European Journal of Cardiovascular Medicine

Contrary to earlier beliefs, late preterm newborns are now recognised to have a greater susceptibility to illness and death, despite being considered as developed as full-term infants in terms of their physical and metabolic development [1, 2]. Due to their higher prevalence, late preterm newborns have a significant influence on the healthcare system in comparison to full term infants. Respiratory diseases frequently occur in late preterm infants and are more prevalent compared to full-term infants. The likelihood of the newborn needing oxygen and ventilatory assistance, as well as being admitted to the intensive care unit, is higher. Common respiratory problems include transitory tachypnoea of the infant, respiratory distress syndrome, pneumonia, and pulmonary hypertension [3, 4].

Addressing these abnormalities beforehand has been a matter of concern, and multiple researchers have proposed that using corticosteroids throughout pregnancy could expedite the development of the lungs in infants born in the late preterm stage. Contrary to earlier beliefs, late preterm newborns are now recognised to have a greater susceptibility to illness and death, despite being considered as developed as full-term infants in terms of their physical and metabolic development [5, 6]. Due to their higher prevalence among premature infants, late preterm infants have a significant influence on the healthcare system in comparison to full term infants. Respiratory diseases frequently occur in infants born late preterm and are more prevalent in this group compared to full-term newborns. The likelihood of the newborn needing oxygen and ventilatory assistance, as well as being admitted to the intensive care unit, is significantly higher. Prevalent respiratory problems include transitory tachypnoea of the infant, respiratory distress syndrome, pneumonia, and pulmonary hypertension [7-9].

Addressing these diseases proactively has been a matter of concern, and multiple researchers have proposed that administering corticosteroids throughout the prenatal period could expedite the development of lungs in infants born during the late preterm stage.  A randomised controlled experiment was conducted to assess the efficacy of administering corticosteroids during the antenatal period (between 34-36 weeks of pregnancy) in lowering the occurrence of neonatal respiratory problems [10, 11]. The purpose of the study was to investigate the efficacy of prenatal corticosteroids in reducing morbidity and mortality in preterm infants.

This was a prospective observational study, and the primary purpose of this study was to determine whether or not the treatment of corticosteroids prior to birth in women who were born prematurely had an impact on the outcomes of their condition. The patients who participated in this study were chosen from the Department of Obstetrics and Gynaecology, Rangaraya Medical College, Kakinada, Andhra Pradesh, India. Between the May 2023 to April 2024, this study was carried out using several methods.

During the specified time frame, there were 1200 full-term births and 110 preterm births, resulting in an overall yearly preterm birth rate of 8.04%. Out of the latter category, there were 77 babies born as late preterm, which accounted for 6% of all live births and 74.4% of all preterm deliveries. Out of all newborns born somewhat before their due date, 63.2% required admission to the neonatal unit for an average duration of days. Out of the total number of newborns admitted to the NICU, 28.2% of them needed to stay in the hospital for an average of 7.11 ± 10.4 days. This accounts for 20.6% of all the newborns admitted to the NICU.

Table 1: Morbidity of late preterm infants 

Table 1 presents the morbidity rates of late preterm newborns. The highest morbidity rate is observed in TTNB, accounting for 18.18%. The morbidity rates for HMD and Pneumothorax are 10.90% and 1.81% respectively. PHT has a morbidity rate of 3.63%, while oxygen therapy, CPAP, CMV, surfactant therapy, and hypoglycemia have morbidity rates of 1.81%, 5.45%, 7.27%, 6.36%, and 1.81% respectively.

Table 2: Comparative study of morbidity and mortality

Table 2 presents a comparative analysis of morbidity and mortality rates among patients who were exposed to corticosteroids versus individuals who were not administered corticosteroids. Table 2 displays the findings of the comparison analysis between the two groups for newborn morbidity and necessary interventions.

Table 3: Comparison of late preterm and term morbidities

Table 3 presents a comparison of the occurrences of illnesses in babies born in the late preterm period and those born at full term. The admission rate to the neonatal ICU was much greater in LPIs who had not received prenatal corticosteroids. The incidence of NICU admission was markedly elevated in this cohort. The incidence of illnesses related to late preterm birth was much lower in the group that received antenatal corticosteroids. Specifically, there were substantial differences in the occurrence of transient tachypnea of the newborn (TTNB), hypoglycemia, digestive intolerance, and jaundice requiring phototherapy. The requirement for breathing assistance through oxygen therapy and nasal CPAP, as well as the need for fluid therapy and parenteral nourishment, were notably greater in the groups with LPI who did not receive prenatal corticosteroids.

Aligned with the literature that was examined, the hospital's preterm birth rate throughout the studied period was 8.04%. Out of the patients in this group, 74.4% were classified as belonging to the LP subgroup. These figures align with the findings published in the majority of wealthy countries, where similar upward patterns have also been documented. Several contributing factors include advanced maternal age in first-time moms, multiple pregnancies, the use of assisted reproductive technology, and an increase in the number of inductions of labour and scheduled caesarean deliveries. [12, 13] The study found that 42.5% of the mothers were 35 years old or older, 46.6% were first-time mothers, 7.7% of pregnancies were the result of assisted reproduction, 24.1% of pregnancies involved multiple gestations, and 41.7% of deliveries were induced due to maternal or foetal indications, which align with previous findings in the literature. These conclusions are logical given the interconnectedness of all these components. Maternal age that is considered advanced is linked to an increased likelihood of obstetric difficulties, which often necessitate the termination of pregnancy at an early stage. Additionally, advanced maternal age is more commonly related with the requirement for assisted reproduction technologies, which raise the chances of having a multiple pregnancy [14-16].

Within our research, a significant proportion of LPIs, specifically 63.2%, were admitted to the neonatal unit. Additionally, 28.2% of these infants necessitated critical care, resulting in a substantial number of hospital hospitalisations. It is worth noting that this group constitutes the greatest subset among preterm newborns [17]. They constitute 17% of all admissions to the Neonatal Intensive Care Unit, and 20.6% of admissions specifically to the NICU. The admission requirements for our hospital include a gestational age of 34 weeks or less. Alternatively, admission is also granted to infants with a gestational age exceeding 34 weeks, but with a birth weight below 2300 g, or those who have any medical condition necessitating monitoring and/or treatment [18-20].

Pharmacologically inducing foetal lung maturity using corticosteroids is the most effective technique for improving the prognosis of preterm newborns, as supported by the evidence. Therefore, both Spanish and American obstetricians and gynaecologists associations suggest giving corticosteroids to pregnant women who are at risk of giving birth prematurely between 24 and 34 weeks of pregnancy. This is done to lower the occurrence of acute respiratory distress syndrome, intraventricular haemorrhage, necrotizing enterocolitis, and/or neonatal death [21-23].

Our study found that 29.6% of LPIs (late preterm infants) had been administered prenatal corticosteroids. Furthermore, the rates of admission were notably higher among LPIs who had not received antenatal corticosteroids, both in the newborn unit and the NICU. Respiratory problems are commonly observed in individuals born late preterm. Within this study, a total of 27.1% of individuals with LPIs experienced respiratory difficulties, with Transient Tachypnea of the Newborn being the most commonly diagnosed condition. The elevated occurrence may be attributed to anomalies or delays in the elimination of fluid from the lungs of the newborn after delivery [25-27]. Multiple studies suggest that the transportation of salt across the alveolar epithelium is the primary mechanism responsible for clearing fluid from the foetal lungs. This process develops as the gestational age progresses and becomes especially significant in the final weeks of pregnancy. The pathogenesis of TTNB may be attributed to the decreased number and underdeveloped salt transport pathways in LPIs. The occurrence of TTNB in the group with LPIs not treated with steroids was markedly higher compared to the group exposed to steroids: 28% versus 2.7% [28, 29]. The disparity can be accounted for by the observation that only corticosteroids appear to enhance the production and function of sodium channels in the alveolar epithelium, so aiding in the absorption of fluid in the lungs. Research indicates that during full-term pregnancy and natural vaginal delivery, there is a notable increase in naturally occurring steroids and catecholamines. These hormonal fluctuations are crucial for the development of the foetus and to ensure a smooth transition to neonatal life. This could explain the increased occurrence of transient tachypnea of the newborn in late preterm infants who have not received corticosteroids, particularly in those born via caesarean section, a more frequent operation in this population [30, 31].

Gaining insight into the morbidity risk among late preterm infants not only aids in predicting and handling these vulnerable newborns, but also assists in identifying the appropriate date for discharge and post-discharge follow-up. Additionally, it informs decisions on non-emergency obstetric interventions. Our investigation revealed that the occurrence of different neonatal health problems and deaths was influenced by the underlying causes. Given that the specific reason is acknowledged as a crucial element in determining the outcome of newborns, it is imperative to prioritise efforts in identifying the cause of late preterm births and taking measures to prevent avoidable occurrences of late preterm births.

Funding

None

Conflict of Interest

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