C. Edward Wells

Subclinical hypothyroidism and pregnancy outcomes.

BACKGROUND: Clinical thyroid dysfunction has been associated with pregnancy complications such as hypertension, preterm birth, low birth weight, placental abruption, and fetal death. The relationship between subclinical hypothyroidism and pregnancy outcomes has not been well studied. We undertook this prospective thyroid screening study to evaluate pregnancy outcomes in women with elevated thyrotropin (thyroid-stimulating hormone, TSH) and normal free thyroxine levels. METHODS: All women who presented to Parkland Hospital for prenatal care between November 1, 2000, and April 14, 2003, had thyroid screening using a chemiluminescent TSH assay. Women with TSH values at or above the 97.5th percentile for gestational age at screening and with free thyroxine more than 0.680 ng/dL were retrospectively identified with subclinical hypothyroidism. Pregnancy outcomes were compared with those in pregnant women with normal TSH values between the 5th and 95th percentiles. RESULTS: A total of 25,756 women underwent thyroid screening and were delivered of a singleton infant. There were 17,298 (67%) women enrolled for prenatal care at 20 weeks of gestation or less, and 404 (2.3%) of these were considered to have subclinical hypothyroidism. Pregnancies in women with subclinical hypothyroidism were 3 times more likely to be complicated by placental abruption (relative risk 3.0, 95% confidence interval 1.1–8.2). Preterm birth, defined as delivery at or before 34 weeks of gestation, was almost 2-fold higher in women with subclinical hypothyroidism (relative risk, 1.8, 95% confidence interval 1.1–2.9). CONCLUSION: We speculate that the previously reported reduction in intelligence quotient of offspring of women with subclinical hypothyroidism may be related to the effects of prematurity. LEVEL OF EVIDENCE: II-2

Subclinical hyperthyroidism and pregnancy outcomes.

OBJECTIVE: Subclinical hyperthyroidism has long-term sequelae that include osteoporosis, cardiovascular morbidity, and progression to overt thyrotoxicosis or thyroid failure. The objective of this study was to evaluate pregnancy outcomes in women with suppressed thyroid-stimulating hormone (TSH) and normal free thyroxine (fT4) levels. METHODS: All women who presented to Parkland Hospital for prenatal care between November 1, 2000, and April 14, 2003, underwent thyroid screening by chemiluminescent TSH assay. Women with TSH values at or below the 2.5th percentile for gestational age and whose serum fT4 levels were 1.75 ng/dL or less were identified to have subclinical hyperthyroidism. Those women screened and delivered of a singleton infant weighing 500 g or more were analyzed. Pregnancy outcomes in women identified with subclinical hyperthyroidism were compared with those in women whose TSH values were between the 5th and 95th percentiles. RESULTS: A total of 25,765 women underwent thyroid screening and were delivered of singleton infants. Of these, 433 (1.7%) were considered to have subclinical hyperthyroidism, which occurred more frequently in African-American and/or parous women. Pregnancies in women with subclinical hyperthyroidism were less likely to be complicated by hypertension (adjusted odds ratio 0.66, 95% confidence interval 0.44–0.98). All other pregnancy complications and perinatal morbidity or mortality were not increased in women with subclinical hyperthyroidism. CONCLUSION: Subclinical hyperthyroidism is not associated with adverse pregnancy outcomes. Our results indicate that identification of subclinical hyperthyroidism and treatment during pregnancy is unwarranted. LEVEL OF EVIDENCE: II-2

Thyroid-stimulating Hormone in Singleton and Twin Pregnancy: Importance of Gestational Age–specific Reference Ranges

OBJECTIVE: To estimate a normal reference range for thyroid-stimulating hormone (TSH) at each point in gestation in singleton and twin pregnancies. METHODS: All women enrolling for prenatal care from December 2000 through November 2001 underwent prospective TSH screening at their first visit. Separate nomograms were constructed for singleton and twin pregnancies using regression analysis. Values were converted to multiples of the median (MoM) for singleton pregnancies at each week of gestation. RESULTS: Thyroid-stimulating hormone was evaluated in 13,599 singleton and 132 twin pregnancies. Thyroid-stimulating hormone decreased significantly during the first trimester, and the decrease was greater in twins (both P < .001). Had a nonpregnant reference (0.4–4.0 mU/L) been used rather than our nomogram, 28% of 342 singletons with TSH greater than 2 standard deviations above the mean would not have been identified. For singleton first-trimester pregnancies, the approximate upper limit of normal TSH was 4.0 MoM, and for twins, 3.5 MoM. Thereafter, the approximate upper limit was 2.5 MoM for singleton and twin pregnancies. CONCLUSION: If thyroid testing is performed during pregnancy, nomograms that adjust for fetal number and gestational age may greatly improve disease detection. Values expressed as multiples of the median may facilitate comparisons across different laboratories and populations. LEVEL OF EVIDENCE: II-2

Sonographic Findings of Morbidly Adherent Placenta in the First Trimester

The purpose of this study was to evaluate the association between first‐trimester sonographic findings and morbidly adherent placenta at delivery.

Vaginal Birth After Cesarean Delivery: Views from the Private Practitioner

This survey was conducted to assess physician opinion regarding vaginal birth after cesarean delivery (VBAC) and to examine how physician and hospital characteristics influence the private obstetrical providers decision to offer or not to offer trial of labor after cesarean delivery. A confidential postal survey of private practicing obstetricians in the Dallas-Ft. Worth Region (n = 774) of North Texas. Of 774 obstetrician-gynecologists, 458 completed and returned the survey for a response rate of 59%. The survey revealed that 52% of respondents offer VBAC to their patients and indicated that the most common reasons for declining use or discontinuation of VBAC were maternal-fetal safety concerns associated with uterine rupture followed by medico-legal liability concerns. Factors associated with physicians not providing VBAC for their patients were physicians in obstetrical practice <10 years, a physicians previous involvement in the care of women with uterine rupture complicated by maternal or neonatal complications, and a physicians previous involvement in cesarean delivery-related medical malpractice litigation.

Placenta accreta and vaginal bleeding according to gestational age at delivery.

OBJECTIVE: To evaluate the incidence of vaginal bleeding in women with placenta accreta according to gestational age at delivery. METHODS: This is a retrospective cohort study of women with prior cesarean delivery and persistent placenta previa delivered at our institution between December 1997 and December 2011. Diagnosis of invasion was based on hysterectomy performed for an abnormally adherent placenta with histologic confirmation. Suspicion for invasion was based on the impression of the attending physician at the time of ultrasonography. Records were reviewed to identify indication for delivery and estimated blood loss. Statistical analyses were performed using Students t test, &khgr;2 test, and Mantel-Haenszel and Jonckheere-Terpstra tests for trend. RESULTS: Of 216 women with prior cesarean delivery and persistent previa, 65 (30%) required cesarean hysterectomy and had histologic confirmation of invasion. Urgent delivery for bleeding was performed in 20% of these pregnancies (13/65). Delivery for bleeding decreased significantly with advancing gestation (P=.001). In our series, 71% with accreta were delivered at 36 weeks of gestation or greater with delivery for bleeding in five (11%), and estimated blood loss was not increased in these pregnancies. Of 79 women with ultrasonographic suspicion for accreta, the incidence of vaginal bleeding prompting urgent delivery also decreased with advancing gestation (P<.001). CONCLUSION: Likelihood of vaginal bleeding necessitating delivery declined with advancing gestation in pregnancies with placenta accreta as did blood loss. Most were delivered at 36 weeks of gestation or greater, nearly 90% in the absence of bleeding complications. Thus, although preterm delivery is an important consideration when placenta accreta is suspected, our findings support individualizing delivery planning. LEVEL OF EVIDENCE: II

Biometric sonographic findings of abnormally adherent trophoblastic implantations on cesarean delivery scars

The purpose of this study was to review first‐trimester transvaginal sonograms of patients with cervicoisthmic implantations and prior cesarean deliveries to determine whether sonographic biometric measurements can distinguish between abnormally adherent trophoblastic implantations and normally implanted pregnancies.

Frequency and consequences of ventricular hypertrophy in pregnant women with treated chronic hypertension

BACKGROUND: Ventricular hypertrophy is a known sequela of long‐standing chronic hypertension with associated morbidity and mortality. OBJECTIVE: We sought to assess the frequency and importance of left ventricular hypertrophy in gravidas treated for chronic hypertension during pregnancy. STUDY DESIGN: This was a retrospective study of pregnant women with chronic hypertension who were delivered at our hospital from January 2009 through February 2015. All women who were given antihypertensive therapy underwent maternal echocardiography and were managed in a dedicated, high‐risk prenatal clinic. Left ventricular hypertrophy was defined using the criteria of the American Society of Echocardiography as left ventricular mass indexed to maternal body surface area with a value of >95 g/m2. Maternal and infant outcomes were then analyzed according to the presence or absence of left ventricular hypertrophy. RESULTS: Of 253 women who underwent echocardiography, 48 (19%) met criteria for left ventricular hypertrophy. Women in this latter cohort were significantly more likely to be African American (P = .031), but there were no other demographic differences. More than 85% of the entire cohort had a body mass index >30 kg/m2 and a third of all women had class III obesity with a body mass index of >40 kg/m2. Importantly, duration of chronic hypertension (P = .248) and gestational age at time of echocardiography (P = .316) did not differ significantly between the groups. Left ventricular function was preserved in both groups as measured by left ventricular ejection fraction (P = .303). Those with ventricular hypertrophy were at greater risk to be delivered preterm (P = .001), to develop superimposed preeclampsia (P = .028), and to have an infant requiring intensive care (P = .023) when compared with women without ventricular hypertrophy. These findings persisted after adjustment for age, race, and parity. The gestational age at delivery according to measured left ventricular size was also examined and with increasing ventricular mass there was a significant association with the severity of preterm birth (P < .001). CONCLUSION: Left ventricular hypertrophy was identified in 1 in 5 women given antepartum treatment for chronic hypertension. Further analysis showed that these women were at significantly greater risk for superimposed preeclampsia and its attendant perinatal sequelae of preterm birth.

Association of Baseline Proteinuria and Adverse Outcomes in Pregnant Women With Treated Chronic Hypertension.

OBJECTIVE: To assess the importance of baseline proteinuria in women treated for chronic hypertension during pregnancy. METHODS: This retrospective cohort study included women with chronic hypertension who received antihypertensive therapy in the first half of pregnancy and completed urine protein quantification before 20 weeks of gestation. Maternal and neonatal outcomes were analyzed according to the presence or absence of baseline proteinuria, defined as 300 mg or greater per 24 hours identified before 20 weeks of gestation. Frequencies of superimposed preeclampsia, preterm birth, and small-for-gestational-age neonates were further evaluated according to stratified urine protein excretion levels from less than 50 mg to greater than 1,000 mg/24 hours. RESULTS: Between January 2002 and December 2014, a total of 447 women met inclusion criteria. Of these, 56 (13%) had baseline proteinuria. Women with baseline proteinuria were statistically significantly more likely to develop superimposed preeclampsia (79% compared with 49%), deliver preterm (18% compared with 6% 30 weeks of gestation or less, 34% compared with 17% 34 weeks of gestation or less, and 48% compared with 26% less than 37 weeks of gestation), and deliver an small-for-gestational-age neonate (41% compared with 22% less than the 10th percentile, 20% compared with 9% less than the third percentile) when compared with women who did not have proteinuria (all P<.05). Furthermore, the rates of superimposed preeclampsia and small for gestational age were significantly increased as 24-hour protein excretion levels increased across stratified levels (P for trend .002 and .015, respectively). When proteinuria levels less than 300 mg/d were analyzed separately, a significant association was observed for rates of superimposed preeclampsia and preterm birth. CONCLUSION: In pregnant women with treated chronic hypertension, baseline proteinuria was significantly associated with increased rates of preeclampsia, preterm birth, and growth restriction—even at proteinuria values previously considered to be within normal range (less than 300 mg/d).

Blood Pressure Profiles Across Pregnancy in Women with Chronic Hypertension

Objective To examine blood pressure patterns across pregnancy in women with treated chronic hypertension according to the occurrence of severe preeclampsia, growth restriction, and preterm birth <34 weeks. Methods This retrospective descriptive case study included only pregnant women receiving antihypertensive therapy. Using a random effects model, mean arterial pressures were plotted across gestation for women with and without preeclampsia, fetal growth restriction, and preterm birth <34 weeks with differences analyzed for each curve. Results Between January 2002 and December 2014, 447 women met inclusion criteria. Of these women, 65% developed severe preeclampsia, 24% delivered an infant weighing <10th percentile, and 15% had a preterm birth <34 weeks. Women diagnosed with either preeclampsia (23.3 vs 26.4 weeks; mean difference, 3.1 weeks; 95% confidence interval [CI], 2.3-4.3), fetal growth restriction (23.5 vs 24.9 weeks; mean difference, 1.4 weeks; 95% CI, 0.2-2.6), or preterm birth (19.8 vs 24.9 weeks; mean difference, 5.1 weeks; 95% CI, 3.7-6.9) reached a blood pressure nadir at a significantly earlier gestational age than those who did not. Conclusion For pregnant women with treated chronic hypertension, blood pressure patterns differ significantly in those who develop severe preeclampsia, fetal growth restriction, and preterm birth <34 weeks.