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Evaluation of the prethrombotic state
ELSEVIER
Evaluation
of the Prethrombotic
To the Editors: Levine et al,’ conclude in their article “Evaluation of the Prethrombotic State in Pregnancy and in Women Using Oral Contraceptives” that oral contraceptives, as well as pregnancy, may produce a prethrombotic state. There are some interesting aspects about this article that I would analyze: 1. They don’t describe the demographic data of their sample: Both age and parity can operate as confounding in the final analysis. 2. We don’t know how long OC users are taking the pill. The relationship between the duration of use of pill and the increase of coagulatory activity was demonstrated by Melis et al,’ who, using another markers (Fibrinopeptid A), conclude that the coagulatory activity during OC intake decreases along the cycles, being less in the 6 cycle than in the 3 cycle. Therefore, it is important to know if the women in the group of OC users are recent users or not. 3. The TAT (thrombin antithrombin III complex) median among OC users (2.3 rig/ml) is higher than
State
controls, but it remains into normal range values (14.1 rig/ml). 4. The F 1 + 2 (prothrombin fragments 1 + 2) median is higher in all groups (1.3, 1.9, 3.4) than normal range values (0.4-1.1 nmol/L). I think that a further needed to conclude that prethrombotic state.
analysis of these data is OC intake may produce a
References 1. Levine AB, Teppa J, McGough B, Cowchock FS. Evalua-
tion to the prethrombotic state in pregnancy and in women using oral contraceptives. Contraception 1996; 53:255-57. 2. Melis GB, Fruzzetti F, Nicoletti I, et al. A comparative study on the effects of a monophasic pill containing desogestrel plus 20 mcg ethinylestradiol, a triphasic combination containing levonorgestrel and a monophasic combination containing gestodene on coagulatory factors. Contraception 1991;43:23-31.
Dr. Lete Lasa I. President of the Spanish Society of Contraception C/Santiago 11 01004.-VITORIA. SPAIN
RESPONSE TO THE EDITOR To the Editors: We thank Dr. Lete Lasa for his interest in our article. 1. The mean age for our patient population is as follows: normal pregnant women 31.9 years 31.6 years nonpregnant women OC user 28.9 years OC nonuser 33.8 years Based on the existing literature, we do not understand why parity would confound the final analysis. 2. All patients in the OC user category were chronic (>3 months) users. Exact duration of OC use was not available for all patients.
0 1997 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
3 + 4. It is likely that the population used to define the reference range by the manufacturer is different than our population.
Amy B. Levine,
M.D.
Department of Obstetrics and Gynecology Division of Maternal-Fetal Medicine Thomas {efferson Medical College Philadelphia, PA 19107-5083
Susan Cowchock,
M.D.
Division of Medical Genetics Thomas Jefferson Medical College
ISSN 0610-7824/97/$17.00 PII SOOIO-7824(96)00254-5
Evaluation
of the Prethrombotic
To the Editors: Levine et al,’ conclude in their article “Evaluation of the Prethrombotic State in Pregnancy and in Women Using Oral Contraceptives” that oral contraceptives, as well as pregnancy, may produce a prethrombotic state. There are some interesting aspects about this article that I would analyze: 1. They don’t describe the demographic data of their sample: Both age and parity can operate as confounding in the final analysis. 2. We don’t know how long OC users are taking the pill. The relationship between the duration of use of pill and the increase of coagulatory activity was demonstrated by Melis et al,’ who, using another markers (Fibrinopeptid A), conclude that the coagulatory activity during OC intake decreases along the cycles, being less in the 6 cycle than in the 3 cycle. Therefore, it is important to know if the women in the group of OC users are recent users or not. 3. The TAT (thrombin antithrombin III complex) median among OC users (2.3 rig/ml) is higher than
State
controls, but it remains into normal range values (14.1 rig/ml). 4. The F 1 + 2 (prothrombin fragments 1 + 2) median is higher in all groups (1.3, 1.9, 3.4) than normal range values (0.4-1.1 nmol/L). I think that a further needed to conclude that prethrombotic state.
analysis of these data is OC intake may produce a
References 1. Levine AB, Teppa J, McGough B, Cowchock FS. Evalua-
tion to the prethrombotic state in pregnancy and in women using oral contraceptives. Contraception 1996; 53:255-57. 2. Melis GB, Fruzzetti F, Nicoletti I, et al. A comparative study on the effects of a monophasic pill containing desogestrel plus 20 mcg ethinylestradiol, a triphasic combination containing levonorgestrel and a monophasic combination containing gestodene on coagulatory factors. Contraception 1991;43:23-31.
Dr. Lete Lasa I. President of the Spanish Society of Contraception C/Santiago 11 01004.-VITORIA. SPAIN
RESPONSE TO THE EDITOR To the Editors: We thank Dr. Lete Lasa for his interest in our article. 1. The mean age for our patient population is as follows: normal pregnant women 31.9 years 31.6 years nonpregnant women OC user 28.9 years OC nonuser 33.8 years Based on the existing literature, we do not understand why parity would confound the final analysis. 2. All patients in the OC user category were chronic (>3 months) users. Exact duration of OC use was not available for all patients.
0 1997 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
3 + 4. It is likely that the population used to define the reference range by the manufacturer is different than our population.
Amy B. Levine,
M.D.
Department of Obstetrics and Gynecology Division of Maternal-Fetal Medicine Thomas {efferson Medical College Philadelphia, PA 19107-5083
Susan Cowchock,
M.D.
Division of Medical Genetics Thomas Jefferson Medical College
ISSN 0610-7824/97/$17.00 PII SOOIO-7824(96)00254-5