Step 2 CK · Obstetrics & Gynecology

Common Complaints, Normal Changes & Acute Care in Pregnancy

Name: Common Complaints, Normal Changes & Acute Care in Pregnancy
Creator: Veli Bakalov, MD

What to leave alone, what to treat, and when pregnancy must never delay care

Obstetrics & Gynecology·Obstetrics·5 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

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Dilutional anemia is normal; anemia in pregnancy means Hb <11 g/dL in the first or third trimester (<10.5 in the second).
Fibrinogen, clotting factors, WBC and alkaline phosphatase rise normally, but raised transaminases or bilirubin always need evaluation.
GFR rises ~50%, so creatinine falls to ~0.5 mg/dL and a creatinine of ~1.0 mg/dL is abnormal.
Progesterone causes a compensated respiratory alkalosis (PaCO2 ~28–32 mm Hg); higher TBG raises total T4 while free T4 stays normal.
A soft systolic flow murmur, S3 and dependent edema are normal; a diastolic murmur needs echocardiography.
Nausea: ginger, then pyridoxine ± doxylamine; supine hypotension: left lateral position; acetaminophen rather than NSAIDs after 20 weeks.
Never withhold indicated imaging: plain films and most CTs deliver <50 mGy, and iodinated contrast is acceptable; avoid gadolinium and radioactive iodine.
After trauma, displace the uterus to the left, monitor the fetus for at least 4–6 hours for occult abruption, and give Rh-negative women anti-D with Kleihauer-Betke dosing.
Maternal arrest after ~20 weeks: perimortem cesarean at 4 minutes to deliver by 5; appendicitis and cholecystitis are operated on without delay.

Normal physiologic changes

Know what not to treat. Pregnancy reshapes nearly every laboratory value and exam finding. Knowing the expected changes prevents needless workups, and knowing their limits exposes real disease.

Normal changes and their red flags

System	Normal in pregnancy	Red flag
Blood	Plasma volume ↑40–50%, red cell mass ↑20–30% (dilutional anemia); WBC up to ~15,000/μL; platelets slightly lower	Hb <11 g/dL in the 1st or 3rd trimester, <10.5 in the 2nd
Coagulation	↑Fibrinogen and factors VII, VIII, IX, X; ↓protein S; ↑ESR and D-dimer	Fibrinogen <200 mg/dL late in pregnancy (abruption, DIC)
Kidney	GFR ↑~50%; creatinine ~0.5 mg/dL; mild glycosuria; right-sided hydronephrosis	Creatinine ~1.0 mg/dL or higher
Liver	↑Alkaline phosphatase (placental); ↓albumin	Raised transaminases, bilirubin or GGT
Lungs	↑Tidal volume and minute ventilation, ↓FRC; PaCO2 ~28–32 mm Hg, HCO3 ~18–22 mEq/L	PaCO2 ~40 mm Hg in a distressed patient
Thyroid	↑TBG, so total T4 and T3 rise; free T4 normal; TSH dips in the 1st trimester	Abnormal free T4
Heart	Cardiac output ↑30–50%, heart rate ↑10–20 bpm, ↓SVR; soft systolic flow murmur, S3, dependent edema	Diastolic or loud systolic murmur, syncope, orthopnea (echocardiogram)

Mechanisms worth knowing. Progesterone stimulates the respiratory center, raising tidal volume rather than rate, and the lower maternal PaCO2 helps the fetus offload CO2; physiologic dyspnea is common and alone needs no workup. Estrogen raises thyroxine-binding globulin, and hCG, which shares its α-subunit with TSH, weakly stimulates the TSH receptor, so the high total T4 needs no treatment. The hypercoagulable shift protects against delivery hemorrhage but raises VTE risk about 4–5-fold, most of all postpartum, and rising ESR and D-dimer lose much of their diagnostic value.

A creatinine of 1.0 mg/dL, normal in a nonpregnant woman, reflects meaningful loss of renal function in pregnancy.

Common complaints

Common complaints and first-line care

Complaint	Cause	Management
Nausea and vomiting	Peaks at 8–12 weeks, settles by 16–20	Small frequent bland meals, ginger → pyridoxine ± doxylamine → antihistamines, metoclopramide or ondansetron
GERD	Progesterone relaxes the lower esophageal sphincter	Small meals, head-of-bed elevation, calcium carbonate → H2 blocker or PPI
Constipation, hemorrhoids	Slowed transit, iron supplements, venous congestion	Fiber, fluids, psyllium, docusate, polyethylene glycol, sitz baths
Round ligament pain	Ligament stretch with sudden movement, often 18–24 weeks	Reassurance, heat, acetaminophen
Back pain	Lordosis, relaxin-driven ligamentous laxity	Exercise, posture, physical therapy, heat
Leg cramps	Nocturnal calf spasm, late pregnancy	Stretching, massage
Carpal tunnel	Fluid retention compresses the median nerve	Night wrist splint; usually resolves after delivery
Varicosities (legs, vulva)	Venous pressure, progesterone venodilation	Elevation, compression stockings
Supine hypotension	Uterus compresses the IVC and aorta after ~20 weeks: dizziness, pallor, hypotension, fetal bradycardia	Left lateral decubitus position

Hyperemesis gravidarum. Persistent vomiting with weight loss >5%, ketonuria and electrolyte disturbance (hypokalemic metabolic alkalosis) requires IV fluids, electrolyte repletion and thiamine before dextrose to prevent Wernicke encephalopathy; look for a molar or multiple pregnancy.

Acetaminophen is the analgesic of choice. Avoid NSAIDs from 20 weeks, when they can impair fetal renal function and cause oligohydramnios, and especially after 30 weeks, when they can close the ductus arteriosus prematurely.

Imaging and contrast

<50 mGyfetal dose with no increase in anomalies, growth restriction or loss

8–15 weekspeak fetal CNS sensitivity, at doses far above diagnostic imaging

Choose, but do not withhold. Ultrasound and MRI without gadolinium carry no known fetal risk and are preferred when they can answer the question. Plain films deliver trivial fetal doses and most CT scans stay below 50 mGy, so an indicated radiograph or CT is never withheld because of pregnancy. Iodinated contrast crosses the placenta but has shown no teratogenic or clinically significant fetal thyroid effects, so it is used when needed. Gadolinium is avoided unless essential, and radioactive iodine is contraindicated because the fetal thyroid concentrates iodine after about 10–12 weeks. Breastfeeding continues after either contrast agent.

Trauma and cardiac arrest

Mother first. Maternal resuscitation is fetal resuscitation. Pregnancy's hypervolemia can hide the loss of about 30–35% of blood volume before tachycardia and hypotension appear, while the uterine circulation is already constricted, so fetal distress may be the first sign of maternal shock.

Primary surveyAirway, oxygen, two large-bore IVs; manual left uterine displacement after ~20 weeks
Secondary surveyFundal height, uterine tenderness, contractions, vaginal bleeding or fluid; ultrasound for viability and placenta
Fetal monitoringContinuous tracing and contraction monitoring for at least 4–6 hours, longer with contractions, bleeding, tenderness or an abnormal tracing
Rh-negative patientAnti-D immune globulin within 72 hours; Kleihauer-Betke sizes the dose

Occult abruption and Rh. Even minor blunt trauma can shear the inelastic placenta off the elastic myometrium, and ultrasound often misses abruption, so frequent contractions or a nonreassuring tracing during monitoring are the clues. The Kleihauer-Betke test measures fetal cells in maternal blood to decide whether more than the standard 300-μg anti-D dose (covering about 30 mL of fetal whole blood) is needed; it does not diagnose abruption. Teach correct seatbelt use (lap belt low across the hips below the uterus, shoulder belt between the breasts) and screen every injured pregnant woman for intimate partner violence.

Maternal cardiac arrest. With the fundus at or above the umbilicus (about 20 weeks), standard ACLS (usual drugs, doses and shocks) proceeds with manual left uterine displacement. If circulation has not returned by 4 minutes, perimortem cesarean begins where the patient lies, aiming for delivery by 5 minutes. Emptying the uterus relieves aortocaval compression and restores venous return, which mainly helps the mother, and early delivery also improves neonatal survival.

Acute surgical problems

The rule. Indicated surgery is never denied or delayed because of pregnancy, whatever the trimester; purely elective operations wait until after delivery, and nonurgent ones are ideally done in the second trimester. Standard anesthetic agents are not teratogenic at clinical doses.

Appendicitis. This is the most common nonobstetric surgical emergency in pregnancy. The enlarging uterus pushes the appendix upward, so late in pregnancy the pain may sit in the right flank or right upper quadrant, and physiologic leukocytosis blunts the WBC. Graded-compression ultrasound comes first, MRI without gadolinium if it is nondiagnostic, and CT if MRI is unavailable. Prompt appendectomy follows, because perforation sharply raises fetal loss.

Gallbladder disease. Estrogen-driven cholesterol secretion and progesterone-slowed emptying make gallstones common. Acute cholecystitis is treated with cholecystectomy in any trimester, laparoscopy is safe, and choledocholithiasis is managed with ERCP.