Human Chorionic Gonadotropin (hCG)
GI GI USMLE TM* Step 2 CK Obstetrics & Gynecology Lecture Notes BL4018J *USMLE is a joint program of the Federation of State Medical Boards of the United States, Inc. and the National Board of Medical Examiners. S2 OB-GYN.indb 1 7/8/13 6:35 PM GI ©2013 Kaplan, Inc. All rights reserved. Published by Kaplan, Inc. 395 Hudson Street New York, NY 10014 No part of these materials may be reproduced, transmitted, downloaded, decompiled, reversed engineered, or stored in or introduced into any information storage and retrieval system, in any form or by any means, whether electronic or mechanical, now known or hereinafter invented, without prior written authorization from Kaplan, Inc. Kaplan, Inc. grants you a non-transferable, non-exclusive license to access the materials and read the text on screen, solely for your personal, non-commercial use. 10 9 8 7 6 5 4 3 2 1 ISBN: 978-1-61865-410-6 GI Author
Elmar Peter Sakala, M.D., M.A., M.P.H., F.A.C.O.G.
Professor of Gynecology and Obstetrics
Division of Maternal Fetal Medicine
Department of Gynecology and Obstetrics
Loma Linda University School of Medicine
Loma Linda, CA
Contributing Editor
Joshua P. Kesterson, M.D.
Assistant Professor
Department of Obstetrics and Gynecology, Division of Gynecologic Oncology
Penn State College of Medicine
Hershey, PA
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Contents
| Obstetrics | |||||||||
| Chapter 1. | Reproductive Basics . . . . . . . . . . . . . . . . . . | . . . | . . . | . | . | .1 . . . . . . . . . . .
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| Chapter 2. | Failed Pregnancy . . . . . . . . . . . . . . . . . . . | . . . . . . . . . 21. . . . . . . . . . . | |||||||
| Chapter 3. | Obstetric Procedures . . . . . . . . . . . . . . . . . | . . . . . . . . | . | . 29. . . . . . . . . | |||||
| Chapter 4. | Prenatal Management of the Normal Pregnancy . | . . . . . . . .33. . . . | |||||||
| Chapter 5. | Prenatal Laboratory Testing . . . . . . . . . . . . | . . . . . . . . . . .39. . . . . . . . | |||||||
| Chapter 6. | Late Pregnancy Bleeding . . . . . . . . . . . . . . | . . . . . . . . . . .47. . . . . . . . | |||||||
| Chapter 7. | Perinatal Infections . . . . . . . . . . . . . . . . . . . | . . . | . . . | . | . 53. . . . . . . . . . . | ||||
| Chapter 8. | Obstetric Complications . . . . . . . . . . . . . . . | . . . . . | . . . . . . | .63 . . | . . . . . | ||||
| Chapter 9. | Hypertensive Complications . . . . . . . . . . . | . . . . . . | . . | . . . . . 77.. . . . . | |||||
| Chapter 10. | Medical Complications in Pregnancy . . . . | . . . . . . . | . . . . .85. . . . . . . | ||||||
| Chapter 11. | Disproportionate Fetal Growth . . . . . . . . . | . . . . . . . . . .101. . . . | . . . . | ||||||
| Chapter 12. | Antepartum Fetal Testing . . . . . . . . . . . . . | . . . . . . . . 103.. . . . . . . . . | |||||||
| Chapter 13. | Fetal Orientation in Utero . . . . . . . . . . . . . | . . . . . . . . . .109. . . . | . . . . | ||||||
| Chapter 14. | Normal and Abnormal Labor . . . . . . . . . . | . . . . . | . . . | . | . 115.. . . . . . . | ||||
| Chapter 15. | Obstetric Anesthesia . . . . . . . . . . . . . . . . . | . . . . . | . . . | . | .123. . . . . . . . | ||||
| Chapter 16. | Intrapartum Fetal Monitoring . . . . . . . . . . | . . . . . | . . . | . | .125.. . . . . . . | ||||
| Chapter 17. | Operative Obstetrics . . . . . . . . . . . . . . . . . | . . . . . . . . . 131.. . . . . . . . | |||||||
| Chapter 18. | Postpartum Issues . . . . . . . . . . . . . . . . . . . | . . . . | . . . | . | .137.. . . . . . . . | ||||
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USMLE Step 2 l Obstetrics and Gynecology
Gynecology
| Chapter 1. | Basic Principles of Gynecology . . . . . . | . . | . . . . . . . | . . . . 145.. . . | . . . . | ||||||||
| Chapter 2. | Pelvic Relaxation . . . . . . . . . . . . . . . . . . | . . | . . . | . . . . | .155. . . . . . . . . . . | ||||||||
| Chapter 3. | Disorders of the Vagina and Vulva . . . | . . | . . . . . . . . . . . | .161. . . . . . . | |||||||||
| Chapter 4. | Disorders of the Cervix and Uterus . . | . . | . . . . . . . . | . . . . .167. . . . . . | |||||||||
| Chapter 5. | Disorders of the Ovaries and Oviducts | . . | . . . . . . . . . | . . . . 187. . . . . . | |||||||||
| Chapter 6. | Gestational Trophoblastic Neoplasia . | . . | . . . . . . . . | . . . . . | .197. . . . . | ||||||||
| Chapter 7. | Sexually Transmitted Diseases . . . . . . | . . | . . . . . . . | . . . . | .201.. . . . . . | ||||||||
| Chapter 8. | Pelvic Pain . . . . . . . . . . . . . . . . . . . . . . | . | . . . . . . . . . .207... . . . | . . . . . | |||||||||
| Chapter 9. | Fertility Control . . . . . . . . . . . . . . . . . . . | . | . . . . . | . . | . . . .215. . . . | . . . . . | |||||||
| Chapter 10. | Human Sexuality . . . . . . . . . . . . . . . . . | . . | . . . . . . . . . 223. . . . . . . . | ||||||||||
| Chapter 11. | Menstrual Abnormalities | . . . . . . . . | .227. . . . . . . | ||||||||||
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| Chapter 12. | Hormonal Disorders . . . . . . . . . . . . . . | . . | . . . . . . . | . . | . . 239.. . . . . . .
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| Chapter 13. The Female Breast . . . . . . . . . . . . . . . . | . . | . . . . . . . . . . 255... . . . . | . . | ||||||||||
| Index . . . . . . . . . . . . . . . | . . . . . . . . . . . . . . . . . . . . . . . . . . | . . . . | . . . . . . . 265. . . . . . . . . . . . . . | ||||||||||
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Obstetrics
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| Reproductive Basics | 1 | |
PHYSIOLOGY OF REPRODUCTION
Human Chorionic Gonadotropin (hCG)
Source—It is produced by the placental syncytiotrophoblast, first appearing in maternal blood10 days after fertilization, peaking at 9–10 weeks, and then gradually falling to a plateau level at 20–22 weeks.
Structure—By chemical structure it is a glycoprotein with two subunits. Thea-subunit is simi-lar to luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyrotropin (TSH). The b-subunit is specific for pregnancy.
Purposes
• Maintain corpus luteum production of progesterone until the placenta can take overmaintenance of the pregnancy.
• Regulate steroid biosynthesis in the placenta and fetal adrenal gland as well.
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• Stimulate testosterone production in the fetal male testes.
If levels are excessive—twin pregnancy, hydatidiform mole, choriocarcinoma, embryonal carcinoma.
If levels are inadequate—ectopic pregnancy, threatened abortion, missed abortion.
Human Placental Lactogen
Structure—Chemically it is similar to anterior pituitary growth hormone and prolactin.
Pregnancy change—Its level parallels placental growth, rising throughout pregnancy.
Effect—It antagonizes the cellular action of insulin, decreasing insulin utilization, therebycontributing to the predisposition of pregnancy to glucose intolerance and diabetes.
If levels are low—threatened abortion, intrauterine growth restriction (IUGR).
Progesterone
Structure—This is a steroid hormone produced after ovulation by the luteal cells of the corpusluteum to induce endometrial secretory changes favorable for blastocyst implantation.
Source—It is initially produced exclusively by the corpus luteum up to 6–7 menstrual weeks.Between 7 and 9 weeks, both the corpus luteum and the placenta produce progesterone. After 9 weeks the corpus luteum declines, and progesterone production is exclusively by the placenta.
OB Triad
Human Chrorionic
Gonadotropin (hCG)
• Produced by syncytiotrophoblast
• Similar to LH, FSH, & TSH
• Mainains corpus luteum
OB Triad
Human Placental Lactogen (hPL)
• Produced by syncytiotrophoblast
• Similar to HGH, prolactin
• Decreases insulin sensitivity
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USMLE Step 2 l Obstetrics
OB Triad
Progesterone
• Produced by corpus luteum
• Prepares endometrium for implantation
• Decreased myometrial contractility
Purposes
• In early pregnancy it induces endometrial secretory changes favorable for blastocystimplantation.
• In later pregnancy its function is to induce immune tolerance for the pregnancy andprevent myometrial contractions.
Estrogen
These are steroid hormones, which occur in 3 forms, each of unique significance during a woman’s life.
Estradiol is the predominant moiety during the nonpregnant reproductive years. It is con-verted from androgens (produced from cholesterol in the follicular theca cells), which diffuse into the follicular granulosa cells containing the aromatase enzyme that completes the trans-formation into estradiol.
Estriol is the main estrogen during pregnancy. Dehydroepiandrosterone-sulfate (DHEAS)from the fetal adrenal gland is the precursor for 90% of estriol converted by sulfatase enzyme in the placenta.
Estrone is the main form during menopause. Postmenopausally, adrenal androstenedione isconverted in peripheral adipose tissue to estrone.
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