CAQ-OBGYN cheat sheet

Gestational age by Naegele rule: first day of last menstrual period plus 280 days; ultrasound dating supersedes LMP when the discrepancy exceeds 7 days in the first trimester.

Estimated blood loss thresholds: postpartum hemorrhage is blood loss of 1000 mL or more, or any loss with hemodynamic instability, within 24 hours of birth.

Magnesium sulfate for eclampsia prophylaxis: 4-6 g IV loading dose over 20 minutes, then 1-2 g/hour; monitor deep tendon reflexes, respiratory rate, and urine output.

Antepartum fetal surveillance: nonstress test is reactive if two accelerations of 15 beats/min for 15 seconds occur within 20 minutes at 32 weeks or later.

Group B streptococcus prophylaxis: intrapartum penicillin G is indicated for colonization, prior infant with invasive disease, or GBS bacteriuria at any colony count.

Preterm birth prevention: vaginal progesterone is used for a singleton pregnancy with a short cervix of 20 mm or less measured in the second trimester.

Preeclampsia with severe features: blood pressure of 160/110 mm Hg or higher, platelets below 100,000, creatinine above 1.1 mg/dL, transaminases twice normal, or pulmonary edema.

Shoulder dystocia maneuvers are performed in sequence: McRoberts position, suprapubic pressure, then internal rotation or delivery of the posterior arm.

RhD immune globulin: 300 mcg at 28 weeks and within 72 hours of delivery of an RhD-positive infant when the mother is RhD-negative and unsensitized.

Abnormal uterine bleeding is classified by the PALM-COEIN system: structural causes are polyp, adenomyosis, leiomyoma, malignancy; nonstructural are coagulopathy, ovulatory, endometrial, iatrogenic, not otherwise classified.

Cervical cancer screening: cytology every 3 years from age 21, or co-testing with HPV every 5 years from age 30; screening may stop at age 65 after adequate prior negative results.

Bacterial vaginosis diagnosis requires three of four Amsel criteria: homogeneous discharge, pH above 4.5, positive whiff test, and clue cells on microscopy.

Ectopic pregnancy: a discriminatory human chorionic gonadotropin zone of 3500 mIU/mL means an intrauterine gestational sac should be visible on transvaginal ultrasound.

Ovarian torsion presents with sudden unilateral pelvic pain and an enlarged ovary; detorsion with ovarian preservation is preferred over oophorectomy.

Contraceptive efficacy: the copper intrauterine device is effective for up to 10 years; the levonorgestrel 52 mg device is approved for up to 8 years.

Endometrial biopsy is indicated for abnormal uterine bleeding in women older than 45 years, or younger women with risk factors such as obesity or chronic anovulation.

Urinary tract infection in pregnancy is treated with a 3-7 day course of a beta-lactam; nitrofurantoin is avoided at term and trimethoprim is avoided in the first trimester.

Ovarian cancer staging: stage I is confined to ovaries, stage II involves pelvic extension, stage III involves peritoneal spread beyond the pelvis, and stage IV is distant metastasis including malignant pleural effusion.

Epithelial ovarian cancer first-line treatment is cytoreductive surgery plus platinum-taxane chemotherapy; BRCA mutation status guides maintenance with a PARP inhibitor.

Cervical cancer staging is clinical per FIGO; stage IB1 is a tumor of 2 cm or less, while stage IB2 exceeds 2 cm and up to 4 cm in greatest dimension.

Endometrial cancer: type I is estrogen-dependent, endometrioid, and typically grade 1-2; type II is serous or clear cell and carries a worse prognosis.

Gestational trophoblastic neoplasia after molar pregnancy is suggested by a plateau of human chorionic gonadotropin over three weeks or a rise over two weeks.

Vulvar cancer most commonly arises in the labia majora; squamous cell carcinoma accounts for the majority, and lymphatic spread follows the superficial inguinal nodes.

Tumor markers: CA-125 is used for epithelial ovarian cancer, alpha-fetoprotein for yolk sac tumors, and beta-human chorionic gonadotropin for choriocarcinoma.

Lynch syndrome screening in endometrial cancer uses immunohistochemistry for mismatch repair proteins, with referral for genetic testing when expression is lost.

Polycystic ovary syndrome is diagnosed by the Rotterdam criteria: two of three findings among oligo-ovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology.

Infertility evaluation begins after 12 months of unprotected intercourse, or 6 months when the woman is 35 years or older; semen analysis and ovulation assessment are first-line tests.

Ovulation induction with clomiphene citrate is started on cycle day 2-5 and monitored with midluteal progesterone above 3 ng/mL to confirm ovulation.

Ovarian reserve is assessed with antral follicle count and anti-Mullerian hormone; a value of 1.1 ng/mL or lower suggests diminished reserve.

Hypothalamic amenorrhea presents with low gonadotropins, low estradiol, and low body mass index; treatment is caloric restoration and pulsatile gonadotropin-releasing hormone when fertility is desired.

Premature ovarian insufficiency is loss of ovarian function before age 40, defined by amenorrhea for 4 months or more with follicle-stimulating hormone above 40 mIU/mL on two occasions.

Ovarian hyperstimulation syndrome is graded by ovarian enlargement, ascites, and hemoconcentration; severe disease includes hematocrit above 45 percent, oliguria, or thromboembolism.

Congenital adrenal hyperplasia from 21-hydroxylase deficiency presents with elevated 17-hydroxyprogesterone and is a cause of hyperandrogenic anovulation.