to be re-evaluated and updated to include longer IPIs (≥36 months) as a risk factor for earlier screening prior to current recommendation of 24 weeks gestational age.

The effect of interpregnancy interval on preterm birth and low birth weight in singleton pregnancies conceived without assistance or by infertility treatments

OBJECTIVE

To determine the association of interpregnancy interval on perinatal outcomes and whether this was influenced by mode of conception.

DESIGN

Retrospective cohort.

SETTING

Centers for Disease Control and Prevention's natality national database.

PATIENT(S)

Patients who had an index singleton live birth with a preceding live birth. Index pregnancies from 2016 to 2019 were conceived with in vitro fertilization (IVF) (n = 32,829) or ovulation induction/intrauterine insemination (OI/IUI) (n = 23,016) or without assistance (n = 7,564,042).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcomes evaluated were preterm birth (<37 weeks) and low birth weight (<2,500 g). Multivariable logistic regression was performed to evaluate the association of interpregnancy intervals with perinatal outcomes stratified by mode of conception. Adjusted odds ratios and 95% confidence intervals (CIs) were presented.

RESULT(S)

Compared with the interpregnancy interval reference group of 12 to <18 months, a <12 month interpregnancy interval was associated with an increase in preterm birth (<37 weeks) for pregnancies conceived with OI/IUI or without assistance (aOR, 1.42; 95% CI, 1.16-1.74, and aOR, 1.14; 95% CI, 1.13-1.15, respectively), whereas IVF was not associated with an increase (aOR, 0.90; 95% CI, 0.77-1.04). A <12 month interpregnancy interval was associated with an increase in low birth weight for pregnancies conceived with IVF or OI/IUI or without assistance (aOR, 1.34; 95% CI, 1.09-1.64; aOR, 1.33; 95% CI, 1.01-1.76; and aOR, 1.26; 95% CI, 1.24-1.27, respectively).

CONCLUSION(S)

An interpregnancy interval of at least 12 months reduces adverse perinatal outcomes for pregnancies conceived with and without infertility treatment.

Interpregnancy interval and subsequent perinatal risk of congenital heart disease in Guangzhou, Southern China: a retrospective cohort study, 2014-2019

BACKGROUND

The association between maternal interpregnancy interval (IPI) and congenital heart disease (CHD) in neonates remains inconclusive. This study aimed to examine the effect of maternal IPI on birth risk of CHD.

METHODS

Chinese women with two consecutive singleton deliveries in Guangzhou between January 2014 and December 2019 were selected as participants. Information on IPI and CHD was extracted from the Guangzhou Perinatal Health Care and Delivery Registry and the Guangzhou Birth Defects Surveillance Program. We stratified IPI into four categories: <24 months, 24-35 months, 36-59 months, and ≥60 months. A multivariate logistic regression model was used to examine the association between IPI and CHD. Subgroup analysis was also performed to assess whether the associations differed across top three CHD subtypes.

RESULTS

For 119,510 women enrolled in this study, the mean ages at two consecutive deliveries were 26.2 ± 3.8 and 28.8 ± 4.0 years, which yielded a median IPI of 51.2 (interquartile range, 32.1-77.2) months. Among them, 828 delivered infants with CHD during their second pregnancy. There was a J-shaped curve relationship between IPI and CHD with the lowest birth prevalence (5.33‰) at 24-35-month interval. Compared to women with an IPI of 24-35 months, those with an IPI ≥60 had an increased risk of delivering infants with CHD (adjusted odds ratio (OR), 1.41; 95% confidence interval (CI), 1.19-1.64). However, for those with an IPI <24 months (adjusted OR, 1.24; 95% CI, 0.97-1.51), IPI was statistically insignificant associated with the risk of delivering infants with CHD (p = .12). There were different patterns of associations for different CHD subtypes.

CONCLUSIONS

Longer maternal IPI (≥60 months) was associated with an increased risk of delivering infants with CHD in the Chinese population.

The P4 study: Subsequent pregnancy maternal physiology after hypertensive and normotensive pregnancies

OBJECTIVES

Hypertensive disorders of pregnancy are associated with subsequent increased risk of cardiometabolic disease. Adverse cardiometabolic measures are noted soon after hypertensive versus normotensive pregnancy (NP); to what degree these persist into a subsequent pregnancy (SP) is unknown. This study aimed to assess women's physiology early in SP after hypertensive pregnancy (HP: preeclampsia or gestational hypertension) or NP and compare SP to 6 months postpartum findings from the index pregnancy.

STUDY DESIGN

Prospective sub-study of the P4 (Postpartum, Physiology, Psychology and Paediatric) observational cohort. Measurements six months after NP versus HP, and the SP at 11-13 weeks gestation.

MAIN OUTCOME MEASURES

Blood pressure (BP), blood and urine tests (urine ACR, HOMA-IR, LDL cholesterol), body composition, and contribution of maternal characteristics and inter-pregnancy factors to BP and body fat (FM%) in SP.

RESULTS

49 women (34 NP, 15 HP). In the SP, post-HP women had higher BP (112/70 mmHg HP vs 102/64 mmHg NP; p < .001), with no significant drop from six months postpartum to early SP. On regression analysis, systolic and diastolic BP at 6-months were the major predictors for SP systolic (p < 0.001) and diastolic (p = 0.009) BP respectively in the SP. Longer interpregnancy interval and increased FM% 6-months postpartum were associated with higher SP FM% (p < 0.001).

CONCLUSIONS

BP and body fat six months postpartum were similar early in the SP for HP group, and postpartum BP and FM% were major predictors of their corresponding SP measurements. Postpartum/inter-pregnancy intervention programs to improve these cardiometabolic risk markers might help improve women's long-term health and require investigation.

Recurrent short interpregnancy interval: Maternal and neonatal outcomes

OBJECTIVE

To evaluate maternal and neonatal outcomes associated with recurrent short interpregnancy interval (IPI) in women in their third delivery.

METHODS

A retrospective computerized database study of all women who delivered their first three consecutive deliveries in a single tertiary medical center over 20 years (1999-2019). Maternal and neonatal outcomes of women with recurrent short IPI (<6 months between the 1st and 2nd pregnancy and the 2nd and 3rd pregnancy) were compared to women with recurrent optimal IPI (18-48 months), and to women with a single short IPI (<6 months between the 1st and 2nd pregnancy followed by an optimal IPI of 18-48 months between the 2nd and 3rd pregnancy). Additionally, in the recurrent short IPI groups, outcomes of the 2nd and 3rd pregnancies were compared in order to achieve an ideal adjustment to background characteristics. Univariate analysis was followed by multiple logistic regression models; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

During the study period 10,569 women had three consecutive deliveries at our medical center, of those 338 (3.2%) women had recurrent short IPIs, and 1,021 (9.7%) had recurrent optimal IPIs. Recurrent short IPI was associated with a significantly higher risk of maternal anemia (Hb < 10gr%) on admission to labor (aOR 3.4 [95% CI 1.09-10.65], p = 0.04) and higher risk of small for gestational age neonates (aOR 10.4 [95% CI 2.32-46.93], p < 0.01), as compared with women with recurrent optimal IPI and significantly higher rates of low neonatal birth weights (2500 gr) and anemia (Hb < 10gr%) alongside lower rates of operative vaginal deliveries as compared with women with single short IPI followed by an optimal IPI. In the recurrent short IPI groups, the 3rd deliveries had significantly higher rates of in-labor cesarean and anemia (Hb < 10gr%) on admission as compared to their 2nd deliveries.

CONCLUSION

Recurrent short IPI is associated with maternal anemia and small for gestational age neonates. Guiding patients towards prolongation of the IPI should include explanatory comments on these outcomes.

The effect of short interpregnancy interval on birthweight and other pregnancy outcomes in Enugu, Southeast Nigeria

The time interval between one pregnancy and the next is a modifiable risk factor, and has an effect on pregnancy outcomes. This study compared the effects of short interpregnancy interval (IPI) on fetal birthweight and selected pregnancy outcomes amongst parturients in Enugu, Nigeria. Group A (Subjects) consisted of parturients with short IPI (IPI < 18 months), while group B (Controls) consisted of parturients with normal IPI (IPI ≥ 18 months). Relevant obstetric data were collected at delivery. Mean birthweight was 2664.13 ± 339.25g vs 3670.63 ± 452.69g in women with short IPI and normal IPI respectively (p < .0001). Women with short IPI were more likely to have low birthweight babies compared to those with normal IPI (OR = 7.331, p < .001). Maternal anaemia, preeclampsia and caesarean delivery were significantly more associated with short IPI. Women with short IPI are at greater risk of delivering newborn babies with significantly lower mean birthweight and other associated pregnancy complications than women with normal IPI.Impact StatementWhat is already known on this subject? Short interpregnancy interval has an adverse effect on pregnancy outcomes as shown in studies from Europe and the Americas.What do the results of this study add? This study adds to the body of evidence of the deleterious effects of inadequately spaced pregnancies and draws attention to this in West Africa, sub-Saharan Africa, and an area with low contribution to studies on the effect of short IPI on pregnancy outcomes.What are the implications of these findings for clinical practice and/or further research? With evidence from our own environment, it will further boost evidence for proper education of our mothers on the need for adequate birth spacing to avoid the adverse effects of a short IPI on the next pregnancy.

How birth outcomes among a cohort of Guatemalan women with a history of prior cesarean vary by mode or birth across different interpregnancy intervals

OBJECTIVES

Our objectives were to analyze how pregnancy outcomes varied by cesarean birth as compared to vaginal birth across varying interpregnancy intervals (IPI) and determine if IPI modified mode of birth.

METHODS

This secondary analysis used data from a prospective registry of home and hospital births in Chimaltenango, Guatemala from January 2017 through April 2020, through the Global Network for Women's and Children's Health Research. Bivariate comparisons and multivariable logistic regression were used to answer our study question, and the data was analyzed with STATA software v.15.1.

RESULTS

Of 26,465 Guatemalan women enrolled in the registry, 2794 (10.6%) had a history of prior cesarean. 560 (20.1%) women delivered by vaginal birth after cesarean with the remaining 2,233 (79.9%) delivered by repeat cesarean. Repeat cesarean reduced the risk of needing a dilation and curettage compared to vaginal birth after cesarean, but this association did not vary by IPI, all p-values > p = 0.05. Repeat cesarean delivery, as compared to vaginal birth after cesarean, significantly reduced the likelihood a woman breastfeeding within one hour of birth (AOR ranged from 0.009 to 0.10), but IPI was not associated with the outcome. Regarding stillbirth, repeat cesarean birth reduced the likelihood of stillbirth as compared to vaginal birth (AOR 0.2), but again IPI was not associated with the outcome.

CONCLUSION

Outcomes by mode of delivery among a Guatemalan cohort of women with a history of prior cesarean birth do not vary by IPI.

Postpartum contraception method type and risk of a short interpregnancy interval in a state Medicaid population

OBJECTIVE

To evaluate the likelihood of a short interpregnancy interval (IPI) resulting in a birth among women covered by Medicaid, as a function of postpartum contraceptive method type.

STUDY DESIGN

We used Medicaid claims and eligibility data to identify women (aged 15-44) who had a Medicaid-financed birth in Delaware in the years 2012-2014 (n = 10,328). Claims were analyzed to determine postpartum contraceptive type within 60 days of the index birth, and linked birth certificates were used to determine the incidence and timing of a subsequent birth through 2018 (regardless of payer). We used logistic regression to analyze the likelihood of having a short IPI following the index birth as a function of postpartum contraceptive type, controlling for preterm births, parity, having a postpartum checkup, and maternal characteristics including age, race, education, and marital status.

RESULTS

Compared to patients receiving postpartum long-acting reversible contraceptive methods (LARC), patients with no contraceptive claims had nearly 5 times higher odds (odds ratio [OR] = 4.98, confidence interval [CI] = 3.05-8.13) and those with claims for moderately effective methods (injectable, pill, patch, or ring) had 3.5 times higher odds (OR = 3.51, CI = 2.13-5.77) of a subsequent birth following a short IPI.

CONCLUSIONS

In a state population of Medicaid-enrolled women, women with claims for postpartum LARC had substantially lower risk of a short IPI resulting in a birth.

IMPLICATIONS

Women who received LARC within 60 days postpartum are less likely to experience a short interpregnancy interval resulting in a birth. The evidence suggests that recent state policy changes that make postpartum LARC more accessible to those that desire it will be an effective strategy in helping patients obtain desired birth intervals.

The additive effect of interpregnancy interval and maternal body mass index on pregnancy induced hypertension in the U.S

OBJECTIVES

The incidence of pregnancy induced hypertension (PIH), one of the most frequent causes of maternal and neonatal morbidity, has increased significantly in the U.S. in last two decades. However, reasons for this rise are not well explored. The interrelationship between interpregnancy interval (IPI), prepregnancy body mass index (BMI), and PIH might play a role in this rise. This study aims to investigate the additive effect of IPI and prepregnancy BMI on PIH.

STUDY DESIGN

The 2018 Vital Statistics Natality Data was analyzed (N = 1,046,350) for this cross-sectional study. A combined variable was created using IPI and prepregnancy BMI. Adjusted odds ratios and 95% confidence intervals were generated for IPI, prepregnancy BMI, and PIH using multiple logistic regression models.

MAIN OUTCOME MEASURE

PIH was defined using the birth certificate variable 'Gestational hypertension- (PIH, preeclampsia)' in the dataset.

RESULTS

IPI and prepregnancy BMI were statistically significantly associated with PIH, both independently and in combination, after adjusting for potential confounders. The largest effect size was observed among women with long IPI and obesity (Adjusted OR = 4.01, 95% CI = 3.84, 4.25). Further, short IPI in combination with underweight BMI was found to be inversely associated with PIH (AOR = 0.64, 95% CI = 0.53, 0.78).

CONCLUSIONS

When combined, IPI and BMI are crucial risk factors for PIH. The highest risk of PIH is in women with long IPI in combination with high BMI categories. Healthcare professionals should be cognizant of the additional increased risk of PIH for the overweight and obese women with long IPI.

Iron status in mid-pregnancy and associations with interpregnancy interval, hormonal contraceptives, dietary factors and supplement use

Adequate iron supply in pregnancy is important for both the woman and the fetus, but iron status is often assessed late in first trimester, if assessed at all. Therefore, identification of factors associated with iron status is important to target vulnerable groups with increased risk of deficiency. Our objectives were to (1) describe iron status in mid-pregnancy and (2) identify sociodemographic and lifestyle predictors of pregnancy iron status. This cross-sectional study uses data from The Norwegian Mother, Father and Child Cohort Study (collected 2002-2008) and The Medical Birth Registry of Norway. Iron status was measured as non-fasting plasma ferritin (P-Fe) and transferrin in gestational week (GW) 18 (n 2990), and by lowest reported Hb in GW 0-30 (n 39 322). We explored predictors of iron status with elastic net, linear and log-binomial regression models. Median P-Fe was 33 μg/l, and 14 % had depleted iron stores (P-Fe <15 μg/l). P-Fe below 30 μg/l was associated with reduced Hb. We identified eleven predictors, with interpregnancy interval (IPI) and parity among the most important. Depleted iron stores was more common among women with IPI < 6 months (56 %) and 6-11 months (33 %) than among those with IPI 24-59 months (19 %) and among nulliparous women (5 %). Positively associated factors with iron status included hormonal contraceptives, age, BMI, smoking, meat consumption and multi-supplement use. Our results highlight the importance of ferritin measurements in women of childbearing age, especially among women not using hormonal contraceptives and women with previous and recent childbirths.

Short interpregnancy interval and low birth weight births in India: Evidence from National Family Health Survey 2015-16

Evidence on the effect of interpregnancy interval (IPI) on low birth weight (LBW) births is limited in developing countries including India. Our study aims to examine association between IPI and LBW births in India. We used data from the fourth round of the National Family Health Survey (NFHS-4) conducted in 2015–16 with a representative sample of 52,825 most recent births for examining the association between IPI and LBW. IPI is defined as the gap between the first month in which the index pregnancy was reported in the reproductive calendar (referred to as the month of conception) and the month of pregnancy outcome (including live births and terminations) of preceding pregnancy. Reproductive calendar data were used to estimate IPI. Association between IPI and LBW were examined using multivariable binary logistic regressions. Seventeen percent of the births in our sample were LBW, and more than half (57.6%) of these were accompanied with IPI less than 18 months. Prevalence of LBW births was highest among mother's who had IPI less than six months (19.4%). Regression results, adjusted for control variables, indicate that the risk of LBW was significantly higher among births whose mothers had IPI less than six months (odds ratio: 1.19, 95% CI:1.05-1.36) compared with those whose mothers had IPI between 18 and 23 months. This study provides additional evidence on the association between short IPI (<6 months) and LBW births in India. Promoting spacing methods of family planning is an option that India may consider for increasing the IPI and thereby reducing LBW births. Ensuring recommended iron and folic acid tablets/equivalent syrup and TT injections for every pregnant woman may offset the adverse consequences of shorter IPI.

•

12% of the LBW births were accompanied with IPI <6 months, 20% between 6 and 11 months, and 25% between 12 and 17 months.

•

The risk of LBW births is higher among mothers having an IPI of <6 months compared with mothers having an IPI of 18–23 months.

•

Promoting spacing methods of family planning may consider for increasing the IPI and thereby reducing LBW births in India.

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Promoting recommended TT injections and iron-folic acid supplements may offset the adverse consequences of short IPI.

Inter-pregnancy interval and long-term neurological morbidity of the offspring

PURPOSE

The purpose of our study was to evaluate the effect of IPI on long-term neurological morbidity of the offspring.

METHODS

In this retrospective cohort study, 144,397 singleton infants born to multiparous mothers, between the years 1991 and 2014 in a tertiary medical center, were evaluated for different perinatal outcomes and were followed until 18 years of age for long-term neurological morbidity according to three IPI groups: Short IPI (< 6 months), long IPI (> 60 months) and intermediate IPI (6-60 months). We used a Kaplan-Meier survival curve to compare cumulative incidence of long-term neurological morbidity, and a Cox regression analysis to control for confounders such as gestational age, birth weight and maternal age.

RESULTS

Offspring born to mothers with long IPI had higher rates of neurological morbidity (3.62% among offspring born after long IPI vs. 3.18% and 3.19% among offspring born after short and intermediate IPI, respectively, p = 0.041). The cumulative incidence of long-term neurological morbidity was significantly higher in the long IPI group (Kaplan-Meier log-rank test p < 0.001). Being born after a long IPI was found to be an independent risk factor for long-term neurological morbidity of the offspring (adjusted hazard ratio 1.2; 95% confidence interval 1.1-1.4; p < 0.001).

CONCLUSION

Long IPI is independently associated with an increased risk of long-term neurological morbidity of the offspring.

Associations between immediate postpartum long-acting reversible contraception and short interpregnancy intervals

OBJECTIVE

We aimed to evaluate the rates of short interpregnancy interval pregnancies and deliveries among women who receive immediate postpartum LARC.

STUDY DESIGN

We conducted a retrospective cohort study of all women who delivered at Montefiore Medical Center between January 2015 and June 2016 (N = 9561). In this cohort, we identified all repeat deliveries and pregnancies within 18 months of the initial delivery. Using logistic regression models, we compared rates of short interpregnancy interval delivery and pregnancy among recipients of an immediate postpartum IUD, immediate postpartum implant, and no immediate postpartum LARC, adjusting for covariates including patient age, mode of delivery, socioeconomic status, and race.

RESULTS

In our cohort, 12.9% of patients received immediate postpartum LARC. The rates of short interpregnancy interval delivery were 3.3% (N = 259/7833) among patients who did not receive immediate postpartum LARC, 1% (N = 6/595) among immediate postpartum IUD recipients, and 0.4% (N = 2/562) among immediate postpartum implant recipients. The rates of short interpregnancy interval pregnancy were 13.8% (N = 1082/7833) among patients who did not receive immediate postpartum LARC, 7.4% (N = 44/595) among immediate postpartum IUD recipients, and 5.2% (N = 29/562) among immediate postpartum implant recipients. Both recipients of immediate postpartum IUDs and immediate postpartum implants had lower rates of short interpregnancy interval delivery and pregnancy compared to patients who did not receive immediate postpartum LARC.

CONCLUSIONS

This study confirms that women who received immediate postpartum IUDs and implants have lower rates of short interpregnancy interval pregnancies.

IMPLICATIONS

Making immediate postpartum LARC widely available is a promising public health approach to help women achieve a longer interpregnancy interval.

Postpartum Contraceptive Use Among Denver-Based Adolescents and Young Adults: Association with Subsequent Repeat Delivery

STUDY OBJECTIVE

To determine the association of postpartum contraceptive use with repeat deliveries among adolescents and youth.

DESIGN

Retrospective, observational analysis of electronic health record data.

SETTING

Single, urban facility in Denver, Colorado, United States.

PARTICIPANTS

Women aged 10-24 years who gave birth between January 1, 2011 and December 31, 2015.

INTERVENTIONS AND MAIN OUTCOME MEASURES

Postpartum contraceptive use and time to subsequent delivery.

RESULTS

Among 4068 women, 1735 (43%) used postpartum contraception. In adjusted analyses, characteristics associated with contraceptive use included Hispanic ethnicity (relative risk [RR], 1.1; P = .03), incremental prenatal visits (RR, 1.01; P = .047), and attendance at postpartum care (RR, 1.60; P < .001). Long-acting reversible contraceptive (LARC) use was higher among women younger than 15 years (reference: 20-24 years; RR, 1.12; P < .001) and lower among women aged 18-19 years (RR, 0.93; P = .009). Hispanic women had higher rates of LARC use than non-Hispanic women (RR, 1.07; P = .02). Compared with inpatient LARC placement, outpatient placement (1-4 weeks and 5 or more weeks) rates were lower (RR, 0.77 and RR, 0.89, respectively; P < .001). Time to subsequent delivery was shorter in non-LARC users (median, 659 days) and contraception nonusers (median, 624 days) compared with LARC users (median, 790 days; P < .001); non-LARC postpartum contraceptive use did not significantly alter time to repeat delivery compared with that in women who used no method (P = .24).

CONCLUSION

Postpartum LARC use reduced the risk of repeat pregnancy with a significant increase in time to the next delivery. Non-LARC use was not different from no contraceptive use in terms of time to repeat delivery.

Interpregnancy Interval in a Rural Guatemalan Population: Results from a Quality Improvement Database

OBJECTIVE

This analysis describes the interpregnancy interval (time from livebirth to subsequent conception) in a convenience sample of women living in Southwest Guatemala and the association of antepartum characteristics and postpartum outcomes with a short interpregnancy interval (< 24 months).

METHODS

This is an observational study of a convenience sample of women enrolled in the Madres Sanas community antenatal/postnatal nursing program supported by the Center for Human Development in Southwest Trifinio, Guatemala, between October 1, 2018 and October 1, 2019. We observed the distribution of interpregnancy intervals among the population of women with a reported date of last live birth, and used bivariate comparisons to compare women with a short interpregnancy interval (< 24 months) to those with an optimal interval ([Formula: see text] 24 months) by antepartum, obstetric and delivery, and postpartum outcomes.

RESULTS

171 parous women enrolled in the Madres Sanas program between October 1, 2018 and October 1, 2019, and reported the date of their last live birth. One hundred-forty-one (82.5%) women delivered and 130 of those women (92.2%) were seen for their 40-day postpartum visit. The mean interval was 37.1 months with a 22.1-month standard deviation. The median interval was 33.7 months with an interquartile range of 19.6-49.5 months. Among these women, 113 (66.1%) the interpregnancy interval was at least 24 months. The only covariate of all sociodemographic, obstetric and antepartum, delivery, and postpartum characteristics that differed between women who achieved an interval ([Formula: see text] 24 months) compared to those that did not (< 24 months), was age (median 22.9, interquartile range (IQR) [19.1,27.0] vs median 24.8, IQR [21.6,27.9], respectively, p = 0.006). A regression model found that with each increasing year of age, the interpregnancy interval increases by 1.08 months, p = 0.025.

CONCLUSION

Among parous women, two-thirds of women space pregnancies at least 24 months. Older women were more likely to have a longer interval between live births.

Fertility intentions and the way they change following birth- a prospective longitudinal study

BACKGROUND

Women's fertility intentions, their desired number of children and desired inter-pregnancy interval (IPI) are related to micro (personal) and macro (socio-cultural) level factors. We investigated factors that contribute to changes in women's fertility intentions in Israel, a developed country with high birth rates.

METHODS

Pregnant women (N = 1163), recruited from prenatal clinics and hospitals in two major metropolitan areas, completed self-report questionnaires prenatally (≥24 weeks gestation) and postpartum (2 months after childbirth). Women reported their socio-demographic background and obstetric history prenatally, their desired number of children and IPI at both time-points, and their objective and subjective birth experiences postpartum.

RESULTS

The findings indicated that background characteristics were related to prenatal fertility intentions. The strongest contributor to prenatal fertility intentions was women's degree of religiosity- the more religious they were, the more children they desired and the shorter their intended IPI. Women's postpartum fertility intentions were mostly consistent with their prenatal reports. In regression models, women who were very-religious, more educated and had previously given birth were less likely to report a lower number of desired of children at postpartum, compared to their prenatal report. Women who reported greater birth satisfaction and gave birth for the first time were less likely to change desired IPI.

CONCLUSION

Having a negative birth experience could adversely affect women's fertility intentions. Yet, in a pronatalist and medicalized birth culture, social pressures may decrease the effects of birth experiences on fertility intentions.

Risk factors and child outcomes associated with short and long interpregnancy intervals

Previous research assessing consequences of interpregnancy intervals (IPIs) on child development is mixed. Utilizing a population-based US sample (n=5,339), we first estimated the associations between background characteristics (e.g., sociodemographic and maternal characteristics) and short (≤ 1 year) and long (> 3 years) IPI. Then, we estimated associations between IPI and birth outcomes, infant temperament, cognitive ability, and externalizing symptoms. Several background characteristics, such as maternal age at childbearing and previous pregnancy loss, were associated with IPI, indicating research on the putative effects of IPI must account for background characteristics. After covariate adjustment, short IPI was associated with poorer fetal growth and long IPI was associated with lower infant activity level; however, associations between short and long IPI and the other outcomes were neither large nor statistically significant. These findings indicate that rather than intervening to modify IPI, at-risk families may benefit from interventions aimed at other modifiable risk factors.

Influence of Caesarean section-pregnancy interval on uterine rupture risk and IVF pregnancy rates: systematic review and mathematical modelling

RESEARCH QUESTION

What is the influence of the Caesarean section-pregnancy interval (CSPI) on the risk of uterine rupture, and what are the repercussions on IVF pregnancy rates of prolonging it?

STUDY DESIGN

Systematic searches were performed using PubMed MEDLINE to identify studies published up until July 2017 for articles with the following keywords: 'interdelivery interval' and 'uterine rupture'; 'interpregnancy interval' and 'uterine rupture'; 'interpregnancy interval' and 'cesarean section'; and 'uterine rupture' and 'cesarean section'. The search identified 1609 articles, of which six were included (involving 56,419 women). Four reported significantly higher uterine rupture rates in cases of a short CSPI.

RESULTS

From the analysis, the uterine rupture rate can be modelled by a formula corresponding to a hyperbolic curve. There is no clear cut-off in uterine rupture in relation to CSPI. The curve showed a sharp decrease in uterine rupture until the 10th month of CSPI (uterine rupture rate 0.7%), then a moderate and steady decrease until the 40th month (uterine rupture rate 0.4%) and afterwards a very mild decrease. From the data it is possible to calculate, according to the age of the woman, the expected reduction in IVF rates and uterine rupture as CSPI increases.

CONCLUSION

The risk of uterine rupture in relation to CSPI can be represented by means of a hyperbolic curve. After a 10-month CSPI, the expected uterine rupture rate is close to 0.7%. The impact of prolonging or reducing this interval on IVF pregnancy rates can be easily obtained from the table included in the article. This should be helpful in the decision-making process for both patients and physicians.

Long interpregnancy interval and mode of delivery

PURPOSE

WHO sets 24 months as the ideal minimum interpregnancy interval (IPI) to minimize maternal and perinatal adverse outcomes. Some studies suggest that an interval longer than 59 months may affect these outcomes, but little is known about its influence on labor. The primary objective of this study was to compare the cesarean delivery rate between primiparous women with a long IPI and, on the one hand, primiparous women with an ideal minimum IPI of 18-24 months and, on the other hand, with nulliparous women.

METHODS

This retrospective cohort study of 17 years included nulliparas and primiparas who gave birth to live singleton fetuses in cephalic presentation after 22 weeks of gestation. Women with an IPI < 18 months or from 24 to 59 months were excluded, as were women with planned cesarean. We analyzed three groups: primiparous women with a long IPI defined as > 59 months, primiparous women with an ideal minimum IPI (18-24 months), and nulliparous women.

RESULTS

The study included 18,503 women: 1342 women in the "long IPI" group, 1388 in the "ideal minimum IPI" group, and 15,773 in the nulliparous women group. The cesarean delivery rate was significantly higher in the long compared to the ideal minimum IPI group [12.2% vs. 6.3%, respectively; aOR = 2.2 (95% CI 1.6-3.1)], but both groups had similar durations of labor, regardless of mode of delivery. Women in the long IPI group had significantly lower cesarean rates than nulliparous women [12.2% and 14.3%, respectively; aOR = 0.5 (95% CI 0.4-0.7)], and the nulliparous women had a significantly longer mean duration of labor.

CONCLUSIONS

Primiparas with a long IPI, compared with ideal minimal IPI have a higher risk of cesarean delivery during labor. Compared with nulliparous women, primiparous women with a long IPI had a lower cesarean rate.

Adolescent Interpregnancy Interval in Colorado Among Women With a Last Live Birth Between 2004 and 2013

PURPOSE

The purpose of the article was to determine risk factors associated with interpregnancy interval (IPI) and how IPI is associated with subsequent pregnancy outcomes.

METHODS

We performed bivariate and multivariable analyses of the Colorado Birth Certificate Registry data from women with a last live birth from 2004 to 2013, among Coloradan women aged 19 years and younger.

RESULTS

Our multivariate analysis found that older adolescents aged 17-19 years had a reduced likelihood of an IPI >18 months (odds ratio [OR] .8; confidence interval [CI] .7-.9). Self-identifying as Hispanic increased the likelihood of an IPI <18 months, whereas delivering during or after 2009 or having Medicaid insurance significantly increased the odds that an adolescent would have an IPI >18 months (OR 1.5 [CI: 1.4-1.6]; OR 1.2 [CI: 1.1-1.2]; OR 1.5 [CI: 1.4-1.6], respectively). We found that an IPI >18 months was associated with the following dependent variables in unique logistic regressions adjusted for age, ethnicity, year of last live birth, and insurance status: reduced risk of neonatal complications (OR .9 [CI: .8-.9]), reduced risk of overweight/obesity (OR .9 [CI: .8-.9]), and an increased likelihood of normal birthweight (OR 1.2 [CI: 1.1-1.4]), term birth (OR 1.3 [CI: 1.1-1.4]), and attending 14 or more prenatal visits (OR 1.3 [CI: 1.2-1.4].

CONCLUSIONS

Having an IPI >18 months in adolescent Coloradan women is associated with an increased likelihood of prenatal care attendance, term birth, and normal birthweight and with a reduced likelihood of neonatal complications.

Short interpregnancy interval and adverse birth outcomes in women of advanced age: a population-based study

PURPOSE

Short interpregnancy interval (IPI) has been linked with adverse birth outcomes. However, the association in advanced age women needs further investigation. This study aims to examine the association between short IPI and adverse birth outcomes including preterm birth, post-term birth, low birth weight, and macrosomia, in a population of advanced age U.S. women.

METHODS

The 2016 U.S. public-use natality data was analyzed. Analysis was restricted to women with second-order singleton live births who were ≥35 years at first live birth (n = 46,684). Multinomial logistic regression analysis was used to examine the association between short IPI and adverse birth outcomes.

RESULTS

Short IPI in advanced age women was significantly associated with higher odds of extremely preterm birth (0-5 months IPI: adjusted odds ratio [AOR] = 2.43, 95% confidence interval [CI] = 1.07-5.52; 6-11 months IPI: AOR = 2.17, 95% CI = 1.09-4.31), very preterm birth (0-5 months IPI: AOR = 1.63, 95% CI = 1.04-2.56), and extremely low birth weight (0-5 months IPI: AOR = 2.43, 95% CI = 1.28-4.60) in the second delivery. An inverse relationship between short IPI and post-term birth was observed and no significant association between short IPI and macrosomia was found.

CONCLUSIONS

Short IPI in advanced age women increases the odds of adverse birth outcomes in the second delivery.

[Effect of interpregnancy interval of childbearing aged women on birth weight of single live birth neonates]

Objective: To understand the effect of interpregnancy interval (IPI) of childbearing aged women on the birth weight of single live birth neonates in Shaanxi province. Methods: A questionnaire survey was conducted among the childbearing aged women selected through multistage stratified random sampling in Shaanxi during 20l0-2013, all the childbearing aged women had definite pregnancy outcomes. The interpregnancy interval of the childbearing aged women and the birth weight of the newborns were used as the independent variables and dependent variables respectively in multiple linear regression model and quantile regression model, and confounding factors were controlled. Results: A total of 13 063 women at childbearing age and their infants were investigated. The incidence of low birth weight and macrosomia was 3.54% and 7.62% respectively. Multiple linear regression analysis showed that there was no significant difference in birth weight among different IPI group and control group. Quantile regression analysis showed when birth weight was at 5 percentiles, the difference in birth weight between newborns whose mothers had short interpregnancy interval (<12 months) and those in control group was significant, when the birth weight was ≥90 percentiles, the birth weights of newborns whose mothers had long interpregnancy interval (60-119 months) were higher than those in control group, the difference was significant. As the increase of the percentiles of birth weight, the extent of changes gradually increased. Conclusion: The analysis indicated that both short (<12 months) and long (60-119 months) interpregnancy interval would had negative effects on birth weights of newborns. Therefore, planning for pregnancy is important for having a good perinatal outcome.

Pregnancy after periviable birth: making the case for innovative delivery of interpregnancy care

Objective: Women who have had a spontaneous periviable delivery are at high risk for recurrent preterm delivery. The objective of our study was to determine interpregnancy interval (IPI) after periviable birth as well as percentage of women taking 17 alpha hydroxyprogesteronecaproate (17OHP-C) after periviable birth. We then examined the association between adherence with a postpartum visit after a periviable birth and IPI as well as receipt of 17OHP-C. Materials and methods: We included all women with a periviable delivery (20-26-week gestation) due to spontaneous preterm birth at Magee Women's Hospital between 2009 and 2014, who had their subsequent delivery at our institution during or before May of 2016. Information on maternal, fetal, and neonatal outcomes was obtained from the Magee Obstetrical Medical and Infant (MOMI) database as well as chart abstraction. We calculated IPI, proportion of women who received 17OHP-C in their next pregnancy, and attendance rates with a postpartum visit. The relationship between attendance with a postpartum visit and IPI, and receipt of 17OHP-C was examined with a logistic regression. Results: During the study period, 361 women had a spontaneous periviable birth. A total of 60 women had a subsequent delivery at Magee Women's Hospital. Only 33/60 (52.5%) presented for a postpartum visit after their periviable delivery. The median IPI for the cohort was 12.5 months (interquartile range: 6.4, 17.5 months) and 21.0% (n = 13) had an IPI less than 6 months. Adherence with the postpartum visit was not associated with an IPI less than 6 months. A total of 18.33% (11 women) did not receive 17OHP-C in their subsequent pregnancy. Women who attended a postpartum visit were much more likely to receive 17OHP-C (p = .001). Conclusions: Many women with a history of a periviable birth do not optimize strategies to reduce their risk of recurrent preterm birth. While attendance with a postpartum visit was associated with greater receipt of 17OHP-C in the subsequent pregnancy, given the overall poor rate of attendance with the postpartum visit in this cohort, novel strategies to counsel women about interpregnancy health are needed.

Racial Differences in the Influence of Interpregnancy Interval on Fetal Growth

Objectives Assess the influence of maternal race on the association between interpregnancy interval (IPI) and risk of small for gestational age (SGA) and large for gestational age (LGA) births. Methods Statewide population-based cohort study of 380,520 singleton births. We calculated risk of SGA and LGA births following IPIs of 0 to <6, 6 to <12, 12 to <24 (referent), 24 to <60 months, and ≥60 months, by maternal race after adjustment for confounding influences. Results The highest risk for SGA among white women followed short IPI of 0 to <6 months [adjRR 1.14 (95 % CI 1.08-1.21)], and long IPI ≥ 60 months [adjRR 1.37 (95 % CI 1.31-1.43)]. Only long IPI ≥ 60 months increased SGA risk in black women [adjRR 1.22 (95 % CI 1.13-1.32)]. LGA risk in white women was lowest with shortest and longest IPIs, 0 to <6 [adjRR 0.80 (95 % CI 0.76-0.84)] and ≥60 months [adjRR 0.68 (95 % CI 0.66-0.70)]. The crude risk of LGA was directly proportional to longer IPIs in black women. However, after adjusting for confounding effects of age, obesity, excessive gestational weight gain, and gestational diabetes, the effect was reversed to reduced risk following long IPI ≥ 60 months [adjRR 0.82 (95 % CI 0.74-0.91)], similar to that of white women. Conclusions In black and white women, an interpregnancy interval of 1-2 years is associated with optimal fetal growth. In addition to birth spacing, addressing modifiable factors such as pre-pregnancy BMI, monitoring gestational weight gain, and control of gestational diabetes in black women may help optimize fetal growth.

Postpartum contraceptive use and interpregnancy interval among women with opioid use disorder

OBJECTIVE

The purpose of this study was to describe postpartum contraceptive utilization patterns among women with OUD and evaluate the relationship between postpartum contraceptive method choice and interpregnancy interval.

METHODS

A retrospective cohort study was conducted with women in Pennsylvania Medicaid with a diagnosis of OUD between 2008 and 2013. Postpartum contraceptive use within 90 days after delivery was identified through claims data and categorized by effectiveness (highly-effective, effective, and no method observed). Kaplan-Meier time-to-event analyses and multivariable-adjusted marginal Cox regression models were used to evaluate the relationship between postpartum contraceptive method choice and interpregnancy interval. Multivariable logistic regression analyses were used to identify risk factors predictive of a short interpregnancy interval (≤18 months).

RESULTS

We identified 7805 women (9260 pregnancies) who had a diagnosis of OUD. Nearly three-quarters (74.5%) had no contraceptive method observed, 18.1% received an effective method, and only 7.4% received a highly-effective method (LARC or female sterilization) during the postpartum period. In Kaplan-Meier analyses, no significant differences were found in the time-to-next pregnancy interval when an effective contraceptive method vs. no contraceptive method was used. In multivariable analysis, predictors of a significantly longer interpregnancy interval were LARC use (HR 0.43, 95% CI 0.26-0.69), gestational hypertension (HR 0.80, 95% CI 0.65-0.97), and age (HR 0.95, 95% CI 0.94-0.96). Approximately 20% of women with OUD had a short interpregnancy interval.

CONCLUSION

Few women with OUD use highly-effective postpartum contraception, which is protective against short interpregnancy intervals.

Interpregnancy Interval and Childbirth Outcomes in California, 2007-2009

Objectives The goals of interconception care are to optimize women's health and encourage adequate spacing between pregnancies. Our study calculated trends in interpregnancy interval (IPI) patterns and measured the association of differing intervals with birth outcomes in California. Methods Women with "non-first birth" deliveries in California hospitals from 2007 to 2009 were identified in a linked birth certificate and patient discharge dataset and divided into three IPI birth categories: <6, 6-17, and 18-50 months. Trends over the study period were tested using the Cochran-Armitage two-sided linear trend test. Chi square tests were used to test the association between IPI and patient characteristics and selected singleton adverse birth outcomes. Results Of 645,529 deliveries identified as non-first births, 5.6 % had an IPI <6 months, 33.1 % had an IPI of 6-17 months, and 61.3 % had an IPI of 18-50 months. The prevalence of IPI <6 months declined over the 3-year period (5.8 % in 2007 to 5.3 % in 2009, trend p value <0.0001).Women with an IPI <6 months had a significantly higher prevalence of early preterm birth (<34 weeks), low birthweight (<2500 g), neonatal complications, neonatal death and severe maternal complications than women with a 6-17 month or 18-50 month IPI (p < 0.005). Comparing those with a 6-17 month vs 18-50 month IPI, there were increased early preterm births and decreased maternal complications, complicated delivery, and stillbirth/intrauterine fetal deaths among those with a shorter IPI. Conclusions for Practice In California, women with an IPI <6 months were at increased risk for several birth outcomes, including composite morbidity measures.

Short interpregnancy interval increases the risk of preterm premature rupture of membranes and early delivery

OBJECTIVES

Preterm premature rupture of membranes (PPROM) is a major contributor to overall preterm birth (PTB) rates. A short interpregnancy interval (IPI) is a well-known risk factor for PTB. It is unknown if a short IPI specifically affects the risk of developing PPROM in a subsequent pregnancy. We sought to determine the association between IPI and the risk of PPROM in a subsequent pregnancy.

METHODS

A retrospective cohort study using the Missouri birth certificate database of singleton births from 2003 to 2013 was conducted. A short IPI (delivery of the prior pregnancy to conception of the index pregnancy) was defined as ≤6 months. IPI >6 months was categorized into two groups: IPI 7-23 months and IPI ≥24 months. PPROM was defined as premature rupture of membranes between 16⁰ and 36⁶ weeks. Multivariable logistic regression was conducted to determine the association between IPI and PPROM while controlling for maternal age, race, body mass index (BMI), education level, use of social services (Medicaid insurance, food stamps, or participation in the WIC [Women, Infants, and Children] program), tobacco use, and history of PTB. Secondary outcome included the gestational age at delivery, categorized into five subgroups (≤24⁰, 24¹-28⁰, 28¹-32⁰, 32¹-34⁰, and 34¹-36⁶ weeks).

RESULTS

474,957 subjects with singleton gestations had data available to calculate the IPI. Of these, 1.4% (n = 6797) experienced PPROM. IPI ≤6 months was significantly associated with an increased risk of developing PPROM compared with patients with IPI ≥24 months (odds ratio (OR) 1.80, 95% CI 1.70-1.90, p < .001). A higher proportion of women with IPI ≤6 months delivered between 28¹ and 32⁰ weeks compared to the other two IPI groups (27.0 versus 15.0 and 16.4%, p < .001). Individual maternal factors associated with an increased risk of PPROM included advanced maternal age, African American race, BMI <18.5 kg/m², BMI ≥30 kg/m², use of social services, tobacco use, and a prior PTB.

CONCLUSION

Our data demonstrate that an IPI of ≤6 months is significantly associated with an increased risk of developing PPROM in the subsequent pregnancy. Of greater clinical relevance is that these women were more likely to deliver between 28¹ and 32⁰ weeks as compared with women with a longer IPI. Novel to this study is the establishment of a specific link between a short IPI and PPROM with subsequent early delivery. Several maternal demographic factors known to be associated with PTB risk were also found to be associated with an increased risk of PPROM. Further studies are necessary to elucidate plausible biologic mechanisms ultimately leading to the development and implementation of preventive and therapeutic strategies for this high-risk cohort.

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

OBJECTIVE

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).

METHODS

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.

RESULTS

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).

CONCLUSION

The findings for CNS anomalies warrant further investigation.

The effect of interpregnancy interval on obesity/overweight among women in the first trimester of pregnancy

OBJECTIVE

To determine the effect of interpregnancy interval (IPI) on obesity/overweight among pregnant Sudanese women in early pregnancy.

METHODS

A cross-sectional study was conducted at Saad Abu-Alela Hospital, Khartoum, Sudan, from January to December 2015. Women with a singleton pregnancy and at least one previous pregnancy were enrolled in the first trimester. A questionnaire was used to collect clinical and sociodemographic data from the participants, and current body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters.

RESULTS

Among 1045 participants, 344 (32.9%), 424 (40.6%), and 277 (26.5%) women had short (<18 months), normal (18-30 months), and long IPIs (>30 months), respectively. BMI indicated 18 (1.7%), 408 (39.0%), 381 (36.5%), and 238 (22.8%) women were underweight (<18.5), normal weight (18.5-24.9), overweight (25.0-29.9), and obese (≥30.0), respectively. Age and proportion using contraceptives were increased among women with long IPI (both P<0.001). When compared with women of normal weight, overweight women and obese women were more likely to have a long IPI (odds ratio 1.72, 95% confidence interval 1.08-2.93; and 1.71, 1.05-2.94, respectively).

CONCLUSION

Long IPI was associated with obesity and overweight, which were prevalent among pregnant Sudanese women.

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

PURPOSE

The prevalence of short interpregnancy intervals (IPIs) and associated rates of preterm birth has been understudied in Asian and Pacific Islander populations. We sought to estimate rates of short IPI among Asian subgroups and Pacific Islanders and associated risk of preterm birth.

MATERIALS AND METHODS

For this retrospective cohort study, we linked records of women in California with a first birth in 1999-2000 and a second birth before 2005 with hospital discharge data. We used multivariate modeling to determine whether specific Asian ethnicities and Pacific Islanders were at greater risk of short IPI (<6 months, 6-18 months) and if a short IPI increased risk for preterm birth in these groups.

RESULTS

Our sample included 189,931 women. In multivariable analyses, Asian subgroups and Pacific Islanders were more likely to have an IPI <6 months than were White women (Pacific Islanders: OR 3.31 (95%CI [2.7, 4.1]); Filipinas: OR 1.51 (95%CI [1.33, 1.71]); Southeast Asians: OR 1.93 (95%CI [1.73, 2.1]); East Asians: OR 1.65 (95%CI [1.48, 1.84]); other Asians: OR 2.04 (95%CI [1.70, 2.4])).

CONCLUSIONS

Asian and Pacific Islander women have higher rates of IPI <6 months, but this did not significantly increase their risk of preterm birth.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

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

OBJECTIVES

We assessed whether interpregnancy interval (IPI) length after live birth and after pregnancy termination was associated with preterm birth (PTB).

DESIGN

Multiyear birth cohort.

SETTINGS

Fetal death, birth and infant death certificates in California merged with Office of Statewide Health Planning and Development.

POPULATION

One million California live births (2007-10) after live birth and after pregnancy termination.

METHODS

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.

MAIN OUTCOME MEASURE

PTB relative to gestations of ≥ 37 weeks.

RESULTS

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.

CONCLUSIONS

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.

TWEETABLE ABSTRACT

Short and long IPI after live birth, but not after pregnancy termination, showed increased odds for PTB.

Effect of interpregnancy interval on adverse pregnancy outcomes in northern Tanzania: a registry-based retrospective cohort study

Background

Both short and long interpregnancy intervals have been associated with an increased risk of adverse pregnancy outcomes. There is limited information about the impact of interpregnancy interval on pregnancy (IPI) outcomes in Tanzania. The objective of this study was to assess the effect of IPI on adverse pregnancy outcomes.

Methods

We performed a retrospective cohort study using maternally-linked data from Kilimanjaro Christian Medical Centre (KCMC) birth registry. A total of 17,030 singlet births from women who delivered singleton infant at KCMC from 2000 to 2010 were studied. Women with multi-fetal gestations and those who were referred from rural areas for various medical reasons were excluded. Outcome variables were preterm birth, low birth weight infants and perinatal death. A multiple logistic regression was used to assess the association between IPI and pregnancy outcomes.

Results

The median IPI was 36 months. Compared with IPIs of 24–36 months (referent group), short interpregnancy intervals (<24 months) was associated with preterm delivery (OR 1 · 52; 95 % CI 1.31–1.74); low birth weight (OR 1 · 61; 95 % CI 1 · 34–1.72) and perinatal death, (OR 1 · 63; 95 % CI 1.22–1.91). The IPI of 37–59 months or longer were also associated with higher risks of preterm birth and low birth weight, but not with perinatal death.

Conclusions

Our study confirmed that both short and long IPI are independent risk factors for adverse pregnancy outcomes. These finding emphasize the importance of providing support for family planning programs which will support optimal IPI and improve pregnancy outcomes.

Interpregnancy interval as a risk factor for postmenopausal osteoporosis

OBJECTIVE

Bone mass loss associated with pregnancy and lactation is usually regained in the postpartum period. However, it is not known whether the bone loss is completely recovered in women with a shortened interpregnancy interval (IPI). The aim of this study was to analyze the effect of IPI and gynecological history on postmenopausal osteoporosis.

STUDY DESIGN

The study was conducted among 537 postmenopausal women who were divided into two groups in accordance with the osteoporosis status. Prior to bone densitometry, the patients were questioned about reproductive history. Dual-energy X-ray absorptiometry was used to measure lumbar spinal, femur neck and total femoral bone mineral density.

MAIN OUTCOME MEASURE

Association between IPI and postmenopausal osteoporosis was analyzed.

RESULTS

The comparison of both groups according to the total duration of breastfeeding did not reveal a considerable variation (p=0.288). In the osteoporosis group the age and duration of menopause were found to be significantly higher (p<0.001) whereas the age of first pregnancy and IPI were notably lower in comparison to the controls group (p<0.001). Multivariate logistic regression analyses revealed that women who have 0-12 months interpregnancy interval have the highest risk for osteoporosis (OR: 4.306; 95% CI, 1.684-11.01). This analysis confirmed that the occurrence of first pregnancy under 27 years of age conveyed a higher risk for osteoporosis, as well.

CONCLUSIONS

Shortened IPI may have a detrimental effect on bone mineral density in postmenopausal age.