High Risk Of Preterm Labor Research Articles

Tissue elastography imaging of the uterine cervix during pregnancy.

Tissue elastography is a recently developed tissue characterization method for estimating tissue stiffness. We investigated the feasibility of using US tissue elastography by evaluating uterine cervical maturation during pregnancy. The principle underlying elastography is that tissue compression produces strain (displacement) within the tissue, and that less strain occurs in hard tissue than in soft tissue. Tissue elastography thus enables the estimation of tissue stiffness by measuring compression-induced tissue strain. Malignant tumors are generally known to be harder than benign tumors in the breast, thyroid, and prostate. Various studies on these organs have demonstrated the usefulness of tissue elastography for differentiating malignant from benign masses in the clinical setting. Based on these results, we have begun to investigate the possibility of using tissue elastography to identify the population at high risk of preterm labor. We used a Hitachi EUB-8500 (Tokyo, Japan) ultrasound system equipped with a 7.5-MHz transvaginal sector probe to carry out transvaginal US examinations. After selecting the transvaginal sagittal image of the uterine cervix as the region of interest (ROI) in B-mode, we began real-time elastography of the ROI using only slight pressure, and displayed both the Bmode and elasticity images side by side on the same monitor screen (Fig. 1).

Treatment options for bacterial vaginosis in patients at high risk of preterm labor and premature rupture of membranes

To estimate the efficacy of different therapeutic modalities on proven cases of bacterial vaginosis (BV) in patients at high risk of preterm labor and premature rupture of membranes. This was a longitudinal prospective comparative study set in the antenatal outpatient clinic of the department of Obstetrics and Gynecology, Faculty of Medicine, Assiut University, Assiut, Egypt. Four hundred and sixty-eight patients with a clinical picture of threatened preterm labor or at high risk of premature rupture of membranes in the third trimester were screened for BV. Positive BV was diagnosed in 156 patients. They were randomly classified into four equal groups according to the line of medical treatment. The treatments were: (i) oral metronidazole, (ii) clindamycin vaginal cream, (iii) oral clindamycin, or (iv) metronidazole vaginal suppositories. The effects of medical treatment on Amsel's criteria as well as maternal and fetal outcomes were measured. Based on Amsel's criteria, 156 patients (33.3%) were diagnosed with BV. There was a significant disappearance of vaginal discharge, with decreased percentages of pH > 4.5, positive amine test, and clue cells after treatment of BV in the four groups without any statistically significant difference between them. There were variable effects of the different treatments on increasing birthweight values, admission to neonatal intensive care units, and prolongation of the gestational age. Some maternal adverse effects have been recorded. There were significant improvements of the outcomes for oral metronidazole and clindamycin compared with outcomes for intravaginal metronidazole and clindamycin. Metronidazole and clindamycin achieve nearly equivalent cure rates when administered orally or vaginally in patients at high risk of preterm labor and premature rupture of membranes. Oral metronidazole is considered the drug of choice in treating BV due its high cure rate, better outcomes, and low cost.

Adnexal mass surgery and anesthesia during pregnancy: a 10-year retrospective review

Many studies have addressed the specific perinatal risks of surgery and anesthesia during pregnancy, but there is still much undetermined. The objective of this retrospective review was to compare the adverse pregnancy outcome in patients undergoing laparoscopy and laparotomy with inhalational or regional anesthesia for adnexal mass in pregnancy. From the records, the case notes of patients who had had surgery for adnexal mass during pregnancy over 10 years in the Cheil General Hospital and Women's Health Center were reviewed. The type of surgery and anesthesia and the outcome were recorded. Of the 235 patients, general anesthesia was employed for laparotomy in 137 and for laparoscopic surgery in 27. Regional anesthesia for laparotomy was administered on 71 occasions. The incidence of preterm labor in the group given regional anesthesia (29.6%) was significantly higher than the groups given general anesthesia (5.8% in the laparotomy group, 0% in the laparoscopy group). The incidences of preterm labor and premature delivery in all surgical patients (preterm labor 12.3%, premature delivery 7.7%) were higher than among the non-surgical pregnant population over the same period (3.2%, 4.8%). Patients undergoing laparotomy with regional anesthesia for adnexal mass in pregnancy may have higher risk of preterm labor than those given general inhalational anesthesia for laparotomy or laparoscopy. Therefore, if regional anesthesia is used for this type of surgery, then precautions should be taken to reduce the risk of preterm labor.

TOCOX—A randomised, double‐blind, placebo‐controlled trial of rofecoxib (a COX‐2‐specific prostaglandin inhibitor) for the prevention of preterm delivery in women at high risk

To assess the safety and efficacy of the long term prophylactic use of rofecoxib (a COX-2-specific inhibitor) in women at high risk of preterm delivery. A randomised, double-blind, placebo-controlled trial. Queen Charlotte's and Chelsea Hospital, London and Guys and St Thomas' Hospitals, London. Ninety-eight singleton pregnancies at high risk of preterm labour. Treatment from 16 to 32 weeks. Weekly ultrasound surveillance. Fetal renal function and ductus arteriosus blood flow changes. Preterm delivery rates and neonatal outcome. Rofecoxib caused a reduction in hourly fetal urine production rates (-34%, 95% CI -13 to -50%, P = 0.004) and amniotic fluid index (-2.2, 95% CI -3.2 to -1.2, P < 0.001). This effect did not increase with time on treatment and reversed in all cases on discontinuation of treatment. Rofecoxib had an effect on the ductus arteriosus, increasing maximum systolic velocity (0.1 m/s, 95% CI 0.03-0.16, P = 0.02) and minimum diastolic velocity (0.007 m/s, 95% CI 0.0007-0.013, P= 0.03). This effect increased with time on treatment but was reversed with discontinuation of treatment and had no long term clinical sequelae. There was no difference in preterm delivery rates <30 weeks (28% on placebo vs 33% on rofecoxib, Mantel-Haensel [M-H]-adjusted risk 1.11, 95% CI 0.67-1.87). There were more deliveries <37 weeks in those on rofecoxib (40%vs 67%, M-H-adjusted risk 1.59, 95% CI 1.09-2.32). Rates of preterm prelabour rupture of membranes (PPROM) were higher in those on rofecoxib (RR 2.5, 95% CI 1.3-4.7). Rofecoxib has a significant but reversible effect on fetal renal function and the ductus arteriosus. It does not reduce the incidence of early preterm delivery <30 weeks and is associated with an increased risk of delivery before 37 weeks in women at high risk.

Editor's choice

Last year we discussed off-label tocolytics. This month we have twocommentaries on misoprostol, another drug often used controversially outside its licensed indications. Marsden Wagner argues (pp. 266–268) against misoprostol as a cervical ripening agent on the grounds that it has not been properly evaluated, and that other licensed drugs are available, while a group of medical campaigners with links to developing countries, argue (pp. 269–272) that it should be used more widely. Their claim is based largely on cost. Misoprostol is cheaper than alternative prostaglandins, although whether this reflects lack of safety evaluation in pregnancy, or a genuinely lower market price because of a more favourable balance between supply and demand, is debatable. The advocates of off-label misoprostol also emphasise its place in abortion or to control post partum haemorrhage, rather than to induce labour. Despite the lack of a licence, the evidence-base for the former indications is relatively strong. For 20 years British paediatricians have notified new cases of a panel of topical but rare childhood conditions to a central office each month. Although it has been a dramatically successful research tool, obstetricians have until now relied on ad hoc surveys, such as the BEST one of eclampsia in 1992. We are now following the paediatricians' lead with the launch of the United Kingdom Obstetric Surveillance System (UKOSS) (pp. 263–265). The proportion of hysterectomy operations performed by the vaginal route varies widely between regions and hospitals according to a survey from the Doctor Foster unit at Imperial College (pp. 326–328). The variation, which was not explained by difference in case mix, is likely to come under close scrutiny in future as the NHS moves towards paying hospitals according to a tariff for work undertaken. If, as the authors claim, the vaginal route is really quicker and safer, managers will have to encourage it. Some people doubt the wisdom of allowing this sort of commercial pressure to influence doctors' decisions but at least the new system will create an incentive for hospitals to collect accurate statistics. On pages 329–333 a group from Kent report a randomised controlled trial of a newish haemostastic device at vaginal hysterectomy. The Ligasure instrument uses controlled pressure and electro-coagulation to occlude the sort of larger vessels which would normally require ligation. The trial confirms that operative time is reduced with the use of the new device, but was too small to estimate relative safety. Audit and case control studies are probably better at evaluating that. Fetal fibronectin in vaginal secretions is a good predictor of pre-term delivery (pp. 293–298). The authors of the present study revealed the results to patients which would have compromised their estimate of test accuracy if treatment had been given, but which gave them the opportunity to measure the resulting patient anxiety. Patients with a positive result at 24 weeks were more anxious, and justifiably so, since nearly half of them were delivered before 30 weeks. Fortunately few other women, outside research projects, need be made anxious, because we have no effective treatment for high risk of preterm labour. Open myomectomy, the conventional treatment for women with symptomatic fibroids who wish to retain fertility, is a major operation with high morbidity. On pages 340–345 Adam Magos and his colleagues from the Royal Free in London report a randomised trial of the use of three haemostatic tourniquets during the operation, one of which was left in situ. The effect on blood loss and need for transfusion was dramatic, although the difference was largely due to a higher than expected blood loss in the control group. There appeared to be no obvious alteration in ovarian function post operatively, but the results of fertility follow-up are awaited. Fibroid embolisation also potentially retains fertility. On pages 321–325 the group from Guildford, with perhaps the most experience in the UK, report the outcome for 26 pregnancies in 22 women. The high rate of preterm delivery was also seen in other series, and the high rate of caesarean section may owe as much to the age of the mothers and their previous history as to the embolisation itself. Social deprivation in adulthood is associated with early menopause, although the effect may be mediated by smoking. On pages 346–354 Hardy and Kuh use data from the Medical Research Council's National Survey of Health and Development to investigate early-life influences. Such factors as parental divorce and having a father in a manual occupation in childhood are more strongly associated with early menopause than later-life stress, and the association is independent of later-life behavioural factors.

TOCOX—a randomised double-blind placebo-controlled trial of rofecoxib (a COX-2 specific PG inhibitor) for the prevention of preterm delivery in high-risk women

The object of this study was to assess fetal side effects of a COX-2 specific PG inhibitor in women at high risk of preterm labour with power to detect a large reduction in delivery <30 weeks. One hundred women at high risk were treated with 12.5 mg rofecoxib or placebo daily from 16 weeks or recruitment. Weekly ultrasound scans for amniotic fluid index (AFI), hourly fetal urine production (HFUPR), ductus arteriosus doppler (DAD) and transvaginal cervical length were undertaken. Treatment was discontinued at 32 weeks if AFI<5, PI <1.9, PPROM or preterm labour occurred. Data for 89 patients having completed treatment are presented. AFI < 5 occurred in 22% (10) on rofecoxib vs. none on placebo. AFI returned to normal within 1 week. No women stopped treatment for PI < 1.9. Mean AFI (−2.05, P < 0.0001) and HFUPR (−0.37 ml/hour, P = 0.007) were significantly lower in those on rofecoxib. DAD parameters were significantly higher in those on rofecoxib: maximum systolic (+0.096 cm/s per week, P < 0.003), minimum diastolic (+0.006 cm/s P = 0.05) and mean (+0.05 cm/s,P < 0.001). Mean PI was not different; however, the expected gestational increase did not occur in those taking rofecoxib. There was no difference in rates of delivery <30 weeks, 37% (rofecoxib) vs. 31% (placebo); however, there were fewer deliveries <37 weeks on placebo (38% vs. 70%).

Ultrasound-indicated cervical cerclage: Outcome depends on preoperative cervical length and presence of visible membranes at time of cerclage

Objective: The purpose of this study was to assess cases of ultrasound-indicated cervical cerclage and to relate preoperative cervical length, operative findings, postoperative cervical length, and pregnancy outcome to establish the appropriate criteria to offer cervical cerclage. Study Design: A prospective observational study comprised 380 women at high risk of preterm labor who underwent serial transvaginal ultrasonographic assessment of cervical length. Seventy-three women had criteria for and underwent cervical cerclage. Data concerning preoperative cervical length, operative findings, postoperative cervical length, and pregnancy outcome were collected. Statistical analysis was performed with Mann-Whitney and Fisher exact tests. Results: There was a significant increase in median cervical length after cerclage, 15.0 versus 25.0 mm (P <.0001). Preoperative cervical length and postoperative upper cervical length were independently better predictors of outcome than postoperative entire cervical length. Fetal membranes were visible in 18% of cases at the time of suture insertion, which was associated with a significantly worse outcome, regardless of preoperative cervical length. Of those 41 women with a very short preoperative cervical length (≤15 mm), outcome was significantly worse in those women with visible fetal membranes at the time of cerclage compared with those women with no visible fetal membranes at the time of cerclage: median gestational age at delivery, 23 weeks versus 37 weeks 4 days (P =.002); suture insertion to delivery interval, 19 days versus 108 days (P =.0004); and fetal survival rates, 50% versus 86% (P =.03). Conclusion: In a high-risk population that undergoes serial transvaginal ultrasound surveillance of cervical length, the presence of visible fetal membranes at the time of suture insertion, regardless of preoperative cervical length, is associated with a poor outcome. Fetal membranes were not visible in any cases with a preoperative cervical length of >15 mm. These findings lend support to a practice of offering cerclage at or above a cervical length of 15 mm. (Am J Obstet Gynecol 2002;187:445-9.)

Cervical incompetence: the use of transvaginal sonography to provide an objective diagnosis.

To investigate the use of transvaginal sonography in monitoring the cervix in women at high risk of a preterm delivery. One hundred and six women at high risk of preterm labor had regular cervical monitoring by transvaginal ultrasound throughout pregnancy from the second trimester to delivery. The study was designed to be observational, but intervention was considered if the cervical length fell below 10 mm. Eleven women demonstrated opening of the cervical canal at rest or with fundal pressure before 24 weeks' gestation. Between 2 and 17 days later all 11 cervices progressively shortened to a cervical length of < 10 mm. Nine women had a cervical cerclage. Seven women had fetal membranes visible within the cervical canal at the time of cerclage. One woman miscarried at 18 weeks, and the other 10 had live births at a median gestational age of 36 (range, 27-38) weeks. Cervical length shortening in the second trimester, once started, progressed to a cervical length under 10 mm. Opening of the cervical os at rest or in response to fundal pressure detected by transvaginal ultrasound appears to be the early ultrasound feature of cervical incompetence.

Multicenter randomized clinical trial of home uterine activity monitoring: Pregnancy outcomes for all women randomized

OBJECTIVE: Our purpose was to evaluate the impact of home uterine activity monitoring on pregnancy outcomes among women at high risk for preterm labor and delivery. STUDY DESIGN: Women at high risk for preterm labor at three centers were randomly assigned to receive high-risk prenatal care alone (not monitored) or to receive the same care with twice-daily home uterine activity monitoring without increased nursing support (monitored). There were 339 women with singleton gestations randomized with caregivers blinded to group assignment. The two groups were medically and demographically similar at entry into the study. RESULTS: Women in the monitored group had prolonged pregnancy survival ( p = 0.02) and were less likely to experience a preterm delivery (relative risk 0.59; p = 0.04). Infants born to monitored women with singleton gestations were less likely to be of low birth weight (<2500 gm; relative risk 0.47, p = 0.003), and were less likely to be admitted to a neonatal intensive care unit (relative risk 0.5, p = 0.01). CONCLUSION: These data show, among women with singleton gestations at high risk for preterm delivery, that the use of home uterine activity monitoring alone, without additional intensive nursing care, results in improved pregnancy outcomes, including prolonged gestation, decreased risk for preterm delivery, larger-birth-weight infants, and a decreased need for neonatal intensive care. (Am J Obstet Gynecol 1996;175:1281-5.)

A multicenter randomized controlled trial of home uterine monitoring: Active versus sham device

OBJECTIVE: Our purpose was to determine the efficacy of a home uterine activity monitoring system for early detection of preterm labor and reduction of preterm birth. STUDY DESIGN: A randomized, controlled, double-blinded trial was performed in which pregnant women between 24 and 36 weeks' gestation and at high risk for preterm labor or birth were assigned to receive twice daily nursing contact and home uterine activity monitoring with either active (data revealed) or sham (data concealed) devices. Study end points included mean cervical dilatation and its mean change from a previous visit at preterm labor diagnosis, preterm birth rate, and infant outcomes. Analysis of variance or logistic models including terms for site and group-by-site interaction effects were constructed for all variables. RESULTS: Of 1355 patients enrolled, 1292 were randomized, 1165 used home uterine activity monitoring devices, and 842 (72.3%) completed the study. Both device groups had similar demographics, enrollment and delivery gestational ages, discontinuation rates, risk factors, birth weights, cervical dilatation at enrollment and at preterm labor diagnosis, change in cevical dilatation at preterm labor diagnosis, rates of preterm labor and birth, and neonatal intensive care requirements. Power to detect a difference in cervical dilatation ≥1 cm at diagnosis of preterm labor was 0.99 for all risk factors. CONCLUSIONS: Uterine activity data obtained from home uterine activity monitoring, when added to daily nursing contact, were not linked to earlier diagnosis of preterm labor or lower rates of preterm birth or neonatal morbidity in pregnancies at high risk for preterm labor and birth.

Bacterial vaginosis in pregnancy: an approach for the 1990s.

It is proposed that clinicians screen all pregnant women at high risk for preterm labor and premature rupture of membranes for bacterial vaginosis, and treat all women when it is diagnosed. This infection is associated with a two to three times increase in preterm labor and delivery, premature rupture of the membranes, and endometritis. Although cause and effect have not been conclusively documented, these associations must be considered in the practice of obstetrics at the present. The paucity of vaginal Lactobacillus spp is pivotal in allowing overgrowth of many other organisms of the vagina. Screening is suggested because 50 percent of bacterial vaginosis is asymptomatic. The diagnosis, which is rapidly made and inexpensive, remains defined by clue cells seen on wet prep, high vaginal pH, and amine odor of the vaginal discharge. Optimal treatment of pregnant women with bacterial vaginosis is via oral or intravaginal metronidazole or clindamycin.

Multicenter randomized, controlled trial of a preterm birth prevention program

The results of a randomized, controlled trial of a preterm birth prevention program at five centers with primarily low-income populations are presented. Pregnant women at high risk for preterm labor were independently randomized into intervention and control groups at each of five centers (2395 women). Specially trained staff instructed women in the intervention group to recognize early signs of preterm labor and to notify the staff should any sign of preterm labor occur, and women came in weekly for pelvic examinations after 20 to 24 weeks' gestation. Because the intervention had very different and contrary effects on preterm birth rates across these sites, the analysis focused on patient risks and on measures of the process of care as possible explanations for the differences in outcomes. The observed spontaneous preterm birth rates, when averaged for all sites, were not lower in the intervention group than in the control groups (16.1% vs 15.4% for < 37 completed weeks' gestation, 11.9% vs 10.9% for < 36 completed weeks). There was substantial heterogeneity of program effects between centers (p < 0.01 for homogeneity test statistic). The differences in intervention effects between centers were explainable only in part by patient risk characteristics (p < 0.10 for homogeneity test statistic). The only intermediate measure of the process of care that tended to differentiate among sites with positive intervention effects was the rate of hospital admission for preterm labor. Sites with elevated admission rates in the intervention group versus the control group tended to have negative intervention effects on outcomes. Because the preterm birth prevention program did not show a reliable benefit and because the reasons for varied outcomes are not understood, the use of the program cannot be recommended for predominantly low-income populations.

Relationship of circadian rhythms of uterine activity with term and preterm delivery

Our aim was to document the presence or significance of circadian uterine activity rhythms in pregnant women who delivered at term and preterm. We measured uterine activity in 19 women divided into a control group (low risk for preterm labor, term delivery, n = 7), a group at high risk for preterm labor, term delivery (n = 6), and a group at high risk for preterm labor, preterm delivery (n = 6). Patients were hospitalized for 24 hours every 2 weeks from 26 weeks' gestation until delivery. Uterine activity was measured continuously by external tocodynamometer. Patients delivering at term demonstrated a nocturnal surge (4 to 7 AM) in uterine activity the last 80 days before delivery (p < 0.05, analysis of variance). Patients delivered preterm showed an initial nocturnal surge of uterine activity similar to those delivered at term, but this disappeared 24 days before delivery (p > 0.05, analysis of variance). Uterine activity nocturnal surges normally precede term delivery. These surges are lost in women who deliver prematurely.

Possible role of asthma in the risk of preterm labor and delivery.

We assessed the relation between maternal respiratory problems and preterm labor and delivery in a cohort of 3,891 women who delivered a singleton livebirth. Study participants were asked about their medical history in the 12 months before conception; women who reported a history of asthma had a higher risk of preterm labor [relative risk (RR) estimate = 2.33, 95% confidence interval (CI) = 1.03-5.26]. Asthmatic women also had an increased risk of preterm delivery (RR = 1.77, 95% CI = 0.60-5.24). Maternal respiratory problems during pregnancy were also associated with an increased risk of both inhibited preterm labor (RR = 2.14, 95% CI = 1.25-3.66) and preterm delivery (RR = 2.03, 95% CI = 1.08-3.82). Birthweight appeared to be unrelated to maternal history of asthma. Logistic regression models that adjusted for potential confounders did not appreciably alter the results. The adjusted odds ratio (OR) estimate for the odds of preterm labor in asthmatics relative to nonasthmatics is 2.42 (95% CI = 0.90-6.54); the analogous OR estimate for those with respiratory problems during pregnancy is 2.16 (95% CI = 1.14-4.10). The adjusted OR estimate for the odds of preterm delivery in asthmatics is 1.78 (95% CI = 0.53-6.02); for those with respiratory problems during pregnancy, the corresponding estimate is 2.00 (95% CI = 0.92-4.13).

Premature labor, Part I: Risk assessment, etiologic factors, and diagnosis.

This paper, the first of a two-part series on premature labor, reviews the recent literature on the causes of and risk factors for preterm labor and methods of diagnosis. A review of the literature on risk determination and diagnosis of preterm labor was conducted by searching MEDLINE files from 1983 to the present, using the key terms "preterm labor," "premature labor," "preterm labor and infection," and "uterine monitoring." Additional references were accessed by cross-referencing the bibliographies of the articles obtained through this search. Risk factors for preterm labor, which include items related to the pregnant woman's demographic characteristics, history, daily habits, and current pregnancy, have been combined into scoring systems commonly used by clinicians and researchers to single out women at risk for preterm delivery. When such systems are tested in obstetric populations, results show variable success in predicting preterm labor or birth. These inconsistent results could be due, in part, to important factors that have often been omitted from scoring systems, such as chemical abuse, poor nutrition, little social support, demanding work, multiple sexual partners, past or current sexually transmitted diseases, and other gynecologic infections. Women who are considered high risk for preterm labor can benefit from participating in preterm birth prevention programs that incorporate home monitoring, patient education regarding the signs and symptoms of preterm labor, frequent contacts with health professionals, and cervical examinations.

Relationship of Measured External Tocodynamometry with Measured Internal Uterine Activity

The use of home uterine activity monitoring for patients at high risk for preterm labor and delivery has become common in clinical perinatology. The ability of the monitoring devices to detect accurately uterine contractions in early pregnancy has not previously been reported. Ten women in labor between 20 and 35 weeks' gestation underwent simultaneous monitoring of uterine activity with a guard-ring tocodynamometer and an intrauterine pressure monitor. When compared with internal monitoring, the external monitor detected 90.8% of uterine contractions with a specificity for uterine quiescence of 98.1%. The predictive value of external monitoring was 97.3% for detecting uterine contractions and 93.6% for recording the absence of uterine contractions. The contractions detected externally were similar in duration: mean 63.7 +/- 23.0 seconds for internal monitoring and 62.2 +/- 22.6 seconds for external monitoring (p greater than 0.05). The intensity of contractions detected externally was less than internally measured contractions, mean difference, 19.7 +/- 15.9 mmHg (p less than 0.001). External tocodynamometry using this guarding tocodynamometer reliably distinguishes between uterine contractions and uterine quiescence in preterm pregnancies but does not adequately measure the intensity of contractions.

Prevention of preterm birth in high-risk patients: The role of education and provider contact versus home uterine monitoring

A total of 394 patients were enrolled in a study to assess the effectiveness of an educational preterm delivery prevention program and to determine whether the addition of home uterine monitoring to the program improved results in patients at high risk of preterm labor. Both the educational program and home uterine monitoring were found to increase the percentage of women with preterm labor who sought care while still favorable for long-term suppression, resulting in a decreased incidence of preterm births and improved outcome when compared with similar high-risk patients who did not participate in these programs. In a randomized, prospective study, addition of home uterine monitoring to the educational program was found to significantly improve outcome in twin gestations but not in singleton gestations. However, the number of singleton pregnancies was too small to rule out possible benefit from home uterine monitoring in that group.

Early Detection of Preterm Labor: Ambulatory Home Monitoring of Uterine Activity

Most women who experience preterm labor cannot receive long-term tocolysis mainly because of belated diagnosis. To detect excessive uterine contractions, an ambulatory tocodynamometer was developed. Sixty-two women, at high risk for preterm labor, monitored uterine activity between 20 and 36 weeks' gestation daily for a total of 200 minutes per day. Twenty-nine women (47%) had episodes of preterm labor. All the episodes were diagnosed by the device, and tocolysis was begun. The mean gestational age at which diagnosis was made was 28 +/- 2 (mean +/- SD) weeks, and the mean time gained in utero was 7.5 +/- 2.6 weeks. The data indicate that ambulatory home monitoring may represent a new and effective means for accurate and early diagnosis of preterm labor.

Assessment of uterine activity in ambulatory patients at high risk of preterm labor and delivery

With use of an ambulatory tocodynamometer, prelabor uterine activity was recorded daily during pregnancy in 34 patients at increased risk of preterm labor and delivery. The data indicate that the frequency of contractions was significantly greater among women who subsequently developed preterm labor when compared to that observed among women who labored at term. This difference was present up to several weeks before the onset of labor. An additional significant rise in frequency of contractions could be observed within the last 24 hours before the development of clinically apparent preterm labor, as evidenced by progressive cervical dilation and effacement. If these results can be reproduced in a larger sample, intermittent ambulatory monitoring may offer an effective way to better identify patients at risk of preterm labor as well as enhance the early diagnosis of this event.

Intrapartum Monitoring and Management of the Low Birth Weight Fetus

All physicians responsible for the care of gravidae at high risk for preterm labor and delivery must be expert in the management of these pregnancies. Only a fraction of women who present in labor remote from term are candidates for long-term tocolysis. Whatever treatment regimen is utilized, the clinician must be familiar with their risks as well as their benefits. The majority of women who present with preterm labor will require delivery or will deliver despite efforts to the contrary. If delivery is imminent or indicated, intensive intrapartum monitoring of these fetuses, especially those weighing less than 1500 gm, is mandatory. The mother should be transferred to a facility that contains both expert obstetric care and a neonatal intensive care unit staffed with individuals experienced in the management of these very low birth weight infants. Attempts at pharmacologic induction of lung maturation should be reserved for those situations in which: (1) the fetal membranes are intact, (2) the fetal lungs are likely to be immature, (3) delivery of the infant may be delayed without undue risk for 48 hours following initiation of therapy, and finally, (4) the informed consent of the parents has been obtained. (By the same token, the probable efficacy of glucocorticoids should not serve as license to deliver the preterm infant.) Preterm infants are viable, even at 25 to 26 weeks of gestation, provided that labor and delivery are managed expertly. When vaginal delivery is contemplated, labor, if induced, should not be forceful. Fetal heart rate and uterine contractions should be monitored continuously. Evidence of fetal jeopardy must be dealt with expeditiously. Nontraumatic delivery, including the liberal use of cesarean section, into the hands of an experienced neonatologist will reduce the number of asphyxiated premature infants and, therefore, the risk of hyaline membrane disease. For the very low birth weight infant presenting as a breech, abdominal delivery is recommended. It is important that the uterine incision, regardless of type, be large enough to allow for nontraumatic delivery of the infant. If greater improvements in the survival and outcome of low birth weight infants are to continue, it is mandatory that there be close collaboration not only between obstetrician and pediatrician, but also between all physicians and nursing staff who care for this group of high-risk patients.