Short Interbirth Intervals Research Articles

Short interbirth interval and adverse pregnancy outcomes: a Bayesian network approach

BackgroundInterbirth interval (IBI), the time between consecutive births, has been tied to perinatal outcomes. ObjectiveTo analyze adverse perinatal events following short IBI in a large South American sample. Study designObservational, retrospective, hospital-based study including malformed and nonmalformed live- and stillbirths. Outcomes were preterm birth (PTB), low birth weight (LBW), and specific birth defects. Logistic regressions were used to evaluate the risk of selected variables for short IBI and for adverse outcomes after short IBI, adjusting by confounders. Bayesian networks exhibited relationships among short IBI, outcomes, and variables. ResultsShort IBI rate was 2%–3%. Maternal age and a previous abortion were the main confounders. A significant high risk for short IBI was found in mothers ≤19 years while mothers ≥30 were at low risk, mediated by a previous abortion. The risk of short IBI, adjusted by confounders, was significant for LBW but not for PTB. An unadjusted risk of short IBI was observed for gastroschisis, which disappeared after adjusting for confounders. Maternal age ≤19 and previous abortion were directly related with gastroschisis; the relationship between gastroschisis and short IBI occurred through any of these two variables. A direct relationship between gastroschisis and maternal age ≥30 was observed. ConclusionsOnly young mothers were directly related with short IBI. In older mothers, a short IBI mainly occurred after a previous abortion. Short IBI was a risk factor only for LBW. The PTB and gastroschisis relationship with short IBI was indirect, mediated by young maternal age and/or a previous abortion.

Postpartum contraception provision across Europe: preliminary findings from a multi country survey

Introduction Looking after a baby and recovering from birth pose barriers to accessing and initiating effective contraception in the postpartum period. Another pregnancy at this time can end in abortion or a short interbirth interval. These are preventable if contraception is provided immediately from maternity settings. Our aim was to survey contraceptive experts across Europe about provision of postpartum contraception (PPC) in their country to develop a greater understanding of availability of and delivery of PPC services within the region. Materials and Methods Contraceptive experts across Europe were invited to participate in an anonymous mixed-methods online survey consisting of free text and fixed-response questions focusing on: (1) national guidelines/policy (2) antenatal contraceptive discussion and (3) immediate postpartum provision of methods. Respondents were asked to rate PPC provision in their region and detail perceived facilitators or barriers. Results Experts from 28 countries completed the survey. Fifteen (40%) reported their country had national guidelines for PPC provision, 40% reported that some antenatal contraceptive counselling was offered and 51% reported that contraceptive methods were provided in some (43%) or all (8%) maternity settings. Country-level PPC provision was reported as ‘poor’ or ‘very poor’ by 54% of respondents. Reported barriers to PPC provision included: cost, lack of policy/government support, awareness and training of maternity staff. Conclusions There is significant variation in PPC provision across Europe. Few countries offer antenatal contraceptive counselling or provide contraception from maternity settings. Introduction of supportive PPC policies, funding and training for staff could improve outcomes for mothers and babies.

An early-life challenge: becoming an older sibling in wild mandrills.

In monotocous mammals, most individuals experience the birth of a younger sibling. This period may induce losses in maternal care and can be physiologically, energetically and emotionally challenging for the older sibling, yet has rarely been studied in wild primates. We used behavioural data collected from a natural population of mandrills to investigate changes in maternal care and mother-juvenile relationship throughout the transition to siblinghood (TTS), by comparing juveniles who recently experienced the birth of a younger sibling, to juveniles who did not. We found that the TTS was associated with an abrupt cessation of the weaning process for the juvenile, and to a decrease in maternal affiliation. Juveniles' reactions were sex-specific, as males associated less with their mother, while females tended to groom their mother more often after the birth of their sibling. Despite the substantial loss of maternal care, juveniles did not show an increase in conflict or anxiety-related behaviours. This study contributes to explain why short interbirth intervals often pose a risk to juveniles' survival in monotocous primates. Our results contrast existing studies and further highlight the importance of examining the TTS in species and populations with various life histories and ecologies.

Factors associated with the absence of postpartum consultations in a high-risk population.

To assess the rate of missed postpartum appointments at a referral center for high-risk pregnancy and compare puerperal women who did and did not attend these appointments to identify related factors. This was a retrospective cross-sectional study with all women scheduled for postpartum consultations at a high-risk obstetrics service in 2018. The variables selected to compare women were personal, obstetric, and perinatal. The variables of interest were obtained from the hospital's electronic medical records. Statistical analyses were performed using the Chi-square, Fisher's exact, or Mann-Whitney tests. For the variable of the interbirth interval, a receiver operating characteristic curve (ROC) was used to best discriminate whether or not patients attended the postpartum consultation. The significance level for the statistical tests was 5%. A total of 1,629 women scheduled for postpartum consultations in 2018 were included. The rate of missing the postpartum consultation was 34.8%. A shorter interbirth interval (p = 0.039), previous use of psychoactive substances (p = 0.027), current or former smoking (p = 0.003), and multiparity (p < 0.001) were associated with non-attendance. This study showed a high rate of postpartum appointment non-attendance. This is particularly relevant because it was demonstrated in a high-risk obstetric service linked to clinical severity or social vulnerability cases. This highlights the need for new approaches to puerperal women before hospital discharge and new tools to increase adherence to postpartum consultations, especially for multiparous women.

A cohort study of maternal near-miss events and its adverse perinatal outcomes: an obstetrical finding in Northwest Ethiopia

Globally, various studies have reported that most adverse perinatal outcomes were associated with maternal near-misses. In Ethiopia, studies on adverse perinatal outcomes from maternal near-miss are scarce. This study aimed to assess the incidence, determinants, and maternal near-miss effects on perinatal outcomes among women at public hospitals in the South Gondar zone in 2021. A facility-based prospective cohort study was conducted from January 10, 2021, to May 10, 2021. The chi-square test, multivariable logistic regression methods, and SPSS software were used. The strength of associations and significance level were examined using P values and odds ratios with 95% confidence intervals, respectively. In addition, multicollinearity and model fitness were checked. A total of 304 respondents (76 exposed and 228 unexposed) were included in the study with a response rate of 100.0%. The incidence rates of adverse perinatal outcomes among exposed and unexposed groups were 71.1% (95% confidence interval, 60.0-73.8) and 21.1% (95% confidence interval, 15.8-28.8), respectively. Multivariable logistic regression showed that short interbirth interval (adjusted odds ratio, 8.39; 95% confidence interval, 5.36-16.08), lower household income (adjusted odds ratio, 3.61; 95% confidence interval, 1.12-6.54), rural residence (adjusted odds ratio, 2.54; 95% confidence interval, 1.21-4.07), previous stillbirth (adjusted odds ratio, 4.24; 95% confidence interval, 1.04-17.31), absence of antenatal care (adjusted odds ratio, 9.84; 95% confidence interval, 4.89-17.51), and anemia (adjusted odds ratio, 4.19; 95% confidence interval, 1.01-17.46) were significantly associated with increased odds of adverse perinatal outcomes. This study revealed that the incidence of adverse perinatal outcomes was significantly higher among exposed groups than unexposed groups. The result signified the need for improving the health of mothers by all stakeholders to improve perinatal outcomes.

Determinants of maternal mortality in south-western Nigeria: Midwives’ perceptions

BackgroundMaternal mortality remains one of Nigeria's most significant public health challenges. In order to address this issue sustainably, it is necessary to consider the perceptions of all stakeholders involved, including midwives. ObjectivesTo examine the determinants of maternal mortality in south-western Nigeria from the midwife's perspective. DesignA cross-sectional study was employed using mixed methods with a semi-structured questionnaire and an in-depth interview guide. ParticipantsQuantitative data were obtained from 215 midwives using a convenience sampling technique. Qualitative data were obtained from 25 midwives from five government health centres, selected using a stratified sampling technique. MethodsQuantitative data were analysed using SPSS Version 20 using descriptive and inferential statistics with 95 % confidence intervals, while qualitative data were analysed using thematic analyses. FindingsThe mean age and work experience of the participants were 35.2 ± 9.3 years and 8.4 ± 7.0 years, respectively. The midwives perceived that the main determinants of maternal mortality were postpartum haemorrhage (86.5 %), hypertensive disorder in pregnancy (80.9 %), mismanagement at mission homes/traditional birth attendant centres (MH/TBAs) (79.1 %) and sepsis (70.1 %). Some of the priority target areas to improve the well-being of pregnant women as identified by the midwives, were increased awareness of pregnancy danger signs (97 %), destigmatising caesarean section (CS) (96 %), regulation of MH/TBAs (92 %), and increased accessibility of hospitals (84 %). Findings from the qualitative data also affirmed that regulating MH/TBAs, destigmatising CS and subsidising healthcare expenses were prerequisites to curbing maternal mortality. Inferential analysis revealed that determinants such as unsafe abortion (p < 0.001), ectopic pregnancy (p = 0.001), domestic violence (p = 0.023), malaria (p = 0.029), short interbirth interval (p = 0.03), and patients’ negative perceptions of CS delivery (p = 0.036) were more commonly perceived to be associated with maternal mortality by younger midwives (age 17–34 years) compared with older midwives. Key conclusionThe results indicate that resolving the maternal mortality crisis sustainably in Nigeria will require increased accessibility to basic health care and health promotion campaigns to counteract unhelpful sociocultural norms. Implications for practiceFuture interventions must be tailored to address both traditional and emerging causes of maternal mortality in southwestern Nigeria.

Socio-demographic and antenatal care-related factors associated with early post-partum family planning use in Ethiopia: evidence from Ethiopian Demographic and Health Survey 2016 data.

Initiation of family planning in the early post-partum period is a strategic move to reduce maternal, neonatal, and child mortality due to the negative consequences of short interbirth interval and the complications of unintended pregnancy. Antenatal care (ANC) is the noteworthy predictor of scaling up early initiation of post-partum family planning (PPFP) and preventing unintended pregnancy before menses resume. Despite the great role of ANC, information is scant about the effect of content, timing, and the number of ANC visits on the early initiation of PPFP in Ethiopia. This study aimed to assess the association of ANC services with the early initiation of PPFP in Ethiopia. The study was based on Ethiopian Demographic and Health Survey 2016 data, which was a cross-sectional survey from 18 January 2016 to 27 June 2016. A total weighted sample size of 2,920 post-partum women was included. A multilevel logistic regression model was used because of the hierarchical data, and variables with a p-value of ≤0.2 in the bivariable multilevel analysis were taken to multivariable multilevel analysis. An adjusted odds ratio with a 95% confidence interval (CI) was used to declare both the direction and strength of the association, and variables with a p-value of <0.05 were considered as statistically significant for the outcome variable. The early initiation of PPFP was 20.4%. Women with at least four ANC visits [adjusted odds ratio (AOR) = 1.31; CI 1.12-2.32], women who started ANC within the first trimester (AOR = 1.25; CI 1.10-2.23), complete routine ANC (AOR = 1.11; CI 1.01-2.03), post-natal care (AOR = 1.45; CI 1.19-1.87), resumption of menses (AOR = 1.67; CI 1.18-1.93), urban residency (AOR = 2.14; CI 1.18-2.51), and high community women's education (AOR = 1.71; CI 1.51-2.11) were variables significantly associated with the early initiation of PPFP. The early initiation of PPFP in Ethiopia was very low. Attention needs to be given to the quality of ANC, post-natal care, resumption of menses, residency, and community-level education of women to increase the prevalence of the early initiation of PPFP in Ethiopia. Therefore, the government should design a program targeting the quality of ANC in rural communities, considering women without menses and scaling up the education of women at the community level to the culture of the early initiation of PPFP in order to achieve reduced maternal, neonatal, and child mortality.

Apolipoprotein-ε4 is associated with higher fecundity in a natural fertility population.

In many populations, the apolipoprotein-ε4 (APOE-ε4) allele increases the risk for several chronic diseases of aging, including dementia and cardiovascular disease; despite these harmful effects at later ages, the APOE-ε4 allele remains prevalent. We assess the impact of APOE-ε4 on fertility and its proximate determinants (age at first reproduction, interbirth interval) among the Tsimane, a natural fertility population of forager-horticulturalists. Among 795 women aged 13 to 90 (20% APOE-ε4 carriers), those with at least one APOE-ε4 allele had 0.3 to 0.5 more children than (ε3/ε3) homozygotes, while those with two APOE-ε4 alleles gave birth to 1.4 to 2.1 more children. APOE-ε4 carriers achieve higher fertility by beginning reproduction 0.8 years earlier and having a 0.23-year shorter interbirth interval. Our findings add to a growing body of literature suggesting a need for studies of populations living in ancestrally relevant environments to assess how alleles that are deleterious in sedentary urban environments may have been maintained by selection throughout human evolutionary history.

Investigating the Relationship Between Body Shape and Life History Traits in Toothed Whales: Can Body Shape Predict Fast-Slow Life Histories?

A widespread pattern in vertebrate life-history evolution is for species to evolve towards either fast or slow life histories; however, the underlying causes of this pattern remain unclear. Toothed whales (Odontoceti) are a diverse group with a range of body sizes and life histories, making them an ideal model to investigate potential drivers of this dichotomy. Using ancestral reconstruction, we identified that certain groups of odontocetes evolved more-streamlined, presumably faster, body shapes around the same time that killer whales (Orcinus orca) evolved into whale predators approximately 1 Mya during the Pleistocene. This suggests that the evolution of a streamlined body shape may have been an adaptation to escape killer whale predation, leading to longer life-history events. To test this hypothesis, we performed a cluster analysis of odontocete whales and confirmed the dual pattern of life-history traits, with one group referred to as ‘reproducers’ characterized by early age of maturity, short gestation, short interbirth interval, and short lifespan, and the other group referred to as ‘bet-hedgers’ exhibiting the opposite pattern. However, we found that life history grouping was relatively unrelated to whale shape (i.e., more streamlined or less streamlined). Therefore, we incorporated principal component results into mixed effects models, and the model results indicated that body shape was positively related to neonate length (a measure of investment in progeny), but not significantly related to the temporal life-history traits. Thus, whale body shape is not a sufficient explanation for the evolution of fast-slow life histories in odontocete whales.

Pregnancy risks and contraceptive use among postpartum mothers in Cameroon: implications for improving the coverage of postpartum family planning services

BackgroundThe health hazards of short inter-birth intervals are severe in Cameroon. One-quarter of inter-birth intervals are less than 24 months and the probability of death before age 5 for children born after a short interval is double that associated with intervals of 36–47 months. We examine the risk of an unintended pregnancy in the 18 months following childbirth in Cameroon, taking into account the protective effects of lactational amenorrhea, delayed resumption of sex as well as contraceptive use.MethodsData from 3007 postpartum women in the nationally representative 2018 Cameroon Demographic and Health Survey were used. Risk of an unintended pregnancy was defined from current status information on resumption of sex and menses, contraceptive use, desire for another child within 12 months, and, for the minority of pregnant women, whether the conception was intended. Predictors of risk, and of modern method use, were assessed by bivariate and multivariate analysis.ResultsIn the first 6 postpartum months, only 8% of women were fully at risk (i.e., sex and menses resumed but no contraceptive use), rising to 24% at 6–11 postpartum months, and further to 30% at months 12–17. Though 89% wanted to delay the next birth by at least 1 year, only 17% were currently using a modern method. Menstruating women were much more likely to be users than amenorrheic women: 27% versus 15% at months 12–17 postpartum. Urban and better educated women recorded higher contraceptive use but lower protection from other factors than rural, less educated women, with the net result that risk differed little across these population strata. Uptake of maternal and child health (MCH) services was high but only one-third of women had discussed family planning at a facility visit during the preceding 12 months.ConclusionsThese results underscore the need for improved postpartum family planning services by means of closer integration with mainstream health services. In view of evidence from other sources of heavy workload and weak motivation of health staff, this will require strong leadership. A related priority is to increase the number of staff trained in provision of long-acting methods, such as implants.

Interbirth interval and maternal anaemia in 21 sub-Saharan African countries: A fractional-polynomial analysis.

BackgroundMaternal anaemia is a global public health problem contributing to adverse maternal and perinatal outcomes. In addition to other risk factors, interbirth interval has been identified as a potentially modifiable risk factor of maternal anaemia. However, the current evidence for the association between interbirth interval and maternal anaemia remains inconclusive. Hence, this study examined the association between the interbirth interval and maternal anaemia in sub-Saharan Africa.MethodsWe conducted a multinational cross-sectional study of interbirth interval (time between two singleton live births) and maternal anaemia (haemoglobin levels < 12 g/dl for non-pregnant women, < 11 g/dl for pregnant women) for 21 sub-Saharan African countries using the most recent nationally representative Demographic and Health Surveys, 2010–2017. A weighted multivariable fractional polynomial function was used to estimate the non-linear relationship between interbirth interval and maternal anaemia, considering interbirth interval as a continuous variable and adjusting for potential confounders. Analyses were stratified by reproductive classification (non-pregnant and pregnant women).ResultsThere were 81,693 women included in the study (89.2% non-pregnant, 10.8% pregnant). Of all women, 32.2% were in their postpartum period. Overall, 36.9% of women had anaemia (36.0% of non-pregnant and 44.3% of pregnant women). Of the participants, 15% had a short interbirth interval (<24 months), and 16% had a long interbirth interval (≥ 60 months). We found that both short and longer interbirth intervals were associated with an increased risk of maternal anaemia in a dose-response fashion. Relatively a lower risk of maternal anaemia was observed between 24 and 40 months of interbirth intervals.ConclusionsOur findings suggest that both short and longer interbirth intervals were associated with an increased risk of maternal anaemia in sub-Saharan Africa.

Multilevel analysis of grand multiparity: Trend and its determinants in the Sidama National Regional State of Ethiopia: a cross-sectional study design from demographic and health survey 2000–2016

ObjectiveThe study was aimed at examining the magnitude, trends and determinants of grand multiparity in the Sidama regional state of Ethiopia.DesignWe retrieved cross-sectional data from the Ethiopia Demographic and Health...

Larger females have more calves: influence of maternal body length on fecundity in North Atlantic right whales

North Atlantic right whales (NARW) are critically endangered and have been declining in abundance since 2011. In the past decade, human-caused mortalities from vessel strikes and entanglements have been increasing, while birth rates in the population are at a 40 yr low. In addition to declining abundance, recent studies have shown that NARW length-at-age is decreasing due to the energetic impacts of sub-lethal entanglements, and that the body condition of the population is poorer than closely related southern right whales. We examined whether shorter body lengths are associated with reduced fecundity in female NARW. We compared age-corrected, modeled metrics of body length with 3 metrics of fecundity: age at first reproduction, average inter-birth interval, and the number of calves produced per potential reproductive year. We found that body length is significantly related to birth interval and calves produced per reproductive year, but not age at first reproduction. Larger whales had shorter inter-birth intervals and produced more calves per potential reproductive year. Larger whales also had higher lifetime calf production, but this was a result of larger whales having longer potential reproductive spans, as body lengths have generally been declining over the past 40 yr. Declining body sizes are a potential contributor to low birth rates over the past decade. Efforts to reduce entanglements and vessel strikes could help maintain population viability by increasing fecundity and improving resiliency of the population to other anthropogenic and climate impacts.

Differences in risk factors for incident and recurrent preterm birth: a population-based linkage of 3.5 million births from the CIDACS birth cohort

BackgroundPreterm birth (PTB) is a syndrome resulting from a complex list of underlying causes and factors, and whether these risk factors differ in the context of prior PTB history is less understood. The aim of this study was to explore whether PTB risk factors in a second pregnancy were different in women with versus without previous PTB.MethodsWe conducted a population-based cohort study using data from the birth cohort of the Center for Data and Knowledge Integration for Health (CIDACS) for the period 2001 to 2015. We used longitudinal transition models with multivariate logistic regression to investigate whether risk factors varied between incident and recurrent PTB.ResultsA total of 3,528,050 live births from 1,764,025 multiparous women were analyzed. We identified different risk factors (Pdifference <0.05) between incident and recurrent PTB. The following were associated with an increased chance for PTB incidence, but not recurrent: household overcrowding (OR 1.09), maternal race/ethnicity [(Black/mixed—OR 1.04) and (indigenous—OR 1.34)], young maternal age (14 to 19 years—OR 1.16), and cesarean delivery (OR 1.09). The following were associated with both incident and recurrent PTB, respectively: single marital status (OR 0.85 vs 0.90), reduced number of prenatal visits [(no visit—OR 2.56 vs OR 2.16) and (1 to 3 visits—OR 2.44 vs OR 2.24)], short interbirth interval [(12 to 23 months—OR 1.04 vs OR 1.22) and (<12 months, OR 1.89, 95 vs OR 2.58)], and advanced maternal age (35–49 years—OR 1.42 vs OR 1.45). For most risk factors, the point estimates were higher for incident PTB than recurrent PTB.ConclusionsThe risk factors for PTB in the second pregnancy differed according to women’s first pregnancy PTB status. The findings give the basis for the development of specific prevention strategies for PTB in a subsequent pregnancy.

Short interbirth interval and associated factors among women with antecedent cesarean deliveries at a tertiary hospital, Southwestern Uganda

BackgroundWomen with previous cesarean deliveries, have a heightened risk of poor maternal and perinatal outcomes, associated with short interbirth intervals. We determined the prevalence of short interbirth interval, and associated factors, among women with antecedent cesarean deliveries who delivered at Mbarara Regional Referral Hospital (MRRH), in southwestern Uganda.MethodsWe conducted a cross-sectional study on the postnatal ward of MRRH from November 2020 to February 2021. We enrolled women who had antecedent cesarean deliveries through consecutive sampling. We obtained participants’ socio-demographic and obstetric characteristics through interviewer-administered structured questionnaires. We defined short interbirth interval as an interval between two successive births of < 33 months. Modified Poisson regression was used to identify factors associated with short interbirth intervals.ResultsOf 440 participants enrolled, most had used postpartum family planning (PPFP) prior to the current pregnancy (67.5%), and most of the pregnancies (57.2%) were planned. The mean age of the participants was 27.6 ± 5.0 years. Of the 440 women, 147 had a short interbirth interval, for a prevalence of 33% (95%CI: 29–38%). In multivariable analysis, non-use of PPFP (adjusted prevalence ratio [aPR] = 2.24; 95%CI: 1.57–3.20, P < 0.001), delivery of a still birth at an antecedent delivery (aPR = 3.95; 95%CI: 1.43–10.9, P = 0.008), unplanned pregnancy (aPR = 3.59; 95%CI: 2.35–5.49, P < 0.001), and young maternal age (aPR = 0.25 for < 20 years vs 20–34 years; 95%CI: 0.10–0.64, P = 0.004), were the factors significantly associated with short interbirth interval.ConclusionOne out of every three womenwith antecedent caesarean delivery had a short interbirth interval. Short interbirth intervals were more common among women with history of still births, those who did not use postpartum family planning methods, and those whose pregnancies were unplanned, compared to their counterparts. Young mothers (< 20 years) were less likely to have short interbirth intervals compared to those who were 20 years or older. Efforts should be made to strengthen and scale up child-spacing programs targeting women with previous cesarean deliveries, given the high frequency of short interbirth intervals in this study population.

On the evolution of distinctive natal coat coloration in primates

AbstractObjectivesNeonates of several primate species are born with very different pelage coloration from their parents but then assume adult coat color within weeks or months of birth. We set out to test the three conventional functional hypotheses for this distinctive transient natal coat coloration in primates (infanticide, allomothering, and confusion of paternity) as well as solicitation of maternal care, and across all neonate primates, background matching, and Gloger's rule (dark coats being associated with humid environments).Materials and MethodsTo examine the functional significance of neonate pelage coloration, we employed five different measures of distinctive coat coloration, new updated information on primate life histories, and a complete primate phylogeny of 286 species to control for shared ancestry.ResultsAcross primates, we found a strong association between distinctive natal coats and the prevalence of infanticide but no support for allomothering or confusing paternity. We also found that species in which young have distinct natal coats have relatively shorter interbirth intervals, as well as a tendency to be weaned earlier which is unrelated to allomothering. Darker primate natal coats (whether distinctive or not) are not found in shadier, warmer, or wetter habitats.DiscussionWhile distinct natal coats in primates are generally found in infanticidal species, we argue on logical grounds that this is not an advertisement to incoming males but instead neonate coloration solicits greater maternal care. This enables infants to pass through this infanticide‐induced mortality‐prone infant phase more rapidly. Conspicuous neonate coats in comparison to adults appear to act as a super‐normal stimulus for mothers to hasten post‐natal development of their offspring.

After short interbirth intervals, captive callitrichine monkeys have higher infant mortality

SummaryLife history theory predicts a trade-off between the quantity and quality of offspring. Short interbirth intervals—the time between successive births—may increase the quantity of offspring but harm offspring quality. In contrast, long interbirth intervals may bolster offspring quality while reducing overall reproductive output. Further research is needed to determine whether this relationship holds among primates, which have intensive parental investment. Using Cox proportional hazards models, we examined the effects of interbirth intervals (short, normal, or long) on infant survivorship using a large demographic dataset (n = 15,852) of captive callitrichine monkeys (marmosets, tamarins, and lion tamarins). In seven of the nine species studied, infants born after short interbirth intervals had significantly higher risks of mortality than infants born after longer interbirth intervals. These results suggest that reproduction in callitrichine primates may be limited by physiologic constraints, such that short birth spacing drives higher infant mortality.

Short interpregnancy interval and its predictors in Ethiopia: implications for policy and practice.

Introductioninterpregnancy interval (IPI) is the time elapsed between the birth of one live child and the conception of subsequent pregnancies. Several studies in Ethiopia indicated a high prevalence of a short interbirth interval - a proxy indicator of IPI. However, these studies were prone to selection bias as they did not include women who did not go on to have another pregnancy. Therefore, this study estimated the incidence of short IPI (< 24 months) and its risk factors among women who had at least one child in Ethiopia.Methodswe used a retrospective analysis of a cross-sectional study from the nationally representative Ethiopian Mini Demographic and Health Survey (EMDHS) conducted in 2019. The event was defined as the conception of the subsequent pregnancy within 24 months following the last child. A weighted Cox Proportional Hazard model was used to estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (CIs).Resultsthe incidence of short IPI was 6%. Rural residence, being young age, low educational attainment, having the last child died and having female last birth were the risk factors for short IPI. However, having higher parity, attending Antenatal Care (ANC) visits, being delivered at a health facility, and receiving Postnatal Care (PNC) visits were the protective factors for short IPI.Conclusionthe incidence of short IPI in Ethiopia was considerable. Sociodemographic and health service-related factors determine the short IPI. Hence, considering the immediate and long-term health and socioeconomic consequences of short IPI, the Ethiopian government should implement holistic and multisectoral interventions.

1344Interbirth interval and maternal anaemia in 21 sub-Saharan African countries: a multinational cross-sectional study

Abstract Background Anaemia is a global public health problem, which disproportionately affects women in sub-Saharan Africa (SSA). The causes of anaemia are multifactorial, and a short interbirth interval has been identified as a potentially modifiable risk factor. However, the current evidence for the association between interbirth interval and maternal anaemia remains inconclusive. Hence, this study aimed at examining the association between the interbirth interval and maternal anaemia in SSA. Methods We conducted a multinational cross-sectional study of interbirth interval (time between two singleton live births) and maternal anaemia for 21 SSA countries using the most recent nationally representative Demographic and Health Surveys, 2010-2017. Modified Poisson regression models were used to estimate the relative risk (RR) and 95% confidence intervals (CIs) after adjusting for confounding variables. Results There were 81,693 women included in the study (89.2% nonpregnant, 10.8% pregnant and 32.2% postpartum). Overall, 36.9% of women had anaemia (36.0% of non-pregnant, 44.3% pregnant, and 38.7% of postpartum women). Compared to a 24-35 months interbirth interval, maternal anaemia was not associated with short (&amp;lt;24 months) interbirth intervals (aRR 1.01, 95% CI; 0. 98, 1.04) or long (≥60 months) interbirth interval (aRR 1.00, 95% CI 0.96, 1. 04). Conclusions Our finding revealed insufficient evidence that both short and long birth intervals were associated with the risk of maternal anaemia in SSA. Key messages It is unlikely that the high prevalence of maternal anaemia in SSA can be reduced by avoiding short nor long interbirth intervals.

Children are important too: juvenile playgroups and maternal childcare in a foraging population, the Agta.

Non-maternal carers (allomothers) are hypothesized to lighten the mother's workload, allowing for the specialized human life history including relatively short interbirth intervals and multiple dependent offspring. Here, using in-depth observational data on childcare provided to 78 Agta children (a foraging population in the northern Philippines; aged 0-6 years), we explore whether allomaternal childcare substitutes and decreases maternal childcare. We found that allomother caregiving was associated with reduced maternal childcare, but the substitutive effect varied depending on the source and type of care. Children-only playgroups consistently predicted a decrease in maternal childcare. While grandmothers were rarely available, their presence was negatively associated with maternal presence and childcare, and grandmothers performed similar childcare activities to mothers. These results underscore the importance of allomothering in reducing maternal childcare in the Agta. Our findings suggest that flexibility in childcare sources, including children-only playgroups, may have been the key to human life-history evolution. Overall, our results reinforce the necessity of a broad conceptualization of social support in human childcare. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.