Platelet Counts throughout Uncomplicated Pregnancies

Abstract It is widely believed that platelet counts decrease during uncomplicated pregnancies, an observation described as gestational thrombocytopenia. However, of the 17 articles identified by our systematic literature review that statistically evaluated platelet counts during uncomplicated pregnancies, only 8 reported a significant decrease, while the remaining 9 articles reported no change. Among the 8 articles reporting decreased platelet counts, the clinical importance was not described. Lower platelet counts may be a physiologic phenomenon of normal pregnancy and represent a small decrease in all women or lower platelet counts may be a pathologic condition and represent a larger decrease in only some women. Our aim was to use electronic medical record data to evaluate platelet counts throughout pregnancy in a large population of women with uncomplicated pregnancies. We included women with uncomplicated pregnancies, ages 13-51, who delivered at the University of Oklahoma Health Sciences Center (OUHSC) between 1/1/2011 and 8/19/2014. If a woman had more than one pregnancy during the study period, we only included her first uncomplicated pregnancy. We excluded women with hypertension, preeclampsia, diabetes, placenta previa, hematologic disorders, cancer or steroid treatment, illegal drug use, premature delivery, stillbirth, women whose delivery gestational age was missing and women who did not have a platelet count at delivery. We used linear mixed models to characterize the change in platelet count during pregnancy and to determine if the change varied by racial/ethnic groups. A comparison group of nonpregnant white, black, and Hispanic women ages 13-51 was derived from the National Health and Nutrition Examination Survey (NHANES) database, excluding women with hypertension, diabetes, and/or cancer. Of 15,723 pregnancies, 8,148 women with one uncomplicated singleton pregnancy and a platelet count at delivery were included; 4,665 (57%) women had a least one previous platelet count during gestation at OUHSC. The median age at the time of delivery for the 8,148 women was 27 years, 46% were white, 13% black, 26% Hispanic, and 15% other races. The mean platelet count decreased significantly throughout pregnancy for white, black, and Hispanic women (Figure, p<0.0001). Mean platelet counts were significantly lower even in the first trimester, at a mean gestational age of 8 weeks, compared to non-pregnant women from NHANES (n=5,920). Compared to the white and Hispanic women, black women had higher mean platelet counts throughout gestation and at delivery, similar to the non-pregnant women. At delivery, the mean platelet counts were significantly different among all three groups of women (p<0.0001) with black women having the highest (222,000/µL; 95% CI=218-225; median=216; range=50-449), white women intermediate (215,000/µL; 95% CI=213-216; median=209; range=60-552) and Hispanic women having the lowest (207,000/µL; 95% CI=205-209; median=202; range=67-451). The mean platelet counts of all 3 race/ethnic groups at delivery were normally distributed indicated by the symmetrical distribution and by the similarity of mean and median values. Data for platelet counts at 4-8 weeks postpartum were available for only 181 (2.2%) women. For these women, the mean platelet count increased significantly from 217,000/µL at delivery to 262,000/µL postpartum (mean difference=44,000/µL; 95% CI=36-53). Conclusion Among women with uncomplicated pregnancies, mean platelet counts decrease significantly, compared to non-pregnant women, throughout pregnancy in all 3 race/ethnic groups. At delivery, the mean platelet counts for the 3 race/ethnic groups were significantly different, with black women having the highest and Hispanic women having the lowest. Platelet counts at delivery were normally distributed, suggesting that the platelet counts of all women decrease similarly and that lower platelet counts are a normal physiologic change during pregnancy. Figure 1. Mean platelet counts and 95% confidence intervals by gestational age stratified by race/ethnicity for women with uncomplicated pregnancies who delivered at OUHSC compared to the mean platelet counts and 95% confidence intervals for non-pregnant US women from NHANES (N) stratified by race/ethnicity. Figure 1. Mean platelet counts and 95% confidence intervals by gestational age stratified by race/ethnicity for women with uncomplicated pregnancies who delivered at OUHSC compared to the mean platelet counts and 95% confidence intervals for non-pregnant US women from NHANES (N) stratified by race/ethnicity. Disclosures No relevant conflicts of interest to declare.

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Time of quickening is associated with the placental site and BMI in nulliparous women

10.1101/2020.11.27.20239665 ◽

2020 ◽

Author(s):

Negin Jaafar ◽

Lars Henning Pedersen ◽

Olav Bjørn Petersen ◽

Lone Hvidman

Keyword(s):

Pregnant Women ◽

Gestational Age ◽

Prospective Observational Study ◽

Nuchal Translucency ◽

Second Trimester ◽

Nulliparous Women ◽

Placental Site ◽

Fetal Movements ◽

The Mean ◽

Important Milestone

AbstractIntroductionQuickening, the first sensation of fetal movements, is an important milestone for pregnant women. Information on the expected gestational age at quickening may reduce anxiety and prevent delayed detection of intrauterine demise but the available data are from the 1980s before the emergence of modern ultrasound techniques.Materials and methodsProspective observational study on nulliparous women blinded for placental location in two hospitals in Denmark. The pregnant women were enrolled at the time of nuchal translucency scan, placental location was determined at time of second trimester scanning.. The women were blinded to placenta location before time of quickening. Time of quickening were reported by 122 women, 65 with an anterior and 57 with a posterior placenta. Thirteen women had a BMI >30 (10.7%).ResultsThe mean gestational age for quickening was 19 + 0 weeks for nulliparous women. The timing depended on placental site; women with an anterior placenta experienced quickening 6.4 days later than the women with a posterior placenta. BMI > 30 was associated with a later time of quickening.ConclusionsAnterior placental location is associated with delay in experience of fetal movements of 6.4 days and this may further be delayed in women with a BMI>30.

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Population based cohort study of fetal deaths, and neonatal and perinatal mortality at term within a Somali diaspora

BMC Pregnancy and Childbirth ◽

10.1186/s12884-021-04163-z ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Stephen Contag ◽

Rahel Nardos ◽

Irina A. Buhimschi ◽

Jennifer Almanza

Keyword(s):

Cohort Study ◽

Black Women ◽

Perinatal Mortality ◽

Gestational Age ◽

Neonatal Death ◽

Fetal Death ◽

Hispanic Women ◽

Place Of Birth ◽

Death Rates ◽

Somali Women

Abstract Background Somali women deliver at greater gestational age with limited information on the associated perinatal mortality. Our objective is to compare perinatal mortality among Somali women with the population rates. Methods This is a retrospective cohort study from all births that occurred in Minnesota between 2011 and 2017. Information was obtained from certificates of birth, and neonatal and fetal death. Data was abstracted from 470,550 non-anomalous births ≥37 and ≤ 42 weeks of gestation. The study population included U.S. born White, U.S. born Black, women born in Somalia or self-identified as Somali, and women who identified as Hispanic regardless of place of birth (377,426). We excluded births < 37 weeks and > 42 weeks, > 1 fetus, age < 18 or > 45 years, or women of other ethnicities. The exposure was documented ethnicity or place of birth, and the outcomes were live birth, fetal death, neonatal death prior to 28 days, and perinatal mortality rates. These were calculated using binomial proportions with 95% confidence intervals and compared using odds ratios adjusted (aOR) for diabetes, hypertension and maternal body mass index. Results The aOR [95%CI] for stillbirth rate in the Somali cohort was greater than for U.S. born White (2.05 [1.49–2.83]) and Hispanic women (1.90 [1.30–2.79]), but similar to U.S. born Black women (0.88 [0.57–1.34]). Neonatal death rates were greater than for U.S. born White (1.84 [1.36–2.48], U.S. born Black women (1.47 [1.04–2.06]) and Hispanic women (1.47 [1.05–2.06]). This did not change after analysis was restricted to those with spontaneous onset of labor. When analyzed by week, at 42 weeks Somali aOR for neonatal death was the same as for U.S. born White women, but compared against U.S. born Black and Hispanic women, was significantly lower. Conclusions The later mean gestational age at delivery among women of Somali ethnicity is associated with greater overall risk for stillbirth and neonatal death rates at term, except compared against U.S. born Black women with whom stillbirth rates were not different. At 42 weeks, Somali neonatal mortality decreased and was comparable to that of the U.S. born White population and was lower than that of the other minorities.

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Abstract MP66: Social Determinants And Co-morbid Conditions In Women Of Child-bearing Age With Hypertension From 2001-2018

Hypertension ◽

10.1161/hyp.78.suppl_1.mp66 ◽

2021 ◽

Vol 78 (Suppl_1) ◽

Author(s):

Lara C Kovell ◽

Claire Meyerovitz ◽

Didem Ayturk ◽

Stephen P Juraschek ◽

Tiffany A Moore Simas ◽

...

Keyword(s):

Black Women ◽

Social Determinants ◽

White Women ◽

Hispanic Women ◽

Private Insurance ◽

Anthropometric Measures ◽

Mortality And Morbidity ◽

Child Bearing ◽

Race Ethnicity ◽

Morbid Conditions

Introduction: Hypertension (HTN) is the most important modifiable risk factor of serious maternal mortality and morbidity. Social determinants, including economic stability and access to healthcare, influence HTN outcomes and are critical to understanding and addressing racial and ethnic differences in HTN control. Objective: To assess social determinants and co-morbidities in US women of child-bearing age with HTN by race/ethnicity Methods: We studied women (age 20-50) with HTN in the National Health and Nutrition Examination Surveys 2001-2018. Social determinants and co-morbid conditions were examined in groups categorized by race/ethnicity - Non-Hispanic White (White), Non-Hispanic Black (Black), and Hispanic. Demographics, anthropometric measures, and co-morbid conditions were compared with White women as reference. Results: In all women with HTN, the mean (SE) age was 36.0 (0.3) years and 63% were on BP medication. Compared to white women, Black and Hispanic women had lower food security, poverty income ratio, smoking use, and private insurance (all p<0.0001, Table ). Black women had higher BP medication use, BMI, and BP compared to White women (all p<0.0001). Hispanic women had higher rates of diabetes (p=0.009) and no place to go for healthcare (p=0.005) compared to White women. Food insecurity was present in 34% of Hispanic women. Conclusions: Despite effective diagnostics and therapy, health inequity is common in women of child-bearing age with HTN, with differences by race/ethnicity in social determinants and co-morbid conditions. Each racial/ethnic group with HTN brings social determinants and comorbid conditions important for providers to recognize.

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The effect of ear acupressure medicine at the “Shen Men” point on the nausea and vomiting during pregnancy

10.53350/pjmhs211551774 ◽

2021 ◽

Vol 15 (5) ◽

pp. 1774-1779

Author(s):

Sanaz Nehbandani ◽

Hajar Salehi ◽

Khadije Rezaie Keikhaie ◽

Hossein Rashki Ghalenow ◽

Fatemeh Mirzaie ◽

...

Keyword(s):

Pregnant Women ◽

Gestational Age ◽

Intervention Group ◽

Nausea And Vomiting ◽

Control Group ◽

Health Clinics ◽

Significant Difference ◽

Quasi Experimental ◽

The Mean ◽

The Difference

Introduction & Objective: Nausea and vomiting during pregnancy is one of the most common gastrointestinal disorders that more than 85% of pregnant women experience. However, controlling and treating this complication is still one of the most important issues in antenatal care. Therefore, the aim of this study was to investigate the effect of ear acupressure at Shen Men point on relieving nausea, vomiting and retching during pregnancy. Materials and Methods: In this quasi-experimental study, 100 pregnant women with a gestational age of less than 16 weeks attending the health clinics of Zabol city during 2019-2020 were studied in two control and intervention groups (n = 50 in each group). The samples in the intervention group were trained to apply pressure on their ears’ Shen Men point with the thumb for three minutes three times a day (morning, noon, and night), for a duration of one month. At the end of second and fourth weeks, the data were collected using the Rhodes index form and then, were analyzed by SPSS software version 22. Results: According to the results, there was no significant difference between the two groups in terms of age, gestational age, occupation and education. The difference in the mean scores of nausea, vomiting and retching was not statistically significant between the control and intervention groups before the study. But four weeks after the study, a significant difference was observed in the mean scores of vomiting, nausea and retching between the two groups, so that the mean scores of vomiting, nausea and retching were significantly lower in the intervention group than in the control group. Conclusion: The ear acupressure medicine at the Shen men point can be used as a non-invasive, safe and inexpensive method to relieve nausea, vomiting and retching during pregnancy. Keywords: Acupressure medicine, Shen Men, Vomiting, Pregnancy, Nausea, Retching, Rhodosis

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Racial/Ethnic Disparities in Mammogram Frequency Among Women With Intellectual Disability

Intellectual and Developmental Disabilities ◽

10.1352/1934-9556-57.3.177 ◽

2019 ◽

Vol 57 (3) ◽

pp. 177-187 ◽

Cited By ~ 1

Author(s):

Evelyn Arana ◽

Amy Carroll-Scott ◽

Philip M. Massey ◽

Nora L. Lee ◽

Ann C. Klassen ◽

...

Keyword(s):

Intellectual Disability ◽

Black Women ◽

Medical Record ◽

Ethnic Groups ◽

White Women ◽

Ethnic Disparities ◽

Medical Record Data ◽

Record Data ◽

Race Ethnicity ◽

Racial Ethnic

Abstract Little information exists on the associations between intellectual disability (ID) and race/ethnicity on mammogram frequency. This study collected survey and medical record data to examine this relationship. Results indicated that Hispanic and Black women with ID were more likely than White women with ID to have mammograms every 2 years. Participants who live in a state-funded residence, were aged 50+, and had a mild or moderate level of ID impairment were more likely to undergo mammography compared to participants living with family or alone, were <50, and had severe ID impairment. Further research is needed to understand the mechanisms explaining disparities in mammograms between these racial/ethnic groups.

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New onset of restless legs syndrome in pregnancy in a prospective multiracial cohort

Neurology ◽

10.1212/wnl.0000000000011082 ◽

2020 ◽

Vol 95 (24) ◽

pp. e3438-e3447

Author(s):

Muzi Na ◽

Jing Wu ◽

Mengying Li ◽

Stefanie N. Hinkle ◽

Cuilin Zhang ◽

...

Keyword(s):

Risk Factors ◽

Black Women ◽

Restless Legs Syndrome ◽

White Women ◽

Hispanic Women ◽

Nutritional Factors ◽

Restless Legs ◽

Relative Risks ◽

Race Ethnicity ◽

In Pregnancy

ObjectiveTo determine whether the incidence and risk factors of restless legs syndrome (RLS) in pregnancy differ by race/ethnicity, we estimated relative risks of demographic, socioeconomic, and nutritional factors in association with risk of any incident RLS in pregnancy in a cohort of 2,704 healthy pregnant women without prior RLS.MethodsUsing data from the multicenter, multiracial National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies–Singletons, we examined the incidence of RLS from early pregnancy to near delivery through up to 6 assessments. Multivariable Poisson models with robust variance were applied to estimate relative risks (RRs).ResultsThe cumulative incidence of RLS in pregnancy was 18.1% for all women, 20.3% for White women, 15.4% for Black women, 17.1% for Hispanic women, and 21.1% for Asian women. Among Hispanic women, older age (RR [reference ≤25 years]: 25–35 years, 1.51; 95% confidence interval [CI] 1.05–2.16; ≥35 years, 1.58; 95% CI 0.93–2.68), anemia (RR [reference no]: yes, 2.47; 95% CI 1.31–4.64), and greater total skinfolds of the subscapular and triceps sites, independent of body mass index (RR [reference quartile 1]: quartile 5, 2.54; 95% CI 1.30–4.97; p trend = 0.01) were associated with higher risk of RLS, while multiparity was associated with a lower risk (RR [reference nulliparity]: 0.69; 95% CI 0.50–0.96). In Black women, greater skinfolds and waist circumference were associated with higher risk of pregnancy RLS, although the trends were less clear.ConclusionsThe incidence of RLS in pregnancy was high and differed by race/ethnicity, which is likely accounted for by differences in other risk factors, such as age, parity, and nutritional factors.

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Association between platelet count and osteoarthritis in women older than 50 years

Therapeutic Advances in Musculoskeletal Disease ◽

10.1177/1759720x20912861 ◽

2020 ◽

Vol 12 ◽

pp. 1759720X2091286

Author(s):

Yu-Jin Kwon ◽

Il-Hyun Koh ◽

Kwangho Chung ◽

Yong-Jae Lee ◽

Hyoung-Sik Kim

Keyword(s):

Platelet Count ◽

Confidence Intervals ◽

Multiple Logistic Regression Analysis ◽

Odds Ratios ◽

Characteristic Analysis ◽

Cross Sectional ◽

Platelet Counts ◽

Health And Nutrition ◽

Inflammatory Processes ◽

The Relationship

Background: Osteoarthritis (OA) is a multifactorial disease involving inflammatory processes. Platelets play important roles in both hemostasis and the inflammatory response; however, the relationship between platelet count and OA is unclear. Our aim was to evaluate the association between platelet count and knee and hip OA in Korean women. Methods: In this cross-sectional designed study, we included a total of 6011 women aged ⩾50 years from the 2010–2013 Korea National Health and Nutrition Examination Survey. Knee and hip OA were defined as Kellgren–Lawrence grade ⩾2 and presence of knee or hip pain, respectively. Platelet counts were divided into quartiles as follows: Q1, 150–212 (103/µl); Q2, 213–246 (103/µl); Q3, 247–283 (103/µl); and Q4, 284–450 (103/µl). Multiple logistic-regression analysis was conducted to calculate odds ratios and 95% confidence intervals. Receiver operating characteristic analysis was performed to determine the optimal platelet count cut-off with which to discriminate participants with knee and/hip OA versus those without OA. Results: Of the 6011 participants, 1141 (18.1%) had knee or hip OA. The mean age of participants without OA was 60.6 years, and that of participants with OA was 68.0 years. Compared with the lowest quartile, odds ratios (95% confidence intervals) for OA were 1.08 (0.84–1.39) for Q2, 0.94 (0.73–1.23) for Q3, and 1.35 (1.08–1.69) for Q4 after adjusting for confounders. The prevalence of OA was significantly higher with platelet counts ⩾288 × 103/µl, compared with platelet counts <288 × 103/µl. Conclusion: High platelet counts within the normal range are significantly associated with knee and hip OA.

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Disparities at the Intersection of Race and Ethnicity: Examining Trends and Outcomes in Hispanic Women With Breast Cancer

JCO Oncology Practice ◽

10.1200/op.20.00381 ◽

2020 ◽

pp. OP.20.00381

Author(s):

Cosette D. Champion ◽

Samantha M. Thomas ◽

Jennifer K. Plichta ◽

Edgardo Parrilla Castellar ◽

Laura H. Rosenberger ◽

...

Keyword(s):

Breast Cancer ◽

Black Women ◽

Racial Differences ◽

White Women ◽

Hispanic Women ◽

Hazard Ratio ◽

Tumor Subtype ◽

Hispanic Patients ◽

Race Ethnicity ◽

Hispanic White

PURPOSE: We sought to examine tumor subtype, stage at diagnosis, time to surgery (TTS), and overall survival (OS) among Hispanic patients of different races and among Hispanic and non-Hispanic (NH) women of the same race. METHODS: Women 18 years of age or older who had been diagnosed with stage 0-IV breast cancer and who had undergone lumpectomy or mastectomy were identified in the National Cancer Database (2004-2014). Tumor subtype and stage at diagnosis were compared by race/ethnicity. Multivariable linear regression and Cox proportional hazards modeling were used to estimate associations between race/ethnicity and adjusted TTS and OS, respectively. RESULTS: A total of 44,374 Hispanic (American Indian [AI]: 79 [0.2%]; Black: 1,011 [2.3%]; White: 41,126 [92.7%]; Other: 2,158 [4.9%]) and 858,634 NH women (AI: 2,319 [0.3%]; Black: 97,206 [11.3%]; White: 727,270 [84.7%]; Other: 31,839 [3.7%]) were included. Hispanic Black women had lower rates of triple-negative disease (16.2%) than did NH Black women (23.5%) but higher rates than did Hispanic White women (13.9%; P < .001). Hispanic White women had higher rates of node-positive disease (23.2%) versus NH White women (14.4%) but slightly lower rates than Hispanic (24.6%) and NH Black women (24.5%; P < .001). Hispanic White women had longer TTS versus NH White women regardless of treatment sequence (adjusted means: adjuvant chemotherapy, 42.71 v 38.60 days; neoadjuvant chemotherapy, 208.55 v 201.14 days; both P < .001), but there were no significant racial differences in TTS among Hispanic patients. After adjustment, Hispanic White women (hazard ratio, 0.77 [95% CI, 0.74 to 0.81]) and Black women (hazard ratio, 0.75 [95% CI, 0.58 to 0.96]) had improved OS versus NH White women (reference) and Black women (hazard ratio, 1.15 [95% CI, 1.12 to 1.18]; all P < .05). CONCLUSION: Hispanic women had improved OS versus NH women, but racial differences in tumor subtype and nodal stage among Hispanic women highlight the importance of disaggregating racial/ethnic data in breast cancer research.

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Evaluation of Serum Magnesium Level in Preeclampsia

Bangladesh Journal of Medical Biochemistry ◽

10.3329/bjmb.v10i1.36693 ◽

2018 ◽

Vol 10 (1) ◽

pp. 10-15

Author(s):

HL Roy ◽

S Nargis ◽

SH Mahmud ◽

NWB Jahan ◽

MS Hossain ◽

...

Keyword(s):

Pregnant Women ◽

Gestational Age ◽

Serum Magnesium ◽

Colorimetric Method ◽

Magnesium Level ◽

Medical Complication ◽

Serum Magnesium Level ◽

Cross Sectional ◽

The Mean ◽

Age Range

Preeclampsia is the most common medical complication of pregnancy associated with increased maternal and infant mortality and morbidity. Reduced serum magnesium level is found to be associated with elevated blood pressure in preeclampsia. The purpose of this cross-sectional study is to evaluate the serum magnesium level in preeclamptic women. For this study 50 preeclamptic patients, with age range 20 to 40 years having gestational age range from 20 to 40 weeks and 50 age and gestational age matched normotensive pregnant women having no proteinuria were enrolled. Serum magnesium was measured by colorimetric method. The mean(±SD) age and mean(±SD) gestational age of preeclampsia was not significantly different from those of normotensive pregnant women (p=0.203 and p=0.251 respectively). The mean(±SD) body mass index of the preeclamptic patients was significantly higher compared to that of normotensive pregnant women (p<0.001). The mean(±SD) serum magnesium level was 3.37±2.05 mg/dl in preeclamptic group and 2.87±1.38 mg/dl in normal pregnant women; the level did not differ significantly between the subject of preeclampsia and normal pregnant women (p=0.153). Findings of this study suggest that serum magnesium has no association with preeclampsia.Bangladesh J Med Biochem 2017; 10(1): 10-15

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A Phase 2 Open-Label, Sequential-Cohort, Dose-Escalation Study of AMG 531 in Japanese Patients with Chronic Immune Thrombocytopenic Purpura (ITP).

Blood ◽

10.1182/blood.v110.11.1308.1308 ◽

2007 ◽

Vol 110 (11) ◽

pp. 1308-1308

Author(s):

Yukari Shirasugi ◽

Kiyoshi Ando ◽

Satoshi Hashino ◽

Toshiro Nagasawa ◽

Yoshiyuki Kurata ◽

...

Keyword(s):

Platelet Count ◽

Dose Escalation ◽

Japanese Patients ◽

Phase 2 ◽

Platelet Response ◽

Phase 3 ◽

Continuation Phase ◽

Platelet Counts ◽

Starting Dose ◽

The Mean

Abstract AMG 531 is a novel thrombopoiesis-stimulating peptibody that is being studied for its ability to increase platelet production by stimulating the thrombopoietin (TPO) receptor. This phase 2 study was conducted to identify the appropriate starting dose of AMG 531 for treatment of chronic ITP in adult Japanese patients. The study consisted of 2 phases: a 2-week cohort dose-escalation phase to determine the starting dose for subsequent phase 3 evaluation, and a treatment continuation phase (that lasted until completion of the dose-escalation phase) which provided continuation of treatment for those with a platelet response. Patients in the continuation phase received the dose of AMG 531 they had received in the dose-escalation phase with the option for subsequent dose adjustments. Twelve patients were enrolled with a mean platelet count of 11.8x109/L and a median age of 60.5 years (range 32 to 63); 8 were female. Four patients enrolled into each of 1μg/kg, 3μg/kg, or 6μg/kg dose cohorts and received AMG 531 by subcutaneous injection on days 1 and 8 with no dose adjustments. Cohort dose escalation was to be stopped in the event of an observed platelet count >1000x109/L. Comparison of dose cohorts showed that the proportion of patients achieving a platelet response (doubling of baseline counts and ≥50x109/L) was greater in cohorts receiving higher doses of AMG 531 (see Table). A dose response was also observed in the mean peak platelet counts, the mean fold changes from baseline in peak platelet counts, and the maximum platelet count. Because one patient in the 6μg/kg cohort had an excessively high platelet count (980x109/L), this dose was eliminated from consideration as the starting dose in phase 3 and further dose escalation to 10μg/kg dose cohort was stopped. Five of 7 eligible patients (3μg/kg, 1/4; 6μg/kg, 4/4) elected to enter the treatment continuation phase. There were no study withdrawals, and no serious adverse events (AEs) were reported during the study in either phase. The most common treatment-related AE in the cohort phase was headache (25%), and in the treatment continuation phase were arthralgia, contact dermatitis, and malaise (each 20%). No patients received rescue medications during the entire treatment period. No antibodies against either AMG 531 or endogenous TPO were detected. AMG 531 was well-tolerated and produced a dose-responsive increase in platelet counts. The phase 3 study in Japanese patients with ITP will be initiated with a starting dose of 3μg/kg based on the outcome of this study. Key Measures of Platelet Response

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