Reduction in cervical length after vaginal progesterone in women with short cervix is significantly associated with preterm delivery at ≤ 34 weeks and < 37 weeks of gestation

OBJECTIVE

To evaluate the association between changes in cervical length (CL) after vaginal progesterone treatment and preterm delivery (PTD).

METHODS

This was a retrospective cohort study that included 197 singleton pregnancies without (n = 178) and with (n = 19) a history of PTD which were found to have a short cervix (≤ 25 mm) between 18 + 0 and 23 + 6 weeks' gestation with a follow-up transvaginal CL measurement taken at least 1 week after vaginal progesterone treatment started. Receiver-operating-characteristics (ROC)-curve analysis was performed and three CL shortening patterns were evaluated: (1) ≥ 10% reduction; (2) ≥ 20% reduction; and (3) ≥ 5 mm reduction relative to the first CL measurement. The predictive performance of each CL reduction cut-off and its association with PTD ≤ 34 weeks and PTD < 37 weeks were evaluated.

RESULTS

Overall, the rate of PTD ≤ 34 weeks was 16.8% (33/197) and that of PTD < 37 weeks was 36.5% (72/197). The area under the ROC curve of cervical shortening expressed in % for predicting PTD ≤ 34 weeks and PTD < 37 weeks was 0.703 and 0.608, respectively. Cervical shortening was observed in 60/197 (30.5%) patients, with 49/60 (81.7%) women showing ≥ 10% reduction, 32/60 (53.3%) ≥ 20% reduction and 27/60 (45.0%) ≥ 5 mm reduction in CL. Sensitivity and specificity for PTD ≤ 34 weeks were, respectively, 48.5% and 79.9% for ≥ 10% reduction; 36.4% and 87.8% for ≥ 20% reduction; and 27.3% and 89.0% for ≥ 5 mm reduction in CL. For PTD < 37 weeks, sensitivity and specificity were, respectively, 36.1% and 81.6% for ≥ 10% reduction; 27.8% and 90.4% for ≥ 20% reduction; and 20.8% and 90.4% for ≥ 5 mm reduction in CL. The highest positive likelihood ratios for PTD ≤ 34 and < 37 weeks were for ≥ 20% CL reduction (2.98 (95% CI, 1.62-5.49) and 2.89 (95% CI, 1.52-5.57), respectively). Despite significant differences in sensitivity among the different cut-offs for cervical shortening, favoring the ≥ 10% reduction cut-off, a reduction of ≥ 20% in CL showed the strongest association with PTD ≤ 34 weeks (odds ratio (OR), 4.11 (95% CI, 1.75-9.62)) and < 37 weeks (OR, 3.62 (95% CI, 1.65-7.96)), as compared with a less pronounced reduction in CL.

CONCLUSIONS

In women with a short cervix treated with vaginal progesterone, a reduction in CL on a subsequent ultrasound scan can predict PTD ≤ 34 and < 37 weeks. A ≥ 20% reduction in CL had the highest positive likelihood ratio and strongest association with PTD ≤ 34 and < 37 weeks compared with ≥ 10% or ≥ 5 mm reduction. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Health resource utilization of labor induction versus expectant management

BACKGROUND

Although induction of labor of low-risk nulliparous women at 39 weeks reduces the risk of cesarean delivery compared with expectant management, concern regarding more frequent use of labor induction remains, given that this intervention historically has been thought to incur greater resource utilization.

OBJECTIVE

The objective of the study was to determine whether planned elective labor induction at 39 weeks among low-risk nulliparous women, compared with expectant management, was associated with differences in health care resource utilization from the time of randomization through 8 weeks postpartum.

STUDY DESIGN

This is a planned secondary analysis of a multicenter randomized trial in which low-risk nulliparous women were assigned to induction of labor at 39 weeks or expectant management. We assessed resource utilization after randomization in 3 time periods: antepartum, delivery admission, and discharge through 8 weeks postpartum.

RESULTS

Of 6096 women with data available, those in the induction of labor group (n = 3059) were significantly less likely in the antepartum period after randomization to have at least 1 ambulatory visit for routine prenatal care (32.4% vs 68.4%), unanticipated care (0.5% vs 2.6%), or urgent care (16.2% vs 44.3%), or at least 1 antepartum hospitalization (0.8% vs 2.2%, P < .001 for all). They also had fewer tests (eg, sonograms, blood tests) and treatments (eg, antibiotics, intravenous hydration) prior to delivery. During the delivery admission, women in the induction of labor group spent a longer time in labor and delivery (median, 0.83 vs 0.57 days), but both women (P = .002) and their neonates (P < .001) had shorter postpartum stays. Women and neonates in both groups had similar frequencies of postpartum urgent care and hospital readmissions (P > .05 for all).

CONCLUSION

Women randomized to induction of labor had longer durations in labor and delivery but significantly fewer antepartum visits, tests, and treatments and shorter maternal and neonatal hospital durations after delivery. These results demonstrate that the health outcome advantages associated with induction of labor are gained without incurring uniformly greater health care resource use.

Neonatal Genetic Variation in Steroid Metabolism and Key Respiratory Function Genes and Perinatal Outcomes in Single and Multiple Courses of Corticosteroids

OBJECTIVE

The aim of the study is to evaluate the association of steroid metabolism and respiratory gene polymorphisms in neonates exposed to antenatal corticosteroids (ACS) with respiratory outcomes, small for gestational age (SGA), and response to repeat ACS.

STUDY DESIGN

This candidate gene study is a secondary analysis of women enrolled in a randomized controlled trial of single versus weekly courses of ACS. Nineteen single nucleotide polymorphisms (SNPs) in 13 steroid metabolism and respiratory function genes were evaluated. DNA was extracted from placenta or fetal cord serum and analyzed with TaqMan genotyping. Each SNP was evaluated for association via logistic regression with respiratory distress syndrome (RDS), continuous positive airway pressure (CPAP)/ventilator use (CPV), and SGA.

RESULTS

CRHBP, CRH, and CRHR1 minor alleles were associated with an increased risk of SGA. HSD11B1 and SCNN1B minor alleles were associated with an increased likelihood of RDS. Carriage of minor alleles in SerpinA6 was associated with an increased risk of CPV. CRH and CRHR1 minor alleles were associated with a decreased likelihood of CPV.

CONCLUSION

Steroid metabolism and respiratory gene SNPs are associated with respiratory outcomes and SGA in patients exposed to ACS. Risks for respiratory outcomes are affected by minor allele carriage as well as by treatment with multiple ACS.

Consequences of smoking and caffeine consumption during pregnancy in women with type 1 diabetes

OBJECTIVE

To test the hypothesis that, in women with type 1 diabetes, prenatal smoking and caffeine consumption during pregnancy are associated with an increased risk of adverse maternal and perinatal outcomes.

METHODS

A secondary analysis of data on pregnant women with type 1 diabetes from an interdisciplinary program of Diabetes in Pregnancy. Women were interviewed monthly, by a trained non-medical member of the research team, using a standardized questionnaire, to ascertain daily smoking habits and caffeine consumption.

RESULTS

Smoking and caffeine information were available on 191 pregnancies, 168 progressing beyond 20 weeks of gestation. Early pregnancy smoking (OR 3.3, 95% CI 1.2, 8.7) and caffeine consumption (OR 4.5, 95% CI 1.2, 16.8) were associated with increased risk of spontaneous abortion when controlling for age, years since diagnosis of diabetes, previous spontaneous abortion, nephropathy and retinopathy. Smoking throughout pregnancy was significantly associated with decreased birth weight and prolonged neonatal hospital stay. Smoking throughout pregnancy (OR 0.2, 95% 0.1, 1.0) and caffeine consumption after 20 weeks (OR 0.3, 95% CI 0.1, 1.0) were associated with reduced risk of pre-eclampsia.

CONCLUSIONS

Caffeine consumption during early pregnancy, regardless of glycemic control, increases the risk of spontaneous abortion. Smoking throughout pregnancy and caffeine consumption are associated with reduced risk of pre-eclampsia.

Spontaneous preterm delivery in the type 1 diabetic pregnancy: the role of glycemic control

OBJECTIVE

To determine the role of glycemic control in spontaneous preterm delivery in type 1 diabetic women.

METHODS

A secondary analysis of data from women enrolled in the Diabetes in Pregnancy Program prior to 20 weeks was performed. Multiple logistic regression was used to analyze the association between glycohemoglobin A1 in women with spontaneous preterm delivery (n = 53) and women who delivered at term (n = 200). Maternal demographics and obstetric outcomes were also compared between the groups.

RESULTS

Glycohemoglobin A1 levels were higher in the spontaneous preterm delivery group than the term group throughout pregnancy, reaching statistical significance after the first trimester. The last glycohemoglobin A1 prior to delivery was 8.1% in the spontaneous preterm delivery group and 7.4% in the term group (p = 0.002). Using multiple logistic regression, each 1% increase in glycohemoglobin A1 increased the risk of spontaneous preterm delivery by 37%.

CONCLUSION

Poor glycemic control is associated with an increased risk of spontaneous preterm delivery, suggesting that strict glycemic control may reduce the rate of preterm delivery in these women.

Pregnancy outcome and progression of diabetic nephropathy. What's next?

OBJECTIVES

The first objective was to assess the association of renal function with maternal and fetal pregnancy outcome in women with diabetic nephropathy. The second objective was to examine the feasibility of a multicenter surveillance program to determine the rates of maternal and fetal pregnancy complications in women with diabetic nephropathy, and to study the effect of pregnancy on the natural history of diabetic renal disease.

METHODS

In order to address the first objective, we analyzed data from women with type 1 diabetes and nephropathy enrolled in the Diabetes in Pregnancy Program at our institution. Women were assigned to one of three groups according to enrolment serum creatinine concentration: < or = 1.0 mg/dl, > 1.0 to 1.5 mg/dl and > 1.5 mg/dl. A pilot surveillance program at six centers included women experiencing pregnancy complicated by diabetic nephropathy. In both studies, medical and obstetric history, and maternal and neonatal outcomes, were recorded. Statistical analysis included chi2, logistic regression and analysis of variance.

RESULTS

There were 72 pregnancies in 58 women with diabetic nephropathy who enrolled in the pregnancy program. High serum creatinine concentration at enrolment was associated with delivery before 32 weeks' gestation, very low birth weight and increased incidence of neonatal hypoglycemia, independent of quantity of total urinary protein excretion and glycemic control in any trimester. To date, pilot surveillance data have been obtained from six centers on 16 women. Serum creatinine concentrations ranged from 0.4 to 1.1 mg/dl and creatinine clearance from 32 to 317 m/min. Gestational age at delivery ranged from 22 to 39 weeks.

CONCLUSIONS

High serum creatinine concentration at enrolment is a risk factor for adverse maternal and neonatal outcome, independent of quantity of total urinary protein excretion and glycemic control during any trimester. A multicenter surveillance program is needed, in order to study less frequent maternal and neonatal outcomes as well as the long-term effects of pregnancy on the natural course of diabetic renal disease.

Mid-trimester endovaginal sonography in women at high risk for spontaneous preterm birth

CONTEXT

Although shortened cervical length has been consistently associated with spontaneous preterm birth, it is not known when in gestation this risk factor becomes apparent.

OBJECTIVE

To determine whether sonographic cervical findings between 16 weeks' and 18 weeks 6 days' gestation predict spontaneous preterm birth and whether serial evaluations up to 23 weeks 6 days' gestation improve prediction in high-risk women.

DESIGN, SETTING, AND PARTICIPANTS

Blinded observational study performed between March 1997 and November 1999 at 9 university-affiliated medical centers in the United States in 183 women with singleton gestations who previously had experienced a spontaneous birth before 32 weeks' gestation.

OBSERVATION

Certified sonologists performed 590 endovaginal sonographic examinations at 2-week intervals. Cervical length was measured from the external os to the functional internal os along a closed endocervical canal. Funneling and dynamic cervical shortening were also recorded.

MAIN OUTCOME MEASURE

Spontaneous preterm birth before 35 weeks' gestation, analyzed by selected cutoff values of cervical length.

RESULTS

Forty-eight women (26%) experienced spontaneous preterm birth before 35 weeks' gestation. A cervical length of less than 25 mm at the initial sonographic examination was associated with a relative risk (RR) for spontaneous preterm birth of 3.3 (95% confidence interval [CI], 2.1-5.0; sensitivity = 19%; specificity = 98%; positive predictive value = 75%). After controlling for cervical length, neither funneling (P =.24) nor dynamic shortening (P =.054) were significant independent predictors of spontaneous preterm birth. However, using the shortest ever observed cervical length on serial evaluations, after any dynamic shortening, the RR of a cervical length of less than 25 mm for spontaneous preterm birth increased to 4.5 (95% CI, 2.7-7.6; sensitivity = 69%; specificity = 80%; positive predictive value = 55%). Compared with a single cervical measurement at 16 weeks' to 18 weeks 6 days' gestation, serial measurements at up to 23 weeks 6 days significantly improved the prediction of spontaneous preterm birth in a receiver operating characteristic curve analysis (P =.03).

CONCLUSIONS

Cervical length assessed by endovaginal sonography between 16 weeks' and 18 weeks 6 days' gestation, augmented by serial evaluations, predicts spontaneous preterm birth before 35 weeks' gestation in high-risk women.

Antiphospholipid antibodies in women at risk for preeclampsia

OBJECTIVE

The aim of this study was to determine whether positive results of tests for any of 5 antiphospholipid antibodies are associated with recurrent preeclampsia among women with a history of preeclampsia in a previous pregnancy.

STUDY DESIGN

Second-trimester serum samples were obtained from 317 women with preeclampsia in a previous pregnancy who were being followed up in a prospective treatment trial. The serum samples were measured by enzyme-linked immunoassay for immunoglobulin G and immunoglobulin M antibodies against 5 phospholipids. Positive results were analyzed with regard to preeclampsia, severe preeclampsia, intrauterine growth restriction, and preterm delivery.

RESULTS

Sixty-two of the 317 women (20%) had recurrent preeclampsia develop, 19 (6%) had severe preeclampsia, and 18 (5.8%) were delivered of infants with growth restriction. Positive results of tests for immunoglobulin G or immunoglobulin M antiphospholipid antibodies were not associated with recurrent preeclampsia. Positive results for immunoglobulin G or immunoglobulin M antibodies at the 99th percentile were also not associated with preterm delivery. Positive results at the 99th percentile for immunoglobulin G antiphosphatidylserine antibody were associated with severe preeclampsia, and positive results at the 99th percentile for immunoglobulin G anticardiolipin, antiphosphatidylinositol, and antiphosphatidylglycerol antibodies were associated with intrauterine growth restriction. The positive predictive values for these outcomes all were approximately 30%.

CONCLUSION

Positive results of testing for antiphospholipid antibodies in the second trimester were not associated with recurrent preeclampsia among women at risk because of a history of preeclampsia. Positive results for immunoglobulin G antiphosphatidylserine antibody were associated with severe preeclampsia, and positive results for immunoglobulin G anticardiolipin, antiphosphatidylinositol, and antiphosphatidylglycerol antibodies were associated with intrauterine growth restriction. However, the positive predictive values for all these associations were modest. Testing for antiphospholipid antibodies during pregnancy is of little prognostic value in the assessment of the risk for recurrent preeclampsia among women with a history of preeclampsia.

Primary, secondary, and tertiary prevention of pre-eclampsia

Pre-eclampsia remains one of the major obstetrical problems in less-developed countries. The causes of this condition are still unknown, thus effective primary prevention is not possible at this stage. Research in the past decade has identified some major risk factors for pre-eclampsia, and manipulation of these factors might result in a decrease in its frequency. In the early 1990s aspirin was thought to be the wonder drug in secondary prevention of pre-eclampsia. Results of large trials have shown that this is not the case: if there is an indication for using aspirin it is in the patient at a very high risk of developing severe early-onset disease. The calcium story followed a more or less similar pattern, with the difference that existing evidence shows that women with a low dietary calcium intake are likely to benefit from calcium supplementation. Proper antenatal care and timed delivery are of utmost importance in tertiary prevention of pre-eclampsia. There is evidence to suggest that the intrinsic direct effect of moderate degrees of maternal hypertension is beneficial to the fetus. Severe hypertension needs treatment. If antihypertensive is indicated, there is no clear choice of a drug. Hydralazine should no longer be thought of as the primary drug, most studies show a preference for calcium channel blockers.

Vaginal fetal fibronectin measurements from 8 to 22 weeks' gestation and subsequent spontaneous preterm birth

OBJECTIVE

We sought to determine the range of fetal fibronectin values in the vagina from 8 to 22 weeks' gestation, the factors associated with both low and high values, and whether high values are associated with gestational age at birth.

STUDY DESIGN

Vaginal fetal fibronectin was quantitatively determined in a prospective cohort study of 13,360 women being evaluated for participation in the National Institute of Child Health and Human Development Maternal-Fetal Medicine Unit treatment trials for bacterial vaginosis and Trichomonas vaginalis. Fetal fibronectin values were correlated with gestational age at screening, race, the presence of bacterial vaginosis and Trichomonas vaginalis, and gestational age at delivery.

RESULTS

Vaginal fetal fibronectin values at each gestational age ranged from unmeasurable to >1000 ng/mL, with median values always being <10 ng/mL. Fetal fibronectin values declined progressively with increasing gestational age at sampling. Bacterial vaginosis and black race were associated with higher values, whereas nulliparity was associated with lower values. High values after 13 weeks' gestation were associated with a 2- to 3-fold increased risk of subsequent spontaneous preterm birth overall and a 4-fold increased risk of very early preterm birth.

CONCLUSION

Elevated vaginal fetal fibronectin levels from 13 to 22 weeks' gestation are associated with a significantly increased risk of spontaneous preterm birth.

Pregnancy outcomes in healthy nulliparas who developed hypertension. Calcium for Preeclampsia Prevention Study Group

OBJECTIVE

To determine maternal and perinatal outcomes in nulliparas with pregnancy-associated hypertension or preeclampsia.

METHODS

We conducted (and reported elsewhere) a randomized, double-masked, placebo-controlled trial calcium supplementation of 4589 healthy nulliparas assigned at 13-21 weeks' gestation. This well-defined and characterized data set provided an opportunity to detail more precisely adverse maternal, fetal, and newborn outcomes in women who developed hypertension among a prospective series of healthy nulliparas.

RESULTS

Of 4302 women observed to or beyond 20 weeks' gestation, 1073 (24.9%) developed mild or severe pregnancy-associated hypertension or preeclampsia. One hundred sixteen women of the 1073 with hypertension (10.8%) and 336 of the 3229 without hypertension (10.4%) were delivered before 37 weeks' gestation. Fetal and neonatal mortality were similar in those groups; however, selected maternal and newborn morbidities were significantly greater in women with hypertension. Significantly increased maternal morbidities included increased cesarean deliveries, abruptio placentae, and acute renal dysfunction; and significantly increased perinatal morbidities included respiratory distress syndrome, ventilatory support, and fetal growth restriction. Adverse outcomes were highest in women with severe pregnancy-associated hypertension or preeclampsia.

CONCLUSION

Hypertension, especially severe hypertension, was associated with an appreciable increase in important maternal and perinatal morbidity but not perinatal mortality.

Maternal calcium supplementation and fetal bone mineralization

OBJECTIVE

To determine the effect of maternal calcium supplementation during pregnancy on fetal bone mineralization.

METHODS

Healthy mothers with early ultrasound confirmation of dates and singleton pregnancies were enrolled in a double-masked study and randomized before 22 weeks' gestation to 2 g/day of elemental calcium or placebo until delivery. Maternal dietary intake at randomization and at 32-33 weeks' gestation was recorded with 24-hour dietary recalls. Dual-energy x-ray absorptiometry measurements of the whole body and lumbar spine of the neonates were performed before hospital discharge.

RESULTS

The infants of 256 women (128 per group) had dual-energy x-ray absorptiometry measurements during the first week of life. There were no significant differences between treatment groups in gestational age, birth weight, or length of the infants, or in the total-body or lumbar spine bone mineral content. However, when bone mineral content was analyzed by treatment group within quintiles of maternal dietary calcium intake, total body bone mineral content (mean +/- standard error of the mean) was significantly greater in infants born to calcium-supplemented mothers (64.1+/-3.2 versus 55.7+/-2.7 g in the placebo group) in the lowest quintile of dietary calcium intake (less than 600 mg/day). The effect of calcium supplementation remained significant after adjustment for maternal age and maternal body mass index and after normalization for skeletal area and body length of the infant.

CONCLUSION

Maternal calcium supplementation of up to 2 g/day during the second and third trimesters can increase fetal bone mineralization in women with low dietary calcium intake. However, calcium supplementation in pregnant women with adequate dietary calcium intake is unlikely to result in major improvement in fetal bone mineralization.

Prostacyclin and thromboxane changes predating clinical onset of preeclampsia: a multicenter prospective study

CONTEXT

An imbalance in vasodilating (prostacyclin [PGI2]) and vasoconstricting (thromboxane A2 [TxA2]) eicosanoids may be important in preeclampsia, but prospective data from large studies needed to resolve this issue are lacking. Because most trials using aspirin to reduce TxA2 production have failed to prevent preeclampsia, it is critical to determine whether eicosanoid changes occur before the onset of clinical disease or are secondary to clinical manifestations of preeclampsia.

OBJECTIVE

To determine whether PGI2 or TxA2 changes occur before onset of clinical signs of preeclampsia.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter prospective study from 1992 to 1995 of subjects from the placebo arm of the Calcium for Preeclampsia Prevention Trial. Women who developed preeclampsia (n = 134) were compared with matched normotensive control women (n = 139).

MAIN OUTCOME MEASURES

Excretion of urinary metabolites of PGI2 (PGI-M) and TxA2 (Tx-M) as measured from timed urine collections obtained prospectively before 22 weeks', between 26 and 29 weeks', and at 36 weeks' gestation.

RESULTS

Women who developed preeclampsia had significantly lower PGI-M levels throughout pregnancy, even at 13 to 16 weeks' gestation (long before the onset of clinical disease); their gestational age-adjusted levels were 17% lower than those of controls (95% confidence interval [CI], 6%-27%; P=.005). The Tx-M levels of preeclamptic women were not significantly higher overall (9% higher than those of controls; 95% CI, -3% to 23%; P=.14). The ratio of Tx-M to PGI-M, used to express relative vasoconstricting vs vasodilating effects, was 24% higher (95% CI, 6%-45%) in preeclamptic women throughout pregnancy (P=.007).

CONCLUSIONS

Our results show that reduced PGI2 production, but not increased TxA2 production, occurs many months before clinical onset of preeclampsia. Aspirin trials may have failed because an increase in thromboxane production is not the initial anomaly. Future interventions should make correcting prostacyclin deficiency a major part of the strategy to balance the abnormal vasoconstrictor-vasodilator ratio present in preeclampsia.

Benefits of maternal corticosteroid therapy in infants weighing </=1000 grams at birth after preterm rupture of the amnion

OBJECTIVE

The aim of the study was to determine the effects of antenatal maternal corticosteroid treatment on selected neonatal outcomes in infants weighing </=1000 g at birth after preterm rupture of membranes.

STUDY DESIGN

In a 1-year (1992-1993) prospective observational study, the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network collected outcome data for 766 infants who did not have a major fetal anomaly and who had a birth weight </=1000 g (378 were born after preterm rupture of membranes). Only fetuses deemed potentially viable by the obstetrician were included in our analysis. Selected neonatal outcomes were compared between mothers who did and did not receive antenatal corticosteroids. Logistic regression variables included birth weight, sex, race, amnionitis, tocolytic therapies, mode of delivery, and surfactant use.

RESULTS

Two hundred fourteen of the 378 infants whose mothers had preterm rupture of membranes were deemed potentially viable; 62 of these mothers received antenatal steroids and 152 did not. Groups were similar with respect to gestational age, birth weight, race, amnionitis, and delivery mode. Women who received antenatal steroids were more likely to have received tocolysis (P <.001). Univariate and regression analyses controlling for multiple confounders confirmed no neonatal benefits of maternal corticosteroid use.

CONCLUSIONS

Corticosteroid treatment in women with preterm rupture of membranes was of no apparent benefit to neonates weighing </=1000 g.

Changes in maternal middle cerebral artery blood flow velocity associated with general anesthesia in severe preeclampsia

In women with severe preeclampsia, significant increases in mean arterial pressures (MAP) are common after rapid induction of general anesthesia (GA) and tracheal intubation. The objectives of this prospective study were to assess the effects of the rapid induction-intubation technique on middle cerebral artery (MCA) flow velocity in severe preeclampsia and to examine the correlation between mean MCA flow velocity (Vm) and MAP. Eight women with severe preeclampsia (study group) and six normotensive women at term (control group) scheduled to undergo cesarean section under GA were studied. Before induction, patients in the study group received i.v. labetalol in divided doses to lower diastolic pressures to <100 mm Hg. Anesthesia was induced with pentothal 4-5 mg/kg, followed by succinylcholine 1.5 mg/kg to facilitate tracheal intubation. A transcranial Doppler was used to measure Vm. Both Vm and MAP were recorded before induction and every minute for 6 min after intubation. In the study group, after the administration of labetalol, MAP decreased from 129 +/- 9 to 113 +/- 9 mm Hg (P < 0.05), and Vm decreased from 59 +/- 11 to 54 +/- 10 cm/s (P < 0.05). After intubation, MAP increased from 113 +/- 9 to 134 +/- 5 mm Hg (P < 0.001), and Vm increased from 54 +/- 10 to 70 +/- 10 cm/s (P < 0.001). In the control group, while MAP increased significantly from 89 +/- 6 to 96 +/- 4 mm Hg (P < 0.05) after intubation, the concurrent increase in Vm from 49 +/- 5 to 54 +/- 7 cm/s was not significant. There was a significant positive pooled correlation between Vm and MAP (r = 0.5, P < 0.0006) in the study group but not in the control group (r = 0.24). After induction and intubation, both Vm and MAP values were significantly increased in the study group patients at all observation points compared with the control group patients. The findings indicate that Vm increases significantly after rapid-sequence induction of GA and tracheal intubation in women with severe preeclampsia, and there seems to be a direct relationship between MAP and Vm.

IMPLICATIONS

In women with severe preeclampsia, rapid-sequence induction of general anesthesia and tracheal intubation can cause severe hypertension. Our results indicate that the increase in blood pressure is associated with a significant increase in maternal cerebral blood flow velocity and that there is a significant correlation between these two variables.

Serial changes in the biophysical profile in patients undergoing cervical ripening with a controlled release PGE2 vaginal pessary

OBJECTIVE

The purpose of this study was to evaluate the effects of exogenous administration of PGE2 upon the components of the biophysical profile.

METHODS

The study group included 17 nulliparas at > or = 38 weeks gestation, with a Bishop score of < or = 4, requiring induction of labor. A controlled release vaginal pessary containing 10 mg of PGE2, designed to release hormones at approximately 0.8 mg per hour in vitro, was used for 12 hours of cervical ripening. The BPP was performed by the same sonographer at three intervals: prior to pessary insertion, at 6 hours, and 12 hours.

RESULTS

None of these patients had membrane rupture or went into spontaneous labor during the ripening process. All patients subsequently required amniotomy and oxytocin. The proportion of patients scoring 2 points for fetal breathing movements decreased from 59% at baseline to 0% at 12 hours, P < 0.0005, and the proportion of patients with fetal body movements decreased from 100% at baseline to 25% at 12 hours, P < 0.0005. However, the other components of the biophysical profile were not affected. The mean maternal plasma PGE2 metabolite concentrations were 235 pg/ml, 475 pg/ml, and 466 pg/ml at 0, 6 and 12 hours, respectively, P < 0.005.

CONCLUSIONS

In term patients, vaginal administration of the PGE2 pessary was associated with improved Bishop score over 12 hours and significant increases in maternal plasma PGEM levels at 6 hours and 12 hours. These changes were inversely related to fetal breathing and body movements.

Maternal serum thromboxane B2 concentrations do not predict improved outcomes in high-risk pregnancies in a low-dose aspirin trial. The National Institute of Child Health and Human Development Network of Maternal-Fetal Medical Units

OBJECTIVE

The aim of the study was too determine whether, in a low-dose aspirin trial in high-risk pregnancies, a decrease in maternal serum thromboxane B2 level predicted improved pregnancy outcomes.

STUDY DESIGN

This multicenter, randomized, double-blind trial included 2539 women, 1010 of whom had sufficient serum samples at enrollment and at 24 to 28 weeks' gestation, 34 to 38 weeks' gestation, or both to assess longitudinal changes in thromboxane B2 level and their effects on pregnancy outcomes. Women were randomly assigned between 13 and 26 weeks' gestation to receive daily aspirin (60 mg) or placebo.

RESULTS

Overall and in all subgroups women assigned to receive aspirin had markedly lower maternal thromboxane B2 concentration values than did those assigned to receive a placebo (P =.0001). Changes in thromboxane levels were not, however, correlated with adverse pregnancy outcomes. Women with >/=50% reduction in maternal serum thromboxane B2 concentrations from baseline had occurrences of preeclampsia (P =.922), preterm birth (P =.375), small for gestational age neonates (P =.938), and grade III or IV intraventricular hemorrhage (P = 1.000) similar to those of women who had <50% reduction. Similar results were found for women with thromboxane B2 level decreases of <15 versus >15 ng/mL and women with thromboxane B2 level decreases to <10 versus >/=10, <5 versus >/=5, and <1 versus >/=1 ng/mL. Maternal thromboxane B2 concentrations at enrollment were also not predictive of adverse outcomes.

CONCLUSION

Neither maternal serum thromboxane B2 concentrations at enrollment nor their subsequent reduction were predictive of adverse pregnancy outcomes in a low-dose aspirin trial.

Predictors of pre-eclampsia in women at high risk. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units

OBJECTIVE

We assessed several variables as predictors for pre-eclampsia risk in a group of women at high risk.

STUDY DESIGN

We studied 2503 women with either diabetes mellitus, chronic hypertension, multifetal gestation, or pre-eclampsia in a previous pregnancy who participated in a multicenter study comparing aspirin and placebo in preventing pre-eclampsia. We evaluated multiple variables for predicting pre-eclampsia risk with use of univariate and multivariable analysis.

RESULTS

Parity and mean arterial pressure at randomization were most predictive of pre-eclampsia risk. The risk was 8% with a mean arterial pressure at enrollment of <75 mm Hg versus 27% with a mean arterial pressure >85 mm Hg (relative risk and 95% confidence interval 3.3 [2.4 to 4.4]). The risk of pre-eclampsia was 26% in nulliparous patients versus 17% in parous subjects (relative risk and 95% confidence interval 1.5 [1.3-1.8]).

CONCLUSIONS

The finding that second-trimester mean arterial pressure affects pre-eclampsia risk suggests that the pathophysiologic process of preeclampsia is initiated before that time.

Low-dose aspirin to prevent preeclampsia in women at high risk. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units

BACKGROUND

Whether low-dose aspirin prevents preeclampsia is unclear. It is not recommended as prophylaxis in women at low risk for preeclampsia but may reduce the incidence of the disease in women at high risk.

METHODS

We conducted a double-blind, randomized, placebo-controlled trial in four groups of pregnant women at high risk for preeclampsia, including 471 women with pregestational insulin-treated diabetes mellitus, 774 women with chronic hypertension, 688 women with multifetal gestations, and 606 women who had had preeclampsia during a previous pregnancy. The women were enrolled between gestational weeks 13 and 26 and received either 60 mg of aspirin or placebo daily.

RESULTS

Outcome data were obtained on all but 36 of the 2539 women who entered the study. The incidence of preeclampsia was similar in the 1254 women in the aspirin group and the 1249 women in the placebo group (aspirin, 18 percent; placebo, 20 percent; P=0.23). The incidences in the aspirin and placebo groups for each of the four high-risk categories were also similar: for women with pregestational diabetes mellitus, the incidence was 18 percent in the aspirin group and 22 percent in the placebo group (P=0.38); for women with chronic hypertension, 26 percent and 25 percent (P= 0.66); for those with multifetal gestations, 12 percent and 16 percent (P=0.10); and for those with preeclampsia during a previous pregnancy, 17 percent and 19 percent (P=0.47). In addition, the incidences of perinatal death, preterm birth, and infants small for gestational age were similar in the aspirin and placebo groups.

CONCLUSIONS

In our study, low-dose aspirin did not reduce the incidence of preeclampsia significantly or improve perinatal outcomes in pregnant women at high risk for preeclampsia.

Renal hemodialysis and maternal serum triple analyte screening

The obstetrical management of women with renal disease is complicated and associated with increased fetal and maternal morbidity. However, maternal serum screening is an integral part of obstetrical care and should be offered to all women. We found that maternal serum levels of a-fetoprotein and human chorionic gonadotropin did not significantly change as a result of hemodialysis, whereas levels of unconjugated estriol were markedly decreased following hemodialysis. Maternal serum screening should be limited to alpha-fetoprotein analysis in women undergoing hemodialysis until the effects of hemodialysis on all serum analytes are better delineated.

Septic shock in pregnancy

OBJECTIVE

To evaluate the etiology, management, and maternal and perinatal outcome in patients with septic shock during pregnancy.

METHODS

In 18 patients with septic shock during pregnancy, the criteria for the diagnosis were sepsis-induced hypotension unresponsive to adequate fluid resuscitation and requirement for vasopressors.

RESULTS

Causes of shock were pyelonephritis (n = 6), chorioamnionitis (n = 3), postpartum endometritis (n = 2), toxic shock (n = 2), and one each of septic abortion, ruptured appendix, ruptured ovarian abscess, necrotizing fasciitis, and bacterial endocarditis. Five women (28%) died. Comparing medians of the initial laboratory data for the 13 survivors with those of the five nonsurvivors revealed significant differences for hematocrit (26 compared with 35%; Z = -2.267, P = .023), aspartate aminotransferase (30 compared with 287 U/L; Z = -2.068, P = .042), total bilirubin (1.6 compared with 5.8 mg/dL; Z = 2.046, P = .045), arterial carbon dioxide pressure (30 compared with 19 mmHg; Z = -2.384, P = .013), and arterial oxygen pressure (62 compared with 104 mmHg; Z = -2.004, P = .048). Comparing medians of the hemodynamic data showed differences in blood pressure (88 compared with 70 mmHg; Z = -2.439, P = .013), stroke volume (74 compared with 52 mL; Z = -2.041, P = .038), and left ventricular stroke work index (42 compared with 12 g.m.m2; Z = -1.929, P = .052). Sixty-four percent of survivors and 80% of nonsurvivors had depressed left ventricular function (Fisher exact test, P > .99). Locating the source of infection was difficult and delayed in eight patients.

CONCLUSION

In women with septic shock, progression to death can be dramatically rapid. Because vascular permeability is increased, it may be appropriate to administer vasopressors early during resuscitation. An initial low cardiac output is a poor prognostic sign.

Recent advances in the management of preeclampsia

The past decade has been characterized by few advances regarding the pathophysiology and prevention but many changes in the clinical treatment of patients with preeclampsia. Specifically, recommendations have been made for home or day-care management of a select group of patients with mild gestational hypertension or preeclampsia. Moreover, three randomized clinical trials revealed that expectant management with close monitoring of maternal and fetal conditions is possible in a select group of patients with severe preeclampsia at less than 34 weeks' gestation. In addition, the efficacy of magnesium sulfate in the prevention and control of eclamptic convulsion has been validated in randomized controlled trials performed worldwide. In contrast, recent randomized trials failed to demonstrate any major benefit from the routine use of low-dose aspirin in pregnancy, whereas a recent meta-analysis found calcium supplementation during pregnancy to be effective in reducing the risk of hypertension.

Postoperative incision complications after cesarean section in patients with antepartum syndrome of hemolysis, elevated liver enzymes, and low platelets (HELLP): does delayed primary closure make a difference?

OBJECTIVE

Our purpose was to evaluate wound complications between patients with antepartum HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome with primary closure versus delayed closure and Pfannenstiel versus midline skin incisions.

STUDY DESIGN

Medical records of patients with antepartum HELLP syndrome undergoing cesarean section were examined for type and timing of skin closure: Pfannenstiel versus midline skin incision and primary versus delayed closure. The immediate (before hospital discharge) and late (2-week postoperative check) wound complications were analyzed with respect to timing of wound closure and type of skin incision.

RESULTS

A total of 104 patients were identified; 75 had a primary skin closure and 29 had a delayed closure 48 to 72 hours postoperatively. Immediate wound complications (wound infection, hematoma), occurred in 18 (26%) patients who had primary closure versus 8 (24%) who had a delayed closure, odds ratio 1.13 (95% confidence interval 0.39 to 3.27). A late wound breakdown was seen in only 1 patient with primary closure but in none with delayed closure. There were no fascial wound dehiscences. No statistical difference in wound complication was found between midline (primary, delayed) and Pfannenstiel (primary, delayed) incisions, odds ratio 0.65 (95% confidence interval 0.23 to 1.88).

CONCLUSION

In women with antepartum HELLP syndrome delivered by cesarean section the frequency of wound complications is not influenced by type of skin incision or time of skin closure (primary or delayed).

Associations between adverse perinatal outcome and serially obtained second- and third-trimester maternal serum alpha-fetoprotein measurements

OBJECTIVE

Our purpose was to determine whether third-trimester maternal serum alpha-fetoprotein predicts adverse perinatal outcome and whether use of both second- and third-trimester maternal serum alpha-fetoprotein enhances the positive predictive value for various abnormal outcomes.

STUDY DESIGN

A cohort study with obstetric outcome assessed by chart analysis after delivery was performed at Regional Medical Center (Memphis, Tennessee), a hospital staffed by university-based physicians serving a large urban population with many indigent patients. A total of 650 women attending prenatal clinics in the above setting with a singleton pregnancy without a neural tube defect, contributing a maternal blood samples in both the second and third trimesters, and delivered in the above hospital participated. Various pregnancy outcomes were correlated with maternal serum alpha-fetoprotein levels in the second and third trimesters and in both.

RESULTS

In the third trimester no significant associations were found between maternal serum alpha-fetoprotein elevations and pregnancy complications. In the second trimester elevation ( > or = 2.0 multiples of the median) were, by contrast, significantly associated with preterm premature rupture of the membranes, preterm birth, and low birth weight. No association was found with certain other complications. When second-trimester data were grouped according to the types of complications occurring in individual women, only preterm premature rupture of the membrane proved statistically significant.

CONCLUSIONS

Second-trimester but not third-trimester maternal serum alpha-fetoprotein is significantly elevated with preterm premature rupture of the membranes, preterm birth, and low birth weight; in this cohort study no association was found with preeclampsia, oligohydramnios, or polyhydramnios.

Antibiotic treatment of preterm labor with intact membranes: a multicenter, randomized, double-blinded, placebo-controlled trial

OBJECTIVE

Although an association between subclinical intrauterine infection and preterm birth is well established, there is conflicting evidence regarding the benefits of antibiotic administration to women in preterm labor with intact membranes. We attempted to determine the effect of ampicillin-amoxicillin and erythromycin treatment on prolongation of pregnancy, the rate of preterm birth, and neonatal morbidity in patients with preterm labor and intact membranes.

STUDY DESIGN

A multicenter, randomized, double-blinded, placebo-controlled trial was designed and implemented by the Maternal-Fetal Medicine Units Network of the National Institute of Child Health and Human Development. Two hundred seventy-seven women with singleton pregnancies and preterm labor with intact membranes (24 to 34 weeks) were randomly allocated to receive either antibiotics or placebos.

RESULTS

Of the 2373 patients screened for participation in this study in six medical centers, 277 women were enrolled (n = 133 for antibiotics group vs n = 144 for placebo group). In each study group, 60% of patients completed all the study medications. The overall prevalence of microbial invasion of the amniotic cavity was 5.8% (14/239). No significant difference between the antibiotic group and the placebo group was found in maternal outcomes, including duration of randomization-to-delivery interval, frequency of preterm delivery (< 37 weeks), frequency of preterm premature rupture of membranes, clinical chorioamnionitis, endometritis, and number of subsequent admissions for preterm labor. Similarly, no significant difference in neonatal outcomes could be detected between the two groups including respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage, sepsis, and admission and duration of newborn intensive special care unit hospitalization.

CONCLUSION

The results of this study do not support the routine use of antibiotic administration to women in preterm labor with intact membranes.

Unexplained elevated maternal serum α-fetoprotein is not predictive of adverse perinatal outcome in an indigent urban population

OBJECTIVE

The null hypothesis of this study is that in an urban, indigent obstetric population at high risk for adverse perinatal outcome, unexplained elevations of maternal serum alpha-fetoprotein are not an additional predictor of adverse perinatal outcome.

STUDY DESIGN

Perinatal outcomes of 72 patients from a clinic for indigent patients with unexplained elevated maternal serum alpha-fetoprotein levels were compared with those of matched controls from the same population with normal maternal serum alpha-fetoprotein levels. Subjects and controls were matched for age, race, parity, and presence or absence of Hollister risk factors. The frequency of adverse perinatal outcome in the two groups was subjected to matched-pair chi 2 analysis.

RESULTS

Adverse perinatal outcome occurred in 38.9% (28 of 72) of subjects with unexplained elevated maternal serum alpha-fetoprotein levels greater than or equal to 2.5 multiples of the median, compared with 31.9% (23 of 72) of controls with normal maternal serum alpha-fetoprotein levels (p = 0.5). No statistically significant difference in adverse perinatal outcomes was found.

CONCLUSIONS

Elevated maternal serum alpha-fetoprotein levels offer little if any additional predictive value for adverse perinatal outcome in populations already at high risk for such outcomes on the basis of obstetric or socioeconomic criteria.

Anesthetic modification of hemodynamic and neuroendocrine stress responses to cesarean delivery in women with severe preeclampsia

We conducted a prospective evaluation of the comparative effects of lumbar epidural and general anesthesia on the hemodynamic and neuroendocrine stress response to cesarean delivery in 21 women with severe preeclampsia. In the epidural group (n = 11), anesthesia extending to the T-4 dermatome level was obtained using 2% plain lidocaine in divided doses. In the general anesthesia group (n = 10), anesthesia was induced after pretreatment with labetalol or nitroglycerin. In the epidural group, mean arterial pressure (MAP) gradually decreased from 133.3 +/- 5.6 mm Hg to 119 +/- 4.4 mm Hg (P less than 0.002). After pretreatment with labetalol or nitroglycerin, MAP in the general group decreased from 131.5 +/- 4.9 mm Hg to 112.2 +/- 3.5 mm Hg (P less than 0.001). At skin incision (after tracheal intubation), MAP increased from 112.2 +/- 3.5 mm Hg to 143 +/- 5.4 mm Hg (P less than 0.001); however, this was not significantly different from baseline MAP. In the epidural group, there were no further changes in MAP. The difference in MAP at skin incision and postpartum period between the two groups was significant (P less than 0.004 and P less than 0.009, respectively). In the general anesthesia group, both adrenocorticotropic hormone and beta-endorphin-like immunoactivity increased significantly from base levels at skin incision. The catecholamines also increased significantly and remained so throughout the study period. In the epidural group, the concentrations of these hormones decreased or remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Labor induction with continuous low-dose oxytocin infusion: a randomized trial

One hundred twenty-three women were randomized to receive either of two regimens of oxytocin for labor induction. Sixty-one received a low-dose regimen, with oxytocin increases at intervals of not less than 60 minutes. Patients with unripe cervices received prolonged low-dose oxytocin priming before membrane rupture. Sixty-two others received a traditional protocol, with oxytocin increased every 20 minutes as required. Both groups had amniotomy when deemed safe and feasible. Oxytocin was adjusted for uterine hyperstimulation or abnormal fetal heart rate patterns in 29 and 58% of low-dose and traditional protocol subjects, respectively (P less than .001, odds ratio 3.6). No significant increase in time to delivery was seen with low-dose oxytocin infusion. Cesarean delivery and cesareans for fetal distress were more frequent in the traditional protocol group. This study demonstrates that a continuous low-dose protocol for oxytocin induction of labor is effective in establishing active labor and achieving vaginal delivery in women with both ripe and unripe cervices. It is also associated with fewer episodes of uterine hyperstimulation requiring adjustments of oxytocin infusion than is the traditional protocol of this institution.

The incidence of significant fetomaternal hemorrhage in patients undergoing cesarean section

To determine the incidence of fetomaternal hemorrhage in patients undergoing cesarean section, Kleihauer-Betke tests were performed in the immediate postoperative period on 199 parturients. Some degree of hemorrhage was detected in 18.5% of patients, with 2.5% demonstrating greater than 30 ml of fetal blood. Comparison of groups on the basis of indication for cesarean delivery revealed no difference in rates of fetal hemorrhage. Because patients with greater than 30 ml of fetal blood would not be adequately protected from Rh sensitization by the standard 300 micrograms dose of Rh immune globulin, we recommend screening all Rh-negative patients undergoing cesarean section for the presence of significant fetomaternal hemorrhage.

The effect of mode of delivery on the perinatal outcome in fetuses with abdominal wall defects

A descriptive study of 125 infants with abdominal wall defects was undertaken to determine the effect of mode of delivery on outcome. Fifty-six infants had gastroschisis and 69 had omphalocele. Overall, there were no differences between the omphalocele and the gastroschisis groups in either cesarean section rate (22% vs 26%) or prematurity rate (26% vs 30%). However, the omphalocele group had a significantly higher infant death rate (22% vs 7%, p less than 0.001), a significantly higher incidence of associated major congenital anomalies (29% vs 5%, p less than 0.001), and a higher incidence of long-term infant morbidity (14.5% vs 8.9%). Within either group there was no significant difference between vaginal and cesarean delivery regarding either infant mortality, acute or long-term infant outcome, or frequency of associated major anomalies. We conclude that vaginal delivery of infants with abdominal wall defects does not adversely affect infant outcome.

Comparison of capillary Accu-Chek blood glucose values to laboratory values

With 2 to 4% of the obstetric population demonstrating glucose intolerance, many authorities advocate the routine screening of all pregnant women. Some have questioned the cost effectiveness of such an approach and have chosen to screen only those with high-risk factors, overlooking a large percentage of gestational diabetics. The purpose of this report was to determine if Accu-Chek glucometer values are sufficiently accurate to substitute for laboratory values in our medical complex. Capillary Accu-Chek glucose values and laboratory values were compared in 140 patients. Values ranged from a low of 43 to a high of 380. The mean +/- SD glucose values were 142 +/- 73 mg/dl and 142 +/- 80 mg/dl, respectively. These values are not significantly different. Using a cutoff of 140 mg/dl as abnormal, the sensitivity of the capillary Accu-Chek was 100% and the specificity was 95% compared with the venous method. A simple linear regression indicated that there was a strong correlation between the capillary Accu-Chek glucose values and the laboratory glucose values (r = 0.95, p less than or equal to 0.0001). The slope was not different from 1 (p = 0.3135), and the intercept was not different from 0 (p = 0.4943), illustrating that there was an equality in the values and that one value may be substituted for the other.

Identification of dynorphin 1-8 in human placenta by mass spectrometry

The human placental villus tissue contains opioid receptors and peptides. The opioid peptides extracted from the villus tissue were fractionated using reverse-phase high performance liquid chromatography and a radio-receptor assay. The presence of dynorphin 1-8 was corroborated by mass spectrometric production of (M + H) ion in the fast atom bombardment mode. This octa-peptide could be the natural ligand of the kappa opioid receptors present in the human placental villus tissue.

Human placental opioid peptides: correlation to the route of delivery

The levels of opioid peptides in placental extracts were determined by means of a radioreceptor assay with two prototypical opioid ligands, 3H-ethylketocyclazocine and 3H-D-ala2-enkephalinamide. Opioid peptide levels were significantly higher in the placentas obtained by the vaginal route than in those by the abdominal route. The different peptides in the extract were detected by reverse phase high-performance liquid chromatography and a radioreceptor assay for all fractions. The presence of dynorphin-like peptides in several fractions suggests that one or more could be the "natural" ligand of the opioid receptors in the human placenta. A role for these peptides in parturition is a viable possibility.

Irregular antibodies: an assessment of routine prenatal screening

In a review of the antenatal-postnatal records of 6062 patients attending the prenatal clinic at a large university perinatal center during 1980, 8.3% of the pregnant patients seen were Rho(D) negative and 91.7% were Rho(D) positive. Through routine antibody screening of all patients, 115 were found to have irregular antibodies which would otherwise not have been detected. Fifteen of these patients were Rho(D) negative, but they would have been included for antibody screening due to their Rho(D) negative status. Of the remaining 100 Rho(D) positive patients, clinically significant antibodies were observed in six patients; however, no maternal morbidity or hemolytic disease of the newborn was reported. Antecedent maternal risk factors for development of irregular antibodies were not sufficiently selective for predicting outcomes of such pregnancies. Furthermore, the only four patients with irregular antibodies requiring blood transfusion were cross-matched without difficulties. Findings suggest that screening all patients for irregular antibodies cannot be justified due to the prohibitive costs involved. However, because of the racially homogeneous population studied, variations in the frequency of red blood cell genotypes between racial groups, and the irregular pattern of occurrence of irregular antibodies, the authors believe that further studies on the clinical impact and cost-effectiveness of screening all antenatal patients for presence of irregular antibodies are necessary.