Risk factors for recurrent preterm delivery

Prenatal care and preterm birth in the Western Brazilian Amazon: A population-based study

Brazil is among the top ten countries in preterm delivery worldwide. This study assesses the factors associated with preterm birth in the Western Brazilian Amazon. A population-based cross-sectional study was held between July 2015 to June 2016 in Cruzeiro do Sul, Brazilian Amazon. A total of 1525 births were included in this analysis. Preterm birth was defined as births at gestational age < 37 weeks. A stepwise multiple logistic regression was used to identify factors associated with preterm delivery. The prevalence rate of preterm birth was 7.9% (n = 120; 95% CI: 6.5-9.3). After adjusting for confounding factors, a positive association with preterm birth was observed for pregnant women who completed less than six antenatal care visits (OR: 2.93; 95% CI: 1.89-4.56), who had a birth interval of < 18 months (OR: 2.65; 95% CI: 1.04-6.75), and who experienced bleeding (OR: 2.17; 95% CI: 1.39-3.38) and hypertension during pregnancy (OR: 1.74; 95% CI: 1.07-2.82). Factors associated with preterm birth in the Western Brazilian Amazon were mostly related to the aspects of health care provided to women, and thus could be prevented. Proper, timely, and regular antenatal care visits can help reduce adverse outcomes, such as hypertension and bleeding.

Assessing the risk factors before pregnancy of preterm births in Iran: a population-based case-control study

Background

Preterm birth is a major cause of prenatal and postnatal mortality particularly in developing countries. This study investigated the maternal risk factors associated with the risk of preterm birth.

Methods

A population-based case-control study was conducted in several provinces of Iran on 2463 mothers referred to health care centers. Appropriate descriptive and analytical statistical methods were used to evaluate the association between maternal risk factors and the risk of preterm birth. All tests were two-sided, and P values < 0.05 were considered to be statistically significant.

Results

The mean gestational age was 31.5 ± 4.03 vs. 38.8 ± 1.06 weeks in the case and control groups, respectively. Multivariate regression analysis showed a statistically significant association between preterm birth and mother’s age and ethnicity. Women of Balooch ethnicity and age ≥ 35 years were significantly more likely to develop preterm birth (OR: 1.64; 95% CI: 1.01–-2.44 and OR: 9.72; 95% CI: 3.07–30.78, respectively). However, no statistically significant association was observed between preterm birth and mother’s place of residence, level of education, past history of cesarean section, and BMI.

Conclusion

Despite technological advances in the health care system, preterm birth still remains a major concern for health officials. Providing appropriate perinatal health care services as well as raising the awareness of pregnant women, especially for high-risk groups, can reduce the proportion of preventable preterm births.

Inter-Pregnancy Weight Change and the Risk of Recurrent Pregnancy Complications

Women with specific adverse pregnancy outcomes in their first pregnancy may be receptive to inter-pregnancy weight management guidance aimed at preventing these complications reoccurring in subsequent pregnancies. Thus the association between inter-pregnancy weight change and the risk of recurrent pregnancy complications at the second pregnancy was investigated in a retrospective cohort study of 24,520 women with their first-ever and second consecutive deliveries in Aberdeen using logistic regression. Compared with women who were weight stable, weight loss (>2BMI units) between pregnancies was associated with an increased risk of recurrent small for gestational age (SGA) birth and elective Cesarean-section, and was protective against recurrent pre-eclampsia, placental oversize and large for gestational age (LGA) birth. Conversely weight gain (>2BMI units) between pregnancies increased the risk of recurrent gestational hypertension, placental oversize and LGA birth and was protective against recurrent low placental weight and SGA birth. The relationships between weight gain, and placental and birth weight extremes were evident only in women with a healthy weight at first pregnancy (BMI<25units), while that between weight gain and the increased risk of recurrent gestational hypertension was largely independent of first pregnancy BMI. No relationship was detected between inter-pregnancy weight change and the risk of recurrent spontaneous preterm delivery, labour induction, instrumental delivery, emergency Cesarean-section or postpartum hemorrhage. Therefor inter-pregnancy weight change impacts the risk of recurrent hypertensive disorders, SGA and LGA birth and women with a prior history of these specific conditions may benefit from targeted nutritional advice to either lose or gain weight after their first pregnancy.

Prevalence and risk factors associated with preterm birth in Ardabil, Iran

BACKGROUND

Preterm birth is a leading cause of perinatal mortality and long-term morbidity as well as the long-term health consequences and cognitive outcomes.

OBJECTIVE

Present study was conducted to determine prevalence and risk factors associated with preterm birth in Ardabil, Iran.

MATERIALS AND METHODS

A case control study was conducted between Nov 2010 and July 2011 in all three maternal hospitals in Ardabil. All the live newborns during the study period were investigated. Of 6705 live births during the study period 346 births occurred in <37 weeks were taken as a case and 589 term neonates were taken as a control group. Data were obtained through review of prenatal and hospital delivery records. Univariate and multivariate logistic regression analysis were applied to obtain magnitude of association between independent variables and preterm birth.

RESULTS

The prevalence rate of preterm birth was 5.1%. History of previous preterm birth (OR=12.7,CI: 3.9-40.4, p<0.001), hypertension (OR=7.3, CI:2.1-25.4, p=0.002), Oligohydramnios (OR=3.9, CI:1.6-9.5, p=0.002), spouse abuse (OR=3.7, CI:1.1-11.8, p=0.024), preeclampsia (OR=3.6, CI:1.3-10.3, p=0.014), premature rupture of membrane (OR=3.1, CI:1.9-4.9, p=0.000), bleeding or spotting during pregnancy (OR=2.0, CI:1.0-3.8, p=0.037), Hyperemesis Gravid arum (OR=2.0, CI: 1.1-3.8, p=0.015), urinary tract infection in 26-30 weeks , (OR=1. 8 CI:1.0-3.2, p=0.04), diastolic blood pressure ≤60 mmg (OR=1.5, CI: 0.99-2.2, p=0.049) were determined as significant risk factors for preterm birth.

CONCLUSION

Early detection and treatment of diseases or disorders among pregnant women especially hypertension, Oligohydramnios, preeclampsia, bleeding or spotting, Hyperemesis Gravid arum, urinary tract infection, and low diastolic blood pressure as well as the improving health care quality delivered to pregnant women may reduce preterm prevalence rate.

Prognostic factors for low birthweight repetition in successive pregnancies: a cohort study

Background

To identify prognostic factors associated with recurrence of low birthweight (LBW) in successive gestations, a study was carried out with a subsample of mothers enrolled in the 2004 Pelotas Birth Cohort.

Methods

Data were collected by hospital-based interviews. Newborns were weighed and measured. Gestational age was defined according to the date of last menstrual period, ultra-sound scan before the 20^th week of pregnancy or the Dubowitz method. Mothers who reported at least one LBW newborn in the two previous gestations were included. Prevalence ratios (PR) and 95% confidence intervals were estimated from Poisson Regression. All estimates were adjusted for parity.

Results

A total of 4558 births were identified in 2004, and 565 met inclusion criteria, out of which 86 (15.2%) repeated LBW in 2004. Among mothers with two LBW babies before 2004, 47.9% presented LBW recurrence. Belonging to the highest socio-economic stratum (PR 0.89; 0.01-0.46) and gaining ≥ 10 kg during pregnancy (PR 0.09; 0.01-0.77) were protective against LBW recurrence. Higher risk of LBW recurrence was observed among mothers with higher parity (≥3 previous deliveries; PR=1.93; 95% CI 1.23-3.02); who had given birth to a previous preterm baby (PR=4.01; 2.27-7.10); who delivered a female newborn in current gestation (PR=2.61; 1.45-4.69); and that had not received adequate antenatal care (PR=2.57; 1-37-4.81).

Conclusion

Improved quality of antenatal care and adequate maternal weight gain during pregnancy may be feasible strategies to prevent LBW repetition in successive pregnancies.

Diabetes mellitus and the risk of preterm birth with regard to the risk of spontaneous preterm birth

INTRODUCTION

It is internationally agreed that diabetes mellitus (DM) is associated with increased maternal and fetal morbidity and long-term complications. To avoid these complications, it is often necessary to induce birth before term. The impact of DM on spontaneous preterm birth (spontaneous labor, preterm premature rupture of membranes and/or cervical incompetence resulting in delivery before the completion of 37 gestation weeks) is still unexplained. Preterm birth accounts for the most neonatal deaths and infant morbidities, and therefore it still remains one of the biggest challenges in obstetrics.

OBJECTIVE

Our study determined if there is an increasing tendency towards spontaneous preterm birth in mothers with gestational and preexisting DM.

METHODS

In this retrospective cohort study, 187 pregnant women with gestational DM and preexisting DM were compared to a randomized control group consisting of 192 normoglycemic women concerning gestational age and perinatal outcome. Data were collected by the Medical University of Vienna. Multiple pregnancies and women with severe maternal diseases, such as preeclampsia, were excluded.

RESULTS

Women with DM tended significantly more often to preterm births (P = 0.002). A significant difference in the incidence of spontaneous preterm birth was found (P = 0.047).

CONCLUSION

DM affects the length of gestation and incidence of spontaneous preterm birth.

The role of prenatal care in recurrent preterm birth

OBJECTIVE

To assess the independent role of prenatal care in preventing recurrent preterm delivery (<37 weeks gestation) and in reducing adverse pregnancy outcomes in recurrent preterm delivery.

STUDY DESIGN

A population-based retrospective cohort study. Participants were 1470 Bedouin women in Southern Israel who at their first delivery (parity 1) gave birth preterm (<37 weeks) and had a consecutive birth (parity 2) at Soroka University Medical Center, the only birth hospital in the area. Multiple gestations were excluded.

RESULTS

The incidence of recurrent preterm delivery was 24.6% (362/1470) and it was not associated with having had prenatal care in the second pregnancy. In a multivariable logistic analysis, young maternal age, pregnancy complications and fetal abnormalities in the second pregnancy, as well as previous miscarriages, short inter-pregnancy interval, and length of gestation in the first pregnancy were significantly associated with recurrence. The incidence of adverse pregnancy outcomes (perinatal mortality, small for gestational age, gestational age <34 weeks, Apgar ≤ 7) in recurrent preterm delivery was 44.8% (162/362). Lack of prenatal care was significantly associated with adverse pregnancy outcomes (odds ratio: 4.03; 95% confidence interval: 2.04-7.97) in a multivariable logistic analysis controlling for all variables significantly associated with adverse pregnancy outcomes at the univariate analysis.

CONCLUSIONS

Prenatal care may reduce the risk of adverse pregnancy outcomes in recurrent preterm delivery, even if recurrence cannot be prevented. It is therefore important that quality prenatal care is accessible to women who had a preterm delivery in the past.

Epidemiology and environmental factors in preterm labour

An epidemiological and environmental approach is the appropriate starting point to understanding preterm labour. Although there are multiple aetiologies it seems likely that anthropometric and environmental risk factors in combination with inherent genetic susceptibilities contribute to an increased risk of preterm labour for certain women. Poct 2pulation-based studies identifying risk factors and quantifying outcomes facilitate informed counselling and provide a framework for developing prediction tools. Carefully conducted case-control and cohort studies identify associations that may contribute to an understanding of causation. A combined approach encompassing epidemiology, pathophysiology and clinical research is required to understand the aetiologies, prevention and optimal management of preterm labour. This review focuses on the epidemiology of preterm labour and the role of environmental factors.

Recurrent preterm birth

Recurrent preterm birth is frequently defined as two or more deliveries before 37 completed weeks of gestation. The recurrence rate varies as a function of the antecedent for preterm birth: spontaneous versus indicated. Spontaneous preterm birth is the result of either preterm labor with intact membranes or preterm prelabor rupture of the membranes. This article reviews the body of literature describing the risk of recurrence of spontaneous and indicated preterm birth. Also discussed are the factors which modify the risk for recurrent spontaneous preterm birth (a short sonographic cervical length and a positive cervicovaginal fetal fibronectin test). Patients with a history of an indicated preterm birth are at risk not only for recurrence of this subtype, but also for spontaneous preterm birth. Individuals of black origin have a higher rate of recurrent preterm birth.

Recurrence risk for preterm delivery

OBJECTIVE

To estimate recurrence risk of preterm delivery in third births.

STUDY DESIGN

We conducted a population-based cohort study of Missouri mothers who delivered 3 consecutive singleton live births during 1989-1997. The recurrence risk was computed for 4 cohorts based on prior preterm delivery status and adjusted using Mantel-Haenszel stratified analysis.

RESULTS

The study population included 19,025 third births. The recurrence risk ranged from 42% (for women with 2 prior preterm deliveries), through 21% (term/preterm) and 13% (preterm/term), to 5% (term/term). The recurrence risk was highest (57%) for women with 2 prior very preterm deliveries (21-31 weeks) and lowest (33%) for those with 2 prior moderate preterm deliveries (32-36 weeks). The recurrence risk was less pronounced for women with 1 prior very or moderate preterm delivery.

CONCLUSION

These data show a strong association between prior preterm delivery and recurrence risk, which is affected by the frequency, order, and severity of prior preterm births.

Is a poor pregnancy outcome related to young maternal age? A study of teenagers in Estonia during the period of major socio-economic changes (from 1992 to 2002)

OBJECTIVE

To assess the risk of low birth weight, preterm birth, stillbirth, neonatal and postneonatal death among primiparous teenagers having singleton births, compared to a similar group of women aged 20-24 years in Estonia during the period of major socio-economic changes.

STUDY DESIGN

Registry study using the data from the Estonian Medical Birth Registry (EMBR) for years 1992-2002; EMBR data were linked with infant deaths in the Estonian Mortality Database. Study population included 51,890 women aged 13-24 years, arranged into three groups: < or =17, 18-19, and 20-24. Crude odds ratios (OR), adjusted ORs and their 95% confidence intervals (CI) for the different outcomes were estimated using multiple logistic regression analysis.

RESULTS

Compared with women aged 20-24 years, the risk of low birth weight and preterm birth was higher among teenagers. The risk of low birth weight and preterm birth within the study group as a whole did not change during the study period. Increased risks in neonatal and postneonatal death among younger teenagers of an age of 17 years and less seem to be a result of prematurity.

CONCLUSIONS

Despite major socio-economic changes resulting in improvements in obstetric care and growth in incomes, teenagers remained a higher risk group.

Cerebral palsy and fetal inflammatory response syndrome: a review

Cerebral palsy (CP) is the most common cause of severe physical disability in childhood. The precise etiological factor for the development of the majority of cases of CP has not been identified, however, prematurity is considered to be the leading identifiable risk factor. During the last decade, intrauterine infection/inflammation has been identified as the most common cause of preterm delivery and neonatal complications. When microorganisms or their products gain access to the fetus they stimulate the production of cytokines and a systemic response termed FIRS (Fetal Inflammatory Response Syndrome). Subsequently, FIRS was implicated as a cause of fetal or neonatal injury that leads to CP and chronic lung disease. Several authors found an increase in the risk for CP in infants born to mothers with clinical chorioamnionitis, especially in preterm neonates. A relationship between CP and intra-amniotic inflammation was demonstrated, intrauterine infection may lead to activation of the cytokine network which in turn can cause white matter brain damage and preterm delivery, as well as the future development of CP. This white matter insult is identified clinically as periventricular leucomalacia (PVL) which is associated with the subsequent development of impaired neurological outcomes of variable severity including CP.

Long-term fetal outcomes in pregnant trauma patients

BACKGROUND

Trauma during pregnancy is associated with significant maternal and fetal morbidity and mortality, typically occurring during the hospital admission. Less is known about the delayed effects of trauma on pregnancy outcome once the patient has been discharged from the hospital with a viable fetus.

METHODS

A retrospective cohort study was conducted of pregnant trauma patients who were discharged from the trauma center with a viable fetus. Risk of preterm delivery (PTD) and low birth weight (LBW) were compared between injured patients (Injury Severity Score > 0) and those without identified injury (Injury Severity Score = 0), for the remainder of pregnancy.

RESULTS

Even after trauma center discharge, injured patients had a nearly 2-fold higher risk of PTD (relative risk, 1.9; 95% confidence interval, 1.1-3.3) and LBW (relative risk, 1.8; 95% confidence interval, 1.04-3.2) for the remainder of the pregnancy. The risk was higher with increasing injury severity and among those injured early in gestation.

CONCLUSION

The risk of PTD and LBW in pregnant trauma patients who were discharged from trauma centers with a viable fetus remains increased throughout the remainder of the pregnancy. A history of trauma during gestation is a risk factor for poor pregnancy outcome.

The Alabama Preterm Birth Project: placental histology in recurrent spontaneous and indicated preterm birth

OBJECTIVE

For unknown reasons, a previous preterm birth (PTB) is a major risk factor for PTB in the current pregnancy. Our goal is to evaluate placental histology for clues related to the recurrent nature of PTB.

STUDY DESIGN

Four hundred fifty-seven mother/infant dyads delivering between 23 and 32 weeks were first classified as having a spontaneous (S) or indicated (I) PTB, and then sorted into the following mutually exclusive categories by pregnancy history: 1) nulliparous; 2) having no previous PTB; 3) having any previous IPTB; or 4) having a previous SPTB. The placentas were evaluated for acute inflammation in the free membranes, umbilical cord, and chorionic plate, chronic inflammation in the membranes and decidua basalis, thrombosis in the chorionic plate and umbilical cord, and diffuse decidual leukocytoclastic necrosis (DDLN), a lesion associated with decreased placental perfusion.

RESULTS

Women who had a SPTB were far more likely (85.5 vs 14.4 P < .0001) to have a SPTB in the previous pregnancy, while women with an IPTB were significantly more likely to have had a previous IPTB (89.7 vs 10.3 P < .0001). Nulliparas and women with previous term births each had about 64% SPTB and 36% IPTB. Acute inflammation at any site was present in 73.9% of SPTB versus 8.0% of IPTB (P < .0001). Chorionic plate thrombosis was also more common in SPTB than IPTB (16.2 vs 7.6, P = .01). Chronic inflammation at any site was more common in IPTB than SPTB (21.0 vs 12.7%, P = .02), as was DDLN (46.5 vs 16.1, P < .0001). When classified by SPTB and IPTB in the current pregnancy, the histologic results were not further influenced by the previous pregnancy history.

CONCLUSION

SPTB and IPTB are strongly repetitive. Women with SPTB are significantly more likely to have acute inflammation in the free membranes, chorionic plate, and cord, and chorionic plate thrombosis, while women with an IPTB are significantly more likely to have chronic inflammation and especially DDLN. Past obstetric history does not further influence the placental histology.

[Risk factors for repetition of low birth weight, intrauterine growth retardation, and prematurity in subsequent pregnancies: a systematic review]

With the aim of collecting evidence on repetition of low birth weight, intra-uterine growth retardation (IUGR), and prematurity in successive pregnancies, a systematic review was conducted on MEDLINE, LILACS, PAHO, and MedCarib from 1965 to 2004, using as descriptors: "low birth weight and recurrence, repetition or previous", "risk factors and repetition, recurrence or previous LBW", "IUGR and recurrence, repetition or previous", "risk factors and repetition, recurrence or previous IUGR", "prematurity and recurrence, repetition or previous", and "risk factors and repetition, recurrence or previous prematurity". Of 24 studies, 18 were excluded due to inconsistency between the title and the actual subject investigated (obstetric history as a risk factor rather than a selection criterion). The most important risk factors associated with repetition of low birth weight were maternal age > 30 years, smoking, short inter-gestational interval, and black skin color; those associated with IUGR were maternal age < 20 or > 35 years, low maternal education, high blood pressure, drug addiction, and non-technical/non-professional paternal occupation; and with preterm birth, premature rupture of membranes, chorioamnionitis, preeclampsia, preterm labor, and inter-gestational interval less than 12 months.

Risk factors for pre-term birth in Iraq: a case-control study

Background

Preterm birth (PTB)is a major clinical problem associated with perinatal mortality and morbidity. The aim of the present study is to identify risk factors associated with PTB in Mosul, Iraq.

Methods

A case-control study was conducted in Mosul, Iraq, from 1^st September, 2003 to 28^th February, 2004.

Results

A total of 200 cases of PTB and 200 controls of full-term births were screened and enrolled in the study. Forward logistic regression analysis was used in the analysis. Several significant risk associations between PTB and the following risk factors were identified: poor diet (OR = 4.33), heavy manual work (OR = 1.70), caring for domestic animals (OR = 5.06), urinary tract infection (OR = 2.85), anxiety (OR = 2.16), cervical incompetence (OR = 4.74), multiple pregnancies (OR = 7.51), direct trauma to abdomen (OR = 3.76) and abortion (OR = 6.36).

Conclusion

The main determinants of PTB in Iraq were low socio-economic status and factors associated with it, such as heavy manual work and caring for domestic animals, in addition to urinary tract infections and poor obstetric history.

Intersections between adverse pregnancy outcomes

Reproductive failure in a variety of forms, whether it be infertility, miscarriage, pre-eclampsia, prematurity or intrauterine growth restriction, may aggregate within individuals. This observation, although rarely studied, suggests that single pathophysiologies may be associated with a variety of reproductive morbidities. In this review, hyperimmune responsiveness to pregnancy is provided as one example of a process leading to a multitude of adverse impacts on healthy childbearing. Further research on reproductive failure as a spectrum is warranted.