Preterm birth risk assessment

Adverse obstetric and perinatal outcomes following treatment of adolescent and young adult cancer: a population-based cohort study

Objective

To investigate obstetric and perinatal outcomes among female survivors of adolescent and young adult (AYA) cancers and their offspring.

Methods

Using multivariate analysis of statewide linked data, outcomes of all first completed pregnancies (n = 1894) in female survivors of AYA cancer diagnosed in Western Australia during the period 1982–2007 were compared with those among females with no cancer history. Comparison pregnancies were matched by maternal age-group, parity and year of delivery.

Results

Compared with the non-cancer group, female survivors of AYA cancer had an increased risk of threatened abortion (adjusted relative risk 2.09, 95% confidence interval 1.51–2.74), gestational diabetes (2.65, 2.08–3.57), pre-eclampsia (1.32, 1.04–1.87), post-partum hemorrhage (2.83, 1.92–4.67), cesarean delivery (2.62, 2.22–3.04), and maternal postpartum hospitalization>5 days (3.01, 1.72–5.58), but no excess risk of threatened preterm delivery, antepartum hemorrhage, premature rupture of membranes, failure of labor to progress or retained placenta. Their offspring had an increased risk of premature birth (<37 weeks: 1.68, 1.21–2.08), low birth weight (<2500 g: 1.51, 1.23–2.12), fetal growth restriction (3.27, 2.45–4.56), and neonatal distress indicated by low Apgar score (<7) at 1 minute (2.83, 2.28–3.56), need for resuscitation (1.66, 1.27–2.19) or special care nursery admission (1.44, 1.13–1.78). Congenital abnormalities and perinatal deaths (intrauterine or ≤7 days of birth) were not increased among offspring of survivors.

Conclusion

Female survivors of AYA cancer have moderate excess risks of adverse obstetric and perinatal outcomes arising from subsequent pregnancies that may require additional surveillance or intervention.

Transvaginal sonographic evaluation of the cervix in asymptomatic singleton pregnancy and management options in short cervix

Preterm delivery (PTD), defined as birth before 37 completed weeks of gestation, is the leading cause of perinatal morbidity and mortality. Evaluation of the cervical morphology and biometry with transvaginal ultrasonography at 16–24 weeks of gestation is a useful tool to predict the risk of preterm birth in low- and high-risk singleton pregnancies. For instance, a sonographic cervical length (CL) > 30 mm and present cervical gland area have a 96-97% negative predictive value for preterm delivery at <37 weeks. Available evidence supports the use of progesterone to women with cervical length ≤25 mm, irrespective of other risk factors. In women with prior spontaneous PTD with asymptomatic cervical shortening (CL ≤ 25 mm), prophylactic cerclage procedure must be performed and weekly to every two weeks follow-up is essential. This article reviews the evidence in support of the clinical introduction of transvaginal sonography for both the prediction and management of spontaneous preterm labour.

Saliva estriol levels in women with and without prenatal antidepressant treatment

BACKGROUND

Prenatal antidepressant use has been associated with shorter pregnancy duration and an increased risk for preterm birth. This study measured saliva levels of estriol, a hormone that increases exponentially in the few weeks before spontaneous labor, in pregnant women with and without antidepressant treatment.

METHODS

Saliva estriol levels were obtained across the day at three time points during pregnancy in 77 subjects with a history of DSM-IV major depressive disorder (MDD) who were treated with antidepressants in pregnancy (Group 1), a history of DSM-IV MDD who were not treated or had limited exposure to antidepressants during pregnancy (Group 2), and a normal control group (Group 3).

RESULTS

Mean estriol levels in the second half of pregnancy were significantly higher for Group 1 (history of MDD, on meds) than Group 2 (history of MDD, off meds) or Group 3 (control).

CONCLUSIONS

Prenatal antidepressant use was associated with significantly higher saliva estriol levels in the second half of pregnancy. Whether estriol reflects a causal mechanism by which women on antidepressants have shorter pregnancy duration remains to be further studied.

Effects of ritodrine hydrochloride tocolysis on echocardiographic parameters

OBJECTIVE

Preterm delivery is a leading cause of perinatal mortality and morbidity. The aim of this study was to determine the effect of ritodrine hydrochloride, used for tocolysis and having serious cardiovascular side effects, on echocardiographic parameters.

METHODS

Sixty-two pregnant women were included in our study. The study and control groups were composed of patients with preterm labor (group A, N = 30) and patients with uneventful pregnancies (group B, N = 32), respectively. While the patients in group A were evaluated before and during treatment, those in group B were evaluated only once for ejection fraction and fractional shortening of the left side of the heart with echocardiography and for the regional systolic and diastolic functions with the tissue Doppler technique. One-way ANOVA and a t-test (paired comparison) were used for statistical purposes.

RESULTS

For the left side of the heart, it was shown that while fractional shortening increased with tocolysis (p < 0.05), neither the ejection fraction nor E/A ratio, showing diastolic function, changed significantly (p < 0.01). While systolic function parameters (S(asep) and S(alat)) increased due to the inotropic and chronotropic actions of the beta-mimetic agents (p < 0.05), regional diastolic function parameters (E(asep)/A(asep) and E(alat)/A(alat)) did not change (p > 0.05).

CONCLUSIONS

Due to its potent inotropic and chronotropic effects, ritodrine hydrochloride increases myocardial oxygen demand significantly. Therefore, it should be used sparingly or avoided altogether in patients with ischemic or structural heart disease.

PAPP-A levels as an early marker of idiopathic preterm birth: a pilot study

OBJECTIVE

To evaluate late PAPP-A levels as predictive of preterm birth in symptomatic women.

STUDY DESIGN

Prospective cohort study of singleton gestations, 23 to 34 weeks, and symptoms of preterm labor. PAPP-A, IGF-I and IGF-III analysis were performed. Primary end point was delivery < or =7 days. Accuracy and optimally predictive PAPP-A values were based on receiver operator characteristic (ROC) curves.

RESULT

In all, 26 women (51%) delivered < or =7 days post-admission (Group 1); 25 women (49%) >7 days (Group 2). Group 1 mean PAPP-A=38 000 vs 55 333 for Group 2 (P<0.04). Group 1 mean gestational age at delivery=29 weeks vs 37 weeks for Group 2 (P<0.00014). PAPP-A level < or =30,000 mU l(-1) had highest specificity (88%), sensitivity (50%), and positive predictive (81%) and negative predictive (62%) values for delivery < or =7 days. ROC area under curve=0.703.

CONCLUSION

PAPP-A levels < or =30,000 mU l(-1) at admission was associated with increased risk for preterm birth < or =7 days, supporting active management and therapeutic approach in these women.

Early prediction of preterm birth for singleton, twin, and triplet pregnancies

OBJECTIVES

To create prediction models of early preterm birth for singletons, twin, and triplet pregnancies.

STUDY DESIGN

We used a historical cohort study with the 1996 birth registration data for singletons and the 1995-1997 linked birth/infant death dataset for multiple births of the United States. Preterm birth was defined as gestational age <32 completed weeks. Eligible study subjects were randomly allocated to two groups: one group (80% subjects) for the creation of the prediction models, and the other group (20% subjects) for the validation of the established prediction models. Multivariate logistic regressions were used to establish the prediction models. We further assessed the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the established prediction models with different cut-off values in the validation group.

RESULTS

The sensitivity, specificity, PPV, and NPV of the established model were 24.58, 93.54, 5.91, and 98.69%, respectively for singletons, 64.66, 57.04, 16.29, and 92.59%, respectively for twins, and 63.57, 53.58, 42.96, and 72.78%, respectively for triplets.

CONCLUSION

The prediction models of early preterm birth for singleton, twin, and triplet pregnancies created by this study could be useful for obstetricians to identify women being at high risk of preterm birth at early gestation.

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.

Female survivors of childhood cancer: preterm birth and low birth weight among their children

BACKGROUND

Improved survival after childhood cancer raises concerns over the possible long-term reproductive health effects of cancer therapies. We investigated whether children of female childhood cancer survivors are at elevated risk of being born preterm or exhibiting restricted fetal growth and evaluated the associations of different cancer treatments on these outcomes.

METHODS

Using data from the Childhood Cancer Survivor Study, a large multicenter cohort of childhood cancer survivors, we studied the singleton live births of female cohort members from 1968 to 2002. Included were 2201 children of 1264 survivors and 1175 children of a comparison group of 601 female siblings. Data from medical records were used to determine cumulative prepregnancy exposures to chemotherapy and radiotherapy. Logistic regression was used to estimate odds ratios (ORs) for the association between quantitative therapy exposures and preterm (<37 weeks) birth, low birth weight (<2.5 kg), and small-for-gestational-age (SGA) (lowest 10th percentile) births. All statistical tests were two-sided.

RESULTS

Survivors' children were more likely to be born preterm than the siblings' children (21.1% versus 12.6%; OR = 1.9, 95% confidence interval [CI] = 1.4 to 2.4; P<.001). Compared with the children of survivors who did not receive any radiotherapy, the children of survivors treated with high-dose radiotherapy to the uterus (>500 cGy) had increased risks of being born preterm (50.0% versus 19.6%; OR = 3.5, 95% CI = 1.5 to 8.0; P = .003), low birth weight (36.2% versus 7.6%; OR = 6.8, 95% CI = 2.1 to 22.2; P = .001), and SGA (18.2% versus 7.8%; OR = 4.0, 95% CI = 1.6 to 9.8; P = .003). Increased risks were also apparent at lower uterine radiotherapy doses (starting at 50 cGy for preterm birth and at 250 cGy for low birth weight).

CONCLUSIONS

Late effects of treatment for female childhood cancer patients may include restricted fetal growth and early births among their offspring, with risks concentrated among women who receive pelvic irradiation.

Pregnancy and lactation

Pregnancy results in physiologic changes in almost all organ systems in the body mediated mainly by female sex hormones. Physiologic changes of pregnancy influence the dental management of women during pregnancy. Understanding these normal changes is essential for providing quality care for pregnant women. This review article briefly discusses the cardiovascular, respiratory, gastrointestinal, urogenital, endocrine, and oral physiologic changes that occur during normal gestation. A summary of current scientific knowledge of ionizing radiation is presented. Information about the compatibility, complications, and excretion of the common drugs during pregnancy is provided. Drugs and their usage during breast-feeding are also discussed. Guidelines for the management of a pregnant patient in the dental office are summarized.

Current status of home uterine activity monitoring

A comprehensive evidence-based review of the clinical data leads to the conclusion that if patients at high risk for preterm birth (eg, prior preterm birth because of preterm labor, twins and higher-order multiple gestation, women who have preterm labor during the current pregnancy tocolyzed effectively) use the comprehensive system of HUAM correctly (ie, daily nursing care and twice-daily monitoring) with appropriate alarm rates and sensitive monitors, the incidence of early diagnosis of preterm labor, effective prolongation of pregnancy with fewer preterm births, and a reduction in neonatal morbidity is always demonstrated when the study group is compared with a control group consisting of women receiving standard care available to obstetricians in the United States. The authors expect that there will always be arguments regarding whether the monitor or the nurse contributes most to preterm birth reduction. Even when the alerts of detected contractions or patient-reported symptoms are sounded, the issue of prompt and effective medical intervention will always be hotly debated. The appropriate research design that tests HUAM while allowing various diagnostic and treatment modalities that physicians employ around the United States must be individualized. Physicians must make the decision, based on the evidence, regarding whether or not this system would benefit their patients. While investigators argue about research designs and statistical analyses, physicians simply want the best outcomes for their patients, which is what women and the whole of society also want. Based on the available evidence, it is clear that when the comprehensive system of HUAM is used appropriately in the right patients, everyone benefits.

Biochemical predictors of preterm labor: fetal fibronectin and salivary estriol

Preterm birth is a major complication of pregnancy and remains a leading cause of neonatal morbidity and mortality worldwide. Improvements in the authors' understanding of the pathophysiology of preterm labor have led to the development of novel diagnostic tools of use to identify women at greatest risk for preterm birth. Currently two FDA-approved biochemical tests are available in the United States: (1) fetal fibronectin and (2) salivary estriol. The presence of a positive fetal fibronectin test in the midtrimester of pregnancy is strongly associated with early spontaneous preterm birth. In contrast, a positive salivary estriol test is associated with late preterm birth, thus limiting its clinical use. Both tests have low test sensitivity and are currently used clinically for their negative predictive values. That is, women who screen negative are at very low risk for preterm birth and, thus, no interventions are indicated to prevent preterm birth. Women with a positive test are at increased risk and would be candidates for intervention. One of the main limitations of fetal fibronectin and salivary estriol, and an array of other proposed markers, is the fact that while these markers may aid in identification of women at increased risk for preterm birth, the authors currently have no clearly effective obstetric interventions for preterm-birth prevention in these high-risk women. Use of tocolytics, antimicrobials, or progesterone therapy currently has limited or unproven benefit in the management of women deemed at increased risk using these markers. Thus, until effective targeted obstetric interventions are available, the use of biochemical markers to identify women at increase risk for preterm birth remains largely research tools.

Pre-B-cell colony-enhancing factor, a novel cytokine of human fetal membranes

OBJECTIVE

Our purpose was to determine whether pre-B-cell colony-enhancing factor (PBEF) is expressed in the human fetal membranes during normal gestation and parturition in the absence of infection and to show its effects on the expression of interleukin (IL)-6 and IL-8.

STUDY DESIGN

PBEF was immunolocalized in the fetal membranes from early pregnancy, at preterm, and at term. Its expression was quantitated by Northern analysis in separated uninfected amnion, chorion, decidua, and placenta of patients at term before labor and in full-thickness membranes before and after spontaneous labor at preterm and at term. Amnion-like epithelial (WISH) cells and fetal membrane explants were treated with recombinant PBEF (rhPBEF), and the expression of IL-6 and IL-8 was quantitated.

RESULTS

PBEF was immunolocalized throughout gestation in the amniotic epithelium and mesenchymal cells as well as the chorionic cytotrophoblast and parietal decidua. Northern analysis showed significantly more (P <.01) PBEF expressed in the amnion than in either chorion or placenta. Its expression increased after labor at both preterm and term and correlated with that of IL-8 (r = 0.87). rhPBEF treatment of WISH cells significantly increased IL-6 (P <.05) and IL-8 (P <.01) gene expression after 4 hours and of IL-8 protein after 24 hours (P <.01); similar 4-hour treatment of fetal membrane explants significantly increased IL-6 (P <.01) and IL-8 (P <.05) gene expression.

CONCLUSION

PBEF is a novel cytokine constitutively expressed by the fetal membranes during pregnancy. It increased the expression of IL-6 and IL-8 and may be important in both normal spontaneous labor and infection-induced preterm labor.