Pregnancy

Essentials of Diagnosis

• Amenorrhea, weight gain, nausea and vomiting, and breast changes

• Positive pregnancy test

General Considerations

• Prompt diagnosis of pregnancy allows early prenatal care and avoidance of harmful activities or exposures

• In the event of an unwanted pregnancy, early diagnosis allows for counseling regarding options

Symptoms and Signs

• Amenorrhea, weight gain

• Nausea and vomiting

• Breast tenderness and tingling

• Urinary frequency and urgency

• "Quickening" (perception of the first fetal movement) is noted at about 18 weeks' gestation

• Signs

  • Breast changes, abdominal enlargement, and cyanosis of the vagina and cervical portio (week 7)

  • Softening of the cervix (week 7)

  • Generalized enlargement and softening of the corpus (post-week 8)

  • Uterine fundus is palpable above the pubic symphysis by 12–15 weeks from last menstrual period

  • Fundus reaches the umbilicus by 20–22 weeks

  • Fetal heart tones heard by Doppler at 10–12 weeks

Differential Diagnosis

• Myomas can be confused with a gravid uterus

• A midline ovarian tumor may displace a nonpregnant uterus

• Ectopic pregnancies may show lower levels of human chorionic gonadotropin (hCG) that level off or fall

• Premature menopause

Laboratory Tests

DIAGNOSTIC TESTS

• All urine or blood pregnancy tests rely on detection of placental hCG and are accurate at the time of a missed period or shortly after it

• Laboratory and home assays use monoclonal antibodies specific for hCG

• hCG levels increase shortly after implantation, double every 48 h (this rise can range from 30% to 100% in normal pregnancies), peak at 50–75 days, and fall in second and third trimesters

SCREENING AT THE TIME OF DIAGNOSIS

• The following are recommended

  • Urinalysis; culture of a mid-stream urine sample

  • Complete blood count (CBC)

  • Random blood glucose

  • Serologic test for syphilis

  • Rubella antibody titer

  • History of varicella

  • Blood group and Rh type

  • Antibody screening

  • Hepatitis B surface antigen testing

• HIV testing should be encouraged

• Women at increased risk for infection should be tested for Chlamydia trachomatis and Neisseria gonorrhoeae using a nucleic acid amplification test (NAAT) of a vaginal or/endocervical swab or first-catch urine

• Testing for abnormal hemoglobins should be done in patients at risk for sickle cell or thalassemia traits

• Tuberculosis skin testing is recommended for high-risk groups

• Screening for Tay-Sachs, Canavan disease, and familial dysautonomia should be offered to

  • Jewish women with Jewish partners (especially those of Ashkenazi descent)

  • Couples of French-Canadian or Cajun ancestry

• Hepatitis C screening should be offered to mothers at high risk

SCREENING DURING PREGNANCY

• In the first and second trimesters, aneuploidy screening should be offered to all women, ideally before 20 weeks gestation

• Noninvasive first trimester screening for Down syndrome includes ultrasonographic nuchal translucency and serum levels of PAPP-A (pregnancy-associated plasma protein A) and the free beta subunit of hCG

• In the second trimester, a "quad screen" blood test can be performed; it measures serum alpha-fetoprotein (msAFP), hCG, unconjugated estriol, and inhibin A

• Noninvasive testing with cell free fetal DNA from maternal plasma screens only for trisomy 13, 18, and 21

• Screening for gestational diabetes by checking glucose 1 h post a 50-g glucose load (26–28 weeks)

• 3-h glucose tolerance test follows up an abnormal 1-h glucose load test

• Repeat Rh testing for negative patients (28 weeks, though result is not required before Rho(D) Ig is given)

• CBC to evaluate for anemia of pregnancy (28–32 weeks)

• Repeat tests for syphilis, HIV, and cervical cultures in at-risk patients (36 weeks to delivery)

• Screening for group B streptococcal (GBS) colonization can be done by rectovaginal culture at 35–37 weeks

  • If negative, no prophylaxis is given

  • Intrapartum prophylaxis with penicillin or clindamycin is given if screening cultures are positive and organism is sensitive

  • Patients with risk factors for GBS or who deliver at < 37 weeks receive intrapartum prophylaxis

  • Patients without a culture at 35–37 weeks receive prophylaxis only for a history of GBS bacteriuria or prior GBS disease in an infant, intrapartum fevers, or membrane rupture > 18 h

Imaging Studies

• Radiographs should be avoided unless essential and approved by a physician and utilize shielding

• Fetal ultrasound for accurate dating and to evaluate fetal anatomy is usually done at 18–22 weeks' gestation

• In multiple pregnancies, ultrasound is repeated every 2–6 weeks to identify discordant growth

Medications

• Prenatal vitamins with iron and folic acid are indicated

• Medications should not be taken unless prescribed or authorized by the patient's provider (Table 19–1)

• For prophylaxis of group B streptococcal infection,

  • Penicillin G, 5 million units intravenously as a loading dose and then 2.5–3 million units intravenously every 4 hours until delivery

  • In penicillin-allergic patients not at high risk for anaphylaxis, 2 g of cefazolin intravenously as an initial dose and then 1 g intravenously every 8 hours until delivery

  • In patients at high risk for anaphylaxis, use vancomycin 1 g intravenously every 12 hours until delivery

  • After confirmed susceptibility testing of group B streptococcal isolate, clindamycin 900 mg intravenously every 8 hours until delivery

Therapeutic Procedures

• Genetic counseling with the option of chorionic villous sampling or amniocentesis should be offered to women 35 or older at delivery, a family history of congenital abnormalities, or previous child with a metabolic disease, chromosomal abnormality, or neural tube defect

Follow-Up

• Prenatal visits should be scheduled

  • Every 4 weeks from 4–28 weeks

  • Every 2 weeks from 28–36 weeks

  • Weekly from 36 weeks to delivery

Complications

• Fetal alcohol syndrome: no safe level of alcohol intake has been established for pregnancy

• Cigarette smoking increases risk of abruptio placentae, placenta previa, and premature rupture of the membranes

• Premature delivery and lower birth weights are more common in children born to smokers

• Maternal cocaine, amphetamine, and opioid use in pregnancy is associated with numerous complications

Prevention

• Decrease caffeine intake

• Avoid ingestion of raw meat, all tobacco, alcohol, and recreational drugs, exposure to environmental tobacco smoke, excessive heat, hot tubs, and saunas, and handling of cat feces or litter

• Regular exercise can be continued at a mild to moderate level

• Exercises that require a great deal of balance should be met with caution