Summary
Nausea and vomiting are common conditions of pregnancy and are typically treated with hydration and nonpharmacologic methods. If nausea is refractory to nonpharmacologic methods, antiemetics should be started and added in a step-wise fashion. Hyperemesis gravidarum is a severe form of nausea and vomiting of pregnancy characterized by ketonuria and weight loss, and typically requires inpatient admission, intravenous fluid hydration, and antiemetic therapy. Cervical insufficiency refers to painless cervical dilation that occurs in the absence of uterine contractions and/or labor, usually in the second trimester of pregnancy, and that may require cervical cerclage. Other maternal complications of pregnancy include peripheral edema, gestational thrombocytopenia, and gestational diabetes.
Nausea and vomiting of pregnancy (uncomplicated)
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Epidemiology
- Occurs in up to 90% of pregnancies
- Onset at 5–6 weeks' gestation
- Peaks at 9 weeks' gestation
- Usually abates by 16–20 weeks' gestation
- Risk factors
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Clinical features
- Nausea and/or vomiting
- Normal vital signs, lab findings, and normal physical examination
- Differential diagnosis: See the differential diagnosis of nausea and vomiting.
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Treatment [1][2][3][4]
- Rehydration (oral hydration is usually sufficient)
- Nonpharmacologic options
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Antiemetic therapy for nausea and vomiting of pregnancy: If the response to an antiemetic from one class is inadequate, add an antiemetic from another class in a stepwise manner, as shown below. [2][5]
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Pyridoxine (vitamin B6) and/or doxylamine
- Oral pyridoxine (Vitamin B6)
- Oral doxylamine
- Oral pyridoxine/doxylamine combination
- For refractory symptoms, add one of the following:
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For refractory symptoms despite combination therapy above, add one of the following:
- Metoclopramide
- Ondansetron
- Promethazine
- Consider also:
- Change oral dimenhydrinate to IV.
- Trimethobenzamide
- Last resort; : Add chlorpromazine or methylprednisolone.
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Pyridoxine (vitamin B6) and/or doxylamine
- Thiamine repletion (in patients with severe recurrent vomiting)
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Acute management checklist for uncomplicated nausea and vomiting of pregnancy
- Rule out alternate etiologies (see differential diagnosis of nausea and vomiting).
- Identify and treat dehydration (see IV fluids).
- If dehydration is present, check urine ketones and serum electrolytes to rule out hyperemesis gravidarum.
- Electrolyte and thiamine repletion (in patients with severe recurrent vomiting)
- Trial nonpharmacologic options (e.g., dietary changes, ginger tea/capsules)
- Replace iron-containing supplements with folate-containing prenatal vitamins.
- Start pyridoxine and/or doxylamine.
- For refractory emesis, add antiemetic therapy in a stepwise manner (see above).
- Consider OB/GYN consult.
In pregnant women, a thorough history, examination, and, if necessary, diagnostics are essential to rule out potential causes of nausea and vomiting that are not pregnancy-related.
Because antiemetics are potentially teratogenic, their use should be considered only if nausea and vomiting are refractory to dietary changes and supportive therapy.
Hyperemesis gravidarum
- Definition: : severe, persistent nausea and vomiting associated with a > 5% loss of pre-pregnancy weight and ketonuria with no other identifiable cause [2]
- Risk factors
- Clinical features: nausea, vomiting, physical signs of dehydration, hypersalivation, orthostatic hypotension, malnourishment
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Diagnosis
- Clinical diagnosis
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Laboratory analysis
- Electrolyte disturbances: hypokalemia and hypochloremic metabolic alkalosis or metabolic acidosis [6]
- Signs of dehydration (e.g., ↑ hematocrit)
- Ketonuria
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Treatment:
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Antiemetic therapy: See antiemetic therapy for nausea and vomiting of pregnancy. [2]
- May require glucocorticoid therapy (see stepwise approach above)
- IV fluid resuscitation/replacement (see IV fluid therapy)
- Electrolyte and thiamine repletion
- Enteral feeding or TPN is recommended in patients with persistent symptoms and weight loss despite antiemetic therapy. [2]
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Antiemetic therapy: See antiemetic therapy for nausea and vomiting of pregnancy. [2]
- Complications [7][8]
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Acute management checklist for hyperemesis gravidarum [1][2][3][4]
- Rule out alternate etiologies (see differential diagnosis of nausea and vomiting).
- Identify and treat dehydration (see IV fluids).
- Thiamine repletion
- Electrolyte repletion
- IV antiemetic therapy (see antiemetic therapy for nausea and vomiting of pregnancy)
- Consider enteral tube feeding (nasogastric/nasoduodenal) or TPN.
- Closely monitor vitals and urine output.
- Monitor urine ketones, BMP, and body weight daily.
- Inpatient admission
- Consult OB/GYN.
Cervical insufficiency
- Definition: painless cervical dilation, in the absence of uterine contractions and/or labor, in the second trimester of pregnancy
- Etiology: Most cases are idiopathic.
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Risk factors [9]
- Previous mid-trimester pregnancy loss and/or preterm birth
- Previous obstetric or gynecological trauma (e.g., termination of pregnancy, rapid delivery, multiple gestations, or cervical conization)
- Cervical connective tissue weakness (e.g., Ehler-Danlos syndrome)
- Diethylstilbestrol exposure
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Clinical features
- Painless cervical dilation with or without prolapsed membranes
- Nonspecific findings
- Pelvic cramps or backache
- ↑ Volume, changed color (yellow or blood-stained), and/or thinner consistency of vaginal discharge
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Diagnosis [9]
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Clinical diagnosis typically before 24 weeks' (may be up to 28 weeks') gestation
OR - History of ≥ 2 previous mid-trimester pregnancy losses or ≥ 3 preterm births not explained by any other cause, and a transvaginal ultrasound cervical length < 25 mm before 24 weeks' gestation (short cervical length)
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Clinical diagnosis typically before 24 weeks' (may be up to 28 weeks') gestation
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Management [10]
- Serial cervical ultrasound monitoring should be commenced in high-risk women (i.e., previous preterm birth) between 16–24 weeks' gestation.
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Cervical cerclage [11][12]
- Definition: placement of a supportive suture in the cervicovaginal junction to prevent early pregnancy loss or preterm birth
- Methods
- McDonald cerclage: a removable suture in the cervix that allows vaginal delivery; Removal is indicated between 36–37 weeks' gestation, before the onset of spontaneous labor.
- Shirodkar cerclage: a permanent suture placed that is placed in the cervical submucosal tissue; Cesarean delivery is necessary.
- Timing: < 24 weeks gestation; most commonly performed at 13–16 weeks gestation
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Indications: only in singleton pregnancies
- Multiple previous preterm births or pregnancy losses in the second trimester
- A previous preterm birth and current ultrasound diagnosis of a shortened cervix (cervix length < 25 mm) at < 24 weeks gestation
- Cervical dilation on inspection at < 24 weeks gestation
- Prior cerclage due to cervical insufficiency at < 24 weeks gestation
- Contraindications
- Preterm labor
- Premature rupture of membranes
- Chorioamnionitis or vaginal infection
- ≥ 24 weeks' gestation
- Unexplained vaginal bleeding
- Multiple gestations
- Progesterone supplementation (vaginal or intramuscular): indicated for a short cervical length at < 24 weeks' gestation in the absence of a previous preterm birth
- Strict bed rest is not recommended.
A shortened cervical length alone is not sufficient to diagnose cervical insufficiency.
Other complications
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Supine hypotensive syndrome: Compression of the vena cava and pelvic veins by the uterus may occur during the third trimester of pregnancy (typically >20 weeks) as a result of the mother lying in a supine position.
- Gravid uterus → compression of the abdominal aorta and IVC → impaired venous return and decrease in cardiac output → placental hypoperfusion → fetal hypoxia → deceleration (CTG)
- After repositioning the mother in the left lateral position, the fetal heart rate recovers.
- In the mother, supine hypotensive syndrome is characterized by tachycardia, dizziness, and nausea, and occasionally causes syncope.
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Peripheral edema
- Very common, benign finding
- Management
- Rule out DVT and preeclampsia
- Monitoring; usually no treatment necessary
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Musculoskeletal pain
- Lower back pain: increased lumbar lordosis caused by relaxation of the ligaments supporting the joints of the pelvic girdle in preparation for childbirth
- Carpal tunnel syndrome (caused by peripheral edema; usually resolves after delivery)
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Gestational thrombocytopenia [13]
- A benign condition characterized by moderate thrombocytopenia (130,000–150,000/mm3)
- If thrombocytopenia is more severe, other etiologies should be investigated.
- Does not require management
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Cephalopelvic disproportion: The fetal size is disproportionately large for the maternal pelvis.
- Can result in a prolonged second stage of labor
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Others
- Hypertensive pregnancy disorders
- Gestational diabetes
- Gastrointestinal reflux
- Bleeding during pregnancy
- Placenta praevia
- Pregnancy luteoma
- Polymorphic eruption of pregnancy
