Effect of inter-pregnancy interval on pregnancy outcome: a prospective study at Fayoum, Egypt

Abstract

Background: Nonoptimal IPI (interpregnancy interval) that is either short or long contributes to adverse maternal
and perinatal outcomes in both low and high income countries.
Methodology: A prospective cohort study was conducted in two urban primary heath care (PHC) centers in
Fayoum district. The study participants were multigravida pregnant women attending the targeted PHC for
antenatal care (ANC) with inclusion criteria of being in the last trimester, with a live singleton in the current
pregnancy, and registered in ANC records within the PHC center.
Results: The mean age of the study women was (27.3 ± 4.95). Women with IPI < 12 months represented 16.2%,
while women with IPI between 12 and 24 months represented 18.0%. Long IPI of more than 59 months represented
nearly 17%. Low birth weight (LBW) and prematurity were significantly related to short IPI i.e., less than
24 months, however, still birth and pregnancy-induced hypertension (PIH) were related to long IPI > 59 months
with a statistical significant difference (P ≤ 0.05).
Conclusion: Both short and long IPIs were associated with adverse pregnancy outcomes. The short IPIs were
associated with increased risk of prematurity and LBW, and long IPIs were associated with increased risk of still
birth and PIH.
Keywords: Interpregnancy interval, pregnancy outcome, prematurity, perinatal mortality

Full text

38
© IJMDC. https://www.ijmdc.com
International Journal of Medicine in Developing Countries
ORIGINAL RESEARCH
Effect of inter-pregnancy interval on
pregnancy outcome: a prospective study
at Fayoum, Egypt
Eman M. Mahfouz1, Naglaa A. El-Sherbiny2, Wafaa Y. Abdel Wahed2*,
Nashwa S. Hamed2
ABSTRACT
Background: Nonoptimal IPI (interpregnancy interval) that is either short or long contributes to adverse mater-
nal and perinatal outcomes in both low and high income countries.
Methodology: A prospective cohort study was conducted in two urban primary heath care (PHC) centers in
Fayoum district. The study participants were multigravida pregnant women attending the targeted PHC for
antenatal care (ANC) with inclusion criteria of being in the last trimester, with a live singleton in the current
pregnancy, and registered in ANC records within the PHC center.
Results: The mean age of the study women was (27.3 ± 4.95). Women with IPI < 12 months represented 16.2%,
while women with IPI between 12 and 24 months represented 18.0%. Long IPI of more than 59 months repre-
sented nearly 17%. Low birth weight (LBW) and prematurity were significantly related to short IPI i.e., less than
24 months, however, still birth and pregnancy-induced hypertension (PIH) were related to long IPI > 59 months
with a statistical significant difference (P ≤ 0.05).
Conclusion: Both short and long IPIs were associated with adverse pregnancy outcomes. The short IPIs were
associated with increased risk of prematurity and LBW, and long IPIs were associated with increased risk of still
birth and PIH.
Keywords: Interpregnancy interval, pregnancy outcome, prematurity, perinatal mortality.
Introduction
Inter-pregnancy interval (IPI) is defined as the time
lapsed between two consecutive pregnancies [1]. Non-
optimal IPI that is either too short or too long contributes
to adverse maternal and perinatal outcomes in both
low and high income countries [2]. The World Health
Organization (WHO) recommended an interval of at
least 24 months from a live birth to the next pregnancy;
and at least 6 months following abortion [1].
A meta-analysis of 67 studies conducted in 62 countries
as well as an additional study from Brazil, revealed that
poor maternal and perinatal outcomes were associated
with IPIs between 6 and 18 months or longer than 59
months [3].
Short IPI of less than 18 months have been associated
with several bad fetal and neonatal outcomes such
as pre-term birth, low birth weight (LBW), small in
size for gestational age, stillbirth, and newborn/infant
mortality. Also, many adverse maternal outcomes have
been associated with short IPIs as maternal mortality,
miscarriage, and induced abortion [4,5].
Closely spaced pregnancies and lack of sufficient time
to return to the normal pre-pregnancy metabolic state
before the next pregnancy may not allow physiological
recovery for the healing of the reproductive tract or for
hormonal changes [6]. It also initiates processes with
long term implications; as a prospective study [7] found
that the risk of maternal obesity increases with each IPI
of less than 12 months.
The health of both parents is affected due to adverse
effects of short IPI [8]. This is explained by the physical,
emotional, and economic strains involved in dealing with
M. Mahfouz et al, 2018;2(2):38–44.
https://doi.org/10.24911/IJMDC.51-1520268317
Correspondence to: Wafaa Y. Abdel Wahed
*Department of Public Health and Community Medicine,
Fayoum University, Fayoum, Egypt.
Email: wafaayousif313@yahoo.com; Wya00@fayoum.
edu.eg
Full list of author informaon is available at the end of
the arcle.
Received: 15 March 2018 | Accepted: 21 April 2018

Effect of inter-pregnancy interval on pregnancy outcome
39
the needs of two or more children close in age. Mothers of
twins, for example, suffer from higher rates of postnatal
depression than mothers of single infants, and multiple
births are associated with higher risks of subsequent
divorce [9]. Stress associated with short IPIs may have
long term health implications for mothers and fathers as
higher mortality and greater use of prescription drugs in
late midlife than parents with IPIs of 31–41 months [10].
Very long gaps between births may result in maternal
physiological regression i.e., risk for mothers (and
infants) related to those associated with primiparous
women [11]. This may explain why intervals greater
than 59 months were associated with increased risk for
eclampsia and pre-eclampsia [12].
Egypt is the most populous country in the Middle East and
North Africa with a population of more than 94 million.
The annual growth rate of the Egyptian population has
increased to 2.04 in the period from 1996 to 2006, and
in the period from 2006 to 2017 it has increased to 2.56
[13]. This increase in the Egyptian annual growth rate
in this period is due to the change in fertility rates. The
total fertility rate rose substantially from three births per
woman to 3.5 births per woman. This increase mandates
more and more efforts in birth spacing activities [14].
The study aimed to determine the maternal health
problems and adverse pregnancy outcomes associated
with different IPIs in Fayoum district, Fayoum
governorate, Egypt.
Subjects and Methods
A prospective cohort study was conducted in two primary
health care (PHC) centers in Fayoum health district EL
Hadeka Urban primary health center (UHC) and El Kiman
UHC. They were selected as they are big centers located
in urban dense population areas and also, serve some of
the small rural communities surrounding the city with a
high rate of women seeking antenatal care (ANC) and their
staff was also ready to collaborate in the study. The average
daily flow for antenatal care seeking service in any of the
two centers ranged from 12 to 15 pregnant women.
The study participants were multigravida pregnant
women attending the targeted PHC for ANC with
inclusion criteria of being in the last trimester, with a live
singleton in the current pregnancy, and registered in ANC
records within the PHC facility.
The sample size was calculated using OpenEpi version
3.01 according to the following data: prevalence of
anemia in married females in the reproductive age is
25%–30% according to Egypt demographic and health
survey (EDHS) 2014 [14] Confidence Interval is 95%
and precision level is 5%. The calculated sample size was
313 and increased by 5% to compensate the unresponded.
Through this work, 359 pregnant women were interviewed
in the first stage, those could be contacted in the second
stage were 319. A representative sample from the overall
attending women fulfilling the inclusion criteria was
selected. A systematic random technique was used to
select the target women. The study included 359 women,
200 women from El-Hadeka UHC, and 159 women from
El Kiman UHC.
In the first phase, during the antenatal period, 359
pregnant women were willing to participate and signed
the consent form. They were interviewed using structured
administered questionnaire. Then, measurement of blood
pressure, weight, and height was done. Their recorded
data concerning hemoglobin concentration and weight
in the first trimester were revised. Their weight gain in
pregnancy was calculated by subtraction of their weight in
the first trimester from their weight in the third trimester.
In the second phase, out of the total number of women,
319 were available and were followed within 7–10 days
after delivery by telephone and checking the records
for women who gave birth in the catchment area of
the two UHC. Both the mother and the newborn were
assessed for adverse outcomes. Maternal outcomes such
as anemia, pregnancy-induced hypertension (PIH), post
or intra-partum hemorrhage, and delivery complications
were assessed. Neonatal complications were still birth,
preterm, LBW, and early neonatal death.
A pre-tested structured questionnaire form was used to
collect data from the study women. Most of the questions
were pre-coded and close ended, so that information
obtained can be easily computed. Data collection form
was used to obtain data from ANC records in the PHC
facility, and also, the post natal period records. Post-
delivery assessment sheet was designed to collect
necessary data about delivery, maternal condition, and
perinatal and neonatal condition (birth weight, preterm,
still birth, and perinatal mortality).
All the study tools were previously tested. A pilot study
was done in the actual field situation with five women
from each of the targeted PHC facility.
All the collected interview questionnaires were revised
for completeness and logical consistency. All the
collected data was translated into English to facilitate
data manipulation. Pre-coded data was entered on the
computer using Microsoft Office Excel software program
for Windows, 2010. IPI in this research considered short
if the span of time between birth and the start of a next
pregnancy was less than 24 months, optimal IPI is
considered between 24 and 59 months, and is considered
long if IPI is more than or equal to 60 months [1].
PIH was diagnosed if systolic blood pressure ≥140
mmHg and/or diastolic blood pressure ≥90 mmHg at ≥20
weeks of gestation [15]. Anemia was defined if maternal
hemoglobin level was less than 11 mg/dl. [16]. Stillbirth
is a baby born with no signs of life at or after 28 weeks’
gestations according to the WHO definition [17]. Preterm
birth, defined as birth before 37 weeks of gestation.
Preterm babies are defined as babies born alive before
completing 37 weeks of pregnancy [18]. LBW has been
defined as weight at birth of less than 2.5 kg (5.5 pounds)

Effect of inter-pregnancy interval on pregnancy outcome
40
[18]. Early neonatal death is defined as the death of the
baby in the first week after birth [17].
Data were analyzed using Statistical Package for Social
Science version 20.0 software, SPSS, Inc., Chicago, IL.
Data were summarized using mean and standard deviation
(SD) values for quantitative data, number, and percentage
for qualitative variables. Analysis of variance test was
used to compare quantitative parameters of mother and
fetus across different IPI categories, a chi-square (X2) test
was used to compare qualitative data of maternal and fetal
characteristics across different IPI categories. The least
statistical significance level used was at P ≤ 0.05.
Results
The mean age of the study women was (27.3 ± 4.95)
years old. The majority of the women were at the peak
of their fertility life, with age ranging from 25 to 34.9
years old constituting 60.2%. As regard to the place of
residency, more than half of the study women were living
in rural areas (52.6%). The level of education of the
women was that almost one quarter 25.3% were illiterate
or could only properly read and write. Almost half of
them, 44.8%, had attained secondary education and only
14.2% had attained university (high) education. The
occupation of the study women reveals that most of the
study women 92.8% were not working (housemakers).
The socio-demographic characteristics of the study
women are shown in Table 1.
Regarding classification of mothers according to IPI,
one-third of the study women 32.9% had IPI between
24 and 36 months. Women with IPI less than 12 months
represented 16.2% while women with IPI of 12–24
months represented about one-fifth of the study women
18.0%. The IPI of 36–59 months was 16.2% and women
with IPI more than 59 months represented nearly 17% as
shown in Figure (1).
Regarding the type of delivery; 70.6% of the study
women had a Cesarean section compared to 29.4% who
had a normal vaginal delivery. The place of delivery was
private clinics in 78.4% of the study women. Prematurity
represented the most frequent complication 15%.
Stillbirth was only 1.6% of the total births and early
neonatal death was 1.3% of the total living births. Most of
the study women 92.5% had no complications. However,
hemorrhage was the most frequent complication
representing 2.5% of the study women.
Table 2 reveals the effect of IPI on fetal outcome.
Stillbirth affected 5.7% of the study women with the IPI
of more than 59 months compared to only 0.9% of the
study women with IPI of less than 24 months.
Regarding maturity of the fetus, there was significant
statistical relation between the maturity of the fetus and
different IPIs (P = 0.000). The percent of premature
neonates (30.2%) born to the study women with IPI of
less than 24 months were about five times more than
premature neonates born to the study women with IPI of
Table 1. Socio-demographic characteristics of the study
women.
Variables Number (359) %
Age ( in years)
Less than 25 108 30.1
25–34.9 216 60.2
More than 35 35 9.7
Mean ± SD 27.3 ± 4.95
Residence
Urban 170 47.4
Rural 189 52.6
Education level of women
Illiterate/read &
write
91 25.3
Primary 35 9.7
Preparatory 20 5.6
Secondary 161 44.8
High education 51 14.2
Education level of husband
Illiterate/read &
write
94 26.2
Primary 33 9.2
Preparatory 21 5.8
Secondary 162 45.1
High education 49 13.6
Occupation of women
No work/house-
maker
333 92.8
Unskilled worker 4 1.1
Semi professional 18 5.0
Professional 4 1.1
Occupation of husband
No work 1 0.3
Industry/agricul-
ture worker
118 32.9
Skilled worker 150 41.8
Semi professional 70 19.5
Professional 20 5.6
Figure 1. Classification of Study women according Inter
pregnancy Interval

Effect of inter-pregnancy interval on pregnancy outcome
41
24–59 months or IPI of more than 59 months (7.6% and
6.0%, respectively).
LBW represented about one-third (29.2%) of the neonates
born to participants with short IPI as compared to a lower
percent of LBW neonates born to the study women with
optimal IPI and those with longer IPI (5.1% and 2.0%,
respectively) with a significant statistical difference
detected (P = 0.000) (Table 2).
The mean birth weight was significantly higher in
neonates born to study women with IPI of more than
59 months was 3.16 ± 0.39 and IPI of 24–59 months
was 3.08 ± 0.39 than those with interval of less than 24
months 2.64 ± 0.44 (P = 0.001).
Table 3 shows that the percentage of women with PIH
was significantly higher in longer interval (16.7%)
in comparison with those of shorter and healthy IPI
Table 2. Effect of the IPI on fetal outcome.
IPI < 24 months IPI 24–59 months IPI > 59 months P value
N (%) N (%) N (%)
Viability
Live birth 106 (99.1) 158 (99.4) 50 (94.3) 0.031*
Still birth 1 (0.9) 1 (0.6) 3 (5.7)
Gestaonal age “Maturity”
Full term 74 (69.8) 146 (92.4) 47 (94.0) <0.001*
Preterm 32 (30.2) 12 (7.6) 3 (6.0)
Early neonatal death
No 103 (97.2) 157 (99.4) 50 (100) 0.202
Yes 3 (2.8) 1 (0.6) 0 (0.0)
Neonatal weight
>2.5 kg “Normal” 75 (70.8) 150 (94.9) 49 (98.0) <0.001*
<2.5 kg “LBW” 31 (29.2) 8 (5.1) 1 (2.0)
*P value signicant at ≤0.05.
Table 3 . Effect of the IPI on maternal complications.
IPI < 24 months IPI 24–59 months IPI > 59 months P value
N (%) N (%) N (%)
Pre-partum complications
Anemia 81(65.9) 98 (55.7) 32 (53.3) 0.137
No anemia 42 (34.1) 78 (44.3) 28 (46.7)
Pregnancy induced 10 (7.4) 10 (5.0) 10 (16.7) 0.031*
No hypertension 113 (92.6) 166 (95.0) 50 (83.3)
Intra or post-partum complicaons
No 97 (90.7) 153 (96.2) 45 (84.9) 0.018*
Yes 10 (9.3) 6 (3.8) 8 (15.1)
*P value signicant at p ≤ 0.05.
Table 4. Mean clinical maternal parameters in different classes of women according to IPI.
IPI < 24 months IPI 24–59 months IPI > 59 months P value
Systolic blood pressure
Range 90–130 80–140 80–150 0.003**
Mean ± SD 107 ± 10.86 107 ± 11.45 113 ± 13.7
Diastolic blood pressure
Range 50–90 50–90 50–100 0.002**
Mean ± SD 69.34 ± 8.8 70 ± 8.8 74 ± 9.8
Hemoglobin
Range 8.5–11.6 8.2–11.9 9–12 0.296
Mean ± SD 10.5 ± 0.57 10.6 ± 0.67 10.7 ± 0.57
Weight gain
Range 4–36 0–24 3–13 0.763
Mean ± SD 8.77 ± 3.2 8.9 ± 2.9 8.6 ± 2.6
**P value signicant at p ≤ 0.05.

Effect of inter-pregnancy interval on pregnancy outcome
42
(P = 0.031). Regarding intra or post-partum complications,
there was significant statistical relation between presence
of these complications and IPI, a lower percent 3.6% of
complication was reported in study women with optimal
IPI in comparison to 9.5% in IPI less than 24 months
and 15% among women with IPI of more than 59 months
with significant difference between complications and
IPIs (P = 0.018). The ratio was about 1:3:5.
There were statistically significant differences in the
mean clinical maternal parameters [systolic blood
pressure (SBP) and diastolic blood pressure (DBP),
among different classes of women according to IPI
(P = 0.003 and 0.002, respectively)]. The mean SBP and
DBP are significantly elevated in women with longer IPI
in comparison with those with optimal and shorter IPI
(Table 4).
Discussion
The intervals between pregnancies; both short (less
than 18 months) and long (60 months and more) have
been associated with increased risk of several adverse
perinatal and maternal outcomes such as preterm birth,
LBW, small for gestational age (SGA), and perinatal
death. This issue is relevant to public health and clinical
practice because if short and/or long IPIs are found to
be independently associated with increased risk of
adverse perinatal and maternal outcomes, birth spacing
might then be considered an intervention to prevent such
adverse outcomes, mainly in the developing world [7].
The duration of short IPI is variable in different
countries. This may be due to different fertility patterns,
population policies, and health services. For example,
studies conducted in the United States considered short
IPI to be less than 18 months [19]. On the other hand,
studies conducted in Africa considered short IPI to be
less than 36 months [20], this is in line with the WHO
recommendations [21]. In this study, short IPI was
considered to be less than 24 months.
Many studies have found an association between short IPI
and adverse neonatal outcomes like still birth, prematurity,
LBW, SGA, and early neonatal or even infant mortality
[5,6,11,22]. The present study revealed that about one-
third of neonates born to women under study with
short IPI were premature with a significant association
(P = 0.000). In a study of Wendt et al. [11], meta-analysis
divided the prematurity into three categories; extreme
prematurity (<33 weeks), moderate prematurity (between
32 and 37 weeks), and all prematurity (<37 weeks). For
an IPI of <6 months and extreme preterm birth, the odds
ratio (OR) was 1.58 (1.40, 1.78). The meta-analysis for
<6 months IPI and all or moderate prematurity had an OR
of 1.41 (1.20, 1.65). For an IPI >6 months and extreme
prematurity, the OR was 1.23 (1.03, 1.46) whereas for
an IPI of >6 months and all or moderate preterm birth,
the OR was 1.09 (1.01, 1.18). Conde-Agudelo et al. [5]
reported similar results in their meta-analysis of preterm
birth. Hogue et al. [22] found that risk of preterm birth was
increased by approximately 40% for IPIs of <6 months.
Regarding LBW, this study found that there was a
significant association between LBW and short IPI
(P = 0.000). The mean birth weight significantly increases
as the IPI increases. The mean birth weight of neonates
born to women with short IPI was 2.64 ± 0.44 compared
to the mean birth weight of optimal and long IPI (3.08 ±
0.39 and 3.16 ± 0.39, respectively). This is similar to what
was found by Van Eijsden et al. [23] that stated that each
increase in the IPI was associated with an increase in the
mean birth weight. Similar findings were also described
in studies conducted in Brazil and Iran [24,25].
Zhu et al. [26] estimated that the population attributed
to the risk of LBW associated with IPIs less than 18–23
months was 9.4%. Conde-Agudelo et al. [5] found an
increased risk of very LBW (<1,500 g) associated with
an IPI of <6 months [OR of 2.01 (1.73, 2.31)] and even
with an IPI of 6–11 months [OR of 1.23 (1.12, 1.35)].
Short IPI may give insufficient time to recover from the
nutritional burden of pregnancy. Van Eijsden et al. [23]
suggested that folate depletion contributes to the risk of
LBW.
As regarded to still birth, the findings of this study
revealed an association between long IPI and stillbirth
(P = 0.031). This may agree with what was found by
Defranco et al. [27] that the lowest frequency of adverse
neonatal outcomes occurred at 40–41 weeks for all IPI
groups. The frequency of other immediate newborn
morbidity was also increased following short and long
IPIs. Inconsistent with other studies that revealed that
short IPIs were associated with adverse neonatal outcome
[3,6]. Moderate evidence was found that an IPI of <12
months increases the risk of still birth, early neonatal
death, preterm birth, and LBW [14].
Previous studies indicate that women with short intervals
(<6 months) between pregnancies are at increased risk of
maternal death, third trimester bleeding and premature
rupture of membranes, puerperal endometritis, and
anemia. Likewise, long intervals (>59 months) were
associated with higher risks of pre eclampsia and
eclampsia. Overall, the evidence did not present a clear
picture of any outcome that was included [14]. Also, a
study conducted in Cairo revealed that the higher adverse
effects on maternal health were associated with IPI of
less than 6 months [28].
This study results didn’t reveal any significant association
between IPI and maternal anemia, post-partum
complications, or weight gain. This is inconsistent with
other studies that showed a decrease in hemoglobin
levels in women with shorter IPIs. Conde-Agudelo et
al. [15] reported an increase in the risk of anemia for
IPIs < 6 months. The quality of evidence assessing the
relationship between IPI and anemia is low [14].
The only significant maternal outcome revealed from this
study is the association between IPI and the occurrence of
PIH. This study revealed significant association between
long IPI and PIH (P = 0.031) as 16.7% of the study
women with long IPI developed PIH compared to those

Effect of inter-pregnancy interval on pregnancy outcome
43
with short or optimal IPI (7.4% and 5.0%, respectively).
Some studies reported an increase in the risk of pre-
eclampsia with increasing IPI between 3 and 7 years. The
study done by Shahi and Kamjou [29] identified that the
rates of pre-eclampsia and eclampsia were highest in the
pregnant women with an interval of >60 months.
In contrast to the results of this study and according
to Mikolajczyk et al. [30], pregnant women with
shorter IPI have a higher risk of maternal mortality and
hypertensive disorders of pregnancy. The limitations
that were encountered by the researcher were children
accompanying their mothers, disturbed them during the
interview, the employed mothers were usually in a hurry
and dependence on mother’s recall for previous child’s
date of birth and her last menstrual period.
Conclusion
Short IPI of less than 24 months is associated with
increased risk of prematurity and LBW while long IPI
more than 59 months is associated with increased risk of
still birth and PIH. Reducing the risk of adverse perinatal
outcomes requires a multidisciplinary approach.
Increasing the prevalence of optimal birth spacing through
increasing the prevalence of the contraceptive utilization
and increasing women awareness may represent an
incremental improvement both in maternal and child
health as well as community and national welfare.
Acknowledgement
The authors would like to thank the managers of UHC
for facilitang Research. We would extend our gratude
to the parcipants for their cooperaon during data
collecon.
List of abbreviaons
ANC Antenatal care
IPI Inter-pregnancy interval
LBW Low birth weight
PHC Primary health care
PIH Pregnancy-induced hypertension
SPSS: Stascal package of social sciences
UHC Urban health center
OR Odds rao
Consent for publicaon
Informed consent form was signed by all the study women
prior to data collecon.
Funding
None.
Declaraon of conicng interests
None.
Ethical approval
This study was reviewed and approved by Fayoum Faculty of
Medicine Research Ethical Commiee.
Author details
Eman M. Mahfouz1, Naglaa A. El-Sherbiny2, Wafaa Yousif
Abdel Wahed2, Nashwa S. Hamed2
1. Department of Public Health and Community
Medicine, Faculty of Medicine, Minia University,
Minia, Egypt
2. Department of Public Health and Community
Medicine, Fayoum University, Fayoum, Egypt
Authors’ contribuon
Eman Mahfouz: Final approval.
Naglaa El sherbiny: Wring, eding, and approval.
Wafaa Abdel Wahed: Wring and stascal analysis.
Nashwa Hamed: Data collecon wring.
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