Risk factors of preterm babies: Regarding to gestational age, maternal medical history, delivery mode and influences

Background: The World Health Organization defines preterm birth as any birth before 37 completed weeks of gestation or fewer than 259 days since the first day of woman’s last menstrual period. Objectives: To identify antepartum, intrapartum, and fetal risk factors of preterm delivery and their effect on neonatal survival. Methods: A cross-sectional study conducted on 185 neonates delivered preterm in neonatal intensive care unit of Misurata Central Hospital, Libya. Retrospective analysis of hospital recorded over a period of one year have be done, that from January to December 2019. Data include the babies’ and mother demographic characteristics; antepartum, intrapartum, postpartum risk factors; and APGAR scores of such babies at 1 min; and survival for preterm baby were analyzed. Results : Majority of cases are born to mothers aged 18-35 years (80%) and that is not significant P≥0.05, while the mode of delivery, C\S was 70% and Antepartum risk factors infection was took the upper hand 40%, and that is highly statistically significant. There is no significant correlation regarding gestational age and gender where P≥0.05, while the weight and APGAR score are highly significant relationship with gestational age (P˂0.05) as shown in. Conclusion: Majority of cases are borne to mothers aged 18-35 years while the mode of delivery, vaginal delivery was the upper hand in extreme preterm while C\S is of priority of others. Antepartum risk factors were took the upper hand 40%. Male and female equally at risk to be delivered prematurely. APGAR score and birth weight improved with increase the gestational age. The mechanical support is one of the early respiratory in extreme babies that improve survival rate.


Introduction
The World Health Organization (WHO) defines preterm birth (PTB) as any birth before 37 completed weeks of gestation or fewer than 259 days since the first day of woman's last menstrual period (LMP) [1].PTB can be sub-categorized as late preterm delivery-34 to 36 completed week's gestation, moderately preterm-32 to 34 completed weeks, very preterm-less than 32weeks, and extremely preterm-less than 28 weeks gestation [2].Being born preterm is a risk factor that put infants at higher risks of chronic diseases and death later in life [3].Babies born preterm have continued to remain below the standard growth curve and demonstrate the reduced ability for catch-up growth in their life [4].Moreover, preterm delivery and its consequences contribute to subsequent disabilities and neurological abnormalities to the infant's potential that may persist all over their lives amongst survivors [2,4,5].
In the USA, 70% of preterm births were idiopathic and the rest were due to preeclampsia (50%), fetal distress (25%) and abruption (25%).In another study, preterm multifetal pregnancies and hypertension introduced as the major factors affecting preterm birth [5].There is an intense survival gap for premature babies depending on where they are born [5,6].Preterm birth is becoming the cause for economic instability in the family, community and the nation at large.It is not only resulted in economic burdens due to initial neonatal treatment but also in substantial costs to health services after discharge from the neonatal unit [5].This is paper was aimed to identify antepartum, intrapartum and fetal risk factors of preterm delivery and their effect on neonatal survival.

Study setting
This study conducted as cross-sectional study at the neonatal intensive care unit of pediatric department at Misurata Central Hospital, one of the largest public sector tertiary care hospitals in Libya.We retrospectively analyzed the hospital records over a period of one year from January to December 2019.Outcome was analyzed as cross-sectional comparative study.

Inclusion criteria
Newborn babies were considered.

Data collection
A retrospective study conducted on 185 neonates delivered preterm in neonatal intensive care unit of Central Hospital at Misurata.The hospital records retrospectively analyzed for one year, investigating the distribution of cases according to risk factors and then comparing the risk factors according to subsequent baby survival or died.The babies' and mothers' demographic characteristics; antepartum, intrapartum, postpartum risk factors; and APGAR (activity (tone), pulse, grimace, appearance, and respiration) scores of such babies at 1min; and survival for preterm baby were analyzed.Maternal characteristics and antepartum risk factors obtained, regarding maternal age, parity, antenatal visits, history of abortion and prior neonatal death, antepartum hemorrhage, anemia, hypertension, toxemia of pregnancy, diabetes mellitus, polyhydramnios and oligohydramnios.In addition, intrapartum risk factors obtained, including vaginal bleeding, umbilical cord prolapse, multiple pregnancy, prolonged labor, malpresentation, PROM (premature rupture of membrane), meconium stained amniotic and mode of delivery.Moreover, postpartum and fetal risk factors were obtained, regarding sex, gestational age and birth weight.

Statistical analysis
The collected data analyzed by SPSS software version 21.The results summarized as frequencies and percentage for qualitative data, (not found in analysis) and then data presented and displayed in suitable tables.In addition, the associated relationship for qualitative data was performed using Chi-square test.The non-parametric Mann-Whitney test used for quantitative measurements.Results were accepted as significant when (p <0.05).

Results
Majority of cases are borne to mothers aged 18-35 years (80%) and that is not significant while the mode of delivery, C\S was 70% and Antepartum risk factors (Infections, maternal disease, none) infection was took the upper hand 40%, and that is highly statistically significant (p <0.05) as shown in (Table, 1).
There is no statistically significant (p-value ˃ 0.05) of relationship among preterm babies gestational age and gender, while the weight and APGAR score are highly statistically significant associated relationship with gestational age (pvalue < 0.05) as shown in (Table, 2).
There is significant different regarding gestational age and, respiratory supportive measure, hospital stay, antibiotics use and survival outcomes of preterm neonates in this study thus shown in (Table,3).

Discussion
PTB is a prevalent obstetric complication associated with significant neonatal mortality and morbidity worldwide.
Addressing the burden of PTB in developing countries is of public health importance due to its high (9 to 16%) prevalence [7].
The studies done so far in Libya in this regard were only a few as reported.Therefore, there is no updated reviews in Libya for support the current findings.In this study, (50 %) are girls and (50%) are boys.This nearly approaches other studies.Independent of biomedical risk, maternal prenatal stress factors are significantly associated with infant birth weight and with gestational age at birth [4].
Majority cases in current study are born to mothers aged 18-35 years (80%) and that is not significant while the mode of delivery, C\S was 70% and Antepartum risk factors (Infections, maternal disease, none) infection was took the upper hand 40%, and that is highly statistically significant.
While, the mode of delivery, vaginal delivery was reached the upper hand the proper cause most likely, the mode of delivery not organized, in other studies; Cesarean delivery was not associated with improved neonatal outcomes in preterm SGA newborns and was associated with an increased risk of respiratory distress syndrome [4].
In this study there is significant associated relationship regarding gestational age and, respiratory supportive measure, hospital stay, antibiotics use and survival outcome of PTB.When, other studies stated that, infants (<28 weeks) can be supported non-invasively at birth with either higher or lower pressures and while higher-pressure support may require less oxygen, it does not eliminate the need for oxygen supplementation [8].Whereas, some studies demonstrated that, the Major neonatal morbidity increases with decreasing gestational age and birth weight [9].

Conclusion
Majority of cases are born to mothers aged 18-35 years and that is not significant while the mode of delivery, vaginal delivery was the upper hand in extreme preterm while C\S is of priority of others.Antepartum risk factors (Infections, maternal disease, none) infection was took the upper hand 40%, and that is highly statistically significant.Male and female equally affected with the risk factors.APGAR score and birth weight improved with increase the gestational age, and they are highly significant.The mechanical support is one of the early respiratory in extreme babies that improve survival rate.

Recommendations
Since preterm delivery is a common problem, while its subsequent sequelae and neonatal death could be prevented once baby delivered preterm, so it is very important to develop strategies for early identification and management of the risk factors associated with preterm birth through community-based interventions involving families, community, health professionals and policy makers.A safe motherhood policy recommended through a minimum of three antenatal visits during pregnancy, screening for high risk, anemia prophylaxis and management, and proper neonatal care and resuscitation.

Table 1
Maternal baseline data of the study population' mother

Table 2
Baseline data of the preterm babies regarding their gestational age

Table 3
Short-term complications of preterm babies regarding their gestational age