How to perform an abdominal exam on pregnant patients

Performing an abdominal exam on a patient who is pregnant presents unique challenges. Patients who are pregnant can still be affected by similar processes as patients who are not pregnant. So, you mustn’t allow the pregnancy to skew your evaluation of the pain. Inspect the patient as you would any other, but pay attention to a few additional considerations for pregnancy.

Before we get into how to perform an abdominal exam on a patient who is pregnant, it’s important to note that the growing uterus can displace other abdominal organs. For example, the appendix can be pushed superiorly into the right upper quadrant (RUQ) as the uterus grows. So, a patient who is pregnant with appendicitis-associated pain may not experience this pain in the typical right lower quadrant (RLQ) area.

To be aware of organ displacement during pregnancy, it is important to recognize the position of the uterus in the abdomen during each trimester of pregnancy. Generally, at less than 20 weeks’ gestation, the uterus will be below the umbilicus. The fundal height (e.g., the location of the top of the uterus) will begin to extend out of the pelvis around 20 weeks. The umbilicus is a helpful landmark since at 20 weeks the fundus height is approximately at the umbilicus. As well, every week after 20 weeks, the fundus height typically grows 1 cm above the umbilicus.

Position the patient

During early pregnancy, typically in the first and second trimesters (e.g., before 28 weeks’ gestation), the patient can be positioned supine with the head of the bed elevated by 15–30°. Later in pregnancy, during the third trimester (e.g., after 28 weeks’ gestation), the patient should be positioned in the left lateral position to avoid inferior vena cava compression. If the patient lies flat on their back, compression from the uterus on the inferior vena cava can cause the patient to feel unwell, become dizzy, and possibly even lose consciousness.

Perform a visual inspection of the abdomen

There are cutaneous (e.g., skin) changes that may be present on the abdomen of a patient who is pregnant. The linea nigra can appear, which is a vertical line of hyperpigmentation in the midline of the abdomen from the pubis to the umbilicus (or sometimes to the xiphoid).

The linea nigra is caused by melanocyte-stimulating hormones made by the placenta. These hormones can also cause melasma gravidarum (e.g., hyperpigmentation on the face) and darkened nipples. It is not pathological and does not occur in all pregnancies. However, it is important to note that it may occur and is completely normal.

Striae gravidarum are pregnancy-related stretch marks that can cause scarring and they can have a slight hue to them. They often decrease over time but may not completely disappear. They are caused by tearing of the dermis, which is often from the stretching of the skin during rapid growth or weight changes during pregnancy. Striae alba are whitish stretch marks, while striae rubra are reddish stretch marks that can occur earlier in the pregnancy.

Palpate the nine regions of the abdomen

Palpate the nine regions of the abdomen with either a one-handed or two-handed technique. Communicate with the patient as you are doing the exam to ensure that they know what you will be doing ahead of time. Continue to communicate with the patient throughout the exam to get feedback about tenderness. As well, assess the patient for tenderness, rebound tenderness, guarding upon palpation, or masses in the abdomen.

Palpate the uterus

Also, palpate the uterus during the abdominal exam. Feel for its upper and lateral edges, and assess if the uterus is tender. Again, keep in mind that the fundal height will be at different locations as the pregnancy progresses:

• 12 weeks at the pubic symphysis
• 20 weeks at the umbilicus
• 36 weeks at the xiphoid process

Palpation of the fundus during the abdominal exam is usually sufficient to assess the uterus. If there are any concerns, consult the obstetrician.

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