Dan Sherman

Ripening of the unfavorable cervix with extraamniotic catheter balloon : Clinical experience and review

The use of an extraamniotic catheter balloon, inflated above the internal cervical os, has been advocated as a nonpharmacological, mechanical method of cervical ripening before induction of labor. Additional measures may include applying traction on the catheter, or the infusion of normal saline (1 ml/min) via the catheters port into the extraamniotic space. The results of catheter balloon cervical ripening are reviewed from 13 published reports and a departmental series of 190 pregnancies with unfavorable cervix, encompassing nearly 1000 patients. A mean change in cervical score of at least 3 points, was noted in most studies after balloon expulsion or removal. The present series and other studies suggest that oxytocin use for induction and/or augmentation of labor is increased after balloon ripening, compared with its use in spontaneous labor or after cervical ripening by prostaglandins. In 11 studies, catheter balloon ripening was compared with cervical ripening by other mechanical, or pharmacological (i.e., oxytocin or prostaglandins) methods. Of these, eight were prospective and randomized-controlled and three were case-controlled studies. It is suggested that ripening efficacy by catheter balloon is similar, or better, than other methods; but there is no significant difference in the mode of delivery or perinatal outcome. This review also suggests that cervical ripening with extraamniotic catheter balloon has the advantages of simplicity, low cost, reversibility, and lack of systemic or serious side effects.

Amniotic fluid volume response to esophageal occlusion in fetal sheep

Although ovine and human fetuses swallow considerable volumes of fluid, the impact of absence of fetal swallowing on amniotic fluid volume regulation is unclear. To study the role of fetal swallowing on urine production and amniotic fluid, seven ovine fetuses (126 +/- 1 days) were chronically prepared with fetal bladder and vascular catheters, an esophageal flow probe, an inflatable esophageal cuff, and amniotic fluid catheters. In the five fetuses that underwent esophageal ligation after the control period, fetal swallowing averaged 0.27 ml/min before occlusion. In response to esophageal occlusion, significant increases were noted in fetal plasma arginine vasopressin (6.9 +/- 2.6 to 16.6 +/- 4.4 pg/ml) and urine osmolality (159 +/- 1 to 324 +/- 30 mOsm/kg), whereas urine volume (0.25 ml/min) did not change. Amniotic fluid volume increased nearly threefold after 3 days of esophageal occlusion (582 +/- 180 to 1530 +/- 271 ml). Amniotic fluid volume remained normal (334 to 419 ml) in the one fetus in which the occluder did not inflate. In the one fetus in which the esophagus was occluded at surgery, amniotic fluid volume was increased after the surgical recovery period (1489 ml). These data indicate an important role of fetal swallowing in amniotic fluid homeostasis and the potential interaction of swallowing with fetal urine production.

Stimuli for fetal swallowing: systemic factors.

Although the fetal gastrointestinal tract is believed to be a major site of amniotic fluid absorption, there is little information with regard to the acute regulation of fetal swallowing. A model for the study of ovine fetal swallowing was developed to incorporate electromyograms, an esophageal flow probe, and a computer data acquisition and analysis program. The fetal swallowing responses to two primary thirst stimuli, plasma hyperosmolality and angiotensin II, were studied. On alternate days, chronically prepared fetal lambs (131 +/- 2 days) received an intravenous infusion of angiotensin II (100 ng/kg per minute) or bolus injections (3 ml) of 0.15 and 3.97 mol/L saline solution. In response to the angiotensin II infusion, fetal systolic (49.3 to 64.7 mm Hg; p less than 0.05) and diastolic (31.1 to 40.5 mm Hg; p less than 0.05) blood pressures significantly increased. However, fetal swallowing did not change from basal rates of 0.85 swallows per minute and a net esophageal flow of 0.98 ml/min. In response to the injection of 3.97 mol/L saline solution, fetal plasma osmolality increased (292 to 306 mOsm; p less than 0.05) and subsequently decreased to 300 mOsm at 15 minutes after the injection. Within 1 minute after injection of the hypertonic saline solution, fetal swallowing activity (6.0 swallows per minute; p less than 0.05) and net esophageal flow (2.4 ml/min; p less than 0.05) significantly increased. Swallowing returned to basal values within 5 minutes after the injection. The data indicate that ovine fetal responses to osmolar thirst challenges are intact at 130 days gestation. Fetal swallowing and thus amniotic fluid volume may be affected by fetal responses to in utero stimuli.

Ripening the Highly Unfavorable Cervix With Extra-Amniotic Saline Instillation or Vaginal Prostaglandin E2 Application

&NA; Extra‐amniotic saline instillation using a 26‐gauge Foley catheter and vaginal application of prostaglandin E2 (PGE2) were compared. Among 52 cases treated with extra‐amniotic saline instillation, the mean Bishop score increased from 1.7 to 7.8 in a mean of 2.8 hours. In all cases but one, an increase of the Bishop score of three or more points occurred during a 6‐hour period. Prostaglandin E2 tablets (3 mg) applied in the posterior vaginal fornix (once or twice) resulted in an increase in the Bishop score of three or more points in 39 of 54 cases during the 12‐hour study period. The mean Bishop score in these “successful” ripenings using PGE2 increased from 1.9 to 5.6 points during a mean time of 8.5 hours. No severe side effects were registered in either procedure. (Obstet Gynecol 73:938, 1989)

Omphalocele delivery enigma: the best mode of delivery still remains dubious

OBJECTIVEnTo determine an optimal route of delivery for fetuses with prenatally diagnosed omphalocele.nnnDATA SOURCEnMEDLINE search of years 1966-1996.nnnRESULTSnDescriptive retrospective analyses do not support the idea that cesarean delivery of fetuses with omphalocele is associated with an improved survival rate. However, most of those studies do not control for confounding variables like type and severity of associated anomalies, omphalocele size, prematurity rate, presence of trial of vaginal delivery, rate of intrapartum sac rupture, tertiary treatment centers accessibility, time and type of surgical correction, and postoperative morbidity. There is no evidence that vaginal delivery is safer than cesarean for fetuses with isolated small omphalocele. Fetuses with giant (>5 cm) omphalocele should be delivered by cesarean section. Vaginal delivery at term is offered for fetuses with coexisting life-threatening anomalies.nnnCONCLUSIONSnWe propose that until randomized trial of vaginal and cesarean delivery for fetal omphalocele is available, the preferred mode of delivery would be the vaginal route as that is safer for the mother.

Fetal Rehydration Via Intraamniotic Fluid: Contribution of Fetal Swallowing

ABSTRACT: Amniotic fluid volume is regulated by a balance of fetal fluid production and resorption. Although fetal swallowing is believed to be a major site of fluid resorption, additional routes of fluid exchange also may contribute. In our present study, five chronically prepared, water-restricted, pregnant ewes with singleton fetuses (128 ± 1 d) were rehydrated via an intraamniotic infusion (100 mL/h over 90 min) of 0.075 M saline. In response to the maternal water restriction, significant increases were noted in maternal and fetal plasma osmolalities (306.6 ± 1.2 to 315.4 ± 2.4; 300.5 ± 1.5 to 311.0 ± 1.6 mosmol/kg, respectively) and arginine vasopressin concentrations (1.9 ± 0.2 to 22.6 ± 5.0; 1.5 ± 0.1 to 8.5 + 2.2 pg/mL, respectively). After the intraamniotic infusion, fetal plasma osmolality (311.0 ± 1.6 to 303.0 ± 1.2 mosmol/kg) and hematocrit (36.7 ± 1.9 to 33.8 ± 1.4%) significantly decreased although there was no change in maternal arterial blood values. Fetal swallowing averaged 0.39 ± 0.10 mL/min during the basal period and 0.34 ± 0.17 mL/min at maximum dehydration, and decreased significantly to 0.19 ± 0.07 mL/min in response to the intraamniotic infusion. These results indicate the rapid absorption of intraamniotic fluid by the dehydrated ovine fetus, despite the suppression of fetal swallowing. The volume swallowed during and after the intraamniotic infusion was insufficient to account for the observed changes in fetal plasma osmolality and hematocrit. Thus, alternative routes of fluid absorption (i.e. intramembranous flow) likely predominate under conditions of increased fetal plasma to amniotic fluid osmotic gradients.

Congenital hypofibrinogenemia in pregnancy: Report of two cases and review of the literature

Fibrinogen abnormalities have been implicated in many adverse pregnancy outcomes, mainly spontaneous abortion, placental abruption, and postpartum hemorrhage. Two new cases of congenital hypofibrinogenemia in pregnancy are reported detailing their obstetric course and management. The relevant obstetric and hematologic literature is reviewed, including previous case reports and studies concerning the mechanisms of pregnancy complications. Suggestions for treatment guidelines and management strategies are detailed. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader should be able to describe how fibrinogen is synthesized and how it functions, to explain the various fibrinogen abnormalities, to outline the various ramifications and manifestations of a patient with a fibrinogen abnormality, and to describe the treatment for fibrinogen abnormalities during pregnancy.

Ovine fetal lung fluid response to intravenous saline solution infusion fetal atrial natriuretic factor effect

The fetal lung, a significant source of in utero fluid production, has been postulated to serve a regulatory role in maintenance of fetal body fluid homeostasis. Whereas the fetus responds to intravascular saline solution infusions with increased urine output, the fetal lung fluid response to this stimulus is unclear. Tracheal fluid output was measured in four chronically catheterized ovine fetuses (mean gestation, 129 +/- 1 days) subjected to successive 40-minute intravenous 0.9% saline solution infusions at rates of 0.5 and 1 ml/min/per kilogram of body weight. Tracheal fluid output decreased significantly (1.7 +/- 0.1 to 1.1 +/- 0.1 ml/10 min, p less than 0.01) during the infusion and returned to basal levels during the recovery period. Lung fluid osmolality and electrolyte concentration did not change. Fetal plasma atrial natriuretic factor increased significantly in response to the saline solution infusion (364 +/- 90 to 790 +/- 286 pg/ml, p less than 0.05) and returned to basal levels during the recovery period. There was a significant inverse correlation between plasma atrial natriuretic factor levels and tracheal fluid output. These results suggest that increased fetal plasma atrial natriuretic factor decreases lung fluid production. Lung fluid does not appear to compensate for fetal body water excess. Rather, lung fluid production appears to promote intrauterine pulmonary growth and to facilitate the transition to the extrauterine environment.

Maternal serum human chorionic gonadotrophin levels in systemic lupus erythematosus and antiphospholipid syndrome

Maternal serum human chorionic gonadotrophin (hCG) levels were measured during the second and the third trimesters of pregnancy in patients with either systemic lupus erythematosus (SLE) or primary antiphospholipid syndrome (APS). All results were expressed in multiples of the gestation‐specific normal medians (MoM). The median MoM level in 17 samples from SLE patients was 1.48 compared with 0.79u2009MoM in 99 controls of similar gestation (p<0.002, Wilcoxon Rank sum test). In contrast the median MoM level in 19 samples from primary APS patients was only 1.14. These preliminary findings should be further studied to evaluate the implications for Down syndrome screening, detection of SLE cases during pregnancy and the prediction of adverse outcome in SLE gestations. Copyright

Ovine fetal lung fluid response to atrial natriuretic factor

The fetal lung is an important site of fluid production and is postulated to serve a regulatory role in fetal fluid balance. To assess the role of atrial natriuretic factor on fetal lung liquid production, we studied the effect of intravenous atrial natriuretic factor infusion on tracheal fluid production in fetal sheep with chronic vascular and tracheal catheters. Ovine fetuses (mean gestation = 130 days +/- 1 day) received successive 40-minute intravenous infusions of increasing doses of synthetic fragment 1-28 atrial natriuretic factor (5, 25, and 100 ng/min.kg-1). In response to the 25 ng/min.kg-1 infusion, fetal tracheal fluid production decreased from 1.2 +/- 0.3 ml/10 min to 0.6 +/- 0.2 ml/10 min (p less than 0.05), and remained suppressed during the 100 ng/min.kg-1 infusion (0.5 +/- 0.2 ml/10 min). There was a significant inverse correlation between tracheal fluid production and fetal plasma atrial natriuretic factor levels (r = -0.61, p less than 0.001). Basal tracheal fluid sodium and potassium concentrations (147 +/- 1 mEq/L and 5 +/- 1 mEq/L) and osmolality (291 +/- 3 mOsm) did not change during the atrial natriuretic factor infusion periods. The observation that atrial natriuretic factor acts to decrease fetal lung fluid production suggests that atrial natriuretic factor may be important in the fetal adaptive response to extrauterine life.