Pre-Natal Care
last authored: Sept 2009, David LaPierre
Introduction
While the primary objective of pre-natal care is to reduce maternal and fetal morbidity and mortality, it is also a unique opportunity to see women regularly and impact their health long term.
Prenatal care includes education, preventive health care, and identification and mitigation of risks to mother and child. Prenatal care can be provided by a number of individuals, including family doctor, nurse practitioner, obstetrician, midwife, or a combination of these.
Identifying Pregnancy
Signs of pregnancy include absence of menstrual period, breast tenderness and fullness, fatigue, nausea, and urinary frequency.
Biochemical testing is done by detecting the beta subunit of the human chorionic gonadotropin (hCG) in urine or blood. Home testing has a sensitivity of 75%, while clinical laboratory testing has a sensitivity between 97-100% for both blood and urine.
False-negative results usually follow testing too close to ovulation.
The Initial Visit
The initial visit should occur within 12 weeks of the LMP, or earlier if the pregnancy is higher risk. It includes a complete history, physical examination, appropriate lab investigations, and counselling.
- History
- Physical Exam
- Lab Investigations
- Counselling
History
Begin with personal and demographic information to learn more about the flavour of the person in front of you.
Menstrual history
- LMP to determine gestational age
- period duration, regularity, severity
- menarche
History of current pregnancy
- confirm gestational age (LMP, ultrasound)
- prenatal vitamins: esp. folic acid
- bleeding/spotting/discharge
- nausea/vomiting
- fever
- substance use
- occupational and environmental hazards
Past obstetrical history
Pregnancy history (ie G4P2A1)
gravida: number of pregnancies
parity: number of deliveries over 20 weeks,
regardless of outcome (twins, triplets, etc = 1)
abortion: number of deliveries under 20 weeks;
can be spontaneous or therapeutic
- year, sex, weights, modes of deliveries, GAs, length of labour
- losses, complications, preterm
- gestational diabetes and pregnancy-induced hypertension
- previous cesarean section(s) (importantly, type of uterine scar is present)
- need for induction/augmentation, epistiotomy
- laceration
- baby size and concerns (NICU admissions)
- breastfeeding
Past medical history and review of systems (optimize treatments)
- gynecologic history (Paps, cervical abnormalities, cone biopsy, LEEP)
- hypertension
- diabetes
- infection, especially STIs
- thyroid
- depression
- eating disorders
- nausea and vomiting in pregnancy thus far
- bleeding
- drugs, alcohol
- nutrition
- ethnicity
- social issues: ie financial concerns
Medications
- prescription and nonprescription drugs
- synthroid; dose may need to decrease (I think) during pregnancy
- "fluroquinolones hurt attachments to the bones" (cartilage)
Immunizations
- varicella (congenital varicella can be extremely damaging); do not use the live vaccine
- rubella
Family medical and genetic history
- miscarriages
- multiple gestation
Social history
- nutrition
- physical fitness
- smoking history
- supports
- domestic violence
- work
- finances
While risk assessments can be done to determine health provider(s) involved in care, this has not been proven to benefit mother or baby and may in fact lead to unnecessary consultations or interventions.
Physical Exam
Physical exam is done to ensure current maternal health and predict any potential problems with the pregnancy.
- weight, BMI, and blood pressure: important for interpreting subsequent values
- pelvic exam, both with speculum and bimanually, to assess uterine size and architecture
- head and neck exam (thyroid)
- breast exam
- heart and lungs
- extremities (varicosities, swelling)
- if appropriate, auscultate fetal heart (about 12 weeks onwards)
Lab Investigations
All tests should be done for reasons.
Routine investigations include:
- CBC (anemia, thrombocytopenia)
- ABO/Rh typing and antibody screening
- rubella, syphilis, hepatitis B, HIV testing
Other inital tests include:
- pap testing
- cervial smears for N. gonorrhea and Chlamydia
- urine dipsticks for proteinuria and glycosuria
Urinanalysis is done, though dipsticks will miss up to 25% of asymptomatic bactiuria (ASB). Urine culture should be done between 12-16 weeks, as this detects 80% of women with ASB during pregnancy. ASB occurs in 2-7% of pregnant women and can lead to pyelonephritis, low birth weight, and preterm delivery (Bachman et al, 1993).
Counselling
Counselling should include avoidance of smoke, alchol, and other drugs, as well as the need to eat a balanced diet.
Exercise:
Nutrition
Weight gain
Work
Travel
Intercourse
Social issues
Smoking
Alcohol
Genetic screening
Referral to perinatal classes should be offered.
Discussion about mode of delivery (vaginal, cesarean, VBAC)
Subsequent visits
Subsequent visits should occur every 4-6 weeks until 28 weeks, every 2 weeks until 36 weeks, and every week thereafter.
- History
- Physical Exam
- Lab Investigations
History
Estimate GA.
Inquire as to
- nausea/vomiting
- cramping/contractions
- bleeding/spotting; other discharge
- fetal movements
- smoking
educational needs
- heartburn
- constipation
- hemorrhoids
- sexuality
- circumcision
- what is to come, ie labor, possibility of cesarian section
- flu vaccine (not currently funded for healthy pregnant women)
- toxoplasmosis: kitty litter and gardening
concerns re: food, shelter, abuse, finances
Physical Exam
- weight
- blood pressure
- symphysis-fundal height
- fetal position, lie, and presentation (especially after 32 weeks)
- fetal heart rate
Lab Investigations
urine dip for protein (kidney function) and glucose (gestational diabetes)
group B strep - some debate about utility of universal screening, though is now recommended by SOGC at 35-37 weeks
Antenatal Screening - 24-28 weeks
- all women should be offered a diabetic screen and repeat HgB
- HIV testing may be reoffered
- women who are Rh- should have a repeat antibody screen if partner is Rh+ or unknown
Genetic Screening
Screening is now carried out for mothers who want information about potential conditions the fetus may have, depending on risk factors. Maternal serum testing should be offered to all women, and those at risk of significant congenital abnormalities should also be referred to Fetal Assessment and Treatment Centre for Early Pregnancy Review (EPR).
- women 35 years and older
- family history of inherited disease or congenital abnormalities
- women or their partners who are African, Asian, Hispanic, Mediterranean, or Middle Eastern are screened for hemoglobinopathies such as thalassemia or sickle cell disease
- women who are Ashkenazi Jewish, Yarmouth County Acadian, Bas-St-Laurent or Saguenay-Lac-St-Jean French should be offered screening for Tay Sachs Disease or Niemann Pick C disease
Early Ultrasound
- 11-14 weeks
- offered to those who are at increased risk, ie mothers over 35
- confirms viability and gestational age
- assesses number of fetuses
- allows measurement of nuchal translucency
First trimester biochemistry
- usually 9-13+6 weeks
- PAPPA - risk of premature delivery, preeclampsia, stillbirth
- free BHCG
- used in combination with the nuchal translucency (early ultrasound)and the 2nd trimester maternal serum screen to give an adjusted risk for Trisomy 21
Second trimester biochemistry (standard)
- between 15-20+6 weeks
- uncongugated estriol
- AFP (usually up in spina bifida)
- hCG
- used to adjust maternal risk for fetal aneuploidy and open neural tube defect
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