Thomas W. Lowe

Maternal youth and pregnancy outcomes: Middle school versus high school age groups compared with women beyond the teen years

OBJECTIVE We sought to measure and compare pregnancy complications in middle school versus high school versus older maternal age groups. STUDY DESIGN From January 1988 through December 31, 1991, maternal and infant data from 16,512 consecutive nulliparous women were collected and electronically stored. These women were divided into three study groups: middle school (11 to 15 years old), high school (16 to 19 years old), and women 20 to 22 years old at delivery. Statistical analysis included logistic regression to control for potentially confounding demographic variables. RESULTS Middle school-aged mothers were disproportionately black (50% vs 36% Hispanic vs 14% white), and very low birth weight (4% vs. 2%, p = 0.003) was increased in these youthful mothers. First births to high school-aged mothers were not found to be compromised compared with those of women 20 to 22 years old, and, indeed, cesarean birth was less frequent in these women compared with those > or = 20 years old. CONCLUSIONS We conclude that the health hazard associated with school-age pregnancy is predominantly prematurity and is increased only in middle school-aged mothers. High school-aged mothers do not experience excess medical complications of pregnancy compared with older women. We suggest that middle school pregnancy, particularly for inner-city teenagers, should be a special focus for pregnancy prevention and intervention.

Vasopressin and Catecholamine Secretion during Metabolic Acidemia in the Ovine Fetus

ABSTRACT: It has been suggested that the substantial rise in fetal plasma arginine vasopressin (AYP) during intrauterine hypoxia/asphyxia reflects decreases in PaO2 and/or pHa; however, the components of these “stresses,” i.e. PO2, PCO2, and pH, have not been controlled. Recently, only modest increases in fetal AVP secretion were seen during hypoxia independent of changes in pH and PCO2. Since the independent effects of metabolic acidosis on fetal AVP secretion are unknown, we induced acute metabolic acidemia in fetal sheep at 137 ± 4 (mean ± SD) days gestation with 1 M NH4C1, while monitoring mean arterial pressure, heart rate, PaO2, PaCO2, pHa, plasma osmolality, and blood concentrations of electrolytes, AVP, dopamine, norepinephrine, and epinephrine. Mean arterial pressure, PaO2, PaCO2, and plasma osmolality and sodium were unchanged; pHa decreased from 7.37 ± 0.01 to 7.04 ± 0.05 (p<0.05) during NH4C1 and did not return to control levels until 24 h later. AVP increased from 2.85 ± 0.23 to 5.26 ± 1. 1 1 μU/ml (p<0.05) at the time of maximum acidosis, correlating with the fall in pHa (r = -0.67, p = 0.001); however, after stopping NH4C1, AVP returned to baseline levels although pHa remained <7.15. In control studies using the same osmolar load, volume, and rate of infusion, AVP levels were unchanged. Only epinephrine was significantly (p<0.05) elevated during acidosis, but did not correlate with pHa or plasma AVP. Marked metabolic acidemia appears to have little or no effect on fetal AVP secretion, and fetal catecholamine secretion is variable.

Sinusoidal fetal heart rate pattern after intrauterine transfusion.

&NA; Two pregnancies complicated by severe Rh‐isoimmunization and the development of sinusoidal fetal heart rate patterns immediately after intrauterine transfusions are presented. An intermittent sinusoidal pattern resolved, in one fetus, with sonographic evidence of delayed but complete absorption of transfused red blood cells. In contrast, the second fetus exhibited a continuous sinusoidal pattern coincident with cardiac decompensation detected by echocardiography, severe anemia, and failure to absorb transfused red blood cells. Possible pathophysiologic mechanisms for the development of sinusoidal patterns after fetal transfusions are discussed. It is concluded that a sinusoidal fetal heart rate pattern may occur after fetal transfusion and that the subsequent course of this pattern provides meaningful information about fetal condition as well as the success of intrauterine transfusion. (Obstet Gynecol 64:21S, 1984)

Ultrasound prediction of fetal weight in prolonged pregnancy

In this study we applied two commonly used birth weight prediction equations to a sample of 121 women with prolonged pregnancies. Subjects had sonographic measurements of biparietal diameter and abdominal perimeter taken within 2 days of delivery at Parkland Memorial Hospital. Although the two prediction equations were obtained from a population of women in New Haven, Connecticut, who delivered over a wide range of gestational ages, when the equations were applied to the sample of prolonged pregnancies in Dallas, Texas, there was a strong correlation (0.71) between predicted and actual birth weight. Moreover, reestimation of the New Haven equations with use of the Dallas data yielded similar regression coefficients. Finally, birth weight prediction equations for black, white, and Hispanic patients in Dallas were not significantly different. These findings suggest a remarkably constant relationship between fetal head and abdominal dimensions and birth weight over different gestational ages and for different population groups.

Liver histopathologic findings in women with sickle cell disease given prophylactic transfusion during pregnancy

Forty women with a major sickle hemoglobinopathy (hemoglobin SS, SC, or S-beta-thalassemia) were given red blood cell transfusions prophylactically during pregnancy. A mean of 13.6 units of erythrocytes per woman was given and none received more than 28 units. Direct-vision needle biopsy of the liver was performed in conjunction with cesarean section or puerperal sterilization. Although iron deposition in hepatocytes and Kupffer cells was identified commonly, neither cirrhosis nor widespread hepatocellular necrosis was found. We conclude that the risk of irreversible hepatic damage is negligible in women with sickle hemoglobinopathies who are given erythrocytes prophylactically during one pregnancy.

Magnetic resonance imaging in obstetric diagnosis

Five patients with abnormal pregnancies were examined with ultrasound (US) and magnetic resonance imaging (MR). Three had a malformed fetus, 1 had a molar pregnancy, and 1 had an ovarian mass. Both maternal and fetal structures were clearly shown, although fetal motion may have resulted in image degradation in some cases. The authors suggest that MR may be useful in obstetric diagnosis.

ACUTE METABOLIC ACIDOSIS: EFFECTS ON ARGININE IN VASOPRESSIN(AVP) RELEASE IN FETAL SHEEP

Acute asphyxia results in AVP hypersecretion in fetal sheep. Since acidosis, hypoxia, and hypercapnea occur simultaneously with asphyxia, it is unclear which is primarily responsible for AVP release. We have shown that hypoxia has no effect until aortic PO2 (PaO2) is <12mmHg, and AVP levels were only 10±3μU/ml ([Xmacr ;[plusmn;SE). To further examine the asphyxial components in fetal AVP release, we studied the effects of metabolic acidosis in 8 fetal sheep at 137±1.4 days. Each was infused with .03-.07mEq NH4Cl/min·kg for 120min while monitoring mean arterial pressure (MAP), heart rate (HR), PaO2, pHa, and PaCO2, and plasma AVP before, during (20min intervals) and repeatedly after NH4Cl. MAP, PaO2, and PaCO2 were unchanged; pHa fell progressively from 7.376±.012 to 6.986±.066* during NH4Cl, rising to 7.356±.021 by 24h. Plasma AVP rose gradually from 2.85±.23 to 5.26±1.1μU/ml* during NH4Cl, falling to 2.77±.41 by 4h. After NH4Cl, HR rose 24±1.1%*. The rise in AVP during NH4Cl was linearly correlated with pHa, r=-.67 (p<.0001, n=37), and PaO2 tended to rise. In only one animal (not included), with pH=7.12 and PaO2=12mmHg, AVP rose >8μU/ml, 30.2μU/ml. We conclude that: 1) acidosis, like hypoxemia alone, does not result in marked fetal AVP release; 2) whereas AVP release is related linearly to pHa, there appears to be a threshold value for PaO2; and 3) acidosis and hypoxia appear synergistic for AVP release, but the role of PaCO2 is unknown. *p<.05.