J. Milton Hutson

Longitudinal study of the renin-angiotensin-aldosterone system in hypertensive pregnant women: Deviations related to the development of superimposed preeclampsia*

A prospective longitudinal study of 25 pregnant women (30 pregnancies) with chronic hypertension, a group prone to development of preeclampsia, was conducted to explore the relationship between the renin-angiotensin-aldosterone system and the development of superimposed preeclampsia. In women with chronic hypertension in whom preeclampsia did not develop (17 pregnancies), blood pressure decreased and the renin-angiotensin-aldosterone system was stimulated, beginning in the first trimester and continuing throughout pregnancy as found previously in normotensive pregnant women (n = 58). Plasma estradiol and progesterone levels also increased progressively. In women with chronic hypertension in whom preeclampsia developed (13 pregnancies), blood pressure decreased and the renin-angiotensin-aldosterone system was stimulated in the first trimester as in the other groups. However, later in pregnancy significant differences were observed. Blood pressure began to rise in the second trimester. Initially the renin-angiotensin-aldosterone system remained stimulated, but in the early third trimester, when preeclampsia was diagnosed, plasma renin activity and urine aldosterone excretion decreased, and atrial natriuretic factor increased. These data provide information that may be useful in the recognition of superimposed preeclampsia, and in the investigation of its pathogenesis.

Selective reduction of multifetal pregnancies to twins improves outcome over nonreduced triplet gestations.

OBJECTIVE Our purpose was to evaluate effects of multifetal pregnancy reduction on pregnancy complications and birth weights of remaining twin fetuses compared with expectantly managed triplets and nonreduced twins. STUDY DESIGN Medical records of 54 triplet pregnancies, 59 twin pregnancies resulting from multifetal pregnancy reduction, and 88 sets of twins conceived with assisted reproductive techniques and delivered at New York Hospital after 24 weeks were retrospectively reviewed. Birth weights were corrected for gestational age at delivery by use of a formula derived from composite standardized growth curves. Statistical analysis was performed with chi(2) analysis and Student t test. RESULTS Twins remaining after reduction and nonreduced twins were less likely to have preeclampsia than were triplets (14% and 23% vs 30%) and to be delivered before 36 weeks (39% and 27% vs 72%). They had birth weights that were > 100 gm larger than those of triplets even when corrected for gestational age. Reduced twins were similar to nonreduced twins in all parameters studied. CONCLUSIONS Multifetal pregnancy reduction results in pregnancy complications, gestational age, and birth weights closer to those of nonreduced twins than to expectantly managed triplets.

Fetal heart rate response to vibratory acoustic stimulation predicts fetal pH in labor

Vibratory acoustic stimulation was performed during labor in 188 instances 60 seconds before fetal scalp puncture was done to determine fetal scalp blood pH. The fetal heart rate response was recorded for both vibratory acoustic stimulation and fetal scalp puncture. No instance of fetal acidosis occurred in the presence of an acceleration to either vibratory acoustic stimulation or fetal scalp puncture. Vibratory acoustic stimulation was more likely to elicit an acceleration than fetal scalp puncture in the nonacidotic fetus. Vibratory acoustic stimulation is less invasive and may be used in some instances in which fetal scalp blood puncture for pH determination is technically impossible.

Multiple gestations from in vitro fertilization: successful implantation alone is not associated with subsequent preeclampsia.

OBJECTIVE Our purpose was to compare the risk for preeclampsia and severe preeclampsia in triplet and twin gestations and to evaluate the effect of successful implantation on the development of preeclampsia and on perinatal outcome in triplet pregnancies conceived by means of in vitro fertilization. STUDY DESIGN A case control study was conducted of triplet pregnancies (n = 38) matched for maternal age, parity, race, and delivery date with twin pregnancies (n = 38) resulting from a single fetal reduction (spontaneously or by means of multifetal pregnancy reduction) after successful implantation of triplets. All pregnancies were conceived by means of in vitro fertilization. Rates of preeclampsia and other maternal complications, factors affecting implantation, and perinatal outcomes were compared. Preeclampsia and severe preeclampsia were defined by The American College of Obstetricians and Gynecologists criteria. The Student t test and the chi(2) test were used for statistical analysis. RESULTS The triplet group had a higher rate of severe preeclampsia (26.3%) than the twin (reduced triplet) group (7.9%). The prevalence of preeclampsia (mild and severe combined) also was higher among the triplet group (44.7%) than among the twin group (15.8%). There was no difference in other maternal complications of pregnancy or in factors potentially affecting implantation, such as assisted hatching. Mean fetal weight was lower among the triplet group, but gestational age at delivery was not significantly different. CONCLUSIONS The rate of preeclampsia is higher among triplets conceived by means of in vitro fertilization than among triplets conceived by means of in vitro fertilization and reduced to twins. This finding suggests that fetal number, placental mass, or factors unrelated to the success of implantation are more important to the development of preeclampsia than is successful implantation alone.

Gelsolin down-regulates lipopolysaccharide-induced intraamniotic tumor necrosis factor-α production in the midtrimester of pregnancy

OBJECTIVE The purpose of this study was to identify gelsolin in midtrimester amniotic fluid and evaluate its interaction with lipopolysaccharide (LPS). STUDY DESIGN Supernatants from 40 midtrimester amniotic fluid samples were incubated with Escherichia coli LPS, and gelsolin binding was measured by enzyme-linked immunosorbent assay. Unfractionated aliquots of 25 of the fluids were cultured ex vivo for 24 hours in the presence of LPS and supernatants tested for tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 production, and the influence of antigelsolin antibody was evaluated. RESULTS Each amniotic fluid was positive for gelsolin that bound to LPS. LPS-induced TNF-alpha production was inversely proportional to the amniotic fluid concentrations of LPS-bound gelsolin (r = -0.5047; P = .006). Preincubation with monoclonal antibody to gelsolin led to an increase in LPS-induced TNF-alpha production (P = .01). There was no relationship between gelsolin and IL-10 production. CONCLUSION Gelsolin is present in midtrimester amniotic fluid, binds to LPS, and inhibits the induction of TNF-alpha.

Donation of blood by the pregnant patient for autologous transfusion

A study was conducted to determine the safety and utility of autologous blood donation in third trimester pregnancy. Thirty-seven obstetric patients, 32 with an obstetric risk factor, donated an average of 485 ml of blood. Twenty-one of the 37 patients were expected to undergo cesarean section. Nonstress testing was performed before and after phlebotomy. Continuous fetal heart rate monitoring was maintained throughout the donation, which lasted an average of 9 minutes. All nonstress test results were normal before and after the phlebotomy except in one case. All fetal heart rates remained stable during phlebotomy and premature labor was not precipitated. All fetal outcomes were normal. One patient delivered on the day of phlebotomy, 6 hours after the procedure. Only one of the autologous units was used, in a patient who had a pelvic infection and moderate anemia. The incidence of primary cesarean section was 35%. Phlebotomy of the mother appears to be safe for the fetus at term. Further investigation is needed to determine the safety of removal of more than 1 unit of blood and blood donation at earlier gestational ages.