The first prenatal examination
First prenatal examination
The physical examination during a first prenatal visit includes an overall assessment of the woman’s health status. This would include vital signs, weight, and urinalysis. The medical assistant must prepare the patient. The patient should be asked if she needs to empty her bladder. If she does, she should collect a urine specimen for a routine urinalysis and a possible pregnancy test. The medical assistant should also prepare the exam room, ensuring that the supplies and equipment necessary to obtain pelvic measurements, perform serologic tests, and prepare for laboratory tests are available. The provider will assess the heart, lung, and thyroid. A physical examination will be done to rule out any other abnormalities. Next, the provider performs an obstetric examination that includes measurement of the height of the uterus and an internal or pelvic examination. A Pap test may be performed if one has not been done in the past year.
Pregnancy test
There are two types of pregnancy tests. One is done with a urine sample, and the other is done with a blood sample. Both tests detect human chorionic gonadotropin (hCG), a hormone produced after implantation that maintains the corpus luteum so it keeps producing the progesterone needed to sustain early pregnancy. Blood (serum) tests can detect much lower hCG concentrations than urine tests, so they can confirm a pregnancy earlier. Blood tests are usually performed at the provider’s office or laboratory. Urine tests can be performed at the provider’s office, or the patient may do a home pregnancy test.
Whether the test is performed at home or in the office, the process is the same: a urine sample is placed on the test stick, and the display - a symbol or a word - indicates a positive or negative result.
The estimated date of delivery (EDD), or due date, will be determined at this visit. There are a number of ways to determine the due date. One method is using a gestational wheel: you line up the wheel’s arrow with the first date of the LMP, then read the EDD at the 40-week mark. For example, if a patient’s LMP was March 1, lining the wheel’s arrow up with that date and reading the 40-week mark gives an EDD of about December 8. The EDD may also be calculated by the electronic health record (EHR) or determined by ultrasound.
A series of blood tests are also performed during the initial prenatal visit. Prenatal blood and laboratory tests include the following:
- Hematocrit and hemoglobin levels to check for anemia.
- Blood type and Rh with antibody screening for possible Rh incompatibility.
- Rubella titer to determine whether the mother is immune to German measles; rubella infection during pregnancy can cause multiple birth defects, including deafness, vision disorders, and intellectual disability.
- Syphilis screening; if the result is positive, antibiotic treatment is initiated to protect the fetus from congenital syphilis.
- Hepatitis B screening because this virus can be passed to the fetus in utero.
- Human immunodeficiency virus (HIV) screening is suggested; if the result is positive, treatment of the mother greatly reduces the risk of transmission to the fetus.
- Gonorrhea and chlamydia cultures to prevent infection of the baby at birth.
- Urinalysis to detect protein, white blood cells, or glucose.
Any concerns that the patient has should be noted and reported to the provider. The medical assistant should be prepared to suggest community resources that can provide assistance to new parents, such as the following:
- Childbirth and parenting classes
- Infant cardiopulmonary resuscitation (CPR) courses
- Nutritional counseling, if needed
- Contact information for the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), which helps lower-income expectant mothers get nutritious food
Hemolytic disease of the newborn (HDN)
The blood is tested for the presence of D antigens to determine if someone’s blood type is Rh positive or Rh negative. Rh-positive blood has D antigens; Rh-negative blood does not. If the blood type with Rh factor shows that the mother has Rh-negative blood, there is a concern that hemolytic disease of the newborn (HDN) could develop if the fetus is Rh positive. HDN is also known as erythroblastosis fetalis. If the mother is Rh negative and her fetus is Rh positive, the mother will form antibodies to the Rh-positive factor. Future Rh-positive pregnancies will be in jeopardy because the mother’s anti-Rh antibodies will cross the placenta and destroy fetal blood cells.
HDN can be prevented by giving the mother Rh immune globulin products. RhoGAM, or anti-D immune globulin, is given at 28 to 30 weeks of gestation to Rh-negative mothers, regardless of the father’s Rh type. After delivery, the cord blood is tested, and a dose of RhoGAM is given within 72 hours of delivery, but only if the baby is Rh positive. RhoGAM is also given for miscarriages or abortions. The immune globulin prevents the infant’s Rh-positive cells from stimulating the mother’s immune system, thus preventing HDN.
