Keywords :Preterm birth ; Very low birth mass infant ; Ultra low birth mass infant
keywords: preterm birth; VLBWI; ELBWI
The incidence of preterm birth varies among countries and regions, ethnic groups and social conditions, and is generally in the range of 5%-10%. Preterm birth is one of the major causes of perinatal mortality and infant disability, but it is the very low birth weight infants (VLB W I, birth weight < 1500 g) and especially the extremely low birth weight infants (E LB W I, birth weight < 1,000 g), which account for a smaller proportion of preterm births, that cause the greatest harm. However, when comparing the mortality, survival, and disability rates of preterm infants in different countries and regions, it is important to first confirm the definition of preterm birth.
The lower limit of the definition of perinatal period in China is at or beyond 28 weeks of gestation, so the definition of preterm birth in China is from 28 weeks to less than 37 weeks. However, in Europe and the United States, the lower limit of the perinatal definition is either 24 weeks or 20 weeks, so the perinatal mortality rate, preterm mortality rate, survival rate and disability rate may be significantly different. In the United States, for example, the incidence of preterm births < 2,500 g was 715% in 1997, and preterm births < 1,500 g accounted for only 114%, but their mortality accounted for 50% of neonatal mortality and 50% of disability. In Australia, the incidence of low birth weight infants (LBWI, birth weight < 2500 g), very low birth weight infants, and very low birth weight infants are 510%, 111%, and 015%, respectively, accounting for 56%, 45%, and 35% of perinatal mortality, respectively.
As medical technology continues to improve, the survival rates of VLBWI and ELBWI will continue to increase, but with the attendant high cost of care and serious sequelae for preterm infants. Therefore, it has been debated which preterm infants need to be resuscitated, and which preterm infants have to be abandoned for comfort care. There are issues of medical standards, economic conditions, and now more and more ethical principles are being considered.
1. Survival rate of preterm infants
The survival of preterm infants and the sequelae of survival depend on the week of gestation at birth and the quality of the body at birth. Even if the gestational weeks and birth masses are the same, the survival rate and the incidence of sequelae of prematurity vary considerably between countries and regions, as shown in Table 1.
At 22 weeks of gestation, the expected survival rate of European infants is 2-3%, regardless of birth mass. After 24 weeks of gestation, the survival rate of infants with different birth masses can vary considerably, given the same gestational age [4-5]. For example, at 24 weeks, the survival rate is 9% (7%-13%) for a birth mass of 250-499 g and 21% (16%-28%) for a birth mass of 1,000-1249 g. At 28 weeks of gestation, the survival rate was 63% (56%-70%) for infants with birth masses of 500 to 749 g (below the 10th percentile), and 56%-70% for infants with birth masses of 1,250 to 14,000 g (below the 10th percentile).
The survival rate of infants with birth masses of 1,250 to 1,499 g was 90% (87% to 92%). At 32 weeks of gestation, the survival rate for infants with a birth mass of 750-999 g is 80% (70%-88%), and the survival rate for infants with a birth mass of 1500-2499 g is 98% (97%-99%).
Most of the studies on the survival of preterm infants at different gestational weeks and low birth masses in China have been reported in small, single-center studies, and no large, multicenter studies have been reported to date. In addition to differences in medical standards, an important social factor is the attitude of medical personnel and parents toward the rescue of preterm infants. For preterm infants with early gestational age and low birth quality, many medical staff and parents adopt a negative attitude, often leading to abandonment of resuscitation and automatic discharge by the parents. Most of the outcomes of spontaneously discharged preterm infants are unavoidable deaths, which are sometimes counted in the provider’s outcome data for preterm infants, but most are not. This seriously affects the reliability of the statistics, which makes it impossible to make a valid and realistic comparison between our data and foreign data.
2. Treatment of preterm low birth weight infants
Maria Serenell a Pignotti and Gianpaolo Donze lli compared and analyzed 15 national and organizational guidelines on the management of ELBWI from Canada, the United States, Germany, Singapore, France, the United Kingdom, Switzerland, the Netherlands, Australia, Spain, and several international academic organizations. The article, published in the official journal of the American Academy of Pediatrics “Pediatrics” 2008, 121: e193-e198, is presented below.
All guidelines are in agreement regarding the smallest gestational age: at ≤22 weeks of gestation, the newborn has no hope of survival and is not treated. The 22-22+6 weeks of gestation is considered the borderline of human survival and active management is not recommended, except for comfort care. For 25-25+ weeks of gestation, all guidelines are also in agreement: glucocorticoids before delivery to promote fetal lung maturation, cesarean delivery if necessary, and aggressive resuscitation of all newborns unless there is a fatal malformation. From these guidelines, the 23-24 week period is the so-called “gray zone”, where the recommendation is to decide on active resuscitation based on “individual circumstances” and “parental wishes”. In some countries, the “gray area” extends to 25-25+ 6 weeks. All management measures are based primarily on the gestational age at birth, and if the gestational age is uncertain, guidelines recommend a detailed assessment at birth. Most of the guidelines emphasize “comfort” care. It is not surprising that all of these official guidelines come from developed countries, since preterm infants require long-term care and intensive care is expensive. For ethical reasons, different countries will have different choices. These guidelines are very useful to help medical staff and parents to make their own choices when faced with the dilemma of ELBWI, but they do not completely change the attitudes and behaviors of physicians, as there are many factors that influence the decision.
3. The current situation of preterm infants in China
Compared with developed countries, there is a big gap in the management of preterm infants, especially VLBWI and ELBWI in China, which is reflected in the following aspects.
3.1 The survival rate of VLBWI and ELBWI is relatively low In the published Chinese literature, the survival rate of VLBWI and ELBWI is generally low, the survival rate of VLBWI is generally 50%-60%, even in Peking Union Medical College Hospital, the survival rate of VLBWI is only 6813%. In general, in tertiary hospitals, the survival of newborns can only be guaranteed if the gestational week reaches 30-32 weeks and the birth mass reaches 1,000-1500g. The “gray area” is generally between 28 and 30 weeks, below 28 weeks when most medical staff and parents will basically choose to give up resuscitation. In the less developed areas of China, the “gray area” extends to 30-32 weeks, and even if the gestational week reaches 30-32 weeks and the birth mass reaches 1,000-1500 g, active resuscitation is not always chosen [6].
3.2 There is no clinical guideline for the management of preterm infants, especially for VLBWI and ELBWI, because of the great variation in medical conditions throughout China. However, without clinical guidelines, it is impossible to standardize clinical practice, improve the management of VLBWI and ELBWI, and reduce perinatal mortality. Therefore, it is necessary to establish guidelines for the treatment of preterm infants, especially VLBWI and ELBWI in China. For the characteristics of China’s medical level, which varies greatly from region to region, it is better to have 2 versions of the guidelines, one is the “basic version”, which adopts the basic standards, targeting at the less developed areas and primary medical institutions; the other is the “standard version”, which adopts the international standards, targeting at the tertiary medical institutions in developed areas.
3.3 Medical institutions have not established their own standards according to the requirements of evidence-based medicine Whether to actively resuscitate or abandon treatment for preterm infants in the “gray area” requires a rational choice by the parents of the infant based on a well-informed and realistic situation. However, this requires the prerequisite that medical personnel are able to provide survival rates, disability rates, and possible medical costs for preterm infants of appropriate gestational age and birth quality. However, most medical institutions are unable to provide these data accurately, and although they can refer to the data presented in the literature, these small sample, single-center data may not be accurate and may not be appropriate for the institution.
4.The “five-step” approach to the management of preterm infants
The Neonatal Intensive Care Center at ProvidenceSt Vincent Medical Center (PS V MC) in Portland, Oregon, USA, has conducted a meaningful exploration of the management of preterm infants, summarized in a “five-step approach” article published in the official journal of the American Academy of Pediatrics “Pediatrics” (2006), which is presented below [ 7 ].
4.1 Step 1: Education Search the literature, mainly recent articles published in major peer-reviewed obstetric and pediatric journals, for mortality and morbidity (especially neurological) in preterm infants born before 27 weeks with a body mass < 1000 g, and compare this information with that of PSVMC.
4.2 Step 2: Review of local medical practice A meeting of maternal-fetal medicine specialists, neonatologists, obstetricians, neonatal nurses, and labor and delivery and NICU nurses is held to review the clinical practice of PSV MC, noting differences in neonatal outcomes from the literature. The impact of personal experience, religious and cultural differences, differences in medical training, social expectations, and lawsuits on clinical practice also need to be discussed. In order to keep things simple for use in steps 3 and 4, a table of survival and neurological disability rates is summarized, with information on survival and neurological disability rates for 22-26 week preterm infants as reported in the literature and presented by PS V MC.
4.3 Step 3: Survey A survey was designed to ask how various health professionals would recommend the management of the mother and newborn in the event of preterm birth at 1-week intervals between 22 and 26 weeks. The survey was conducted voluntarily and anonymously, and participants had to have first attended Step 1 and Step 2 training to compare the results of maternal-fetal medicine specialists and neonatologists with those of obstetricians, neonatal nurses, maternity wards, and NICU nurses.
4.4 Step 4: Develop guidelines Based on the findings of Step 3 and the tables on neonatal outcomes summarized in Steps 1 and 2, guidelines for clinical staff were developed to assist in the counseling of potentially viable preterm infants prior to delivery and after birth. Between 22 and 26 weeks, the guidelines provide clear and practical advice on the management of the mother and newborn in each week of pregnancy when preterm delivery is imminent. All health professionals are encouraged to use this guide when counseling pregnant women and family members about the prognosis of their newborns, and it is recommended that a copy of the guide be given to pregnant women for reference. Nurses are also encouraged to be aware of and familiar with the guideline, as they have more time with patients and interact well with them. The guidelines focus on survival and neurodevelopmental issues, but the neonatologist will also discuss other common complications such as chronic lung disease and neonatal necrotizing colitis when communicating with the mother and family members.
4.5 Step 5: Post-consultation survey Three to four days after the consultation with the maternal-fetal medicine and neonatology specialists, each woman is asked to participate in a survey to assess her understanding of the consultation process and the clinical guidelines of the medical staff. Informed consent was obtained prior to the survey, and the results were analyzed by hospital clerks who were not involved in the medical process.
Participating mothers found the consultation process easy to understand (80%), useful (95%), consistent (89%), and conducted in a very comfortable manner (100%), and all mothers (100%) felt they were given enough information to help them make very important decisions. (1) The process respects each woman’s situation and choices, as well as the physician’s personal consultation. (2) The tables summarize information from the complex literature in a concise manner and provide a rational basis for discussion. (3) The document provides a consensus of colleagues’ recommended opinions.
Therefore, it is now very easy to answer the question posed in the title of this paper: How early is too early for preterm birth? There is no standard answer! The answer from Shanghai does not apply to Guangxi, and the answer from a tertiary hospital does not apply to a first or second level hospital. A more rational approach is to use the “five-step approach” introduced by PS V MC to find the answer that really belongs to our own medical institution.