Recurrence of preterm birth in singleton and twin pregnancies.

OBJECTIVE: To assess recurrence of preterm birth and its impact on an obstetric population. METHODS: Women with consecutive births at our hospital beginning with their first pregnancy were identified (n = 15,945). The first pregnancy was categorized as delivered between 24 and 34 weeks' gestation or 35 weeks or beyond, singleton or twin, and spontaneous or induced. The risk of preterm delivery in these same women during subsequent pregnancies was then analyzed. RESULTS: Compared with women who delivered a singleton at or beyond 35 weeks' gestation in their first pregnancy, those who delivered a singleton before 35 weeks were at a significant increased risk for recurrence (odds ratio [OR] 5.6, 95% confidence interval [CI] 4.5, 7.0), whereas those who delivered twins were not (OR 1.9, 95% CI 0.46, 8.14). The OR for recurrent spontaneous preterm birth presenting with intact membranes was 7.9 (95% CI 5.6, 11.3) compared with 5.5 (95% CI 3.2, 9.4) with ruptured membranes. Of those women with a recurrent preterm birth, 49% delivered within 1 week of the gestational age of their first delivery and 70% delivered within 2 weeks. Among 15,863 nulliparous women with singleton births at their first delivery, a history of preterm birth in that pregnancy could predict only 10% of the preterm births that ultimately occurred in the entire obstetric population. CONCLUSION: In a population-based study at our hospital, women who initially delivered preterm and thus were identified to be at risk for recurrence ultimately accounted for only 10% of the prematurity problem in the cohort.

An appraisal of treatment guidelines for antepartum community-acquired pneumonia.

OBJECTIVE: The optimal strategy for the initial evaluation and management, including criteria for hospitalization, of pregnant women with pneumonia has not been defined. Our purpose was to evaluate a treatment protocol for antepartum pneumonia and to identify criteria for selection of women for potential outpatient treatment. STUDY DESIGN: A protocol based on British and American Thoracic Society guidelines was introduced and included prompt hospitalization and empiric initiation of erythromycin therapy. Maternal and neonatal outcomes were analyzed to assess the efficacy of the protocol. A second analysis involved the retrospective application of published guidelines to ascertain for which women outpatient management might have been appropriate. RESULTS: There were no maternal deaths among the 133 women studied, and in 14 (10%) women there was a misdiagnosis at admission. Erythromycin monotherapy was judged adequate in all but one of the 99 women so treated. Using a modified version of the American Thoracic Society guidelines, we project that only 25% of the women hospitalized with pneumonia could have been managed safely as outpatients. CONCLUSION: Most pregnant women with pneumonia respond well to monotherapy with erythromycin. Outpatient management may be a reasonable option for selected women.

Infection and preterm labor.

There are many conditions, such as non-white race, young maternal age, and uterine malformations, that have been associated with preterm birth that are not amenable to intervention. Maternal cervical and intrauterine infection and inflammation may have a primary causative role in a fraction of the cases of preterm birth and preterm rupture of membranes and may also interact adversely with a variety of maternal (shortened cervix, smoking) and fetal factors (polyhydramnios, multifetal gestation) to decrease the threshold to preterm birth. Further studies are needed to better-define the link between various maternal microbial colonizations and preterm delivery, with the possibility to establish new screening and treatment recommendations. Because of the innumerable causes of preterm birth, a new strategy of targeted treatment of cervical or vaginal infections may lead to only a modest reduction in the incidence of this devastating problem of modern obstetrics.

Pitfalls in ultrasonic cervical length measurement for predicting preterm birth.

OBJECTIVE: To describe the anatomic and technical difficulties encountered with transvaginal ultrasound imaging of the cervix in a consecutive series of women at risk for preterm delivery. METHODS: Three groups of women had cervical ultrasound examinations: those with histories of preterm birth, those with incompetent cervices, and those admitted for preterm labor that did not progress. Standardized ultrasound examinations of the cervix involved measuring the length of the endocervical canal, funneling length, and internal os dilation with and without fundal pressure. RESULTS: Sixty consecutive women had transvaginal ultrasound examinations for assessment of the cervix. Forty-six had histories of preterm birth, five had incompetent cervices, and nine had arrested preterm labor. Six types of problems arose, which can be divided into anatomic or technical considerations, with an overall frequency of 27% (95% confidence interval 16%, 40%). Anatomic pitfalls that hampered identification of the internal os included an undeveloped lower uterine segment (n = 5), a focal myometrial contraction (n = 1), rapid and spontaneous cervical change (n = 1), and an endocervical polyp (n = 1). Technical pitfalls included incorrect interpretation of internal os dilation because of vaginal probe orientation (n = 7) and artificial lengthening of the endocervical canal because of distortion of the cervix by the transducer (n = 1). CONCLUSION: We caution those who perform cervical length examinations to be wary of falsely reassuring findings due to potential anatomic and technical pitfalls.

Postpartum regression rates of antepartum cervical intraepithelial neoplasia II and III lesions.

OBJECTIVE: To study the histologic regression and progression rates of cervical intraepithelial neoplasia (CIN) II and III after delivery and the effect the route of delivery has on the regression rates of CIN. METHODS: Pregnant patients with satisfactory colposcopic examinations and biopsy-proven CIN II and III were identified. Delivery information and postpartum biopsy results were obtained by chart review. RESULTS: Two hundred seventy-nine patients had antepartum biopsies of CIN II or CIN III. Of these, 126 women were excluded for the following reasons: lost to follow-up (75), human immunodeficiency virus positive (two), cesarean hysterectomy (four), and inadequate postpartum follow-up (45). This yielded a study group of 153 patients consisting of 82 with CIN II and 71 with CIN III. The regression rates were 68% and 70% among CIN II and CIN III patients (P = .78), respectively. Seven percent of patients with CIN II progressed to CIN III on postpartum evaluation. Twenty-five percent of those patients with CIN II and 30% of those with CIN III remained the same postpartum. No CIN lesions progressed to invasive carcinoma. There were no differences in regression rates or progression rates among the women who had vaginal deliveries (130), women who labored and then underwent cesarean (17), or women who proceeded to a cesarean without laboring (six). CONCLUSION: We found similar high postpartum regression rates despite the route of delivery. We recommend conservative antepartum management with postpartum colposcopic evaluation regardless of route of delivery because we are unable to predict which of these lesions are more likely to regress.