Michael J. McMahon

Comparison of a Trial of Labor with an Elective Second Cesarean Section

BACKGROUND In an attempt to reduce the rate of cesarean section, obstetricians now offer a trial of labor to pregnant women who have had a previous cesarean section. Although a trial of labor is usually successful and is relatively safe, few studies have directly addressed the maternal and perinatal morbidity and mortality associated with this method of delivery. METHODS We performed a population-based, longitudinal study of 6138 women in Nova Scotia who had previously undergone cesarean section and had delivered a singleton live infant in the period from 1986 through 1992. RESULTS A total of 3249 women elected a trial of labor, and 2889 women chose to undergo a second cesarean section. There were no maternal deaths. The overall rate of maternal morbidity was 8.1 percent; 1.3 percent had major complications (a need for hysterectomy, uterine rupture, or operative injury) and 6.9 percent had minor complications (puerperal fever, a need for blood transfusion, or abdominal-wound infection). Although the overall rate of maternal complications did not differ significantly between women who chose a trial of labor and the women who elected cesarean section (odds ratio for the trial-of-labor group, 0.9; 95 percent confidence interval, 0.8 to 1.1), major complications were nearly twice as likely among women undergoing a trial of labor (odds ratio, 1.8; 95 percent confidence interval, 1.1 to 3.0). Apgar scores, admission to the neonatal intensive care unit, and perinatal mortality were similar among the infants whose mothers had a trial of labor and those whose mothers underwent elective cesarean section. CONCLUSION Among pregnant women who have had a cesarean section, major maternal complications are almost twice as likely among those whose deliveries are managed with a trial of labor as among those who undergo an elective second cesarean section.

Placental apoptosis in preeclampsia.

Objective To determine whether preeclampsia is associated with an increase in placental apoptosis and differential expression of mediators of apoptosis. Methods Placental samples from 31 preeclamptic women and 31 normotensive controls were analyzed using terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling staining. Expression of Fas, Fas ligand, Bcl-2, and Bax was assessed using immunohistochemistry. Results The median percent apoptotic nuclei was significantly higher for the study group than for the controls (0.49 versus 0.19; P = .001), as was the median percent apoptotic nuclei in the trophoblast nuclei (0.33 versus 0.09; P < .01). Fas ligand expression was significantly less and Fas expression significantly greater in the villus trophoblast among the study subjects compared with controls. There was no difference in the expression of Bax or Bcl-2 between groups. Conclusion Placental apoptosis and altered expression of Fas and Fas ligand in trophoblast might influence pathogenesis or sequelae of preeclampsia.

Psychosocial Factors and Preterm Birth Among African American and White Women in Central North Carolina

Objectives. We assessed associations between psychosocial factors and preterm birth, stratified by race in a prospective cohort study.Methods. We surveyed 1898 women who used university and public health prenatal clinics regarding various psychosocial factors.Results. African Americans were at higher risk of preterm birth if they used distancing from problems as a coping mechanism or reported racial discrimination. Whites were at higher risk if they had high counts of negative life events or were not living with a partner. The association of pregnancy-related anxiety with preterm birth weakened when medical comorbidities were taken into account. No association with preterm birth was found for depression, general social support, or church attendance.Conclusions. Some associations between psychosocial variables and preterm birth differed by race.

Use of magnetic resonance imaging and ultrasound in the antenatal diagnosis of placenta accreta

Objective: To determine whether magnetic resonance imaging (MRI) and ultrasound (US) are effective methods for diagnosing placenta accreta, increta, or percreta antenatally. Methods: We retrospectively reviewed radiologic reports of patients who had the diagnosis of placenta accreta, percreta, or increta by pathologic analysis. The gestational age at first ultrasound diagnosis of accreta and first MRI diagnosis of accreta was recorded. Ultrasound and MRI reports were examined for findings of a distorted retroplacental myometrial zone, disrupted uterine-bladder interface, focal exophytic masses, and presence of vascular placental lacunae. Surgical history, cesarean hysterectomy, and blood loss were also recorded. Results: Thirteen patients were identified, and 14 had true pathologic confirmation of accreta, increta, or percreta. Nine of thirteen had MRI, and of those, seven received gadolinium. Placenta accreta was diagnosed by MRI in five of nine patients, but only four were confirmed pathologically to have accreta. Four women who had a normal MRI had accreta confirmed by pathology (sensitivity 38%). Of the 13 patients who had US, four were considered to have an accreta, and these four had pathologic confirmation. Nine were negative for accreta by US; however, eight of those women had pathologic confirmation of accreta, and one was normal (sensitivity 33%). Conclusion: Both MRI and US had poor predictive value in the diagnosis of placenta accreta, and further refinement in the techniques of both MRI and US is needed for these tests to be used to reliably diagnose these pathologic conditions.

Impaired glucose tolerance in pregnant women with polycystic ovary syndrome.

OBJECTIVE To determine whether women with polycystic ovary syndrome (PCOS) are more likely to develop gestational diabetes mellitus compared with age- and weight-matched controls. METHODS This retrospective cohort study compared reproductive-age women with and without PCOS who received prenatal care at the University of North Carolina Hospitals between April 1989 and June 1998. We reviewed the medical charts of 22 women with PCOS diagnosis before pregnancy based on menstrual histories, elevated androgen levels, and LH-FSH ratios greater than 2. These women were compared with 66 women without PCOS matched for age and weight. Gestational diabetes mellitus (GDM) was diagnosed in women if they had abnormal results on a 50-g glucose screening test and at least two abnormal plasma glucose values during a 100-g glucose tolerance test. Medical complications of pregnancy, pregnancy complications, and birth outcomes were compared between women with and without PCOS. RESULTS Nine of 22 women with PCOS also had GDM diagnosis, compared with two of 66 controls (odds ratio [OR] 22.2; 95% confidence interval [CI] 3.8, 170.0), and these women exhibited increased plasma glucose values for all measurements except fasting. Five of 22 women with PCOS developed preeclampsia compared with one of 66 controls (OR 15.0; 95% CI 1.9, 121.5). CONCLUSION Women with PCOS are at increased risk of glucose intolerance and preeclampsia during pregnancy.

Physical exertion at work and the risk of preterm delivery and small-for-gestational-age birth.

OBJECTIVE: To assess whether exposure to standing, lifting, night work, or long work hours during 3 periods of pregnancy are associated with an increased risk of preterm or small-for-gestational-age birth. METHODS: The Pregnancy, Infection and Nutrition study is a prospective cohort with a nested case–control component that was conducted through clinic and hospital settings in Central North Carolina. A total of 1,908 women pregnant with a singleton gestation were recruited during prenatal visits from January 1995 through April 2000 and provided information during telephone and face-to-face interviews about physical exertion for the 2 longest-held jobs during pregnancy. RESULTS: No significant elevations in preterm delivery were observed among women who lifted repeatedly or stood at least 30 hours per week, with no changes in risk estimates over the course of pregnancy. A 50% elevation in the risk of preterm delivery (relative risk 1.5, 95% confidence interval 1.0–2.0; first trimester) was observed among women who reported working at night (10:00 PM to 7:00 AM), whereas a 40% reduction in risk was observed among women working at least 46 hours per week (relative risk 0.6, 95% confidence interval 0.4–0.9; first trimester), regardless of period of exposure. No elevations in small-for-gestational-age birth were observed among women exposed to any of the 4 types of occupational exertion. CONCLUSION: Physically demanding work does not seem to be associated with adverse pregnancy outcomes, whereas working at night during pregnancy may increase the risk of preterm delivery. Studies to examine the effect of shift work on uterine activity would help to clarify the possibility of a causal effect on preterm birth. LEVEL OF EVIDENCE: II-2

Twin delivery and neonatal and infant mortality: A population-based study*

Objective To examine the effect of mode of delivery on twin survival, especially among very premature twin births, in a population-based historical cohort study. Methods A total of 4428 pairs of live-born twins, birth weight 500 g or greater, were included based on data from vital records of the entire state of North Carolina for the period 1988-1991. The main outcome measures were Apgar score at 5 minutes (less than 7 versus 7 or greater), neonatal death, and infant death. Results After controlling for birth weight, twin order, fetal presentation, ethnicity, maternal age, marital status, and adequacy of prenatal care, we found that cesarean delivery was associated with reduced risks (by 50-60%) of low 5-minute Apgar score and neonatal and infant deaths among infants born weighing 500-749 g (P < .05). The cesarean delivery benefited the second twins more than the first twins. Among infants weighing more than 1000 g, the mode of delivery was not associated with either low Apgar score or neonatal and infant mortality. Conclusion Our study suggests that cesarean delivery for twins with estimated fetal weights less than 1000 g together with a more liberal use of vaginal delivery for twins with estimated fetal weights more than 1000 g would have a net effect of increasing perinatal survival while lowering the overall cesarean delivery rate.

Pregnancy in transplant recipients.

A growing number of transplant recipients are women of reproductive age or children who will reach reproductive age. Thus, menstrual function and pregnancy increasingly are important issues because fertility is restored to women who were previously unable to conceive. To date, successful pregnancies have been reported in female recipients of kidney, liver, heart, pancreas-liver, bone marrow, and lung transplants. Women often become pregnant while being maintained on numerous medications, including immunosuppressive agents, and their care providers must be able to counsel and care for them. Information to date suggests that immunosuppressive medications are safe for use during pregnancy and are important in preventing maternal and fetal complications secondary to graft rejection. Although no formal guidelines have been established due to limited clinical experience, there are a few criteria that are commonly agreed on to improve the probability of a successful pregnancy outcome and the maintenance of graft function in transplant patients. Successful management of the pregnant transplant patient requires a cooperative effort between the obstetrician and transplant team. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader will be able to identify the complications associated with transplant recipients during pregnancy, to outline the potential immunosuppressive drug therapies and how they relate to pregnancy, and to list some of the effects of pregnancy on transplant function.

Human Immunodeficiency Virus Counseling and Testing Practices Among North Carolina Providers

OBJECTIVE To estimate the percentage of prenatal care providers who offer human immunodeficiency virus (HIV) testing to pregnant women, investigate how strongly testing is encouraged, and explore testing barriers. METHODS Between January 2001 and March 2001, we sent surveys to 1381 prenatal care providers in North Carolina, comprised of obstetricians, family physicians who practice obstetrics, and nurse‐midwives. A total of 653 questionnaires were returned. RESULTS Overall, 95.5% of providers who responded reported recommending HIV testing to all pregnant patients. Only 69.2% strongly recommend testing, with obstetricians (73.4%) and family physicians (70.1%) doing so at higher rates than nurse‐midwives (55.9%). Almost all respondents (96.9%) strongly recommend testing for women they perceive to be high risk, whereas 39.7% strongly recommend testing to women who have had an HIV test in the past 6 months. When women refuse testing, 48.1% of practitioners inquire about the reason, and 28.2% reoffer the test at a future prenatal appointment. The most significant testing barriers were treating an HIV‐positive woman (18.4%) and informing a patient she is HIV positive (14.8%). Respondents report that low literacy and culturally appropriate patient education materials would be most helpful to them. CONCLUSION Among respondents, most prenatal care providers report that they recommend HIV testing to all pregnant women. However, many respondents base their decision about how strongly to recommend HIV testing on an assessment of the womans risk for HIV exposure. Significant barriers to offering HIV testing were associated with managing an HIV‐positive patient. Providers were most in need of patient education materials.

Gastroschisis: The effect of labor and ruptured membranes on neonatal outcome

OBJECTIVES The purpose of this study was to examine the relationship between labor and ruptured membranes on the neonatal outcome of infants with gastroschisis. STUDY DESIGN We reviewed the outcomes of 60 neonates who were prenatally diagnosed with gastroschisis and who were delivered at the University of North Carolina Hospitals between June 1989 and April 1999. RESULTS The mean gestational age at delivery was 36 weeks. Four infants (7%) died in the neonatal period, and 19 infants (32%) had a major morbidity. No significant differences appeared in any of the neonatal outcomes when they were stratified by the presence or absence of labor and presence or absence of ruptured membranes. After being controlled for confounding variables, the risk of neonatal death or major neonatal morbidity because of exposure to either labor or ruptured membranes was no different than the risks caused by no labor or intact membranes, respectively. CONCLUSION Labor and ruptured membranes do not appear to be associated with increased neonatal morbidity or mortality rates in neonates with gastroschisis.