Change in mononuclear leukocyte responsiveness in midpregnancy and subsequent preterm birth.

OBJECTIVE: To estimate the associations of change in immune response with preterm delivery, omega-3 supplementation, and fish diet. METHODS: This was an ancillary study to a randomized trial of omega-3 fatty acid supplementation for the prevention of recurrent preterm birth. In vitro maternal peripheral blood mononuclear leukocyte production of the anti-inflammatory cytokine, interleukin-10, and the proinflammatory cytokine, tumor necrosis factor-α, in response to stimulation with lipopolysaccharide, was measured at 16-22 weeks of gestation (baseline) and again at 25-28 weeks of gestation (follow-up) among women with prior spontaneous preterm birth. Changes in concentrations from baseline to follow-up ([INCREMENT]) were compared separately among groups defined by gestational age category at delivery, fish diet history, and omega-3 compared with placebo treatment assignment with Kruskal-Wallis tests. RESULTS: Interleukin-10 [INCREMENT] differed by gestational age category among 292 women with paired assays. Concentrations increased less in women delivering between 35 and 36 6/7 weeks of gestation (48.9 pg/mL) compared with women delivering at term (159.3 pg/mL) and decreased by 65.2 pg/mL in women delivering before 35 weeks of gestation (P=.01). Tumor necrosis factor-α Δ also differed by gestational age category among 319 women, but the pattern was inconsistent. Those delivering between 35 and 36 6/7 weeks of gestation exhibited decreased concentrations of tumor necrosis factor-α at follow-up compared with baseline (-356.0 pg/mL); concentrations increased among women delivering before 35 weeks of gestation and those delivering at term, 132.1 and 86.9 pg/mL (P=.03). Interleukin-10 Δ and tumor necrosis factor-α Δ were unaffected by either omega-3 supplementation or fish diet. CONCLUSION: Recurrent preterm birth was associated with decreased peripheral blood mononuclear leukocyte production of interleukin-10 in response to a stimulus during the second trimester. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902. LEVEL OF EVIDENCE: II.

Customized versus population approach for evaluation of fetal overgrowth.

OBJECTIVE: To compare the ability of customized versus normalized population fetal growth norms in identifying neonates at risk for adverse perinatal outcomes (APOs) associated with fetal overgrowth and gestational diabetes (GDM). STUDY DESIGN: Secondary analysis of a multicenter treatment trial of mild GDM. The primary outcome was a composite of neonatal outcomes associated with fetal overgrowth and GDM. Birth weight percentiles were calculated using ethnicity- and gender-specific population and customized norms (Gardosi). RESULTS: Two hundred three (9.8%) and 288 (13.8%) neonates were large for gestational age by population (LGApop) and customized (LGAcust) norms, respectively. Both LGApop and LGAcust were associated with the primary outcome and neonatal hyperinsulinemia, but neither was associated with hypoglycemia or hyperbilirubinemia. The ability of customized and population birth weight percentiles for predicting APOs were poor (area under the receiver operating characteristic curve < 0.6 for six of eight APOs). CONCLUSION: Neither customized nor normalized population norms better identify neonates at risk of APOs related to fetal overgrowth and GDM.

The utility of uterine artery Doppler velocimetry in prediction of preeclampsia in a low-risk population.

OBJECTIVE: The underlying pathophysiology of preeclampsia is thought to be abnormal trophoblast invasion of the spiral arteries leading to maldevelopment of uteroplacental perfusion. We estimated whether uterine artery Doppler measurements made in the early second trimester would predict the subsequent development of preeclampsia. METHODS: Uterine artery Doppler measurements before 21 weeks of gestation (median 16.6 weeks) were correlated with subsequent development of preeclampsia in a cohort of 2,188 low-risk nulliparous women in a randomized control trial of antioxidant supplementation for prevention of preeclampsia. Preeclampsia developed in 165 (7.5%) women. RESULTS: Development of preeclampsia overall was associated with increased resistance index, pulsatility index, a pulsatility index or resistance index multiple of the median at or above the 75th percentile but not the presence of a notch or a bilateral notch before 21 weeks of gestation. The sensitivity was 43% (95% confidence interval [CI] 35-51) and specificity 67% (95% CI 65-69) for prediction of preeclampsia overall. The presence of a notch or bilateral notch, resistance index, and pulsatility index multiple of the median was significantly associated with early onset (before 34 weeks of gestation) compared with late onset or no preeclampsia (odds ratio [OR] 6.9, 95% CI 2.3-20.9; sensitivity 78%, 95% CI 52-94; specificity 66%, 95% CI 64-68). The presence of a notch or resistance index multiple of the median at or above the 75th percentile increased the odds of developing severe compared with mild or no preeclampsia (OR 2.2, 95% CI 1.4-3.7; sensitivity 53%, 95% CI 40-65; specificity 66%, 95% CI 64-68). CONCLUSION: Our data show poor sensitivity of second-trimester Doppler ultrasound measurements for prediction of preeclampsia overall in a well-characterized, low-risk, nulliparous population. The technique has utility in identifying poor trophoblast invasion of spiral arteries of a magnitude that severely compromises uteroplacental blood flow and gives early-onset disease. LEVEL OF EVIDENCE: II.

First-trimester prediction of preeclampsia in nulliparous women at low risk.

OBJECTIVE: To identify clinical characteristics and biochemical markers in first-trimester samples that would possibly predict the subsequent development of preeclampsia. METHODS: We conducted a multicenter observational study in 2,434 nulliparous women at low risk to identify biomarkers that possibly predict preeclampsia. Clinical history, complete blood count, and biochemical markers were assessed in the first trimester. The trophoblast and angiogenesis markers ADAM-12, pregnancy-associated plasma protein-A, placental protein 13, placental growth factor, soluble fms-like tyrosine kinase-1, and endoglin were measured in a case-control subset of 174 women with preeclampsia and 509 women in the control group. RESULTS: Univariable analysis revealed maternal age, race, marital status, years of education, source of medical payment, prenatal caregiver, body mass index (BMI, calculated as weight (kg)/[height (m)]), and systolic blood pressure at enrollment were significantly associated with preeclampsia. Mean platelet volume was greater at enrollment in women who later had development of preeclampsia (median 9.4 compared with 9.0 femtoliter (fl); P=.02). First-trimester concentrations (multiples of the median) of ADAM-12 (1.14 compared with 1.04; P=.003), pregnancy-associated plasma protein-A (0.94 compared with 0.98; P=.04), and placental growth factor (0.83 compared with 1.04; P<.001) were significantly different in women who had development of preeclampsia compared with women in the control group. The optimal multivariable model included African American race, systolic blood pressure, BMI, education level, ADAM-12, pregnancy-associated plasma protein-A, and placental growth factor, and yielded an area under the curve of 0.73 (95% confidence interval 0.69-0.77) and a sensitivity of 46.1% (95% confidence interval 38.3-54.0) for 80% specificity. CONCLUSION: A multivariable analysis of clinical data and biochemical markers in the first trimester did not identify a model that had clinical utility for predicting preeclampsia in a nulliparous population at low risk. LEVEL OF EVIDENCE: II.

Maternal insulin resistance and preeclampsia.

OBJECTIVE: The purpose of this study was to determine whether mid-trimester insulin resistance is associated with subsequent preeclampsia. STUDY DESIGN: This was a secondary analysis of 10,154 nulliparous women who received vitamin C and E or placebo daily from 9-16 weeks gestation until delivery. Of these, 1187 women had fasting plasma glucose and insulin tested between 22 and 26 weeks gestation. Insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR) and the quantitative insulin sensitivity check index. RESULTS: Obese women were twice as likely to have a HOMA-IR result of ≥75th percentile. Hispanic and African American women had a higher percentage at ≥75th percentile for HOMA-IR than white women (42.2%, 27.2%, and 16.9%, respectively; P < .001). A HOMA-IR result of ≥75th percentile was higher among the 85 nulliparous women who subsequently had preeclampsia, compared with women who remained normotensive (40.5% vs 24.8%; adjusted odds ratio, 1.9; 95% confidence interval, 1.1-3.2). Quantitative insulin sensitivity check index results were similar to the HOMA-IR results. CONCLUSION: Midtrimester maternal insulin resistance is associated with subsequent preeclampsia.

Fish consumption, erythrocyte fatty acids, and preterm birth.

OBJECTIVE: To estimate the association between fish consumption and erythrocyte omega-3 long-chain polyunsaturated fatty acids and preterm birth in a high-risk cohort. METHODS: This was an ancillary study to a randomized trial of omega-3 supplementation to prevent preterm birth in women with at least one previous spontaneous preterm delivery. Dietary fish intake was assessed by questionnaire and erythrocyte fatty acids were measured at enrollment (16-21 completed weeks of gestation). The association between fish consumption and preterm delivery was modeled with linear and quadratic terms. RESULTS: The probability of preterm birth was 48.6% among women eating fish less than once a month and 35.9% among women eating fish more often (P<.001). The adjusted odds ratio for preterm birth among women reporting moderately frequent fish consumption (three servings per week) was 0.60 (95% confidence interval 0.38-0.95), with no further reduction in preterm birth among women who consumed more than three servings of fish per week. Erythrocyte omega-3 levels correlated weakly but significantly with frequency of fish intake (Spearman r=0.22, P<.001); women in the lowest quartile of erythrocyte omega-3 levels were more likely to report consuming less than one fish meal per month (40.3%) than were women in the highest three quartiles (26.3%, P<.001). CONCLUSION: Moderate fish intake (up to three meals per week) before 22 weeks of gestation was associated with a reduction in repeat preterm birth. More than moderate consumption did not confer additional benefit. These results support the recommendations of the U.S. Food and Drug Administration and the American Congress of Obstetricians and Gynecologists for fish consumption during pregnancy. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902.

The role of human decay-accelerating factor in the pathogenesis of preterm labor.

Complement activation is thought to contribute to the pathogenesis of preterm labor (PTL). Decay-accelerating factor (DAF) is a natural complement pathway inhibitor. Our hypothesis was that DAF expression on maternal white blood cells (WBCs) in women with preterm labor is elevated compared with women with no preterm labor. Our secondary objective was to determine if differences in upregulation of DAF levels correlated with clinical outcomes. Serial blood samples were obtained from 30 patients with a clinical diagnosis of PTL and a control group of 30 pregnant individuals (same gestational age range) to determine DAF expression in peripheral WBCs in both groups. DAF expression was higher in women with PTL (less than 37 weeks) compared with the control group without PTL. Subjects with PTL who delivered before 34 weeks had less DAF expression and different kinetics of expression compared with those carrying pregnancies beyond 34 weeks. These data suggest that women with a clinical diagnosis of preterm labor have increased DAF expression on peripheral WBCs. Furthermore, it appears that failure to elevate DAF expression is associated with a risk of early premature delivery.

Glycemic characteristics and neonatal outcomes of women treated for mild gestational diabetes.

OBJECTIVE: To estimate the association between fasting and 2-hour postprandial blood glucose levels and neonatal outcomes in women treated for mild gestational diabetes. METHODS: In this secondary analysis of a multicenter randomized treatment trial of mild gestational diabetes, the median fasting and 2-hour postprandial glucose levels were analyzed in 2-week intervals and change over time (slope) was calculated for women with gestational diabetes (abnormal oral glucose tolerance test) and a fasting glucose less than 95 mg/dL who received nutritional management with self blood glucose monitoring and insulin as needed. Regression analyses were performed to estimate the relationship between median fasting and postprandial glucose and neonatal fat mass, cord blood C-peptide, birth weight, large-for-gestational-age neonates, macrosomia (greater than 4,000 g), and neonatal hypoglycemia. RESULTS: Among 460 women with gestational diabetes, median fasting (P<.001), postprandial breakfast (P<.001), and postprandial lunch (P<.001) glucose values declined over the treatment period, whereas postprandial dinner values remained stable (P=.83). Higher median fasting glucose during the first 2 weeks of treatment was significantly associated with increased odds ratios for neonatal fat mass (1.35; 95% CI 1.09-1.66; P=.006) and elevated C-peptide (1.29; CI 1.09-1.52; P=.003). Higher median fasting glucose during the last 2 weeks before delivery was associated with higher rates of large-for-gestational-age neonates (1.27; CI 1.05-1.53; P=.01), macrosomia (1.32; CI 1.04-1.65; P = .02), and elevated C-peptide (1.19; CI 1.03-1.38; P=.02). CONCLUSION: In women treated for mild gestational diabetes, higher fasting glucose during initiation of diet therapy was associated with increased neonatal fat mass and elevated C-peptide and during the last 2 weeks before delivery with macrosomia, large-for-gestational age, and elevated C-peptide. LEVEL OF EVIDENCE: II.

The relationship between maternal glycemia and perinatal outcome.

OBJECTIVE: To examine the relationship between varying degrees of maternal hyperglycemia and pregnancy outcomes. METHODS: This was a secondary analysis of a treatment trial for mild gestational diabetes including four cohorts: 1) 473 women with untreated mild gestational diabetes; 2) 256 women with a positive 50-g screen and one abnormal oral glucose tolerance test (OGTT) value; 3) 675 women with a positive screen and no abnormal OGTT values; and 4) 437 women with a normal 50-g screen. Groups were compared by test of trend for a composite perinatal outcome (neonatal hypoglycemia, hyperbilirubinemia, elevated cord C-peptide level, and perinatal trauma or death), frequency of large for gestational age neonates, shoulder dystocia, and pregnancy-related hypertension. Three-hour OGTT levels (fasting, 1-, 2-, and 3-hour) levels were divided into categories and analyzed for their relationship to perinatal and maternal outcomes. RESULTS: There were significant trends by glycemic status among the four cohorts for the composite and all other outcomes (P<.001). Analysis for trend according to OGTT categories showed an increasing relationship between fasting and all postload levels and the various outcomes (P<.05). Fasting glucose 90 mg/dL or greater and 1 hour 165 mg/dL or greater were associated with an increased risk for the composite outcome (odds ratios and 95% confidence intervals of 2.0 [1.03­4.15] and 1.46 [1.02­2.11] to 1.52 [1.08­2.15] for the fasting and 1 hour, respectively). A 1 hour glucose 150 mg/dL or greater was associated with an increased risk for large for gestational age (odds ratios, 1.8 [1.02­3.18] to 2.35 [1.35­4.14]); however, 2- and 3-hour glucose levels did not increase the risk for the composite or large for gestational age until well beyond current gestational diabetes diagnostic thresholds. CONCLUSION: A monotonic relationship exists between increasing maternal glycemia and perinatal morbidity. Current OGTT criteria require reevaluation in determining thresholds for the diagnosis and treatment of gestational diabetes. LEVEL OF EVIDENCE: II

Failed labor induction: toward an objective diagnosis.

OBJECTIVE: To evaluate maternal and perinatal outcomes in women undergoing labor induction with an unfavorable cervix according to duration of oxytocin administration in the latent phase of labor after ruptured membranes. METHODS: This was a secondary analysis of a randomized multicenter trial in which all cervical examinations from admission were recorded. INCLUSION CRITERIA: nulliparas at or beyond 36 weeks of gestation undergoing induction with a cervix of 2 cm or less dilated and less than completely effaced. The latent phase of labor was defined as ending at a cervical dilation of 4 cm and effacement of at least 90%, or at a cervical dilation of 5 cm regardless of effacement. RESULTS: A total of 1,347 women were analyzed. The overall vaginal delivery rate was 63.2%. Most women had exited the latent phase after 6 hours of oxytocin and membrane rupture (n=939; 69.7%); only 5% remained in the latent phase after 12 hours. The longer the latent phase, the lower the vaginal delivery rate. Even so, 39.4% of the 71 women who remained in the latent phase after 12 hours of oxytocin and membrane rupture were delivered vaginally. Chorioamnionitis, endometritis, or both, and uterine atony were the only maternal adverse outcomes related to latent-phase duration: adjusted odds ratios (95% confidence intervals) of 1.12 (1.07, 1.17) and 1.13 (1.06, 1.19), respectively, for each additional hour. Neonatal outcomes were not related to latent-phase duration. CONCLUSION: Almost 40% of the women who remained in the latent phase after 12 hours of oxytocin and membrane rupture were delivered vaginally. Therefore, it is reasonable to avoid deeming labor induction a failure in the latent phase until oxytocin has been administered for at least 12 hours after membrane rupture. LEVEL OF EVIDENCE: III.

Cytokine gene polymorphisms and length of gestation.

OBJECTIVE: To estimate whether there is an association between length of gestation and gene polymorphisms that effect transcription of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), or interleukin-1ß (IL-1ß). METHODS: Blood for DNA analysis was collected from 834 women at high risk enrolled in a randomized, clinical trial of omega-3 fatty acid supplementation for the prevention of recurrent preterm birth. Genotyping was performed for three single nucleotide polymorphisms (SNPs), TNF-α -308, IL-6 -174, and IL-1ß +3954. Women with the homozygous minor genotype were compared with women with either the heterozygous or the homozygous major genotype. Kaplan-Meier curves of gestational age at delivery and odds ratios for extreme preterm delivery were adjusted for African-American race and treatment group. RESULTS: Women who were homozygous for the minor allele at the -308 position in the promoter region of the TNF-α gene had significantly shorter length of gestation than women who were either heterozygous or homozygous for the major allele (adjusted hazard ratio 1.74, 95% confidence interval [CI] 1.04-2.90, P=.03). Among women with this genotype, 20% (3/15) experienced extreme spontaneous preterm delivery (less than 28 weeks of gestation; adjusted odds ratio 7.51, 95% CI 1.84-30.72, P=.005). There was no difference in length of gestation or risk of extreme spontaneous preterm delivery by genotype for the IL-6 -174 or the IL-1ß +3954 SNP. CONCLUSION: Polymorphism at the -308 position in the TNF-α promoter region is associated with shorter gestation and an increased risk of spontaneous extreme preterm delivery. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902. LEVEL OF EVIDENCE: II.

Omega-3 fatty acid supplementation to prevent recurrent preterm birth: a randomized controlled trial.

OBJECTIVE: To assess whether the addition of an omega-3 long-chain polyunsaturated fatty acid supplement would reduce preterm birth in women with at least one prior spontaneous preterm birth receiving 17alpha-hydroxyprogesterone caproate. METHODS: We conducted a randomized, double-masked, placebo-controlled trial in 13 centers. Women with a history of prior spontaneous singleton preterm birth and a current singleton gestation were assigned to either a daily omega-3 supplement (1,200 mg eicosapentaenoic acid and 800 mg docosahexaenoic acid) or matching placebo from 16-22 through 36 weeks of gestation. All participants received weekly intramuscular 17alpha-hydroxyprogesterone caproate (250 mg). The primary study outcome was delivery before 37 weeks of gestation. A sample size of 800 was necessary to have 80% power to detect a 30% reduction in the primary outcome from 30%, assuming a type I error two-sided of 5%. RESULTS: A total of 852 women were included, and none was lost to follow up. Delivery before 37 weeks of gestation occurred in 37.8% (164/434) of women in the omega-3 group and 41.6% (174/418) in the placebo group (relative risk 0.91, 95% confidence interval 0.77-1.07). CONCLUSION: Omega-3 long-chain polyunsaturated fatty acid supplementation offered no benefit in reducing preterm birth among women receiving 17alpha-hydroxyprogesterone caproate who have a history of preterm delivery. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902. LEVEL OF EVIDENCE: I.

Second-stage labor duration in nulliparous women: relationship to maternal and perinatal outcomes.

OBJECTIVE: The purpose of this study was to assess maternal and perinatal outcomes as a function of second-stage labor duration. STUDY DESIGN: We assessed outcomes in nulliparous laboring women who were enrolled in a trial of fetal pulse oximetry. RESULTS: Of 5341 participants, 4126 women reached the second stage of labor. As the duration of the second stage increased, spontaneous vaginal delivery rates declined, from 85% when the duration was <1 hour to 9% when it was > or =5 hours. Adverse maternal outcomes that were associated significantly with the duration of the second stage of labor included chorioamnionitis (overall rate, 3.9%), third- or fourth-degree perineal laceration (overall rate, 8.7%), and uterine atony (overall rate, 3.9%). Odds ratios for each additional hour of the second stage of labor ranged from 1.3-1.8. Among individual adverse neonatal outcomes, only admission to a neonatal intensive care unit was associated significantly with second stage duration (odds ratio, 1.4). CONCLUSION: The second stage of labor does not need to be terminated for duration alone.

Comprehensive changes in the learning environment: subsequent step 1 scores of academically at-risk students.

BACKGROUND: During the past 10 years at our institution, a number of changes have been instituted in the learning environment, including instructional techniques, assessment methods, academic support, and explicit board preparation. METHOD: The authors studied the Step 1 performance of students with MCAT scores of 20 to 25 in our former and current curricula. Effect sizes were calculated for score improvement using adjusted means from ANCOVA with covariates of MCAT and age. RESULTS: The overall effect size was 0.48, with larger effects seen for underrepresented minority students overall (d = 0.64) and African American students especially (d = 0.77), representing medium to large effects. Overall failure rates decreased by two thirds. CONCLUSIONS: Comprehensive changes in the learning environment were followed by substantial improvement in Step 1 performance among academically at-risk students.

In utero programming of adult vascular function in transgenic mice lacking low-density lipoprotein receptor.

OBJECTIVE: The objective of this study was to examine the role of maternal hypercholesterolemia in fetal programming of adult vascular function using transgenic mice lacking the low-density lipoprotein receptor (LDLR). STUDY DESIGN: Homozygous LDLR knockout mice (B6.129S7-Ldlr(tm1Her)/J, LDLR(-/-KO)) and their wild-type controls (C57BL/6J, LDLR(+/+WT)) were cross-bred to produce 4 litter groups: LDLR(-/-KO), maternally derived heterozygous (LDLR(+/-Mat)), paternally derived heterozygous (LDLR(+/-Pat)) and LDLR(+/+WT). Female and male offspring were killed at 10-12 weeks of age, and carotid arteries were used for in vitro experiments. RESULTS: The dose responses to phenylephrine were significantly higher in LDLR(-/-KO) and LDLR(+/-Mat) male offspring. The contractile responses to phenylephrine in female mice were significantly increased only in the LDLR(-/-KO) offspring. Maximal Ca(2+) contraction was higher in LDLR(-/-KO) male and female offspring. CONCLUSION: Despite being genomically similar, heterozygous offspring that developed in a hypercholesterolemic maternal environment had abnormal vascular responses later in life compared with those that developed in a normal environment.

Follow-up of children exposed in utero to 17 alpha-hydroxyprogesterone caproate compared with placebo.

OBJECTIVE: To assess whether there are evident adverse effects of 17 alpha-hydroxyprogesterone caproate after in utero exposure. METHODS: This study evaluated surviving children of mothers who participated in a multicenter placebo-controlled trial of weekly intramuscular 17 alpha-hydroxyprogesterone caproate, with a 2:1 allocation to 17 alpha-hydroxyprogesterone caproate and placebo, respectively. The guardian was interviewed about the child's general health. Children underwent a physical examination and developmental screen with the Ages and Stages Questionnaire. Gender-specific roles were assessed with the Preschool Activities Inventory. RESULTS: Of 348 eligible surviving children, 278 (80%) were available for evaluation (194 in the 17 alpha-hydroxyprogesterone caproate group and 84 in the placebo group). The mean age at follow-up was 48 months. No significant differences were seen in health status or physical examination, including genital anomalies, between 17 alpha-hydroxyprogesterone caproate and placebo children. Scores for gender-specific roles (Preschool Activities Inventory) were within the normal range and similar between 17 alpha-hydroxyprogesterone caproate and placebo groups. CONCLUSION: 17 alpha-hydroxyprogesterone caproate seems to be safe for the fetus when administered in the second and third trimesters.

Gender-specific effect of overexpression of sFlt-1 in pregnant mice on fetal programming of blood pressure in the offspring later in life.

OBJECTIVE: The purpose of this study was to determine whether fetal programming of adult blood pressure is altered in a previously characterized mouse model of preeclampsia that was induced by sFlt-1. STUDY DESIGN: CD-1 mouse mothers at day 8 of gestation were injected with an adenovirus carrying Flt 1-3 (10(9) plaque-forming units) or with an adenovirus carrying mFc as control (10(9) plaque-forming units). The resulting pups were followed until 6 months of age, at which time blood pressure (BP) was recorded continuously for 6 days. The offspring weight was also recorded from weaning until adulthood. RESULTS: BP was significantly higher in the male offspring that were born to sFlt-1-treated mothers compared with the controls. Male offspring from sFlt-1-treated mothers were significantly smaller from weaning until adulthood. However, there were no significant differences in BP and postweaning weight in female offspring between the 2 groups. CONCLUSION: Our findings highlight the role of the intrauterine environment in the developmental origin of adult disease.

Effect of a previous pregnancy on vascular function in endothelial nitric oxide synthase 3 knockout mice.

OBJECTIVE: Nitric oxide deficiency has been implicated in adverse pregnancy outcomes. Mice that lack endothelial nitric oxide synthase (NOS3) have abnormal in vitro vascular reactivity. Our objective was to assess the effect of a previous pregnancy on the abnormal vascular function of NOS3 knockout mice. STUDY DESIGN: Carotid arteries from pregnant NOS3 knockout (NOS3(-/-KO)) and wild-type control mice (NOS3(+/+WT)) from first and second pregnancy were obtained for in vitro vascular reactivity studies. Vascular responses to cumulative concentrations of the vasoconstrictors phenylephrine, serotonin, and thromboxane and the vasorelaxants acetylcholine, sodium nitroprusside, and isoproterenol were determined. RESULTS: In the first pregnancy, contractile responses were exaggerated in the knockout animals, compared with the wild-type animals. However, the second pregnancy in knockout animals was associated with normalization of responses to phenylephrine and serotonin and increased responses to the endothelium-independent relaxants. CONCLUSION: The vascular function of NOS3 knockout mice improves with subsequent pregnancy becoming comparable to wild-type animals.

The effect of the postnatal environment on altered fetal programming of adult vascular function in mice that lack endothelial nitric oxide synthase.

OBJECTIVE: The purpose of this study was to investigate vascular reactivity in heterozygous and homozygous offspring with a genetic predisposition for hypertension after postnatal cross-fostering to mothers with the opposite genetic inheritance of the NOS3 knockout allele. STUDY DESIGN: Homozygous NOS3 knockout (C57BL/6J-NOS3(-/-KO)) and wild-type mice (NOS3(+/+WT)) were bred to obtain heterozygous litters with a paternally derived (NOS3(+/-pat)) or maternally derived (NOS3(+/-mat)) knockout allele. After delivery, heterozygous and homozygous litters were cross-fostered to a mother with the opposite NOS3 gene status. Carotid arteries were placed in a wire myograph for isometric tension recording with the use of contractile and relaxant agents. Statistical analysis with 1-way analysis of variance and Neuman-Keuls post-hoc testing was performed. RESULTS: Increased sensitivity to phenylephrine and absent relaxation to acetylcholine in NOS3(+/-mat) was reversed with cross-fostering, and vasorelaxation to isoproterenol was increased. Contraction to calcium was increased in the cross-fostered paternally derived and wild-type litters. CONCLUSION: Postnatal interventions may alter the adult vascular profile favorably that is the result of an abnormal intrauterine environment.