Introduction

Routine prenatal care labs and screening tests should be performed throughout pregnancy for all women to identify risk factors and initiate preventive care measures. Maintaining maternal health optimizes the success for positive pregnancy outcomes. Screening, treatment and documentation requirements per trimester are listed below.

Initial Visit

The initial visit optimally should occur in the first trimester. The following screening should be performed regardless of the gestational age at the initial visit:

1. Lab screening:

Blood type and Rh factor with antibody screening to identify isoimmunization. Patients found to be Rh negative should be rescreened in the second trimester and given RhoGAM at 28 weeks and again after delivery, if the infant is Rh positive.

Hct or Hgb Blood volume in pregnancy increases more than red cell volume and hematocrit typically falls. Therefore, Hct or Hgb levels should be monitored for anemia. A normal term pregnancy requires approximately 1 gm of iron, an amount often not adequately supplied in the diet. Anemia is often caused by iron-deficiency and should be treated with supplemental iron, taken in addition to routine prenatal vitamins. 

Rubella to determine if the mother is susceptible or immune. If susceptible, she should receive vaccination postpartum.

Varicella to determine if the mother is susceptible or immune. If susceptible, she should receive vaccination postpartum.

VDRL or RPR to check for serologic evidence syphilis so treatment can be initiated as soon as possible to avoid vertical transmission and the sequelae of congenital syphilis.

Gonorrhea and Chlamydia tests-to identify and treat infection.

Urine culture to identify and treat urinary tract infection, including asymptomatic bacteruria which is associated with an up to 25% risk of pyelonephritis if left untreated. 

Hepatitis B surface antigen to identify women whose infants need immunoprophylaxis post-delivery to minimize the risk of congenital infection and carrier status

Human immunodeficiency virus serology Antiretroviral therapy during gestation and around the time of delivery can decrease the risk of vertical transmission to less than 2%. HIV positive women should be counseled on the risks and benefits of treatment and mode of delivery.

Pap Smear Women 21 and older should have a pap smear performed, if not documented within the last year. The most recent ASCCP guidelines suggest that the risks of adverse events related to colposcopy and treatment with LEEP or CKC exceed the risks of invasive cancer in younger women, especially since these lesions are more likely the regress spontaneously.

Discussion of prenatal screening for chromosome abnormalities, genetic disease, and birth defects should be performed and documented in the patient’s medical record. Topics to be addressed include:

  • Prenatal Screening and Diagnostic Tests for chromosome abnormalities—options include first trimester screening, quad screen, and integrated/sequential screening. AFP alone is NOT an acceptable screening strategy for chromosome abnormalities.
  • AFP for neural tube defect screening.
  • Cystic fibrosis carrier screening—offered to Caucasians and discussed with other patients as they desire.
  • Hemoglobin electrophoresis for patients at risk of sickle cell trait, thalassemia, or other hemoglobinopathies—includes African American patients, patients of Mediterranean or Asian ancestry (Sickle prep or sickle dex is inadequate because it only screens for hemoglobin S).
  • Tay-Sachs, Canavan, and Familial Dysautonomia for patients of Eastern European Jewish ancestry
  • TB skin test for patients at risk—recent immigrants from developing countries, inmates, residents mental institutions or group homes.

2. History and physical:

Assessment of obstetric risk factors for adverse pregnancy outcomes including previous preterm birth, history of pre-eclampsia/eclampsia, history of gestational diabetes or macrosomic infant, previous C/S, history of IUGR infant. Plans for assessment of risk in this pregnancy and risk reduction strategies should be documented.

Smoking and substance abuse assessment and cessation counseling with follow up every trimester.Nicotine replacement therapy and quitline referral can be considered.

Immunization status and plan for vaccinations. See APEC immunization guideline #14 for additional information

  • Inactive Influenza vaccine-annual
  • Tdap at 27-36 weeks of gestation

Family history of congenital defects or disorders.

Family planning counseling.

Depression assessment scale.

Domestic violence screening.

Discussion of weight gain recommendations:

  • BMI <18.5: 28-40 lbs
  • BMI 18.5-24.9: 25-35 lbs
  • BMI 25.0-29.9: 15-25 lbs
  • BMI >30: 11-20 lbs

Discussion of feeding plans, breastfeeding experience and breast care.

3. Ultrasound

A first trimester crown-rump length measurement is the most accurate method of dating a pregnancy, except for those conceived with advanced reproductive technologies. Early establishment of certain dating criteria is vital in later management decisions such as screening windows, preterm labor management, and delivery timing.

Subsequent PNC Visits

At each prenatal care visit, routine assessments include: weight, blood pressure, urine dipstick results including glucose, albumin and ketones; after 10 weeks documentation of fetal heart rate via auscultation or US (see below); and after 20 weeks, documentation of fetal movement and fundal height.

Prenatal care visits should occur with the following frequency:

  • Prior to 20 weeks, ideally every 4 weeks but no less than every 6 weeks for lower-risk women
  • 20 to 28 weeks, every 4 weeks
  • 28 to 36 weeks, every 2-3 weeks, 3 weeks for lower-risk women
  • 36 weeks to delivery, at least every week

Urine dipstick for protein, glucose, and ketones should be performed at all prenatal visits. The lower socioeconomic status of our Alabama Medicaid population is a risk factor for many adverse pregnancy outcomes thus, routine urine dip testing during each prenatal visit is recommended. A baseline assessment of protein in the first trimester may play an important role in making a differential diagnosis. In addition, early pregnancy glycosuria may be an indicator of maternal glucose intolerance and should trigger consideration of early screening for gestational diabetes.

Fundal height measurements obtained after 20 weeks of gestation are a simple, effective screening test for fetal growth and amniotic fluid disturbances. When performed properly, the FH measurement in centimeters should approximate the gestational age in weeks. Guidelines for fundal height assessment:

  • Measure from the symphysis pubis to the top of the fundus
  • Centimeter measurement should be within 3 weeks of gestational age
  • If measurements differ >3 cm, ultrasound for fetal growth and fluid should be performed if normal fluid and growth have not been documented within the last 4 weeks.
  • In obese patients, assessment of fundal height is less reliable. In many obese women, the fundus cannot be clearly identified. Even in those in whom the fundus is identifiable, the pannus may distort or interfere with accurate measurement. Although the evidence suggests that a trend of repeated measurements in obese women remains fairly sensitive in identifying growth disturbances, the reproducibility of the measurement, especially when performed by different providers, is lacking. Therefore, in obese patients for whom the fundus cannot be reliably palpated (usually women with BMI >35), this should be documented in the prenatal chart and an alternative plan for screening for growth abnormalities outlined. In general a reasonable alternative is serial ultrasounds for fetal growth every 4-6 weeks beginning at 26-28 weeks.
  • Monitor maternal weight gain.
  • Query for contractions, leakage of fluid, and vaginal bleeding.

Second Trimester Assessments

1. Fetal Ultrasound

In general, all patients should ideally have a fetal  anatomic assessment performed at 17-20 weeks. While it is optimal to perform anatomy ultrasounds at an earlier GA, thus allowing the patient to maximize her reproductive options, the anatomy scans can occur between 17-22 weeks.

  • This time window optimizes the ability to accurately visualize fetal anatomy and provides adequate time for subspecialty consultation if abnormalities are visualized.
  • In patients with risk factors for fetal abnormalities, subspecialty consultation should be considered for patient counseling and fetal anatomic assessment.
  • If the initial anatomic assessment is normal, ultrasounds should be repeated only as clinically indicated. If an abnormality was visualized, the specific finding should dictate the need for further ultrasound evaluations.

2. Lab Screening

Maternal serum screening for chromosome abnormalities and neural tube defects should be offered at 15-20 weeks. See APEC Prenatal Screening for Fetal Birth Defects and Aneuploidy guideline #19 for additional information. Patient decisions regard uptake of testing should be noted in the chart

  • AFP alone is not an adequate screening test for chromosome abnormalities.

At 24-28 weeks:

  • Hct/Hgb for anemia.
  • Screening for gestational diabetes using either a two stage approach (50gm 1-hour oral glucose challenge test, followed by a 3-hour oral glucose tolerance test if abnormal). The two step approach provides better specificity and data cutoffs for predicting adverse obstetric outcomes. See APEC Gestational Diabetes Mellitus guideline #6 for additional information.
  • Earlier screening should be considered for women at increased risk of gestational diabetes including those with GDM or a macrosomic infant in a prior pregnancy, glycosuria, BMI>40
  • If Rh negative, repeat antibody screen and administer Rh-immune prophylaxis

3. Screening

Repeat Depression and domestic violence screening Women with evidence of depression in the antenatal period are at increased risk for a major depressive episode, including psychosis, in the post-partum period. Treatment of depressive symptoms prior to delivery can minimize this risk.

Repeat Smoking and Substance Abuse assessment and cessation counseling.

Breastfeeding intentions are greatly influenced by health care providers’ opinions and support.  Breast milk provides immunologic protection against infection. All women should be counseled on the nutritional advantages of human breast milk and encouraged to breastfeed their baby.  


Third Trimester Assessments

The lower socio-economic status of our Alabama Medicaid population is a risk factor for many adverse pregnancy outcomes including STD transmission.

1. Lab Screening

At 32-34 weeks:

  • Hct/Hgb
  • VDRL/RPR-given the high rate of endemic syphilis in Alabama, repeat this serologic in the 3rd trimester to identify those in whom infection may have occurred since the first trimester and in whom treatment is key to reduce the risks of congenital syphilis
  • Repeat Human Immunodeficiency Virus serology—patients at high risk for HIV acquisition should be rescreened because of the potential benefit of anti-retroviral therapy. Patients with multiple sexual partners and those who acquire STDs since the last time should be counseled and rescreened
  • Repeat Gonorrhea and Chlamydia tests-should be strongly considered.

At 35-37 weeks

  •  GBS culture Up to 20-25% of reproductive age women have colonization of their gastrointestinal or lower genital tract with Group B Streptococcus. GBS is a leading cause of early-onset neonatal sepsis and is highly lethal for those infected infants. Intrapartum treatment of colonized mothers with appropriate antibiotics will reduce the risk of vertical transmission substantially. All women should have an anovaginal culture performed at 35-37 weeks except for those in whom intrapartum treatment is already indicated—a) Prior child with GBS disease; b) urine culture this pregnancy with GBS bacteruria.

2. Screening

Repeat Depression and domestic violence screening.

Repeat Smoking and Substance Abuse assessment.

Continue breastfeeding discussion provide encouragement, education and support.

 

Quality Indicators/Benchmarks

 

Initial Visit Second Trimester Third Trimester
VDRL/RPR Fundal height after 20 wks Fundal Height
Urine Culture 17-22 wk anatomy scan VDRL/RPR
HIV 15-20 wk MSAFP & aneuploidy GBS screen

 

 


References

American College of Obstetricians and Gynecologists, ACOG Committee on Adolescent Health Care.

(2010, August). ACOG Committee Opinion No. 463: Cervical cancer in adolescents: screening, evaluation, and management. Retrieved February 14, 2010, from http://www.acog.org/About_ACOG/ACOG_Departments/Adolescent_Health_Care/Committee_Opinion__Human_Papillomavirus_Vaccination

American College of Obstetricians and Gynecologists, ACOG Committee on Genetics. (2005, October).

ACOG Committee Opinion No. 318: Screening for Tay-Sachs disease. Retrieved February 14, 2012 form http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Genetics/Screening_for_Tay_-_Sachs_Disease

American College of Obstetricians and Gynecologists, ACOG Committee Obstetric Practice. (2010,

February). ACOG Committee Opinion No. 453: Screening for depression during pregnancy. Retrieved February 14, 2012 form http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Screening_for_Depression_During_and_After_Pregnancy

American College of Obstetricians and Gynecologists, ACOG Committee Obstetric Practice. (2011,

September). ACOG Committee Opinion No. 504: Screening and diagnosis of gestational diabetes mellitus. Retrieved February 14, 2012 form http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Screening_and_Diagnosis_of_Gestational_Diabetes_Mellitus

American College of Obstetricians and Gynecologists, ACOG Committee on Obstetric Practice. (2011,

April). ACOG Committee Opinion No. 485: Prevention of early-onset group B streptococcal disease in newborns. Retrieved February 14, 2012 form http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Prevention_of_Early-Onset_Group_B_Streptococcal_Disease_in_Newborns

American College of Obstetricians and Gynecologists, ACOG Committee on Obstetric Practice. (2008,

September). ACOG Committee Opinion No. 418: Prenatal and perinatal human immunodeficiency virus testing: expanded recommendations. Retrieved February 14, 2012 form http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Prenatal_and_Perinatal_Human_Immunodeficiency_Virus_Testing_-_Expanded_Recommendations

American College of Obstetricians and Gynecologists, ACOG Committee on Obstetric Practice. (2008,

September). ACOG Committee Opinion No. 315: Obesity in Pregnancy. Retrieved February 14, 2012 form http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Obesity_in_Pregnancy

 

American College of Obstetrics and Gynecology, Guidelines for Prenatal Care 6th edition. (2007).

Retrieved May 5, 2012 from http://www.acog.org/Resources_And_Publications/Guidelines_for_Perinatal_Care

Queenan, J. T., Hobbins, J. C., Spong, C.Y. (Eds.). Protocol 5: Routine and Prenantal Screening. Protocols

 for High-Risk Pregnancies (5th ed.) (pp. 43-59, 60-61.) New Jersey: Wiley-Blackwell.

Weight Gain During Pregnancy: Reexamining the Guidelines . (2009). Retrieved February 14, 2012 from

Institute of Medicine of the National Academies Web site: http://www.iom.edu/Reports/2009/Weight-Gain-During-Pregnancy-Reexamining-the-Guidelines.aspx

Cunningham, F.G., Leveno, K. J., Bloom, S.L., Hauth, J.C., Rouse, D.J, Spong, C.Y. (2010). Williams

 Obstetrics(23rd ed.) (pp. 199-200, 1095, 1237-1238) New York: McGraw-Hill.

Initial Visit

Labs
Blood type and Rh factor GC/ Chlamydia
Antibody screening VDRL/RPR
HCT/HGB Urine culture
Pap smear age 21 and up HB S AG
Rubella & Varicella HIV
Other screening as clinically indicated: drug screen, TB skin test, Hgb electrophoresis, Tay-Sachs, Cystic fibrosis, familial dysautonomia

Assessment

  • History and physical exam
  • Family planning counseling
  • Assess and adapt care plan for risk factors (prior PTD or C/S, H/O GDM, H/O IUGR)
  • Immunizations: Flu (annual) & Tdap (27-36 weeks)
  • Smoking and substance abuse assessment and cessation counseling as indicated
  • Depression scale and domestic violence assessment
  • Ultrasound for dating
  • Discuss weight gain recommendations
  • Discuss screening for aneuploidy birth defects
  • Discuss risks associated with births prior to 39 weeks GA
  • Discuss feeding plans, encourage and promote breastfeeding

Subsequent PNC Visits

Assessment Each Visit:

  • Weight gain
  • Urine dip: glu/alb/ketones
  • Blood Pressure
  • FHR present/absent
  • Fetal move present/absent
  • Fundal height
  • Signs and symptoms of labor

Frequency of visits

  • Up to 20 wks q 4-6 wks (6 wks lower-risk)
  • 20 to 28 wks q 4 wks
  • 28 to 36 wks q 2-3 wks (3 wks lower-risk)
  • 36 wks to delivery q week

Second Trimester Assessments

  • 17-20(22) weeks-anatomy ultrasound
  • 15-20 weeks-MSAFP and aneuploidy screening
  • 24-28 weeks-Hct/Hgb
  • Diabetes screening-50gm OGTT
  • Glucose tolerance test if OGTT abnormal
  • Rh antibody screen if Rh negative
  • Rh-immune prophylaxis if indicated
  • 27-36 weeks Tdap
  • Repeat depression scale and domestic violence assessment
  • Repeat smoking and substance abuse assessment and cessation counseling as indicated
  • Provide breastfeeding encouragement, education and support
Weight gain recommendations
BMI‹18.5: 28-40 lbs
BMI 18.5-24.9: 25-35 lbs
BMI 25.0-29.9: 15-25 lbs
BMI >30: 11-20 lbs
Fundal ht guidelines
Symphysis pubis to top of fundus
≥ weeks cm = GA
GA and cm off>3 order US
BMI 36-40: sonar for growth @ 28 weeks followed by growth Ultrasound every 4-6 weeks.

 

Third Trimester Assessments

At 32-34 weeks

  • Repeat VDRL/RPR
  • GC and Chlamydia tests
  • Hct/Hgb
  • Repeat HIV

At 35-37 weeks

  • GBS culture
  • Depression scale and domestic violence assessment
  • Repeat smoking and substance abuse assessment
  • Ultrasound if clinically indicated
  • Provide breastfeeding encouragement, education and support

Quality Indicators/Benchmarks

Initial Visit 2nd Trimester 3rd Trimester
VDRL/RPR Fundal Height after 20 weeks Fundal Height
Urine culture 17-22 wk anatomy scan VDRL/RPR
HIV 15-20 wk MSAFP and aneuploidy screening GBS screening