Nancy W. Hendrix

Perinatal outcome and amniotic fluid index in the antepartum and intrapartum periods: A meta-analysis

OBJECTIVE Our purpose was to perform a meta-analysis of studies on the risks of cesarean delivery for fetal distress, 5-minute Apgar score <7, and umbilical arterial pH <7.00 in patients with antepartum or intrapartum amniotic fluid index >5.0 or <5.0 cm. STUDY DESIGN Using a MEDLINE search, we reviewed all studies published between 1987 and 1997 that correlated antepartum or intrapartum amniotic fluid index with adverse peripartum outcomes. The inclusion criteria were studies in English that associated at least one of the selected adverse outcomes with an amniotic fluid index of </=5.0 cm versus >5.0 cm. Contingency tables were constructed for each study, and relative risks and standard errors of their logs were calculated. Fixed-effects pooled relative risks were calculated for groups of studies that were homogeneous, whereas random-effects pooled relative risks were calculated for significantly heterogeneous groups of studies. RESULTS Eighteen reports describing 10,551 patients met our inclusion criteria. An antepartum amniotic fluid index of </=5.0 cm, in comparison with >5.0 cm, is associated with an increased risk of cesarean delivery for fetal distress (pooled relative risk, 2.2; 95% confidence interval, 1.5-3.4) and an Apgar score of <7 at 5 minutes (pooled relative risk, 5.2; 95% confidence interval, 2.4-11.3). An intrapartum amniotic fluid index of </=5.0 cm is also associated with an increased risk of cesarean delivery for fetal distress (pooled relative risk, 1.7; 95% confidence interval, 1.1-2.6) and an Apgar score <7 at 5 minutes (pooled relative risk, 1.8; 95% confidence interval, 1.2-2.7). A poor correlation between the amniotic fluid index and neonatal acidosis was noted in the only study that examined this end point. More than 23,000 patients are necessary to demonstrate that the incidence of umbilical arterial pH <7.00 is 1.5 times higher among those with oligohydramnios in labor than among those with adequate amniotic fluid index (alpha = 0.05; beta = 0.2) CONCLUSIONS An antepartum or intrapartum amniotic fluid index of </=5.0 cm is associated with a significantly increased risk of cesarean delivery for fetal distress and a low Apgar score at 5 minutes. There are few reports linking amniotic fluid index and neonatal acidosis, the only objective assessment of fetal well-being. A multicenter study with sufficient power should be undertaken to demonstrate that a low amniotic fluid index is associated with an umbilical arterial pH <7.00.

Non-Placental Causes of Intrauterine Growth Restriction

Placental insufficiency, in some form or fashion, is associated with the majority of cases of intrauterine growth restriction (IUGR). There are numerous causes of IUGR which are not caused primarily by placental insufficiency, but indirectly lead to it. The causes of IUGR can be subdivided into fetal and maternal etiologies. The fetal etiologies consist of genetic diseases, congenital malformations, infections, multiple gestations, and placental/cord abnormalities. The maternal etiologies are categorized as follows: (1) decreased uteroplacental blood flow, (2) reduced blood volume, (3) decreased oxygen carrying capacity, (4) nutrition status, (5) teratogens, and (6) miscellaneous causes such as short interpregnancy intervals, race, maternal age, and low socioeconomic status. Knowledge of the etiologies of fetal growth restriction is essential, so that future care can be targeted at prevention. There are several primary and secondary prevention strategies that can be adopted.

Intrauterine growth restriction: comparison of American College of Obstetricians and Gynecologists practice bulletin with other national guidelines

OBJECTIVE The objective of the study was to compare national guidelines regarding small for gestational age (SGA). STUDY DESIGN Along with American College of Obstetricians and Gynecologists (ACOG) practice bulletin on abnormal growth, guidelines from England, Canada, Australia, and New Zealand were reviewed. RESULTS There are no guidelines on SGA from Canada, Australia, and New Zealand. The Royal College of Obstetricians and Gynaecologists (RCOG) guideline agrees with ACOGs definition of abnormal growth, but there are noticeable variances in the diagnosis and management of SGA. RCOG has more recommendations than ACOG (18 vs 4, respectively). The articles referenced varied, with only 13 similar articles being cited by the both committees. CONCLUSION The differences in the 2 guidelines suggest that there is variance in how 2 committees synthesize the literature and issue recommendations.

A review of sonographic estimate of fetal weight: Vagaries of accuracy

Purpose. To determine the factors that might influence the accuracy of sonographic estimated fetal weight. Study design. A PubMed search (Jan 1975 to Jan 2003) of articles published in the English language was carried out and the inclusion criterion was that estimates were within 10% of birth weight. A Chi-square test for trend was used and odds ratio (OR) with 95% confidence intervals (CI) was calculated. Results. Over 28 years, 175 articles were identified but only 54 (31%) met the inclusion criterion. Overall 62% (8895/14 384) of the predictions were within 10% of the actual weight. The accuracy was significantly different in articles where <7 vs. >7 days were allowed to lapse between examination and delivery (OR 2.17, 95% CI 1.93, 2.45); where examinations were done by registered diagnostic medical sonographers (RDMS; 65%) versus physicians (59%) or residents (57%; p < 0.0001); in term vs. preterm patients (OR 1.97, 95% CI 1.67, 2.13); and in studies with >1000 vs. <1000 cohorts (OR 1.62; 95% CI 1.51, 1.74). Conclusions. If feasible the sonographic examination should be done by RDMS and within a week of delivery.

STERILIZATION AND ITS CONSEQUENCES

UNLABELLED The purpose of this review is to analyze critically the two techniques of sterilization (bilateral tubal ligation [BTL] and vasectomy) so that a physician may provide informed consent about methods of sterilization. A MEDLINE search and extensive review of published literature dating back to 1966 was undertaken to compare preoperative counseling, operative procedures, postoperative complications, procedure-related costs, psychosocial consequences, and feasibility of reversal between BTL and a vasectomy. Compared with a vasectomy, BTL is 20 times more likely to have major complications, 10 to 37 times more likely to fail, and cost three times as much. Moreover, the procedure-related mortality, although rare, is 12 times higher with sterilization of the woman than of the man. Despite these advantages, 300,000 more BTLs were done in 1987 than vasectomies. In 1987, there were 976,000 sterilizations (65 percent BTLs and 35 percent vasectomies) with an overall cost of

Intrapartum oligohydramnios does not predict adverse peripartum outcome among high-risk parturients☆☆☆★★★

1.8 billion. Over

Shoulder Dystocia: Comparison of the ACOG Practice Bulletin with Another National Guideline

260 million could have been saved if equal numbers of vasectomies and BTLs had been performed, or more than

Detection of growth-restricted fetuses in preeclampsia: a case-control study ☆

800 million if 80 percent had been vasectomies, as was the case in 1971. The safest, most efficacious, and least expensive method of sterilization is vasectomy. For these reasons, physicians should recommend vasectomy when providing counseling on sterilization, despite the popularity of BTL. TARGET AUDIENCE Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES After completion of this article, the reader will be able to predict the failure rates and likelihood of successful reversal of tubal ligation and vasectomy; to recall the difference in cost between the two sterilization procedures, and to describe the short-term and long-term complications associated with each of the two methods of sterilization.

Cesarean delivery for fetal distress: Rate and risk factors

OBJECTIVE Oligohydramnios can be defined by an amniotic fluid index < 5th percentile for gestational age or an amniotic fluid index < or = 5.0 cm regardless of gestational age. The purpose of this prospective study was to determine whether oligohydramnios by either definition predicts accurately, in a high-risk population, the risks for cesarean section for fetal distress, Apgar score < 7 at 5 minutes, and neonatal acidosis. STUDY DESIGN An amniotic fluid index was obtained in 490 consecutive parturients with medical or obstetric complications and a reliable gestational age. After each delivery, an umbilical arterial blood gas analysis was obtained. Both measures of amniotic fluid index were rated as screening tests with use of sensitivity, specificity, predictive values, and receiver-operator characteristic curves. RESULTS The incidences of cesarean section for fetal distress and umbilical arterial pH < 7.00 were 14% and 1.8%, respectively. The 70 neonates delivered by cesarean section for distress, compared with the 420 without, had a significantly higher incidence of pH < 7.00 (8.5% vs 0.7%, p = 0.0004, relative risk 5.0, 95% confidence interval 2.9 to 8.4). Sensitivity and positive predictive values of an amniotic fluid index < 5th percentile for gestational age to predict pH < 7.00 were 0.8% and 22%, respectively, and for an amniotic fluid index < or = 5.0 cm, 0.5% and 11%, respectively. Receiver-operator characteristic curves indicate that an amniotic fluid index between 0 and 20 cm cannot predict accurately which parturients will have cesarean sections for distress or be delivered of a newborn with a low Apgar score at 5 minutes or a pH < 7.10. CONCLUSION Both criteria for oligohydramnios are poor predictors of adverse outcome for high-risk intrapartum patients.

Neonatal organ dysfunction among newborns at gestational age ⩾ 34 weeks and umbilical arterial pH < 7.00

Our objective was to compare national guidelines regarding shoulder dystocia. Along with the American College of Obstetricians and Gynecologists (ACOG) practice bulletin on shoulder dystocia, guidelines from England, Canada, Australia, and New Zealand were reviewed. The Royal College of Obstetricians and Gynaecologists (RCOG) guideline agrees with the ACOG definition of shoulder dystocia, but there are variances in the management of suspected macrosomia and resolution of impacted shoulders. How recommendations are categorized differ also. Only 53% (20 of 38) of eligible references are cited by both publications. The two national guidelines on shoulder dystocia have differences and disagreements with each other, raising concerns about how the literature is synthesized and which is more comprehensive.