ABPS Obstetrics & Gynecology cheat sheet

Estimated due date (EDD) by Naegele's rule: first day of last menstrual period + 280 days.

First-trimester ultrasound (crown-rump length) is the most accurate method for dating pregnancy (accurate to ±5–7 days).

Group B Streptococcus (GBS) screening: vaginal-rectal swab at 36 0/7–37 6/7 weeks; intrapartum antibiotic prophylaxis for positive carriers, preterm labor, prolonged rupture of membranes ≥18 hours, or intrapartum fever ≥38.0°C.

Active phase of labor begins at 6 cm dilation; arrest of active phase is ≥6 cm dilation with ruptured membranes and no cervical change ≥4 hours of adequate contractions or ≥6 hours with inadequate contractions.

Postpartum hemorrhage definition: cumulative blood loss ≥1000 mL or blood loss with signs/symptoms of hypovolemia within 24 hours after birth.

Uterine atony is the most common cause of postpartum hemorrhage; initial management includes uterine massage, oxytocin, and uterotonics (e.g., methylergonovine, carboprost, misoprostol).

Magnesium sulfate for preeclampsia/eclampsia: 4–6 g IV loading dose over 15–20 min, then 1–2 g/hour maintenance; monitor reflexes, respiratory rate, and urine output; calcium gluconate is the antidote for toxicity.

Shoulder dystocia management: McRoberts maneuver and suprapubic pressure are first-line; avoid fundal pressure and excessive traction.

Preeclampsia without severe features: blood pressure ≥140/90 mmHg on two occasions ≥4 hours apart after 20 weeks gestation plus proteinuria (≥300 mg/24h or protein/creatinine ratio ≥0.3) or other maternal organ dysfunction; severe features include BP ≥160/110, platelets <100,000, elevated liver enzymes, pulmonary edema, or new cerebral/visual symptoms.

Preeclampsia with severe features at ≥34 weeks gestation: recommend delivery; at <34 weeks, expectant management may be considered if maternal and fetal status are reassuring.

Gestational diabetes screening: 50-g glucose challenge test at 24–28 weeks; diagnostic 100-g 3-hour OGTT uses Carpenter-Coustan or NDDG criteria.

Fetal heart rate category II includes baseline 110–160 bpm with moderate variability but with recurrent variable decelerations or late decelerations; category III includes absent variability with recurrent late/variable decelerations or bradycardia.

RhD immune globulin (300 mcg) at 28 weeks and within 72 hours postpartum if infant is RhD positive; also for antepartum bleeding, amniocentesis, or external cephalic version.

Preterm birth prevention: vaginal progesterone for singleton pregnancy with short cervix (≤25 mm) at 16–24 weeks; cerclage for history of preterm birth with short cervix or cervical insufficiency.

Magnesium sulfate for fetal neuroprotection: consider for imminent preterm birth <32 weeks; dosing typically 4 g IV load then 1 g/hour until delivery.

Twin-twin transfusion syndrome (TTTS) diagnosis: oligohydramnios (deepest vertical pocket ≤2 cm) in donor and polyhydramnios (DVP ≥8 cm) in recipient; treatment is fetoscopic laser photocoagulation.

Cervical cancer screening: start at age 21 with cytology every 3 years; age 30–65 can have cytology every 3 years, HPV testing every 5 years, or co-testing every 5 years.

Abnormal uterine bleeding in reproductive-age women: first evaluate pregnancy (urine/serum hCG) and then use PALM-COEIN classification for etiology.

Bacterial vaginosis: Amsel criteria (≥3 of: homogeneous discharge, clue cells, pH >4.5, positive whiff test); treatment is metronidazole or clindamycin.

Vulvovaginal candidiasis: pruritus, thick white discharge, pH <4.5; treat with topical azoles or single-dose oral fluconazole (avoid in pregnancy).

Endometriosis: dysmenorrhea, dyspareunia, chronic pelvic pain; definitive diagnosis by laparoscopy; first-line treatment includes NSAIDs and combined hormonal contraceptives.

Polycystic ovary syndrome (PCOS) Rotterdam criteria: ≥2 of oligo/anovulation, clinical/biochemical hyperandrogenism, polycystic ovaries on ultrasound.

Menopause diagnosis: 12 months of amenorrhea in a woman ≥45 years without other causes; hormone therapy is the most effective treatment for vasomotor symptoms.

Osteoporosis screening: DXA for women ≥65 years or younger with risk factors (e.g., prior fracture, low body weight, smoking).

Endometrial cancer is the most common gynecologic malignancy; risk factors include obesity, unopposed estrogen, tamoxifen, and Lynch syndrome; postmenopausal bleeding is the classic presentation.

Ovarian cancer: most common histologic type is epithelial (serous); CA-125 is used for monitoring, not screening; risk-reducing salpingo-oophorectomy for BRCA1/2 carriers.

Cervical cancer staging (FIGO 2018) includes clinical examination and imaging; stage IB1 is ≤2 cm with stromal invasion >5 mm; treatment for early stage is surgery or radiation.

Vulvar cancer: most common type is squamous cell carcinoma; treatment is wide local excision with inguinal lymph node evaluation; HPV and smoking are risk factors.

Gestational trophoblastic neoplasia: persistent elevated β-hCG after molar pregnancy; treatment is chemotherapy (methotrexate for low-risk, EMA-CO for high-risk).

Ovarian cancer screening: no effective screening for average-risk women; transvaginal ultrasound and CA-125 are not recommended for screening.

Lynch syndrome: associated with endometrial and ovarian cancer; screening with immunohistochemistry for mismatch repair proteins on tumor tissue.

Chemotherapy-induced nausea and vomiting: use 5-HT3 antagonist plus dexamethasone plus NK1 antagonist for highly emetogenic regimens.

Infertility definition: failure to achieve pregnancy after 12 months of regular unprotected intercourse (6 months if female age ≥35).

Ovulation induction first-line for anovulatory infertility (e.g., PCOS): letrozole is preferred over clomiphene citrate.

Clomiphene citrate mechanism: selective estrogen receptor modulator; anti-estrogenic at hypothalamus, increasing GnRH and gonadotropin release; risk of multiple gestation and ovarian hyperstimulation syndrome (OHSS).

Ovarian hyperstimulation syndrome (OHSS): enlarged ovaries, hemoconcentration, ascites, electrolyte imbalance; prevention with low-dose gonadotropins, GnRH antagonist protocol, and GnRH agonist trigger in high-risk patients.

Primary ovarian insufficiency: amenorrhea ≥4 months with FSH >25 IU/L on two occasions ≥4 weeks apart in women <40 years.

Luteal phase defect: short luteal phase or inadequate progesterone; treatment with progesterone supplementation.

Endometriosis-associated infertility: surgical ablation/excision improves spontaneous pregnancy rates; IVF for severe disease.

Male factor infertility: semen analysis is the first test; referral for urology if abnormal; ICSI for severe male factor.

Stress urinary incontinence (SUI): leakage with increased intra-abdominal pressure (cough, sneeze); first-line treatment is pelvic floor muscle training; surgical options include midurethral sling and Burch colposuspension.

Overactive bladder (OAB): urgency, frequency, nocturia with or without urge incontinence; first-line treatment is behavioral therapy plus bladder training; second-line pharmacotherapy (antimuscarinics or beta-3 agonist).

Pelvic organ prolapse quantification (POP-Q) system: points Aa, Ba, C, D, Ap, Bp, gh, pb, tvl; stage 0 = no prolapse, stage IV = complete eversion.

Anterior compartment prolapse (cystocele) is the most common type of pelvic organ prolapse; posterior (rectocele) and apical (uterine/vault) also occur.

Pessary use: ring or Gellhorn for prolapse; follow-up every 3–6 months for vaginal erosion; local estrogen for atrophy.

Urodynamic testing: indicated for complex incontinence, prior surgery, or suspected detrusor overactivity; not required before first-line treatment.

Sacral neuromodulation: for refractory OAB or fecal incontinence; test phase with temporary lead, then permanent implant.

Perioperative care in urogynecology: vaginal estrogen before surgery for atrophy; antibiotic prophylaxis for mesh implantation.

Antibiotic prophylaxis for hysterectomy: first-generation cephalosporin (cefazolin) within 60 minutes before incision; add metronidazole for vaginal hysterectomy.

Venous thromboembolism (VTE) prophylaxis: use Caprini score; mechanical prophylaxis for moderate risk, pharmacologic (e.g., heparin) for high risk; early ambulation.

Enhanced recovery after surgery (ERAS) principles: preoperative counseling, carbohydrate loading, opioid-sparing multimodal analgesia, early feeding, and early mobilization.

Laparoscopic entry: Veress needle or open (Hasson) technique; Palmer's point for obese patients or suspected adhesions.

Hysterectomy approaches: vaginal, laparoscopic, abdominal; minimally invasive preferred when feasible; morcellation requires containment for suspected malignancy.

Postoperative fever workup: atelectasis (most common early), urinary tract infection, wound infection, deep vein thrombosis, and abscess; evaluate with history, exam, urinalysis, and imaging.

Surgical site infection prevention: chlorhexidine-alcohol skin prep, maintain normothermia, supplemental oxygen, and glucose control.

Bowel preparation: not routinely needed for benign gynecologic surgery; mechanical bowel prep may be considered for extensive endometriosis or malignancy.

USPSTF breast cancer screening: biennial mammography for women 50–74 years; individualized decision for 40–49 years.

USPSTF cervical cancer screening: cytology every 3 years for ages 21–29; for ages 30–65, cytology every 3 years, HPV testing every 5 years, or co-testing every 5 years.

USPSTF colorectal cancer screening: start at age 45 for average-risk adults; options include colonoscopy every 10 years or stool-based tests.

Immunizations: Tdap during each pregnancy (27–36 weeks); HPV vaccine for ages 9–26 (catch-up to 45); annual influenza vaccine.

Osteoporosis screening: DXA for women ≥65 years; for younger postmenopausal women with risk factors (e.g., low body weight, prior fracture).

Informed consent: must include diagnosis, nature of procedure, risks, benefits, alternatives, and consequences of refusal; patient must have decision-making capacity.

Confidentiality: HIPAA permits disclosure for treatment, payment, and operations; exceptions for public health reporting, imminent danger, and court orders.

Mandatory reporting: suspected child abuse, elder abuse, and certain communicable diseases; report to appropriate authorities.