Obstetric History and Maternal Complications Related to Preterm Birth

1 Neonatologist nurse. Doctoral student at the Graduate of the Federal University of Rio Grande do Norte Program. CAPES scholarship holder. 2 Midwife nurse. PhD in Health Sciences, Federal University of Rio Grande do Norte. Health School professor at the Federal University of Rio Grande do Norte. 3 Nurse. Master studies at the Graduate of the Federal University of Rio Grande do Norte Program. 4 Midwife Nurse. PhD in Nursing from the Federal University of Rio Grande do Norte. Health School professor at the Federal University of Rio Grande do Norte. 5 Physiotherapist. Post PhD in Neuroscience and Behavior, University of São Paulo-USP. Specialist in Physical Therapy in Intensive Care Neonatology and Pediatrics. Adjunct Professor of Physical Therapy and Multidisciplinary Residency Program of the Federal University of Rio Grande do Norte, UFRN/FACISA/HUAB. 6 Nurse. Integrated Schools in Patos.


Introduction
Preterm birth, less than 37 weeks of pregnancy, is considered a problem of public health worldwide.That is because preterm birth is considered one of main risk factors for neonatal morbidity and mortality.[1] Prematurity is responsible for 14% of the causes of child deaths in the world1.In addition, amount of preterm and low birth weight infants at birth has increased steadily in recent decades.Complications of preterm birth are a major cause of global neonatal deaths.In addition, number of preterm and low birth weight infants at birth has increased steadily over recent decades.Overall 11.1% of babies are born preterm equivalent to more than 15 million children or more than 1 in 10 children.In this regard more than 60% of births occur in Africa and South Asia, however, the 10 countries with the highest rates include Brazil, the USA India and Nigeria.[2,3,4] Additionally, preterm birth cause clinical consequences that require care more complex and sometimes throughout life.These types of repercussions result in a high social and economic cost to countries because preterm birth arises from a set of interrelated factors.Such factors impact upon quality of life of those who survive bearing sequels or repercussions in infant mortality [5].
This reality has aroused concern regarding the quality of prenatal and postpartum care.This concern is justified given that the fetal growth and development are important predictors of child health.Furthermore, predictors also relate to the health status in adult life [6][7].So, it is essential the early identification of risk factors for the birth of premature baby.
Thus, following research question has emerged: What is production of scientific knowledge on obstetric history, maternal complications and types of pregnancy as risk factors related to preterm birth?Thereby, present study aims to synthesize knowledge produced in scientific articles on obstetric history, maternal complications and types of pregnancy as risk factors related to preterm birth.

Method
This study is an integrative review carried out in five steps: identification of guiding research ques-tion, search of literature in databases, evaluation of the documents concerning methodological rigor, data analysis and presentation of results.Such steps intended to develop scientific knowledge synthesis on: obstetric history, maternal complications and types of pregnancy as risk factors related to preterm birth.Allied to the synthesis also carried out there was purpose of incorporating applicability of results of significant studies in developed practice [8].
To perform integrative review, two investigators conducted searches in databases during the months of February and March 2015.Databases used were: LILACS (Literatura Latino-Americana e do Caribe em Ciências da Saúde), CINAHL (Cumulative Index to Nursing and Allied Health Literature) and Pubmed.
Regarding the time frame it were selected studies published since 2006.It is justified this time period considering that it provides evaluation of scientific production and of current reality of the risk factors for preterm birth.Then it was proceeded by reading titles and abstracts applying the inclusion criteria: full articles electronically available and free in selected databases of capes periodic portal; published in Portuguese, English and Spanish; beyond that addressed the topic under study.
In addition, it was adopted exclusion criteria described below: letters to the editor; editorials; literature review and integrative review, cross-sectional studies, qualitative studies, which presented secondary data and/or those who did not include the theme of the present integrative review.
The extent that these eligibility criteria were applied, repeated articles were counted only once.Full texts of these studies were transferred and stored on the computer.After these steps, complete reading of these articles was conducted by considering: methodological rigor regarding clarity of the trajectory of the method; identifying limitations and bias; evidence level for the selection and presentation of results.Whole process resulted in 32 articles (02 CINAHL, 09 LILACS, 21 of pubmed).
Thus, these articles were organized in framework containing: identification of studies, year of publication, objective, methodological design, level of evidence and place of study.Regarding level of evidence [9] studies were classified according to Table 1.Moreover, risk factors related of preterm birth; maternal reproductive history; maternal complications during pregnancy and type of pregnancy were presented descriptively and analyzed based on of the relevant literature.

Results
Table 2 shows description of the 32 studies that present risk factors related to preterm birth.It is observed predominantly in evidence IV level that is considered moderate level which corresponding to methods of Cohort and case-control.In addition, only eight of these studies were done in Brazil.

Place of study
1F [15] To identify whether the use of herbal products during pregnancy is very common and whether everyday use of almond oil spread in the skin is associated with premature birth Cohort study IV Italy 1G [16] To investigate the association between sociodemographic data and obstetrical risk factor in preterm birth in five hospitals of Maternal and Child Health in Beijing, China Case-control study IV China 1H [17] To investigate whether there is an association between use of antiretroviral combination therapy during pregnancy by women infected with HIV and risk of prematurity Cohort study IV France 1I [18] To analyze determinants of low birth weight, small for pregnancy and premature births in Lombok, Indonesia Randomized clinical trial II Indonesia 1J [19] To determine the genitourinary infections as risk factors for preterm birth in teenagers Case-control study IV Mexico 1K [20] To analyze the risk factors for preterm birth in the city of Campina Grande, State of Paraiba, Brazil Case-control study IV Brazil 1L [21] To determine the bio-psycho-social risk factors for preterm birth in a sample of Turkish women without chronic diseases and evaluate their anxiety and depression in early postpartum period Case-control study IV Europe 1N [22] To investigate whether in utero exposure to antiretroviral therapy is associated with low birth weight and / or premature birth in a population of South African women who advanced HIV disease Cohort study IV Africa 1º [23] To examine the associations between systolic and diastolic blood pressure in different trimesters of pregnancy and both fetal growth characteristics measured repeatedly and risks of adverse birth Cohort study IV Holand 1P [24] To investigate whether the use of highly active antiretroviral therapy (HAART) during pregnancy has been linked to premature births

Randomized clinical trial II United States
1R [25] To analyze the relationship of gestational Malaria and its effects in newborns in a region endemic for malaria in Colombia between 1993 and 2007 Cohort study IV Colombia 1S [26] To evaluate the relationship between presence of Chlamydia trachomatis and placenta signs of inflammation in women who gave birth at 32 weeks gestation or less Cohort study IV Holand 1T [27] To evaluate the risks of preterm delivery and hypertensive disease specific to pregnancy among pregnant women with mood disorders and migraine

Discussion
Results presented that only 8 of the 32 studies were carried out in Brazil.methodological design of Cohort study and case-control was the best and both present moderate level of evidence.However, the case-control method aims to identify risk factors which this study proposes.
In this search, risk factors related to preterm birth that were identified are the following: a history of preterm birth, hypertensive disease with eclampsia and no eclampsia, genitourinary infection and antiretroviral therapy in pregnancy.In addition to this are twin pregnancy, vaginal bleeding and bacterial vaginosis.
The previous history of prematurity was one risk factor associated with prematurity which appeared more repeatedly in studies under review.In the articles consulted previous prematurity was described as jointly responsible for influencing by up to 2.37 times episodes of preterm birth in subsequent pregnancies [20].
Given the risks of chronic hypertension and / or gestational for mother and baby dyad, World Health Organization (WHO) recommends a minimum of 6 prenatal consultations.Blood pressure and weight should be checked in all consultations to identify possible complications in a timely manner.[4] That is because overweight and obesity increases the risk of preeclampsia and women should preferentially point normal weight before pregnancy.[42] Following these guidelines of WHO, the Ministry of Health (MH) of Brazil establishes the procedure for hypertensive sídromes of pregnancy according to the classification: mild pre-eclampsia, severe pre-eclampsia, eclampsia, acute hypertension and HELLP syndrome.This classification is designed to minimize damage to maternal and child health.Specifically for eclampsia, MH recommends that in case the pregnant woman is with gestational age greater than or equal to 34 weeks she should be prepared for pregnancy termination or delivery [43].
Additionally, preterm birth can be caused by interrelated factors, such as: genitourinary infection, factors associated with premature rupture of membranes, premature labor and chorioamnionitis.Through the release of endotoxins and exotoxins arising from the urinary tract infection, it begins the process of parturition because the infection exacerbates uterine contractility and maturation of the cervix.This leads to premature birth occurs [44].
Thus, about 17% to 20% of pregnant women have clinical condition symptomatic of Urinary Tract Infection (UTI) mediated by hormones that cause glycosuria and aminoaciduria favorable to microbial growth and infections.The UTI ranges from asymptomatic bacteriuria which can progress to acute pyelonephritis, but also may develop inro cystitis.Thus, the MH recommends performing urinalysis during prenatal low risk periods in the first and third trimester of pregnancy.In addition, all pregnant women with evidence of bacteriuria should be treated.This is intended to serve as a preventive measure of progression to cystitis or pyelonephritis which cause complications to the health of the mother-infant dyad [45,46].
Even though studies suggest the Antiretroviral Therapy (ART) as a risk factor for preterm birth, MH of Brazil recommends its prescription in pregnancy as prophylaxis of vertical transmission or treatment of infection to Human Immunodeficiency Virus (HIV).This ART should be initiated after first trimester of pregnancy.That is because rate of vertical transmission of HIV without intervention stands at approximately 25.5%.Thus, it is possible to re-duce vertical transimssão through ART combined with: elective cesarean delivery; chemoprophylaxis of azidothymidine (AZT) in laboring women and newborn; besides not breastfeeding [43].However, despite the benefit of reducing vertical transmission study indicates that antiretroviral therapy can increase the risk of pulmonary arterial hypertension in pregnant women [47].
Corroborating with other risk factors, twin pregnancy is presented as predisposition to complications such as: vaginal bleeding, congenital anomalies and preeclampsia which culminate in preterm birth and low birth weight.Thus, it is necessary to detect pathological changes of women in multiple pregnancy and to intervene in prevention of greater damages to mothers and children [48].
Therefore, early identification of women at risk of preterm delivery allows the use of strategies that may postpone occurrence of delivery till conditions are viable for the mother-infant pair.Thus, it is possible to reduce maternal and neonatal morbidity and mortality.In this sense, the Family Health Strategy (FHS) is a technological innovation not material in area of Brazilian health policy.This strategy adopts a broader concept of the health-disease through promotion, prevention, cure and rehabilitation.Therefore it can be expanded to offer assistance to people and community in an area linked to the services provided [49].

Conclusion
The study found several risk factors related to preterm birth among which are obstetric history and maternal complications.There was emphasis in the quantitative of research on the previous history of prematurity.In addition, these articles also revealed other risk factors such as maternal complications amenable to screening, treatment and prevention.
Among complications cited are hypertensive disease with eclampsia and no eclampsia and genitourinary infections associated with premature bir-th.Furthermore, antiretroviral therapy has also been found as a risk factor for preterm birth.
Therefore, through the synthesis of scientific knowledge produced in this study, it is expected to contribute to the knowledge of physicians and midwives of the Family Health Strategy which provide maternal and infant care.From this, there is the intention to create opportunities expanded vision to professionals so that they can identify in a timely manner women with risk factors associated to preterm birth.These professionals can then minimize complications and reduce maternal and neonatal morbidity and mortality based on scientifically supported results.

Table 2 .
Characterization of articles according to year of publication, study objective, method, level of evidence and place of study.Natal, Brazil, 2015.

Table 3 .
Risk factors of preterm birth according to categories.Natal, Brazil, 2015.